CDR EXCHANGED TYPE [...] ANTI- CEA HUMANISIERTE MONOCLONAL ONE MOUSE ANTI-BODY
The invention relates to immunological reagents for diagnostic and therapeutic use in colon and other cancers. In particular, the invention relates to humanized anti-carcinoembryonic antigen ("CEA") monoclonal antibodies ("mAbs") that have the binding affinity characteristics of corresponding mouse anti-CEA mAb (MN14) and the antigenic and effector properties of a human antibody. Further, the invention relates to humanized mAbs in which the complementarity determining regions ("CDRs") of an anti-CEA murine mAb is grafted into the framework regions of a human antibody, to DNAs that encode such CDR-grafted antibodies, to vectors and transformed hosts for propagating and expressing the DNAs, and to conjugates of the antibodies useful in diagnostic and therapeutic applications. A promising approach to cancer diagnosis and therapy involves the use of targeting antibodies to deliver diagnostic and therapeutic agents directly to the site of a malignancy. over the past decade, a wide variety of tumor-specific antibodies and antibody fragments have been developed, as have methods to conjugate the antibodies to drugs, toxins, radionuclides or other agents, and to administer the conjugates to patients. These efforts have produced great progress, but a variety of largely unanticipated problems have limited the diagnostic and therapeutic utility of some of the reagents thus far developed. Among the most intractable problems is that which is caused by the human immune system itself, which may respond to the targeting conjugate as a foreign antigen. For instance, patients treated with drugs or radionuclides complexed with murine monoclonal antibodies (which have been the most commonly used targeting antibodies for human) develop circulating human antimouse antibodies (HAMAs) and a generalized immediate type-III hypersensitivity reaction to the antibody moiety of the conjugate. Furthermore, even when adverse side effects are minimal (for example, as in a single administration), circulating HAMAs decrease the effective concentration of the targeting agent in the patient and therefore limiting the diagnostic or therapeutic agent from reaching the target site. Several approaches have been developed to overcome or avoid this problem, with only limited success. One strategy has been to chemically modify the targeting antibody to suppress its antigenicity. For example, conjugation of polyethylene glycol to the targeting antibody (PEGylation) is reported to reduce antigenicity of antibodies. Another approach has been to characterize the situs of antigenicity in an antibody and then remove it. In this vein, Fab', F(ab)2 and other antibody fragments have been used in place of whole IgG. In addition, attempts have been made to reduce the adverse effects of HAMA by plasmaphoretically removing HAMA from blood. Immunosuppressive techniques also have been used to ameliorate the adverse effect of the foreign antibody sufficiently to permit multiple treatments with the targeting agent. None of these approaches has proven altogether satisfactory. An important need persists for a means to reduce or eliminate the adverse immune response to targeting antibody and antibody conjugates in order to gain the full benefit of these diagnostic and therapeutic agents. This goal has been achieved with the CDR-grafted humanized murine anti-human CEA mAbs that are described below. It is an object of the present invention to provide a humanized Class III anti-CEA mAb in which the CDRs of a murine Class III anti-CEA mAb (MN14) are functionally engrafted to the amino acid sequence of a human antibody or antibody fragment to provide an immunological reagent with the anti-CEA binding properties of the murine Class III, anti-CEA mAb and the immunogenic properties of a human mAb in a human patient. It is another object of the present invention to provide DNA constructs encoding such antibodies. Particular objects in this regard are substrate DNAs that facilitate genetic manipulation to produce improved antibodies and DNAs encoding the antibodies with advantageous properties in cell culture and antibody production. Yet another object of the invention is to provide vectors for propagating the DNA and for expressing the antibody. A related object of the invention is to provide cells containing a vector for the purposes of storage, propagation, antibody production and therapeutic applications. Still another object of the invention is to provide compositions comprising the antibodies for use in diagnosis and therapy. In this regard it is an object of the invention to provide conjugates comprising the antibodies complexed with imaging agents and therapeutic agents for In accomplishing the foregoing objects, there has been provided, in accordance with one aspect of the present invention, a humanized mouse mAb as defined in claim 1, comprising the CDRs of a murine Class III, anti-CEA mAb (MN-14) engrafted to the framework regions of a heterologous (human) antibody, wherein the thus humanized mAb antibody retains the Class III, anti-CEA binding specificity of the murine mAb but in the patient is less immunogenic than is the parent MN-14 murine monoclonal antibody. The light chain variable regions of the humanized antibody are characterized by the formula: FRL1-CDRL1-FRL2-CDRL2-FRL3-CDRL3-FRL4 wherein each FR is separately a framework region of a human antibody, and each CDR is separately in a complementarity-determining region of the light chains of MN-14, and the subscripts refer to light ("L") chain regions, the heavy chain variable regions are characterized by the formula: FRH1-CDRH1-FRH2-CDRH2-FRH3-CDRH3-FRH4 wherein FR and CDR have the same meanings as above, and wherein the subscripts "H" refer to heavy chain regions, whereby CDRL1 has the amino acid sequence KASQD VGTSVA (SEQ. ID NO. 20); CDRL2 has the amino acid sequence WTSTR HT (SEQ. ID NO. 21); CDRL3 has the amino acid sequence QQYSL YRS (SEQ. ID NO. 22); CDRH1 has the amino acid sequence TYWMS (SEQ. ID. NO. 23); CDRH2 has the amino acid sequence EIHP DSSTI NYAPS LKD (SEQ. ID NO. 24); and, CDRH3 has the amino acid sequence LYFGF PWFAY (SEQ. ID NO. 25), the FRL1 has the amino acid sequence DIQLT QSPSS LSASV GDRVT ITC (SEQ. ID NO. 26); FRL2 has the amino acid sequence WYQQK PGKAP KLLIY (SEQ. ID NO. 27); FRL3 has the amino acid sequence GVP(S or D)F SGS(G or V)S GTDFT FTISS LQPED IATYY V (SEQ. ID NO. 28); FRL4 has the amino acid sequence FGQGT KVIEK (SEQ. ID NO. 29); FRH1 has the amino acid sequence EVQLV ESGGG WQPG RSLRL SCSSS GFDFT (SEQ. ID NO. 30), EVQLV ESGGG WQPG RSLRL SCSAS GFDFT (SEQ. ID NO. 31), or QVQLQ ESGPG LVRPS QTLSL TCTSS GFDFT (SEQ. ID NO. 32) ; FRH2 has the amino acid sequence WVRQA PGKGL EWVA (SEQ. ID NO. 33), WVRQA PGKGL EWIA (SEQ. ID NO. 34), or WVRQP PGRGL EWIA (SEQ. ID NO. 35); FRH3 has the amino acid sequence RFTIS RDNSK NTLFL QMDSL RPEDT GVYFC AS (SEQ. ID NO. 36), RFTIS RDNAK NTLFL QMDSL RPEDT GVYFC AS (SEQ. ID NO. 37), or RVTML RDTSK NGSFL RLSSV TAADT AVYYC AS (SEQ. ID NO. 38); and FRH4 has the amino acid sequence WGQGT PVTVS S (SEQ. ID NO. 39), or WGQGT TVTVS S (SEQ. ID NO. 40); and wherein C may be in the sulfhydryl or disulfide form. Another preferred embodiment comprises a diagnostic or therapeutic agent complexed to Class III, anti-CEA humanized mAb as defined in claim 1 wherein the conjugate retains the Class III, anti-CEA binding specificity of MN-14. Other objects, features and advantages of the present invention will become apparent from the following detailed description and appended claims. The following terms or abbreviations are used in the present application. The meanings set out in this glossary are for illustrative purposes only. The full meaning of the terms will be apparent to those of skill in the art. "CDR" is used as an abbreviation for Complementarity Determining Region. These are the regions within the variable regions of an antibody that are primarily, but not exclusively, responsible for antigen-antibody binding. "FR" is an abbreviation for Framework Region. Broadly speaking, these are the portions of the variable regions of an antibody which lie adjacent to or flank the CDRs. In general, these regions have more of a structural function that affects the conformation of the variable region and are less directly responsible for the specific binding of antigen to antibody, although, nonetheless, the framework regions can affect the interaction. "Chimeric" refers to an antibody in which the variable region is derived from a mouse antibody and the constant region is derived from an antibody from a heterologous (other) species. "Humanized" refers to a chimeric antibody as defined above, but one in which the FR variable regions are derived from a human antibody. "HAMA" refers to human antibodies directed to a mouse antibody, that are produced when a mouse antibody is administered to a human subject. "HAHA" refers to human antibodies directed to a humanized mouse antibody. "CEA" refers to carcinoembryonic antigen, a 180 kDa glycoprotein that is expressed in most adenocarcinomas of endodermally-derived digestive system epithelia and in some other cancers such as breast cancer and non-small cell lung cancer. The letter "h" as a prefix means "humanized". Other abbreviations are used in accordance with These and other terms used in the present disclosure are used in the same sense as ordinarily they are employed in the arts to which this invention pertains. Notwithstanding past failures to develop an effective non-HAMA-inducing anti-CEA antibody having the CEA-binding characteristics of MN-14, it has been discovered that the CDRs of the MN-14 mAb can be grafted onto the FRs of a human antibody to provide antibodies and antibody-derived reagents that have the antigen binding properties of the MN-14 anti-CEA mAb, while also exhibiting reduced induction of HAMA and augmented effector activities. The murine anti-CEA IgG1 monoclonal antibody MN-14, and its production, have been described previously. Blocking studies are carried out according to Alternate to the aforementioned HRP-labeled mAbs, antibodies can be radioiodinated conventionally with, for example,131I by the chloramine-T method to a specific activity of about 10 mCi/µg, and free radioisotopes removed by chromatography on acrylamide gel columns (see Hansen et al., 1993, above). Molecular biological techniques suitable to carrying out the invention as herein described also are known to those skilled in the art. Suitable teachings are described in numerous manuals and primary publications, including inter alia, MN-14 light and heavy chain CDRs disclosed herein, and modified MN-14 CDRs can be integrated into other antibodies using well-known recombinant techniques, such as those described in the above references. Specific methods suitable to this end are shown below in the examples. Based on the amino acid sequences set forth herein, oligonucleotides encoding MN-14 CDRs can be synthesized. Oligonucleotides that encode modified CDRs may be made, as well as those that encode exactly the amino acid sequences herein set forth. Also, the oligonucleotides may contain nucleotides in addition to those of an MN-14 CDRs, to facilitate cloning, for instance. Oligonucleotide synthesis techniques are well known, and can be carried out on automated equipment available from a number of manufacturers. Moreover, oligonucleotides of any specified sequence can be obtained commercially. Oligonucleotides encoding the MN-14 CDRs and/or specific FR residues. or representing the complementary strand thereof, may be used to introduce codons for these residues into VH or VK DNA by site-directed mutagenesis provided that the ends of the oligonucleotides, generally 12 nucleotides, are designed to anneal perfectly to the template DNA. The template DNAs are typically single-stranded DNAs representing M13 vectors that carry a variable region DNA encoding the required FRs. In one method, the mutagenic oligonucleotides are phosphorylated at their 5' ends and, together with an oligonucleotide priming 5' to variable region DNA, are annealedd to the ssDNA template. The oligonucleotides are extended usinh T7 polymerase and the fragments linked together by T4 DNA ligase to give a complete mutant strand covering the whole variable region. Using the mutant strand as a template, multiple copies of its complementary strand can be synthesized from a suitable primer using Taq DNA polymerase in a thermal cycling reaction. Once the mutant strand has been preferentially amplified in this manner, the DNA can be amplified by conventional PCR for cloning, sequencing and expression. Suitable antibody-encoding DNAs are illustrated by the disclosure herein, but include practically any such DNA. A variety of human antibody genes are available in the form of publically accessible deposits. Many sequences of antibodies and antibody-encoding genes have been published and suitable antibody genes can be synthesized from these sequences much as described above. The scope of this invention encompasses all alleles, variants and mutations of the DNA sequences described herein. CDR grafting in accordance with the present disclosure may be carried out using established techniques. Antibody-producing cell lines may be selected and cultured using techniques well known to the skilled artisan. Such techniques are described in a variety of laboratory manuals and primary publications. For instance, techniques suitable for use in the invention as described below are described in RNA may be isolated from the original hybridoma cells by standard techniques, such as guanidinium isothiocyanate extraction and precipitation followed by centrifugation or chromatography. Where desirable, mRNA may be isolated from total RNA by standard techniques such as chromatography on oligodT cellulose. Techniques suitable to these purposes are well known in the art as described in the foregoing references. cDNAs that encode the light and the heavy chains of the antibody may be made, either simultaneously or separately, using reverse transcriptase and DNA polymerase in accordance with well known methods. It may be initiated by consensus constant region primers or by more specific primers based on the published heavy and light chain DNA and amino acid sequences. PCR also may be used to isolate_DNA clones encoding the antibody light and heavy chains. In this case the libraries may be screened by consensus primers or larger homologous probes, such as mouse constant region probes. The necessary techniques are well known to those of skill in the art, are set forth in the foregoing Sambrook and Ausubel references and are illustrated by the examples set forth below. cDNAs that encode the light and the heavy chain of an antibody can be propagated in any suitable vector in any suitable host prior to isolation of the CDR. Often the clones will most conveniently be propagated for this purpose in DNA, typically plasmid DNA, may be isolated from the cells, restriction mapped and sequenced in accordance with standard, well known techniques set forth in detail in the foregoing references relating to recombinant DNA techniques. DNAs encoding antibody heavy and light chains and fragments thereof in accordance with the vector are used to construct chimeric and CDR-grafted humanized MN-14 antibodies. The CDRs of the MN-14 anti-CEA mAb are herein identified and described, and illustrated in Figures 1 and 2 (SEQ. ID NOS. 2 and 4, respectively). Using these sequences, CDRs of the MN-14 heavy and light chain can be synthesized for use in the present invention. It is not necessary to reclone MN-14 CDRs from a natural source. The DNA and amino acid sequences are set forth herein. Oligonucleotide synthesis techniques suitable to this aspect of the invention are well known to the skilled artisan and may be carried out using any of several commercially available automated synthesizers. In addition, DNAs encoding the CDRs set forth herein can be obtained through the services of commercial DNA synthesis vendors. Polynucleotides synthesized in accordance with this aspect of the invention may include those not derived from an MN-14 CDR as well as those that make up the CDR. The additional bases may be included to facilitate joining the CDR to the FRs from a heterologous source. They may comprise restriction sites or overlapping complementary regions for this purpose. The synthesis of longer, double-stranded DNAs from shorter, overlapping, single-stranded DNAs is well known to those of skill in the art. Likewise, well known is the end-to-end joining of DNAs, including blunt-ended DNAs and those with at least partially overlapping complementary termini. These -techniques are illustrated in the foregoing references on recombinant DNA techniques, for instance. The CDRs of the MN-14 heavy and light chains may also be modified particularly after incorporation into a chimeric or humanized antibody using well-known recombinant DNA techniques for deleting, inserting and altering bases in a cloned or synthetic DNA or RNA. Site-specific mutagenesis techniques suitable to this end are well known to those of skill in the art, and are illustrated in the foregoing references on recombinant DNA techniques. Also illustrated are deletional and insertional techniques. These methods can be used to introduce practically any desired alteration into polynucleotides that encode the MN-14 CDRs or into other regions of a closed heavy or light chain gene. MN-14 CDRs and modified MN-14 CDRs can be introduced into practically any set of FRs in accordance with the present invention. It will be appreciated by those of skill in the art that a variety of well known techniques for cloning and manipulating polynucleotides may be effectively employed in this regard. Such techniques are illustrated by the methods set forth in the foregoing recombinant DNA-related references. In a particularly preferred embodiment of the present invention, MN-14 CDRs are grafted into a human antibody. It will be understood that human antibody in this context refers to any antibody that occurs in a human or an engineered antibody that has been designed, in some respect, to be compatible with the human immune system. Particularly preferred for this purpose are antibodies that, broadly, do not engender an adverse immune response in a patient. More particularly, the expression "human antibody" is intended to mean an antibody encoded by a gene actually occurring in a human, or an allele, variant or mutant thereof. Once DNA encoding an MN-14-derived CDR-grafted antibody has been assembled from MN-14 VH and VK region DNAs and the variable regions thus formed combined with their respective light and heavy chains of human constant domains, it may be inserted into a vector for propagation and expression by conventional techniques. In this manner desired amounts of the antibody may be obtained. The MN-14 CDR-grafted human antibody can be used in imaging applications by administrating to a subject the humanized antibody or Fab' thereof conjugated with an imaging compound or isotope. The antibody is conjugated to a label for imaging using conventional methods. Such conventional methods include, but are not restricted to: 1) direct radioiodination of the antibody protein or fragments thereof or 2) direct attachment to the antibody or fragments thereof of metallic nuclides (see, e.g., The reaction of serum antibody with the MN-14 CDR-grafted antibody and imaging agent portions of the conjugate can be determined over the course of the diagnostic procedures, including the reaction of control sera obtained prior to administration of conjugate. Similar determinations are made in other patients treated with similar conjugates of MN-14 itself. The sera antibody reactive with CDR-grafted MN-14 human antibodies detected by these tests is much less than the antibody reactive with antibody portion of the conjugate in patients treated with the murine MN-14-containing conjugates. Humanized MN-14 antibodies conjugated to aminodextran and to boron may be used for diagnostic purposes. MN-14 and CDR-grafted MN-14 antibodies can be prepared as set forth above for conjugation to an aminodextran-boron adduct. Amino-dextran-boron adducts can be prepared by reaction of a suitable boron cage compound (e.g., a 12-boron carborane suitably derivatized with an amino-dectran functional group). In a preferred embodiment, the amino-dextran is reacted with an excess of a haloacetyl acid ester or anhydride (such as iodoacetic anhydride), thereby producing an amino-dextran with a desired number of haloacetyl groups, usually ranging from 10-1000 groups, depending on the reaction conditions and the size of the amino-dextran. A suitable boron derivative such as mercaptocarborane-B12 is reacted, in a desired molar excess, with the haloacetyl-amino-dextran via an alkylation reaction. In a preferred embodiment, a number of haloacetyl groups on the boronated haloacetyl amino-dextran remain unreacted, and can be used as a "handle" to attach the adduct to protein thiol groups. MN-14 CDR-grafted humanized antibodies and their derivatives, because of their reduced immunogenicity, are useful in therapy, for passive immunization without negative immune reactions such as serum sickness or anaphylactic shock, for localization and Preferred are pharmaceutical preparations for parenteral administration, such as are described in Remington's Pharmaceutical Sciences, Mack Publishing Co., Easton, PA, 1989. The final preparations contain from 0.01% to 50% of active ingredients. Methods for the production of such conjugates and their use in diagnostics and therapeutics are provided in, for example, Shih et al., As noted above, for purposes of therapy, a humanized antibody conjugate and a pharmaceutically acceptable carrier are administered to a patient in a therapeutically effective amount. A combination of a conjugate and a pharmaceutically acceptable carrier is said to be administered in a "therapeutically effective amount" if the amount administered is physiologically significant. An agent is "physiologically significant" if its presence results in a detectable change in the physiology of a recipient patient. A targeted therapeutic agent is "therapeutically effective" if it delivers a higher proportion of the administered dose to the intended target than accretes at the target upon systemic administration of the equivalent untargeted agent. To be therapeutically effective the conjugate and carrier may need to be administered in combination with other therapeutic agents or as part of a broader treatment regimen. Physicians are currently of the opinion that the effectiveness of targeted therapeutics can often be greatly increased when used in a combination therapy approach. For example, high-dose radioimmunotherapy for B-cell lymphomas, which causes severe hematologic toxicity when used alone, has been shown to be highly effective when used in combination with autologous bone marrow reinfusion. Invivo experiments using conjugates of the humanized MN-14 with diagnostic and therapeutic agents have been carried out with animal models and with human patients (see Example 11 below). The CDR-grafted humanized antibody conjugate exhibited a better therapeutic profile and could be used in longer treatment regimens than the parental MN-14 antibody conjugate. The CDR-grafted antibody conjugate provided a better therapeutic effect and fewer deleterious side effects than the control murine antibody conjugates. For example, the antibody was covalently complexed to aminodextran-conjugated methotrexate using the method described by Shih Aminodextran, average molecular mass 40 kDa, is oxidized by NaIO4 to form aldehydes (by the oxidation of hydroxyl groups). About 50 to 150 moles of aldehydic groups are introduced per mole of aminodextran by careful control of the reaction conditions and timing. The aldehydes then are reacted with an excess of 1,3-diamino-2-hydroxypropane to form Schiff bases with virtually all of the aldehydes. The Schiff bases are then reduced by treatment with excess NaBH4. The amine-derivatized dextran then is purified by gel-exclusion chromatography. The cytotoxic drug methotrexate (MTX) is activated by treatment with dicyclocarbodiamide, followed by reaction with N-hydroxysuccinimide, both in dimethylformamide. Activated MTX is mixed in a 50:1 ratio with the amino derivatized dextran in aqueous solution. The product provides, after purification, MTX-derivatized dextran having about 35 MTX moles per mole. The MTX adduct thus obtained is conjugated to a MN-14 CDR-grafted antibody using methods described in Shih, et al., supra. For example, the antibody carbohydrates are oxidized and the resultant aldehydes are reacted with the remaining amines on the dextran in the adduct. The Schiff-base product obtained thereby is reduced by treatment with sodium cyanoborohydride in 10-fold molar excess over antibody. The reduced antibody-dextran-MTX product is thoroughly purified prior to assay, and formulated for administration to patients. Parental MN-14 antibody is conjugated to dextran-MTX in the same way, as a control. The purified CDR-grafted antibody conjugate can be administered to patients with a CEA-producing cancer (see above). The response to therapy is monitored, including adverse side effects, particularly those which are mediated by the patient's immune systems. Patients treated with the CDR-grafted antibody conjugate show improved therapeutic results, decreased immune response to the agent and notably decreased immune-mediated adverse effects of therapy. Therapy with the CDR-grafted antibody conjugate can be carried out at higher dosages and for longer periods of time then with the parental murine MN-14 antibody, allowing more aggressive therapies and improved responses. The present invention is further described by reference to the following, illustrative examples. It will be appreciated that the techniques related to isolating DNA clones encoding MN-14 light and heavy chain genes are illustrated by cloning techniques useful to isolate light and heavy chain genes of any antibody from producing cells. There is no necessity, given the disclosed sequence, to reisolate MN-14 heavy and light chain genes to carry out the invention. It should be understood that the detailed description and the specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the following illustrative description. A mouse/mouse hybridoma cell line producing Class III, anti-CEA monoclonal antibodies was established according to Hansen et al. (1993) above and Primus et al. (1983) above. Cells were selected for secretion of MN-14-producing cells were expanded in culture, collected by centrifugation and washed. Total RNA was isolated from the cells in the pellet according to mRNA from MN-14 producing cells was used to synthesize cDNA using standard techniques of cDNA synthesis and DNA amplification by PCR, as described below. In general, the primers used for PCR included a restriction endonuclease cleavage site at their 5' ends to facilitate cloning of the amplification product. An oligonucleotide complementary to the end of the sense strand of the DNA encoding the first constant region domain of the murine IgG1 heavy chain ("CH1") was used to prime first strand cDNA synthesis by reverse transcriptase. The sequence of this primer, CG1FOR, is shown in Table 1. Table 1 below provides other oligonucleotide sequences used herein. Restriction sites incorporated in primers to facilitate cloning are underlined. The variable region of the heavy chain ("VH") cDNA then was amplified by the PCR using the same primer, CG1FOR, and a primer based on the consensus sequence of the 5' end of VH genes (VH1BACK), as described in Orlandi For confirmatory sequences from a second cDNA preparation, signal sequence primers were used in the PCR to allow determination of the authentic amino acids of the N-terminus. SH1BACK and SH2BACK, degenerate oligonucleotides based on heavy chain signal sequence coding regions, were used in separate reactions in concert with CG1FOR. A diffuse product band was obtained from CG1FOR, SH1BACK amplification. In order to increase the VH content of the product it was excised from low melting point agarose and amplified using SH1BACK and an oligonucleotide complementary to a fourth framework region consensus sequence, VHlFOR. This product of this reaction was a discrete band when analyzed by agarose gel electrophoresis. The amplification product obtained using the CG1FOR, VH1BACK primer pair was digested with The sequencing confirmed the presence of this additional, unexpected PstI site, which was close to the 3' end of the sequence of the CG1FOR primer partially encoding the final two amino acids of the VH. Although several full length VH clones were obtained by this method, further PCR product DNA was cloned as In order to confirm the VH sequence from a second cDNA preparation and, at the same time, to obtain the authentic, rather than primer-dictated, DNA sequence corresponding to the N-terminus of the VH, the PCR product from VH1FOR and SH1BACK primers was cloned. These primers contain In all, 20 full-length MN-14 VH clones were obtained. Five transition mutations were observed amongst the sequences in the MN-14 VH region clones. These mutations are likely to have been introduced during amplification as a result of misincorporation by The amino acid sequence of murine MN-14 heavy chain variable region, translated from the VH DNA sequence, is shown in Figure 1 (SEQ. ID. NOS. 1 and 2). Comparison of this sequence with sequences representing the murine VH subgroups indicated that the variable heavy region of MN-14 belongs to subgroup IIIB (see, The MN-14 CDR sequences are different from any of those reported by Kabat Any unusual residues in the VH or VK may represent somatic mutations which proved advantageous to the binding of murine MN-14. cDNA encoding the kappa light chain of MN-14 was cloned in much the same fashion as the cDNA encoding the variable region of the heavy chain, as described above. Several primers were used to prime reverse transcriptase for synthesis of the first strand of the The first strand DNA product was amplified by PCR using a number of primer pairs. Synthesis in one direction was primed by the primers used to make the first strand. Polymerization in the other, "backward," direction initiated from a series of The amplification products were analyzed by gel electrophoresis in the manner described in the Examples above. The products from the reactions primed by VK1BACK, VK3BACK, VK5BACK, VK7BACK and VK8BACK gave rise to the expected 350 bp band. Selected PCR products were cloned into M13mp18 and 19 using the restriction sites included in the amplification primers in a manner similar to that described for VH in Example 4 above. Nucleotide sequencing revealed that most inserts were not VK-related. This is not uncommon when attempting to clone VK cDNAs and it appears to be more difficult to design VK-specific primers than VH specific primers. From the VK1FOR/VK8BACK combination, a VK cDNA insert was obtained, but this did not yield a functional VK due to a frameshift within the cDNA encoding CDRL3 and absence of the invariant Cys at position 23. This VK cDNA has been isolated from other hybridoma cells and it is derived from the Sp2/0 fusion partner. CK2FOR/VK1BACK product yielded a further four different aberrant VK cDNA inserts, in this case lacking the conserved residues of framework 4. A fifth VK insert obtained using this primer pair was that of a functional VK with the exception of a frameshift at the 3'end of VK1BACK, a phenomenon apparently due to mismatch-induced slippage of the primer. This problem may be avoided by the use of VK8BACK which does not extend as far into the VK gene. However, analysis of further clones from VK1FOR/VK8BACK product did not yield the desired insert. In order to amplify preferentially the putative VK, VK3FOR was designed from its genuine fourth framework sequence, and synthesized as an alternative to VK1FOR. This strategy proved successful when amplification of VK3FOR-primed cDNA with VK3FOR and VK8BACK yielded 4 clones containing the desired VK. The DNA and amino acid sequuence of the murine MN-14 In the production of a chimeric antibody consisting of murine variable regions and human constant regions, testing alongside the parent mouse antibody served to check that the correct variable region cDNAs have been isolated. A successful chimeric antibody also acts as a useful control when assessing the binding of humanized versions. The scheme used in cloning the variable regions for expression is described by Orlandi VH DNA was amplified from the M13 clone MNVH41 using the PCR with oligonucleotides VH1BACK and VH1FOR. The The human IgG1 constant region gene, published by VK DNA was similarly obtained from the M13 clone MNVK154 by PCR amplification with the primers VK8BACK and VK3FOR and the The HindIII-BamHI fragment of M13KLHuVHAIGA was inserted into a plasmid pSVgpt to yield the expression vector pSVgptKLHuAIGAHuIgG1. Similarly, the HindIII- Wells which contained colonies of surviving cells were identified. The supernatant medium was removed from these wells and assayed for human antibody. Colonies that secreted antibodies were expanded to give 0.5 L of conditioned medium for isolation of larger amounts of antibody. Antibody was purified conventionally from the medium by protein-A agarose affinity chromatography, initially. The purified antibody was characterized further with reference to native MN-14 antibody, human antibodies and other controls. The antibody was also characterized by its reaction profile in a MN-14 blocking assay, which provided an informative comparison of CEA binding affinities of the hybrid antibodies with CEA binding by the MN-14 murine antibody which served as a positive control. The human NEWM VH, KOL VH and REI VK frameworks were chosen as the basis for reshaping the antibody, as they are likely to be tolerated in humans. Alignments of the MN-14 VH (SEQ. ID NO. 2) and VK (SEQ. ID NO. 4) with these human variable regions are shown in Figure 5 (SEQ. ID. NOS. 5-7). The starting points for the introduction of MN-14 CDRs are DNAs encoding the required FRs and irrelevant CDRs. These template variable regions are in a form compatable with the expression vectors used, that is, within HindIII-BamHI fragments, that also include promotor regions, signal peptide and intron DNA (Figures 3 and 4). For the NEWM VH version, the template is M13VHPCR1 (Orlandi et al, above, and section 8.3 below). A derivative of this template, containing KOL FRs and irrelevant CDRs, was used to generate the KOL coding region. A derivative of M13VKPCR1 (Orlandi The NEWM FR is described in The alignment of the different versions of the NEWM VH frameworks (SEQ. ID NOS. 5 and 8-11) with the MN-14 VH (SEQ. ID NO. 2) is shown in Figure 6. Each of these versions has been paired with the same HuVK. The inclusion of either the TLY or KFIVS motifs gave about a two-fold improvement. There are 2 differences from the NEWN framework sequences given in Kabat et. al (1987) above: S107 to T and L108 to T. Kabat lists residue 1 as PCA and residues 5 and 6 as E or Q. In parallel to the use of NEWM VH, we have also reshaped the human KOL VH. KOL VH is described in Ala24 - The loop of CDR1 is anchored by the penetration of the side chain of residue 29 into the framework. Residue 24 is one of those with which it interacts ( Ile48Gly49 - Although both these residues are adjacent to the CDR2 hypervariable region they are far removed from the actual structural loop. Both residues are completely buried ( Ala74 - This residue is part of the fourth loop found at the VH antigen-binding surface and its side chain is almost completely exposed to solvent (Padlan, 1991 above). Direct interaction of this residue with antigen could be envisaged. Tyr79 - Like residue 74, this residue is close to the antigen-binding site and could effect binding. The alignment of the different versions of KOL VH frameworks (SEQ. ID NOS. 7 and 12-15) with NEWM based versions (SEQ. ID NOS. 5 and 8-11) and the murine MN14 (SEQ. ID NO. 2) is shown in Figure 6. The DNA sequences and translation products of MN14HuVH and MN14HuVL are shown in Figures 7 and 8, 0respectively (SEQ. ID NOS. 16-19, respectively). The humanized KLHuVH variants, such as antibody KLHuVHAIGA/HuVK, were purified and tested-in a blocking assay carried out as follows. Antibodies were added at the indicated concentrations together with HRP-labeled MN-14 to a final volume of 0.1 ml. Following 30 mins. of incubation at 37°C, and washing to remove unbound antibodies, the relative affinities of the antibodies were determined from the remaining bound peroxidase activity. A shown by the assay data of Figure 9, the activity of the "reshaped" (i.e., CDR-engrafted on FR) humanized antibody was similar to that of chimeric and murine positive controls. Results obtained using supernatant fluids from cells secreting KLHuVHAIG/HuVK and KLHuVHAIGAY/HuVK antibodies suggests that these have blocking activities that are similar to that of the KLHuVHAIGA/HuVK antibody. REI VL is described in Cells that were stably transformed for expression of the MN-14 CDR-grafted human antibodies were selected in the manner described above and cloned out to establish individual producer lines. Each of the lines was assayed to determine production of the correct antibody and to assess the efficiency of production. The antibody class was determined and the anti-CEA binding affinity assessed. The best producers were further characterized for the overall amount of the antibody produced and, for the best of these, sequences were obtained from the mRNA to insure that the mutation has not occurred in the antibody genes during transfection, integration, propagation or selection. The best producer lines of the MN-14 CDR-grafted human antibody were cultured, the growth medium collected and filtered through a 0.2 micron membrane. The antibody was then purified by protein A chromatography followed by other conventional purification steps such as ion exchange and size exclusion chromotography. The cells were pelleted and from the supernatant by conventional centrifugation. The antibody was purified from the supernatant fluid as described above. The biodistribution of labeled humanized MN-14 IgG in nude mice bearing human colon cancer was determined. For radiolocalization studies, at 4-5 weeks female athymic mice (nu/nu, Harlan, Indianapolis, IN) were given s.c. 0.2 ml of a 10% suspension of LS174T human colon adenocarcinoma prepared from a xenograft serially propagated in an athymic mouse ( The results show excellent tumor accretion of the antibody, with maximum accretion occuring within 2 days. Blood clearance of the hMN-14 antibody was more rapid than the parental mMN-14 antibody. In addition, there was higher uptake of hMN-14 by the spleen than there was of mMN-14, reflecting the fact that the former antibody is "foreign" to the mouse. Tumor:nontumor ratios were excellent. These results demonstrate that the inventive hMN-14 mAb is capable of targeting CEA-producing tumors. Patients were entered into an Institutional Review Board-approved protocol at the Center for Molecular Medicine and Immunology, Newark, NJ for a pilot investigation of the targeting and pharmacokinetic behavior of the humanized MN-14 -IgG. In the case the results of which are shown in Figure 12, the male patient had colorectal cancer that had metastasized to the liver. He was injected i.v. with131I-hMN-14 IgG (8 mCi, 0.6 mg antibody) and images were taken over a six day period. The patient was subsequently injected with an identical dose of mMN-14 IgG. The images shown in Figure 12 shaw the anterior abdominal view about 140 h after each injection. The images are adjusted to exactly the same intensity so that they are directly comparable. The results indicate that the humanized antibody is taken up by the CEA-producing tumor as well as the parental murine antibody. These experiments establish the practical utility of diagnosing human CEA-producing colon cancers with the inventive humanized MN-14 mAb. A humanized monoclonal antibody, comprising the complementarity-determining regions of a parental murine Class III, anti-CEA monoclonal antibody engrafted to the framework regions of a heterologous antibody, wherein the humanized monoclonal antibody retains the binding specificity of, but is less immunogenic in a heterologous host than, the parental murine monoclonal antibody. A preferred murine Class III, anti-CEA monoclonal antibody is the MN-14 antibody and the preferred heterologous antibody is from a human. Also provided are DNA constructs and vectors for producing the humanized monoclonal antibodies, and diagnostic and therapeutic conjugates using same. A humanized monoclonal antibody, comprising the complementarity-determining regions (CDRs) of a parental murine class III anti-CEA MN-14 monoclonal antibody engrafted to the framework regions (FRs) of a human antibody, wherein said humanized antibody retains the specificity of said MN-14 monoclonal antibody but is less immunogenic in a human subject than is said parental murine MN-14 monoclonal antibody, and wherein said humanized monoclonal antibody is selected from the mutation variant group consisting of KLHuVHAIG/HuVK: SEQ.ID.NO.13, KLHuVHAIGA/HuVK: SEQ.ID.NO.14 and KLHuVHAIGAY/HuVK: SEQ.ID.NO.15 wherein:
(a) the light chain variable regions are characterised by the formula:
FRL1-CDRL1-FRL2-CDRL2-FRL3-CDRL3-FRL4,
wherein each FR is a different framework region of a human antibody, and each CDR is a different complementarity determining region of the light chain of MN-14; and,(b) the heavy chain variable regions are characterized by the formula:
FRH1-CDRH1-FRH2-CDRH2-FRH3-CDRH3-FRH4,
wherein each FR is a different framework region of a human antibody and each CDR is a different complementarity determining region of the heavy chain of MN-14 and wherein:
CDRH1 is TYWMS: SEQ.ID.NO. 23;CDRH2 is EIHPD SSTIN YAPSL KD: SEQ.ID.NO. 24;CDRH3 is LYFGF PWFAY: SEQ.ID.NO. 25;CDRL1 is KASQD VGTSV A: SEQ.ID.NO. 20;CDRL2 is WTSTR HT: SEQ.ID.NO. 21;CDRL3 is QQYSL YRS: SEQ.ID.NO. 22;FRL1 is DIQLT QSPSS LSASV GDRVT ITC: SEQ.ID.NO. 26;FRL2 is WYQQK PGKAP KLLIY: SEQ.ID.NO. 27;FRL3 is GVP (S or D) R FSGS (G or V) SGTDF TFTIS SLQPE DIATY YC: SEQ.ID.NO. 28;FRL4 is FGQGT KVIEK: SEQ.ID.NO. 29;FRH1 is EVQLV ESGGG VVQPG RSLRL SCSSS GFDFT: SEQ.ID.NO. 30;EVQLV ESGGG VVQPG RSLRL SCSAS GFDFT: SEQ.ID.NO. 31 or QVQLQ ESGPG LVRPS QTLSL TCTSS GFDFT: SEQ.ID.NO. 32;FRH2 is WVRQA PGKGL EWVA: SEQ.ID.NO. 33;WVRQA PGKGL EWIA: SEQ.ID.NO. 34 or WVRQP PGRGL EWIA: SEQ.ID.NO. 35;FRH3 is RFTIS RDNSK NTLFL QMDSL RPEDT GVYFC AS: SEQ.ID.NO. 36,RFTIS RDNAK NTLFL QMDSL RPEDT GVYFC AS: SEQ.ID.NO. 37 orRVTML RDTSK NGSFL RLSSV TAADT AVYYC AS: SEQ.ID.NO. 38; andFRH4 is WGQGT PVTVS S: SEQ.ID.NO. 39 or WGQGT TVTVS S: SEQ.ID.NO. 40;
and wherein C may be in the sulfhydryl or disulfide form. A conjugate comprising a diagnostic or therapeutic agent bound to a humanized monoclonal antibody of claim 1. A conjugate according to claim 2 wherein said therapeutic agent comprises a cytotoxic agent. A conjugate according to claim 2 wherein said diagnostic reagent comprises an imaging agent. Use of a conjugate comprising a therapeutic agent as described in any one of claim 2 - 4 for the manufacture of a medicament. Use of a conjugate comprising a diagnostic agent as described in any one of claim 2 - 4 for the manufacture of a diagnostic means. An isolated, purified chimeric DNA that encodes the CDRs of the light and heavy chains of a parental MN-14 murine Class III anti-CEA monoclonal antibody and the FRs of a heterologous antibody, wherein said heterologous antibody can be derived from any species including human, wherein the antibody expressed by said chimeric DNA retains the Class III anti-CEA binding specificity of said parental murine Class III anti-CEA monoclonal antibody, but is less immunogenic in a heterologous subject than is said parental monoclonal antibody and wherein said humanized monoclonal antibody is selected from the mutation variant group consisting of KLHuVHAIG/HuVK : SEQ.ID.NO.13, KLHuVHAIGA/HuVK; SEQ.ID.NO.14 and KLHuVHAIGAY/HuVK: SEQ. ID. NO.15 wherein:
(a) the light chain variable regions are characterised by the formula:
FRL1-CDRL1-FRL2-CDRL2-FRL3-CDRL3-FRL4,
wherein each FR is a different framework region of a human antibody, and each CDR is a different complementarity determining region of the light chain of MN-14; and,(b) the heavy chain variable regions are characterized by the formula:
FRH1-CDRH1-FRH2-CDRH2-FRH3-COH3-FRH4,
wherein each FR is a different framework region of a human antibody and each CDR is a different complementarity determining region of the heavy chain of MN-14 and
wherein:
CDRH1 is TYWMS:SEQ.ID.NO. 23;CDRH2 is EIHPD SSTIN YAPSL KD:SEQ.ID.NO. 24;CDRH3 is LYFGF PWFAY:SEQ.ID.NO. 25;CDRL1 is KASQD VGTSV A:SEQ.ID.NO. 20;CDRL2 is WTSTR HT:SEQ.ID.NO. 21;CDRL3 is QQYSL YRS:SEQ.ID.NO. 22;FRL1 is DIQLT QSPSS LSASV GDRVT ITC: SEQ.ID.NO. 26;FRL2 is WYQQK PGKAP KLLIY: SEQ.ID.NO. 27;FRL3 is GVP (S or D) R FSGS (G or V) SGTDF TFTIS SLQPE DIATY YC:SEQ.ID. NO. 28;FRL4 is FGQGT KVIEK:SEQ.ID.NO. 29;FRH1 is EVQLV ESGGG VVQPG RSLRL SCSSS GFDFT:SEQ.ID.NO. 30,EVQLV ESGGG WQPG RSLRL SCSAS GFDF:SEQ.ID.NO. 31 orQVQLQ ESGPG LVRPS QTLSL TCTSS GFDFT:SEQ.ID.NO. 32;FRH2 is WVRQA PGKGL EWVA: SEQ.ID.NO. 33,WVRQA PGKGL EWIA: SEQ.ID.NO. 34 orWVRQP PGRGL EWIA SEQ.ID.NO. 35;FRH3 is RFTIS RDNSK NTLFL QMDSL RPEDT GVYFC AS:SEQ.ID.NO. 36,RFTIS RDNAK NTLFL QMDSL RPEDT GVYFC AS:SEQ.ID.NO. 37 orRVTML RDTSK NGSFL RLSSV TAADT AVYYC AS:SEQ.ID.NO. 38; andFRH4 is WGQGT PVTVS S:SEQ.ID.NO. 39 orWGQGT TVTVS S:SEQ.ID.NO. 40; and
wherein C may be in the sulfhydryl or disulfide form. An isolated polynucleotide comprising a DNA sequence encoding the VH amino acid chain of the humanized MN-14 monoclonal antibody, whereby the heavy chain variable regions are characterized bv the formula:
FRH1-CDRH1-FRH2-CDRH2-FRH3-CDRHD-FRH4,
wherein each FR is a different framework region of a human antibody and each CDR is a different complementarity determining region of the heavy chain of MN-14 and wherein:
CDRH1 is TYWMS: SEQ.ID.NO. 23;CDRH2 is EIHPD SSTIN YAPSL KD: SEO.ID.NO. 24;CDRH3 is LYFGF PWFAY: SEQ.ID.NO. 25:FRH1 is EVOLV ESGGG VVQPG RSLRL SCSSS GFDFT: SEQ.ID.NO. 30;EVOLV ESGGG VVOPG RSLRL SCSAS GFDFT: SEQ.ID.NO. 31 orQVQLQ ESGPG LVRPS QTLSL TCTSS GFDFT: SEQ.ID.NO. 32;FRH2 is WVRQA PGKGL EWVA: SEQ.ID.NO. 33;WVRQA PGKGL EWIA: SEQ.ID.NO. 34 orWVRQP PGRGL EWIA: SEQ.ID.NO. 35;FRH3 is RFTIS RDNSK NTLFL QMDSL RPEDT GVYFC AS: SEQ.ID.NO. 36,RFTIS RDNAK NTLFL QMDSL RPEDT GVYFC AS: SEQ:ID.NO. 37 orRVTML RDTSK NGSFL RLSSV TAADT AVYYC AS: SEQ.ID.NO. 38; andFRH4 is WGQGT PVTVS S: SEQ.ID.NO. 39 orWGQGT TVTVS S: SEQ.ID.NO. 40; and
wherein C may be in the sulfhydryl or disulfide form. A protein encoded by the DNA sequence of claim 8. An isolated polynucleotide comprising a DNA sequence encoding the VK amino acid chain of the humanized MN-14 monoclonal antibody and whereby the light chain variable regions are characterised by the formula:
FRL1-CDRL1-FRL2-CDRL2-FRL3-CDRL3-FRL4,
wherein each FR is a different framework region of a human antibody, and each CDR is a different complementarity determining region of the light chain of MN-14; andwherein:
CDRL1 is KASQD VGTSV A: SEQ.ID.NO. 20;CDRL2 is WTSTR HT: SEQ.ID.NO. 21;CDRL3 is QQYSL YRS: SEQ.ID.NO. 22;FRL1 is DIQLT QSPSS LSASV GDRVT ITC: SEQ.ID.NO. 26;FRL2 is WYQQK PGKAP KLLIY: SEQ.ID.NO. 27;FRL3 is GVP (S or D) R FSGS (G or V) SGTDF TFTIS SLQPE DIATY YC: SEQ.ID.NO. 28;FRL4 is FGQGT KVIEK: SEQ.ID.NO. 29;
and wherein C may be in the sulfhydryl or disulfide form. A protein encoded by the DNA sequence of claim 10. A vector for the expression of a humanized chimeric Mn 14 heavy chain as defined in claim 8, said vector being designated pSVgptMnl4MuVHHuIgGl. A vector for the expression of a humanized chimeric Mn 14 kappa light chain as defined in claim 10, said vector being designated pSVhygMn14MuVKHuCK. A method for the expression of a humanized chimeric MN-14 monoclonal antibody, comprising the steps of:
(a) linearizing vectors pSVgptMn14MuVHHuIgG1 as defined in claim 12 and(b) pSVhygMn14MuVKHuCK as defined in claim 13;(c) transfecting mammalian lymphoma cells with said linearized vectors;(d) selecting said transfected cells for those expressing the gpt gene; and(e) selecting from said cells expressing said gpt gene cells secreting said humanized chimeric monoclonal antibody. A vector for the expression of a reshaped humanized MN-14 variable heavy chain as defined in claim 8, designated pSVgptMnl4NEWMHulgGl,wherein Mn 14 amino acid residues at positions 24, 27, 28, 30, 71 and 94 are mutated into said variable heavy chain along with the CDRs of said MN-14 variable heavy chain. A vector for the expression of a reshaped humanized MN-14 variable kappa light chain as defined in claim 10, designated pSVhgrMn14REIHuCK, wherein Mn 14 amino acid residues 24, 27, 28, 30, 71 and 94 are mutated into said variable kappa light chain along with the CDRs of said MN-14 variable kappa light chain. Transformed cells expressing the chimeric gene contained in the vector according to claim 12 or 13.BACKGROUND OF THE INVENTION
SUMMARY OF THE INVENTION
ILLUSTRATIVE GLOSSARY
BRIEF DESCRIPTION OF THE FIGURES
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLE 1
Culturing Antibody Producer Cells
EXAMPLE 2
Isolating RNA From Producing Cell Lines
EXAMPLE 3
cDNA Synthesis And Amplification Of The Heavy Chain Variable Region
CG1FOR 41 5' GGAAGCTTAGACAGATGGGGGTGTCGTTTTG 3' VHlFOR 42 5' TGAGGAGACGGTGACCGTGGTCCCTTGGCCCCAG 3' VHIBACK 43 5' AGGTSMARCTGCAGSAGTCWGG 3' SH1BACK 44 5' TGGAATTCATGGRATGGAGCTGGRTCWTBHTCTT 3' SH2BACK 45 5' TGGAATTCATGRACTTCDGGYTCAACTKRRTTT 3' CK2FOR 46 5' GGAAGCTTGAAGATGGATACAGTTGGTGCAGC 3' VK1FOR 47 5' GTTAGATCTCCAGCTTGGTCCC 3' VK3FOR 48 5' GTTAGATCTCCAGTTTGGTGCCT 3' VK1BACK 49 5' GACATTCAGCTGACCCAGTCTCCA 3' VK2BACK 50 5' GACRTTCAGCTGACCCAGGMTGMA 3' VK3BACK 51 5' GACATTCAGCTGACCCA 3' VK4BACK 52 5' GACATTGAGCTCACCCAGTCTCCA 3' VK5BACK 53 5' TTGAATTCGGTGCCAGAKCWSAHATYGTKATG 3' VK6BACK 54 5' TTGAATTCGGTGCCAGAKCWSAHATYGTKCTC 3' VK7BACK 55 5' TTGAATTCGGAGCTGATGGGAACATTGTAATG 3' VK8BACK 56 5' CWGAGAAATTCAGCTGACCCAGTCTC 3' EXAMPLE 4
Cloning And Sequencing DNA Encoding The MN-14 Heavy Chain Variable Region Obtained By PCR
EXAMPLE 5
Analysis Of The Amino Acid Sequence Of The Heavy Chain Variable Region Of MN-14
EXAMPLE 6
cDNA Synthesis And Amplification Of DNA Encoding The MN-14 VK
EXAMPLE 7
Cloning and Sequencing the MN-14 Kappa Light Chain Variable Region Obtained by PCR
EXAMPLE 8
Grafting of the MN-14 VH and VK CDRs into Variable Regions of Human Antibody
8.1. Construction of chimeric antibody excression vectors
8.2 Expression and testing of the hybrid antibody
8.3 Humanization of the MN-14 antibody
A. NEWM based humanization.
B. KOL based humanization.
Mutation rationale
C. REI based humanization
EXAMPLE 9
Expression of MN-14 CDR-grafted Humanized Antibodies
EXAMPLE 10
Purification of MN-14 CDR-grafted Humanized Antibodies Expressed in Cell Culture
EXAMPLE 11
USES OF HUMANIZED MN-14 MONOCLONAL ANTIBODY IN DIAGNOSES
A. Animal studies
LS174T 11.8 ± 2.9 18.1 ± 14.9 32.6 ± 17.2 30.2 ± 13.4 10.6 ± 15.2 11.6 ± 5.6 weight 0.31 ± 0.07 0.37 ± 0.02 0.27 ± 0.08 0.31 ± 0.9 0.3 ± 0.2 0.40 ± 0.07 Liver 10.8 ± 2.1 6.0 ± 3.3 2.8 ± 0.5 0.8 ± 0.4 0.5 ± 0.7 0.08 ± 0.05 Spleen 17.0 ± 4.8 10.5 ± 8.8 4.9 ± 0.4 1.3 ± 0.6 0.6 ± 0.8 0.14 ± 0.09 Kidney 7.0 ± 0.8 3.1 ± 0.7 2.3 ± 0.9 0.9 ± 0.4 0.4 ± 0.6 0.07 ± 0.04 Lungs 8.7 ± 0.4 3.7 ± 1.4 3.7 ± 1.4 1.4 ± 0.6 0.6 ± 1.0 0.11 ± 0.08 Blood 16.4 ± 6.8 5.5 ± 4.7 6.8 ± 4.1 2.3 ± 1.2 0.9 ± 1.8 0.14 ± 0.13 Tissue Tumor (LS1474T)/Nontumor Ratios (N = 4 to 5 animals) Time Post-Injection131l-hMN-14 IgG 4 hour 1 day 2 days 5 days 7 deys 14 days Liver 1.1 ± 0.3 5.0 ± 5.0 11.1 ± 4.7 39.5 ± 7.5 24.6 ± 4.8 160 ± 28 Spleen 0.7 ± 0.3 4.2 ± 4.6 6.6 ± 3.4 24.7 ± 7.8 15.8 ± 4.4 91 ± 21 Kidney 1.7 ± 0.5 5.3 ± 3.5 13.3 ± 3.6 36.1 ± 4.0 38.4 ± 12.9 173 ± 41 Lungs 1.4 ± 0.4 4.2 ± 2.2 6.2 ± 2.1 22.3 ± 2.1 25.4 ± 7.3 112 ± 16 Blood 0.9 ± 0.6 3.7 ± 0.9 6.4 ± 1.4 14.2 ± 2.9 26.0 ± 12.9 111 ± 36 B. Clinical Studies with131I-labeled Humanized MN-14 IgG
SEQUENCE LISTING