# Patent

## Title
Antibody to serine protease precursor

## Abstract

A molecule which (i) binds human membrane-bound carcinoembryonic antigen, (ii) binds a hybrid polypeptide consisting of residues 1 to 314 of human biliary glycoprotein joined (N-C) to residues 490 to C-terminus of human carcino embryonic antigen, but (iii) does not bind to human biliary glycoprotein excluding an intact mouse monoclonal antibody comprising an IgG group IIA heavy chain and a kappa group V light chain wherein the sequence of the V.sub.H chain is QVKLQQSGPELKKPGETVKISCKASGYTFTVFGMNWVKQAPGKGLKWMGWIN-TKTGEATYVEEFKGRFAFSLE TSATTAYLQINNLKNEDTAKYFCARWDFYDYVEAMDYWGQGTTVTVSS, or wherein the sequence of the V.sub.H chain is as given immediately above but the first amino acid residue of the V.sub.H CDR1 is glutamine and in either case the sequence of the V.sub.L chain is GDIVMTQSQRFMSTSVGDRVSVTCKASQNVGTNVAWYQQKPGQSPKALIYSASYRYSGVPDRFTGSG-SGTDFT LTISNVQSEDLAEYFCHQYYTYPLFTFGSGTKLEMKR. Preferably the molecule is a monoclonal antibody.

## Background
This application is a 371 of PCT/GB94/01816, filed Aug. 19, 1994.

The present invention relates to antibodies useful in diagnosing and treating colorectal cancer.

Antibodies are known that react with carcino-embryonic antigen (CEA), but they react with both membrane-associated CEA and soluble CEA and so are not especially useful in diagnosing colorectal cancer.

Monoclonal antibody PR1A3 was raised by fusion of NS1 (P3/NS1/I-Ag-4-1) myeloma cells with spleen cells from mice immunised with normal colorectal epithelium (Richman & Bodmer 1987). PR1A3 reacts strongly to both well and poorly differentiated colorectal carcinomas and has advantages over other colorectal epithelium-reactive antibodies since its antigen appears fixed to the tumour and does not appear in the lymphatics or normal lymph nodes draining a tumour (Granowska et al 1989). PR1A3 reacted with 59/60 colorectal tumours (Richman & Bodmer 1987), whereas CEA reactive B72.3 reacted with only 75% (Salvatore et al 1989). Although there is some evidence for weak binding to normal cells of the stomach, ileum, oesophagus, trachea and breast, in vivo studies have shown that the basement membrane prevents access by the antibody to these tissues (Granowska et al 1990).

Sheahan et al (1990) Am. J. Clin. Path. 94, 157-164 discusses two monoclonal antibodies (D14 and B7.1) which appear to be specific for carcino embryonic antigen.

Sakurai et al (1989) J. Surg. Oncol. 42, 39-46 discusses various monoclonal antibodies which appear to be specific for carcino embryonic antigen.

PR1A3 has been distributed publicly, as immunoglobulin, although the hybridoma has not been made available. The precise epitope to which PR1A3 binds has not previously been known.

The present invention seeks to provide further molecules, including monoclonal antibodies with the same or better specificity for colorectal cancer as PR1A3. Such antibodies may be prepared by raising MAbs to the newly discovered PR1A3 epitope which we have now found is part of the carcino-embryonic antigen (CEA), a tumour marker expressed in colorectal carcinomas.

A first aspect of the present invention provides a molecule which (i) binds membrane-bound human carcinoembryonic antigen (CEA), (ii) binds a hybrid polypeptide consisting of residues 1 to 314 of human biliary glycoprotein (BGP) joined (N-C) to residues 490 to C-terminus of intact human CEA, but (iii) does not bind to human BGP, but excluding an intact mouse monoclonal antibody comprising an IgG.sub.1 group IIA heavy chain and a kappa group V light chain wherein the sequence of the V.sub.H chain is VEEFKGRFAFSLETSATTAYLQINNLKNEDTAKYFCARWDFYDYEAMYWGQGTTVTVS S(SEQ ID No 1)

,or wherein the sequence of the V.sub.H chain is as given immediately above but the first amino acid residue of the V.sub.H CDR1 is glutamine and in either case the sequence of the V.sub.L chain is DRFTGSGSGTDFTLTISNVQSEDLAEYFCHQYYTYPLFTFGSGTKLEMKR        (SEQ ID No 2)

The sequence of the V.sub.H chain can also be written as: Lys Pro Gly Glu Thr Val Lys Ile Ser Cys Lys Ala Ser Gly Tyr Thr Phe Thr Val Phe Gly Met Asn Trp Val Lys Gln Ala Pro Gly Lys Gly Leu Lys Trp Met Gly Trp Ile Asn Thr Lys Thr Gly Glu Ala Thr Tyr Val Glu Glu Phe Lys Gly Arg Phe Ala Phe Ser Leu Glu Thr Ser Ala Thr Thr Ala Tyr Leu Gln Ile Asn Asn Leu Lys Asn Glu Asp Thr Ala Lys Tyr Phe Cys Ala Arg Trp Asp Phe Tyr Asp Tyr Val Glu Ala Met Asp Tyr Trp Gly Gln Gly Thr Thr Val Thr Val Ser Ser

The sequence of the V.sub.L chain can also be written as: Ser Thr Ser Val Gly Asp Arg Val Ser Val Thr Cys Lys Ala Ser Gln Asn Val Gly Thr Asn Val Ala Trp Tyr Gln Gln Lys Pro Gly Gln Ser Pro Lys Ala Leu Ile Tyr Ser Ala Ser Tyr Arg Tyr Ser Gly Val Pro Asp Arg Phe Thr Gly Ser Gly Ser Gly Thr Asp Phe Thr Leu Thr Ile Ser Asn Val Gln Ser Glu Asp Leu Ala Glu Tyr Phe Cys His Gln Tyr Tyr Thr Tyr Pro Leu Phe Thr Phe Gly Ser Gly Thr Lys Leu Glu Met Lys Arg

The first amino acid residue of the V.sub.H CDR1 is a position 31 in the V.sub.H sequence given.

It is preferred if the molecule is an antibody.

The hybrid polypeptide consisting of the N-A1-B1-(N-terminal half of A2) domains of BGP joined (N-C) to the (C-terminal half of A3)-B3-GPI domains of human CEA is described in detail in Example 1 and shown diagrammatically as chimaera 1 in FIG. 8. It consists of residues 1 to 314 of BGP fused to residues 490--C-terminus of CEA in a N-C fashion. The C-terminus of intact CEA is residue 668.

By "membrane-bound" we mean CEA as found in a colon carcinoma cell, for example the HT-29 cell line, a moderately well-differentiated grade II human colon adenocarcinoma cell line available from the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852, USA under catalogue number ATCC HTB 38.

By "binding" we mean that, when assessed by indirect immunofluorescence of acetone-fixed CEA-positive cell monolayers grown in cover slips, a positive signal is seen following incubation with a fluorescence conjugate anti-mouse (or human) IgG antibody. Example 7 describes a method of acetone fixation of cells and determination of binding.

That an antibody heavy chain is IgG.sub.1 can be determined by reaction with antisera specific for the isotype sera in immunodiffusion gels (Ouchterlony technique) or by enzyme-linked immunosorbent assays (ELISA). Monoclonal antibodies which react against, and are diagnostic for, mouse IgG heavy chain are commercially available, for example the rat monoclonal antibody clone name LO-MG1-2 available from Serotec, 22 Bankside, Station Approach, Kidlington, Oxford OX5 1JE, UK, and has an avidity of 9.times.10.sup.8 M.sup.-1.

That an antibody light chain is kappa can be determined by reaction with specific antisera in immunodiffusion gels and by ELISA. Monoclonal antibodies which react against, and are diagnostic for, mouse kappa light chain are commercially available, for example the rat monoclonal antibody clone name MRC OX-20 available from Serotec.

IgG group IIA and kappa group V refer to sub-types of the V-regions and are defined by the sequence of the V-region frameworks as described by Kabat et al (1991) Sequence of Proteins of Immunological Interest, fifth edition, US Department of Health and Human Services, NIH Publication No 91-3242 incorporated herein by reference.

It is preferred if the molecule does not bind substantially to other naturally occurring human proteins that are present in the human body and whose location is in the bowel. Such proteins include collagen and serum albumin. It is preferred if the molecule does not bind to N-A1-Fc, N-A1-B1-Fc or N-A1-B1-A2-Fc where in A1, B1 and A2 are domains of CEA and Fc is the Fc portion of immunoglobulin.

It is further preferred if the molecule does not bind a B3 hybrid wherein the GPI anchor is removed or wherein the GPI anchor is replaced with a BGP transmembrane segment.

When the molecule is an antibody it is preferred if it comprises a human framework region and at least the complementarity determining regions of the V.sub.H chain and V.sub.L chain as defined in claim 1 wherein for the V.sub.H chain CDR1 is VFGMN (SEQ ID No 3), CDR2 is WINTKTGEATYVEEFKG (SEQ ID No 4) and CDR3 is WDFYDYVEAMDY (SEQ ID No 5) and for the V.sub.L chain CDR1 is KASQNVGTNVA (SEQ ID No 6), CDR2 is SASYRYS (SEQ ID No 7) and CDR3 is HQYYTYPLFT (SEQ ID No 8).

PR1A3 is a mouse monoclonal antibody comprising an IgG.sub.1 group IIA heavy chain and a kappa group V light chain wherein the sequence of the V.sub.H chain is as stated above in the exclusion from the first aspect of the invention or wherein the first amino acid residue of the V.sub.H CDR1 is glutamine and the sequence of the V.sub.L chain is as stated above in the exclusion from the first aspect of the invention.

CEA is a member of the immunoglobulin super-gene family (reviewed in Thompson & Zimmermann 1988; Thompson et al 1991). CEA has a domain structure of N-A1-B1-A2-B2-A3-B3-GPI where GPI is a glycophosphatidylinositol membrane anchor. A significant degree of sequence homology exists between the domains of CEA and with other members of the family such as NCA.

Biliary glycoprotein (BGP) is also a member of the immunoglobulin gene super-family and has a domain structure of N-A1-B1-A2-TM, where TM is a transmembrane domain, but the domains A1, B1 and A2 of BGP are not identical to those named A1, B1 and A2 in CEA.

By "antibody", we include monoclonal and polyclonal antibodies and we include antibody fragments which bind specifically but reversibly to (i) human CEA, (ii) a hybrid polypeptide consisting of residues 1 to 314 of human BGP joined (N-C) to residues 490 to C-terminus of human CEA but (iii) do not bind to human BGP excluding an intact mouse monoclonal antibody comprising an IgG1 group IIA heavy chain and a kappa group V light chain wherein the sequence of the V.sub.H chain is (as defined in FIG. 1) or wherein the first amino acid residue of the V.sub.H CDR1 is glutamine and the sequence of the V.sub.L chain (is as defined in FIG. 2).

It is preferred if the antibody or antibody fragment is derived from a monoclonal antibody.

Monoclonal antibodies may be prepared generally by the techniques of Zola, H. (1988) ("Monoclonal Antibodies--A manual of techniques" CRC Press) which is incorporated herein by reference. Antibody fragments such as Fab, (Fab).sub.2, Fv, scFv or dAb fragments may be prepared therefrom in known ways. The antibodies may be humanized in known ways for example, by inserting the CDR regions of mouse antibodies into the framework of human antibodies. Antibody-like molecules may be prepared using the recombinant DNA techniques of WO 84/03712. The region specific for the protein may be expressed as part of a bacteriophage, using the technique of McCafferty et al (1990) Nature 348, 552-554.

Antibody-like molecules of the invention may be selected from phage display libraries using the methods described in Griffiths et al (1993) EMBO J. 12, 725-734 where CEA or hybrid proteins expressed in cells are immobilized and used to select phages. Also, appropriate cells grown in monolayers and either fixed with formaldehyde or glutaraldehyde or unfixed can be used to bind phages. Irrelevant phages are washed away and bound phages recovered by disrupting their binding to the CEA or hybrid protein and reamplifying in bacteria. This selection and amplification process is done several times to enrich the phage population for those molecules which are the antibody-like molecules of the invention.

We also include peptides selected from random peptide libraries in a similar way to those from phage display libraries in the antibody-like molecules of the invention.

The variable heavy (V.sub.H) and variable light (V.sub.L) domains of the antibody are involved in antigen recognition, a fact first recognised by early protease digestion experiments. Further confirmation was found by "humanisation" of rodent antibodies. Variable domains of rodent origin may be fused to constant domains of human origin such that the resultant antibody retains the antigenic specificity of the rodent parented antibody (Morrison et al (1984) Proc. Nat. Acad. Sci. USA 81, 6851-6855) or "CDR grafting" can be used to humanise rodent antibodies. Additionally or alternatively, recombinant monoclonal antibodies may be "primatised", ie antibodies formed in which the variable region of the heavy and light chains, or parts thereof, and the constant regions are derived from two different primate species, preferably the variable regions of the antibody from the macaque monkey, and the constant regions from human. The advantages of such antibodies include high homology to human immunoglobulin, presence of human effector functions, reduced immunogenicity and longer serum half-life (Newman et al (1992) Biotechnology 10, 1455).

That antigenic specificity is conferred by variable domains and is independent of the constant domains is known from experiments involving the bacterial expression of antibody fragments, all containing one or more variable domains. These molecules include Fab-like molecules (Better et al (1988) Science 240, 1041); Fv molecules (Skerra et al (1988) Science 240, 1038); single-chain Fv (ScFv) molecules where the V.sub.H and V.sub.L partner domains are linked via a flexible oligopeptide (Bird et al (1988) Science 242, 423; Huston et al (1988) Proc. Natl. Acad. Sci. USA 85, 5879) and single domain antibodies (dAbs) comprising isolated V domains (Ward et al (1989) Nature 341, 544). A general review of the techniques involved in the synthesis of antibody fragments which retain their specific binding sites is to be found in Winter & Milstein (1991) Nature 349, 293-299.

By "ScFv molecules" we mean molecules wherein the V.sub.H and V.sub.L partner domains are linked via a flexible oligopeptide.

In certain circumstances there are advantages of using antibody fragments, rather than whole antibodies. The smaller size of the fragments allows for rapid clearance, and may lead to improved tumour to non-tumour ratios. Fab, Fv, ScFv and dAb antibody fragments can all be expressed in and secreted from E. coli, thus allowing the facile production of large amounts of the said fragments.

Whole antibodies, and F(ab').sub.2 fragments are "bivalent". By "bivalent" we mean that the said antibodies and F(ab').sub.2) fragments have two antigen combining sites. In contrast, Fab, Fv, ScFv and dAb fragments are monovalent, having only one antigen combining site.

The art of "antibody engineering" is advancing rapidly, as is described in Tan, L. K. and Morrison, S. L. (1988) Adv. Drug Deliv. Rev. 2: 129-142, Williams, G. (1988) Tibtech 6: 36-42 and Neuberger, M. S. et al (1988) 8th International Biotechnology Symposium Part 2, 792-799 (all of which are incorporated herein by reference), and is well suited to preparing antibody-like molecules derived from the antibodies of the invention.

The antibodies may be used for a variety of purposes relating to the study or isolation and purification of the antigen to which they specifically bind and the imaging and treatment of cells exhibiting the antigen. In other embodiments, the antibody of the invention is coupled to a scintigraphic radiolabel, a cytotoxic compound or radioisotope, an enzyme for converting a non-toxic prodrug into a cytotoxic drug, a compound for activating the immune system in order to target the resulting conjugate to a colon tumour, or a cell-stimulating compound. Such conjugates have a "binding portion", which consists of the antibody of the invention, and a "functional portion", which consists of the radiolabel, toxin or enzyme etc.

The antibody may alternatively be used alone in order simply to block the activity of the CEA antigen, particularly by physically interfering with its binding of another compound.

The binding portion and the functional portion of the conjugate (if also a peptide or polypeptide) may be linked together by any of the conventional ways of cross-linking polypeptides, such as those generally described in O'Sullivan et al (1979) Anal. Biochem. 100, 100-108. For example, one portion may be enriched with thiol groups and the other portion reacted with a bifunctional agent capable of reacting with those thiol groups, for example the N-hydroxysuccinimide ester of iodoacetic acid (NHIA) or N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP). Amide and thioether bonds, for example achieved with m-maleimidobenzoyl-N-hydroxysuccinimide ester, are generally more stable in vivo than disulphide bonds.

Alternatively, if the binding portion contains carbohydrates, such as would be the case for an antibody or some antibody fragments, the functional portion may be linked via the carbohydrate portion using the linking technology in EP 0 088 695.

The functional portion of the conjugate may be an enzyme for converting a non-toxic prodrug into a toxic drug, for example the conjugates of Bagshawe and his colleagues (Bagshawe (1987) Br. J. Cancer 56, 531; Bagshawe et al (1988) Br. J. Cancer 58, 700; WO 88/07378) or cyanide-releasing systems (WO 91/11201).

It may not be necessary for the whole enzyme to be present in the conjugate but, of course, the catalytic portion must be present. So-called "abzymes" may be used, where a monoclonal antibody is raised to a compound involved in the reaction one wishes to catalyse, usually the reactive intermediate state. The resulting antibody can then function as an enzyme for the reaction.

The conjugate may be purified by size exclusion or affinity chromatography, and tested for dual biological activities. The antigen immunoreactivity may be measured using an enzyme-linked immunosorbent assay (ELISA) with immobilised antigen and in a live cell radio-immunoassay. An enzyme assay may be used for .beta.-glucosidase using a substrate which changes in absorbance when the glucose residues are hydrolysed, such as oNPG (o-nitrophenyl-.beta.-D-glucopyranoside), liberating 2-nitrophenol which is measured spectrophotometrically at 405 nm.

Stability of the conjugate may be tested in vitro initially by incubating at 37.degree. C. in serum, followed by size exclusion FPLC analysis. Stability in vivo can be tested in the same way in mice by analysing the serum at various times after injection of the conjugate. In addition, it is possible to radiolabel the antibody with .sup.125 I, and the enzyme with .sup.131 I before conjugation, and to determine the biodistribution of the conjugate, free antibody and free enzyme in mice.

Alternatively, the conjugate may be produced as a fusion compound by recombinant DNA techniques whereby a length of DNA comprises respective regions encoding the two portions of the conjugate either adjacent one another or separated by a region encoding a linker peptide which does not destroy the desired properties of the conjugate.

Conceivably, the two functional portions of the compound may overlap wholly or partly. The DNA is then expressed in a suitable host in known ways.

The conjugates may be administered in any suitable way, usually parenterally, for example intravenously or intraperitoneally, in standard sterile, non-pyrogenic formulations of diluents and carriers, for example isotonic saline (when administered intravenously). Once the conjugate has bound to the target cells and been cleared from the bloodstream (if necessary), which typically takes a day or so, the pro-drug is administered, usually as a single infused dose, or the tumour is imaged.

If needed, because the conjugate may be immunogenic, cyclosporin or some other immunosuppressant can be administered to provide a longer period for treatment but usually this will not be necessary.

The timing between administrations of conjugate and pro-drug may be optimised in a non-inventive way since tumour/normal tissue ratios of conjugate (at least following intravenous delivery) are highest after about 4-6 days, whereas at this time the absolute amount of conjugate bound to the tumour, in terms of percent of injected dose per gram, is lower than at earlier times.

Therefore, the optimum interval between administration of the conjugate and the pro-drug will be a compromise between peak tumour concentration of enzyme and the best distribution ratio between tumour and normal tissues. The dosage of the conjugate will be chosen by the physician according to the usual criteria. At least in the case of methods employing a targeted enzyme such as .beta.-glucosidase and intravenous amygdalin as the toxic pro-drug, 1 to 50 daily doses of 0.1 to 10.0 grams per square meter of body surface area, preferably 1.0-5.0 g/m.sup.2 are likely to be appropriate. For oral therapy, three doses per day of 0.05 to 10.0 g, preferably 1.0-5.0 g, for one to fifty days may be appropriate. The dosage of any conjugate will similarly be chosen according to normal criteria, particularly with reference to the type, stage and location of the tumour and the weight of the patient. The duration of treatment will depend in part upon the rapidity and extent of any immune reaction to the conjugate.

The functional portion of the conjugate, when the conjugate is used for diagnosis, usually comprises and may consist of a radioactive atom for scintigraphic studies, for example technetium 99 m (.sup.99m Tc) or iodine-123 (.sup.123 I), or a spin label for nuclear magnetic resonance (nmr) imaging (also known as magnetic resonance imaging, mri), such as iodine-123 again, iodine-131, indium-111, fluorine-19, carbon-13, nitrogen-15, oxygen-17, gadolinium, manganese or iron.

When used in a compound for selective destruction of the tumour, the functional portion may comprise a highly radioactive atom, such as iodine-131, rhenium-186, rhenium-188, yttrium-90 or lead-212, which emits enough energy to destroy neighbouring cells, or a cytotoxic chemical compound such as methotrexate, adriamicin, vinca alkaloids (vincristine, vinblastine, etoposide), daunorubicin or other intercalating agents.

The radio- or other labels may be incorporated in the conjugate in known ways. For example, the peptide may be biosynthesized or may be synthesized by chemical amino acid synthesis using suitable amino acid precursors involving, for example, fluorine-19 in place of hydrogen. Labels such as .sup.99m Tc, .sup.123 I, .sup.186 Rh, .sup.188 Rh and .sup.111 In can be attached via a cysteine residue in the peptide. Yttrium-90 can be attached via a lysine residue. The IODOGEN method (Fraker et al (1978) Biochem. Biophys. Res. Commun. 80: 49-57 can be used to incorporate iodine-123. "Monoclonal Antibodies in Immunoscintigraphy" (Chatal, CRC Press 1989) describes other methods in detail.

Thus, a second aspect of the invention provides a molecule, preferably an antibody, as defined in the first aspect of the invention for use in medicine.

A third aspect of the invention provides a use of a molecule, preferably antibody, as defined by the first aspect of the invention in the manufacture of a medicament for use in the diagnosis or treatment of colorectal carcinoma.

A fourth aspect of the invention provides a process for making a monospecific antibody, the process comprising screening a pool of antibodies to select those monospecific antibodies which bind (i) human membrane-based CEA, (ii) bind a hybrid polypeptide consisting of residues 1 to 314 of human BGP joined (N-C) to residues 490 to C-terminus of human CEA, but (iii) do not bind to human BGP.

It is preferred if the monospecific antibody is a monoclonal antibody and the pool of antibodies is a pool of monoclonal antibodies. It is further preferred if the antibodies within the pool comprise antibodies produced by recombinant DNA methods.

In the preferred embodiment the screening steps are for antibodies that:

(1) Bind to human tumour cells such as colorectal carcinoma cells (Richman & Bodmer (1987) Int. J. Cancer 39, 317-328) and the human gastric carcinoma cell line MKN 45 (Kojama et al (1990) Jpn. J. Cancer 81, 967-970). Binding is detected in indirect immunofluorescent assays where the cells are fixed to microscope slides or cover slips, for example with acetone, and antibody binding detected by a second fluorescently-labelled anti-species antibody, for example a FITC labelled anti-mouse IgG if the first antibody is a mouse IgG. Alternatively antibody binding to cells in suspension could be measured; and antibody binding could be detected by radioactively-labelled second antibody, for example by .sup.125 I-labelled anti-mouse IgG.

(2) Bind to cells transfected with and expressing the human CEA. For example, these could be the simian virus 40-transformed monkey fibroblast line COS-7 transfected by electroporation with a CEA cDNA (Beauchemin et al (1987) Mol. Cell. Biol. 7, 3221-3230) in the vector pCDM8 (Invitrogen); Chinese hamster ovary cells (CHO) transfected by electroporation with a CEA cDNA in the dexamethasone inducible vector pMAMneo (Clontech): a cosmid clone for CEA (Wilicocks, T. C. & Craig, I. W. (1990) Genomics 8, 492-500) co-transfected into the mouse colorectal carcinoma cell line CMT93 by lipofection with the plasmid pSVneo2; CHO cells transfected with a yeast artificial chromosome or YAC containing the CEA gene cluster, eg ICRFy9000C02400 from the q13.1-q13.3 region of the long arm of chromosome 19 and modified to include a neomycin resistance (neo.sup.R) gene by homologous recombination with the plasmid vector pRAN4 (Ragoussis et al (1992) Nucleic Acids Res. 290, 3135-3138) with the right hand vector arm of pYAC4, transfection could be by yeast spheroplast cell fusion (Burgers, P. & Percival, K. (1987) Anal. Biochem 163, 391-397).

(3) Bind to cells transfected with and expressing the hybrid gene BGP-CEAB3-GP1, for example COS-7 cells transfected by electroporation with the plasmid pCDM8 carrying the hybrid gene. Electroporation is described in Example 6.

(4) Do not bind to cells expressing BGP but not expressing CEA, for example COS-7 cells transfected with the plasmid pCDM8 carrying the cDNA for BGP.

(5) Do not bind to cells expressing NCA but not expressing CEA, for example COS-7 cells transfected with the plasmid pCDM8 carrying the cDNA for NCA (Hefta et al (1990) Cancer Res. 50, 2397-2403).

(6) Do not bind to cells expressing the hybrid BGP-CEAB3 but without the GPI anchor, these cells could be transfected COS-7 cells transfected with the plasmid pCDM8 carrying the hybrid gene for BGP-CEAB3 where a stop codon is introduced into the CEAB3 sequence at the beginning of the position of the hydrophobic tail which is normally processed off and replaced by a GPI anchor. PCR can be used to introduce such a stop codon.

(7) Do not bind to a cell expressing BGP-CEAB3-BGP TM, for example COS-7 transected with pCDM8 carrying the hybrid gene where the transmembrane domain of BGP was added to the B3 domain of CEA in place of the processed hydrophobic segment of CEA.

A useful control antibody that does not bind CEA is one that, for example, recognises the T-cell marker CD4. Suitable anti-CD4 antibodies are available from the ATCC, for example OKT4 (anti-human helper T cell subset; ATCC CRL 8002).

Selecting the antibodies of the invention can be done using the above steps in any permutation.

It is preferred if primary screening is done on a CEA-expressing cell line which can be a human tumour cell line or a transfectoma expressing CEA from a cDNA or cosmid.

It is preferred if secondary screening is done on cell lines transfected with the above mentioned genes and hybrid genes.

NCA is non-specific cross reacting antigen and comprises N, A1 and B1 domains and a GPI anchor (see Thomson & Zimmerman (1988) Tumour Biol. 9, 63-83 and Thomson et al (1991) J. Clin. Lab. Analysis 5, 344-366 for reviews).

Suitable parent cell lines for expression include COS cells and CHO cells which do not express CEA.

The invention will now be described in detail with reference to the following Examples and Figures wherein:

FIG. 1 shows the deduced amino acid sequence for the V.sub.H chain of murine monoclonal antibody (murine heavy; SEQ ID No 1), its comparison with the V.sub.H sequence of the human antibody RF-TS3'CL used to provide the framework sequences for humanisation (RF-TS3 backbone; SEQ ID No 27), and the humanised sequence created (humanised heavy; SEQ ID No 28). The sequence of RF-TS3'CL is disclosed in Pascual et al (1990) J. Clin. Invest. 86, 1320-1328 incorporated herein by reference.

FIG. 2 shows the deduced amino acid sequence for the V.sub.L chain of murine monoclonal antibody (murine kappa; SEQ ID No 2), its comparison with the V.sub.L sequence of the human antibody REI used to provide the framework sequences for humanisation (REI backbone; SEQ ID No 29), and the humanised sequence created (humanised kappa; SEQ ID No 30).

FIG. 3 shows the amino acid sequence comparison between CEA and NCA-50. Corresponding domains are grouped together. In each case, dots indicate identity to the amino acids of the CEA domains shown in the top line of each group. Dashes indicate amino acid deletions in comparison with CEA. Potential N-glycosylation positions are underlined.

FIG. 4 shows the cDNA sequence (SEQ ID No 31) and deduced amino acid sequence (SEQ ID No 32) of BGP.

FIG. 5 shows the structures of GPI.

FIG. 6 shows the construction of a humanised heavy chain. FR indicates framework regions; CDR indicates complementarity determining regions; = indicates double stranded DNA encoding humanised heavy chain; and .fwdarw. indicates synthetic oligonucleotides, showing direction 5'-3', used as primers for overlapping PCR.

FIG. 7 shows the construction of a humanised light chain. FR indicates framework regions; CDR indicates complementarity determining regions; =indicates double stranded DNA encoding humanised heavy chain; and .fwdarw. indicates synthetic oligonucleotides, showing direction 5'-3', used as primers for overlapping PCR.

FIG. 8 shows the BGP-CEA chimaeric constructs.

FIG. 9 shows a model of the V-domain of humanised antibody. The positions of the complementarity determining regions (CDRs) 1 to 3 of the light (L) and heavy (H) chains are shown. The two glutamic acid residues implicated in antigen recognition E(H:106)--position 106 of the heavy chain, and E(H:57)--position 57 of the heavy chain are marked.

FIG. 10 shows a model of the B3 domain of CEA. The positions of the lysine and arginine residues are marked. In vitro mutagenesis of KG36 (lysine at position 636) and R594 (arginine position 594) destroys PR1A3 binding to the antigen.

FIG. 11 shows the cDNA sequence (SEQ ID No 33) and deduced amino acid sequence (SEQ ID No 34) of NCA.

FIG. 12 shows the cDNA sequence (SEQ ID No 35) and deduced amino acid sequence (SEQ ID No 36) of CEA.

FIG. 13 shows the cDNA sequence (SEQ ID No 37) and deduced amino acid sequence (SEQ ID No 38) of the PR1A3 kappa light chain.

FIG. 14 shows the cDNA sequence (SEQ ID No 39) and deduced amino acid sequence (SEQ ID No 40) of the PR1A3 heavy chain.

YAC (yeast artificial chromosome) and cosmid studies have mapped the gene encoding the PR1A3 antigen to the chromosomal region in which the CEA gene is located and, like CEA, the PR1A3 epitope was shown to be up-regulated by .gamma.-interferon. Transfection of a cDNA for CEA into a variety of cells gave the appearance of the PR1A3 epitope on these cells, thus indicating that the monoclonal antibody PR1A3 recognises an epitope on CEA.

Domains of CEA were expressed in COS cells as fusions to the Fc portion of immunoglobulin as N-A1-Fc, N-A1-B1-Fc and N-A1-B1-A2-Fc. None of these constructs produced protein which reacted with PR1A3, therefore the epitope is not located in the N-A1-B1-A2 region.

Hybrid constructs of BGP and CEA were made such that the (C-terminal half of A3)-B3-GPI domains of CEA were fused to the N-A1-B1-(N-terminal half of A2) domains of BGP. Amino acid sequences for CEA and BGP are shown in FIGS. 3 and 4. The hybrid construct number 1 contained BGP up to cysteine 314 and from glutamic acid 490 to the C-terminus of CEA (see FIG. 8). The hybrid construct was expressed in COS cells from the expression plasmid pCDM8. When analysed in immunofluorescence assays the transfected COS cells gave a positive signal with both the mouse PR1A3 antibody and a human/mouse chimaeric antibody (see below). This confirms that the PR1A3 epitope is in the region of the B3-GPI region. The plasmid pCDM8 is described in Seed & Aruffo (1987) Proc. Natl. Acad. Sci. USA 84, 3365-3369.

A stop codon was inserted into the hybrid construct number 1 such that no GPI anchor was added to the protein. The CEA portion should no longer be membrane bound but soluble and secreted. The stop codon was inserted at a position equivalent to residue 644 of CEA and a protein of (N-A1-B1-(N-terminal half of A2)) BGP--((C-terminal half of A3)-B3) CEA was formed (construct number 2; FIG. 8). Transfection of this construct into COS cells using the vector pCDM8 gave cells which were positive in immunofluorescent studies with an antibody, 3B10, which cross-reacts with BGP, but negative for PR1A3. This confirms expression of the hybrid protein but that the PR1A3 epitope is absent when the hybrid is not membrane bound.

Chimaeric constructs 3a and 3b were made and the structures are as indicated in FIG. 8.

PCR methods used in making expression constructs

For cloning BGP the following primers were used: 5' + HindIII site: CTCAAGCTTATGGGGCACCTC (SEQ ID No 9) 3' + XbaI site: GGTCTAGACTATGAAGTTGGTTG (SEQ ID No 10) ______________________________________

For cloning CEA the following primers were used: 5' + HindIII site: CTCAAGCTTATGGAGTCTCCC (SEQ ID No 11) 3' + XbaI site: GGTCTAGACTATATCAGAGCAAC (SEQ ID No 12) ______________________________________

For chimaera 1 BGP and CEA fragments were amplified by PCR from parent molecules. Products were cut with ClaI and ligated. 5' and 3' ends of the annealed product were cut with HindIII and XbaI for ligation into the HindIII-XbaI site of pCDM8 vector for transient expression in COS-7 cells.

The following primers were used: 5' + HindIII site: CTCAAGCTTATGGGGCACCTC (SEQ ID No 9) 3' B1 loop + ClaI site: GGATCGATGCAGGTCAGGTT (SEQ ID No 13) 5' IIIA Ioop + ClaI site: CTCATCGATGAACCTGAGGCT (SEQ ID No 14) 3' + XbaI site: GGTCTAGACTATATCAGAGCAAC (SEQ ID No 15) ______________________________________

Chimaera 2 was amplified from chimaera 1 and cut with HindIII and XbaI for ligation into pCDM8.

The following primers were used: 5' + HindIII site: CTCAAGCTTATGGGGCACCTC (SEQ ID No 9) 3' + STOP + XbaI site: GGTCTAGACTAAGATGCAGAGAC (SEQ ID No 16) ______________________________________

For making chimaeras 3a and 3b 5' portion of the molecule was amplified from chimaera 1 template using BGP 5' primer and antisense overlapping primer complementary to the required join. The BGP transmembrane domain was amplified from BGP using sense overlapping primer and BGP 3' primer.

To assemble the annealed molecule, the two complementary fragments were subjected to 18 PCR cycles to allow formation of "primer-dimer" before addition of BGP 5' and 3' outside primers for 12 further PCR cycles.

The following primers were used for construct 3a: 5' + HindIII site: CTCAAGCTTATGGGGCACCTC (SEQ ID No 9) Overlapping primers: TCTGCATCTGGACTCTCACCTGGGGCC (sense) (SEQ ID No 17) GGCCCCAGGTGAGAGTCCAGATGCAGA (antisense) (SEQ ID No 18) 3' + XbaI site: GGTCTAGACTATGAAGTTGGTTG (SEQ ID No 10) ______________________________________

The following primers were used for construct 3b: 5' + HindIII site: CTCAAGCTTATGGGGCACCTC (SEQ ID No 9) Overlapping primers: ACAGTCTCTGCACAAGAAAATGGC (sense) (SEQ ID No 19) GCCATTTTCTTGTGCAGAGACTGT (antisense) (SEQ ID No 20) 3' + XbaI site: GGTCTAGACTATGAAGTTGGTTG (SEQ ID No 10) ______________________________________

Anchor structures are reviewed in Ferguson (1992) and a generic structure for a mammalian GPI is shown in FIG. 5. Studies with CEA released from MKN45 cells by incubation with a phospholipase, which cleaves the lipid tail from GPI anchors to give a soluble product, produces CEA which contains the PR1A3 epitope. When examined by SDS PAGE and western blotting a weak signal is given if this antigen is boiled in 2% SDS sample buffer with reducing agent dithiothreitol to break disulphide bridges. When the antigen is examined in the same way, but the reducing agent omitted to retain the disulphide bridges intact, a strong signal is given. This suggests the epitope is at least partly conformational. Furthermore, NCA is related to CEA, with a high degree of sequence homology, and has a GPI anchor, but does not react with PR1A3. Therefore the GPI is unlikely to be sufficient for the epitope.

Molecular models of the antibody PR1A3 demonstrate the presence of two unusual unpaired negative charges in the CDR region of the antibody. These charges may indicate the presence of complementary charges in the epitope recognised by the antibody (see FIGS. 9 and 10).

Analysis of the B3 domain of CEA and comparison with another family member, NCA, indicated that there were three residues carrying positive charges which could play an important role in the antibody antigen interaction. The residues were, lysines at positions 610 and 636 and arginine at position 514 in the CEA B3 domain. In order to assess the role of the individual charges in the epitope recognised by the antibody PR1A3, these residues were changed from lysine or arginine, to alanine. It is possible to alter these amino acids by changing the sequence of the DNA. The polymerase chain reaction may be used to introduce point mutations which are incorporated into one of the amplification primers. The fragment is then blunt-ended with Klenow fragment or digested with restriction endonucleases and ligated into the appropriate vector to allow the product to be sequenced. Alternatively, to introduce a mutation into the middle of a sequence, two fragments encompassing the mutation are annealed with each other and extended by mutually primed synthesis. The fragment may then be digested as before and ligated into an appropriate vector to be sequenced.

PCR may also be used to incorporate a phosphorylated oligonucleotide during amplication with Taq polymerase and Taq ligase (Michel, BioTechniques 16(3), 410-412).

Mutations may also be introduced by construction of a totally synthetic gene or portion of the gene.

The method which we used to introduce changes into the sequence was oligonucleotide directed mutagenesis by the method of Kunkel (1985) Proc. Natl. Acad. Sci. USA 82, 488-492).

The repetitive nature of CEA meant that in order to carry out the mutagenesis the B3 domain and downstream sequences of CEA had to be isolated from similar upstream sequences. This region was amplified with primers to introduce a ClaI site 5' and an XbaI site 3' and the fragment was cloned into pBluescriptII KS-. The plasmid was transformed into a dut.sup.- ung.sup.-  F' strain of E. coli (CJ236) which will produce plasmid with a number of uracil residues in place of thymine. Single stranded template was produced by superinfection with a helper phage M13 K07. A phosphorylated oligonucleotide containing the mutant sequence is annealed to the template and extended in the presence of T4 DNA polymerase and ligase to produce a double-stranded circular molecule. Introduction of this heteroduplex molecule into a wild-type (dut.sup.+ ung.sup.+) strain resulted in degradation of the uracil containing wild-type strand and replication of the mutant strand. Colonies were isolated and the DNA sequenced to ensure that the mutant genotype was present.

Mutations WILD-TYPE ATC    GCC    AAA  ATC  ACG  (SEQ ID No 21) SEQUENCE K1 MUTANT ATC    GCC    GCA  ATC  ACG  (SEQ ID No 22) OLIGO WILD-TYPE ATA    GTC    AAG  AGC  ATC  (SEQ ID No 23) SEQUENCE K2 MUTANT ATA    GTC    GCG  AGC  ATC  (SEQ ID No 24) OLIGO WILD-TYPE TCT    TGG    GGT  ATC  AAT  (SEQ ID No 25) SEQUENCE R1 MUTANT TCT    TGG    GCT  ATC  AAT  (SEQ ID No 26) OLIGO ______________________________________

After the mutant constructs were sequenced, these B3 domains were used to reconstitute the chimeric proteins consisting of residues 1-314 of BGP and residues 490-668 of CEA. These constructs have been shown to be positive for PR1A3 binding when transiently expressed in COS cells.

After insertion into pCDM8 and expression in COS cells, immunofluorescence experiments demonstrated that the constructs carrying the K2 (lysine 636.fwdarw.alanine) and R3 (arginine 594.fwdarw.alanine) mutations were no longer recognised by PR1A3 whereas the K1 (lysine 610 alanine) mutation had no effect on binding (see FIG. 10). These results implicate the residues K2 and R3 in the epitope recognised by PR1A3.

Monoclonal antibodies reactive against CEA were prepared by the method of Richman & Bodmer (1987).

Tissues, cells, cell culture

Fresh samples of normal large intestine and colorectal tumours were used. These were snap-frozen in liquid nitrogen and stored at -70.degree. C. Frozen samples of extra-colonic normal human adult and fetal tissues were used.

The colorectal carcinoma cell lines used originated from different tumours. HT29 colon carcinoma cell line (Fogh and Trempe, 1975) was maintained in medium RPM1 1640 containing 10% fetal calf serum (FCS) and 37.degree. C. in 5% CO.sub.2 in air at 100% humidity. LS174T, SW1222, SW48, SW620 and SW837 colorectal carcinoma cell lines (Tom et al., 1976; Leibovitz et al., 1976) were maintained in Dulbecco's modified Eagle's medium containing 10% FCS at 37.degree. C. in 10% CO.sub.2 in air at 100% humidity.

P3/NS1/1-Ag-4-1 (NS1) is an 8-azaguanine-resistant BALB/c myeloma cell line. This was maintained in RPMI 1640 with 10% FCS and 2.times.10.sup.-5.sbsp.M 6-thioguanine.

Hybridomas produced in this study were initially cultured in RPMI 1640 with 20% FCS, 10.sup.-4.sbsp.M hypoxanthine, 1.6.times.10.sup.-5.sbsp.M thymidine and 10.sup.-5.sbsp.M methotrexate (HAT). After cloning, hybridoma cells were weaned off HAT and maintained in RMPI 1640 with 10% FCS.

Immunizing materials

BALB/c mice were immunized with 4 different preparations.

1. Normal colorectal mucosal scrapings. Samples of normal large intestine were pinned onto a cork board. After thorough rinsing (10 times) in cold, sterile phosphate-buffered saline-A, pH 7.4 (PBS-A), the mucosa was dissected from the muscularis mucosae by scraping with a scalpel. Mucosal scraping were snap-frozen in liquid nitrogen and mechanically vibrated to a powder in a polypropylene vial containing a tungsten ballbearing. This material was emulsified in 0.2 ml complete Freund's adjuvant and 0.2 ml PBS-A. Animals received 0.2 g wet tissue in 0.4 ml emulsion per inoculation.

2. Crude membrane preparations from normal colorectal epithelium. Fresh normal colorectal mucosal scrapings were prepared as above. One gram of wet tissue was used for each membrane preparation. Tissue samples were thawed and Dounce-homogenized in 10 ml sucrose buffer containing dithiothreitol (DTT) (250 mM sucrose-RNase free: 50 mM triethanolamine-HCl pH 7.5; 60 mM MgCl.sub.2 ; 2 mM DTT). Following centrifugation at 40,000 g for 15 min, the nuclear and mitochondrial pellet was discarded. The supernatant was then centrifuged for a further 30 min at 20,000 g. The microsomal pellet was retained and resuspended in 40% sucrose in 10 mM Tris HCl pH 7.4. The sucrose solution was adjusted to obtain a refractometer reading of 1.392-5, overlaid with 25% sucrose in 10 mM Tris HCl pH 7.4 (refractometer reading 1.375) and the sucrose gradient was centrifuged at 4.degree. C. for 15 hr at 65,000 g. Membranes were recovered from the interface and washed twice in 10 mM Tris pH 7.4; protein content was estimated by the method of Lowry et al. (1951). One gram of wet tissue yielded approximately 1 mg of membrane protein. The membranes were suspended in PBS-A and complete Freund's adjuvant for injection. Animals received 0.4 ml emulsion per inoculation.

3. H729 colon carcinoma cell line. Animals received 2.times.10.sup.6 live trypsinized cells suspended in 0.4 ml PBS-A per inoculation.

4. Epitope as immunogen. The immunogen is a cell carrying hybrid BGP-CEA B3-GPI protein or a cell transfected with CEA cDNA or cosmid. A mouse L cell transfected with CEA gene is used to immunise an appropriate mouse strain to give antibodies to CEA. Human tumour cells expressing CEA can also be used.

Immunization and production of hybridomas

Three fusions were carried out using spleens from BALB/c mice immunized by intraperitoneal inoculations according to the following protocol. In fusions 1 and 2, mice were immunized and boosted with mucosal scrapings and membrane preparations of normal colorectal epithelium (see "Immunizing materials" above). In fusion 3, initial immunization was with membrane preparations of normal colon and subsequent booster inoculations were with HT29 colon carcinoma cells. Animals received intraperitoneal injections of these materials 6 weeks, 2 weeks and 4 days prior to each fusion. In each case, the spleen was removed aseptically; a single-cell suspension was prepared mechanically and the spleen cells were fused with 10.sup.8 NSI myeloma cells using 50% polyethyleneglycol 4,000 (Merck) in RPMI 1640. The cells were plated into 24- or 96-well plates (Linbro, Flow, Irvine, Scotland) containing RPMI 1640 with HAT plus 20% FCS and mouse spleen cells as a feeder layer. The plates were incubated at 37.degree. C. in 5% CO.sub.2 in air at 100% humidity. Hybridomas were generally visible microscopically at 14-21 days; initial screening to identify interesting colonies was performed prior to cloning. These colonies were cloned twice by picking single cells with a drawn-out Pasteur pipette, transferring them to individual wells of 96-well Microtitre plates containing mouse spleen cell feeders overlaid with 2 ml RPMI 1640, HAT and 20% FCS, and cultured at 37.degree. C. in 5% CO.sub.2 in air in 100% humidity.

Screening assay for antibody production

Screening for antibody production from all fusions was performed on tissue sections using an indirect immunoperoxidase technique. Cryostat sections (6 .mu.m thickness) were cut from snap-frozen cubes of normal large intestine. The sections were picked up on 10-well multitest slides (C. A. Hendley-Essex, England) precoated with 0.1% poly-1-lysine and allowed to dry in air for 30 min at room temperature. The sections were fixed in acetone for 15 min. Individual wells were incubated with 20 .mu.l unconcentrated hybridoma tissue culture supernatant for 30 min at room temperature in a humid chamber. Slides were washed twice in Tris-buffered saline (TBS) pH 7.6 (Tris, 605 mg, NaCl, 8 g in 1 l distilled water) before incubation for 30 min at room temperature with peroxidase-conjugated rabbit anti-mouse immunoglobulin (DAKO, Copenhagen, Denmark) diluted 1:50 in TBS containing 5% normal human serum. The slides were washed again in TBS and then flooded with freshly prepared filtered solution of diaminobenzidine (Sigma. St. Louis, Mo.) 5 mg in 10 ml Tris HCl pH 7.6 containing 0.03% hydrogen peroxide. The peroxidase substrate reaction was stopped after 5 min by washing in tap water and the slides were counterstained with Heyer's haematoxylin, dehydrated in alcohol and mounted in DPX (BDH, Poole, UK).

Immunohistochemical methods

1. Indirect immunoperoxidase staining of formalin-fixed tissue. To determine the reactivity of the MAbs with formalin-fixed, paraffin-embedded tissues, samples of normal large intestine were fixed in either (a) 10% neutral buffered formalin or (b) acid formalin (2% acetic acid in 10% formalin) for 2 hr. After routine processing 3-4 .mu.m sections were stained by the indirect peroxidase technique as described above (see "Screening"). Prior to staining, endogenous peroxidase activity was blocked by incubating the sections for 10 min in a humid chamber at room temperature with a freshly prepared solution of 0.5% hydrogen peroxide in methanol. After washing in tap water, slides were treated in one of 3 ways irrespective of the type of fixative used. (i) Stained directly; (ii) Digested in trypsin. For digestion slides were warmed at 37.degree. C. in distilled water and transferred to a freshly prepared solution of 0.1% trypsin (Sigma, type II), 0.1% CaCl.sub.2, pH 7.8 with NaOH for periods of 5-40 min (iii) Digested with other protease solutions. Warmed slides were transferred to a solution of protease (Sigma, type IV), 0.025% in TBS pH 7.6 for 5-15 min.

In (i) and (ii) above, enzyme reactions were stopped with cold running water. After thorough washing in water and TBS the digested sections were stained by the indirect immunoperoxidase technique.

2. Indirect immunoperoxidase staining of frozen tissue sections. Frozen sections of normal large intestine, other normal tissue and colorectal tumours were prepared as described above (see "Screening"). They were picked up on 4-well multitest slides (C. A. Hendly-Essex) and stained. They were not enzyme-digested and endogenous peroxidase activity was not blocked. All tissues were counterstained in Meyer's haematoxylin, dehydrated in a graded alcohol series, cleared in xylene and mounted in DPX.

3. Immunofluorescence of frozen sections. Frozen sections of both normal colorectal tissue and some tumours were also examined by indirect immunofluorescence. After fixing in acetone for 15 min, sections were washed in phosphate-buffered saline (PBS). Sections were then incubated with 20 .mu.l unconcentrated hybridoma supernatant for 30 min in a humid chamber, washed 3 times in PBS and incubated for a further 30 min with fluorescein-conjugated rabbit anti-mouse IgG (DAKO) diluted 1:40 in PBS. After 3 further washes in PBS and a final wash in distilled water, the sections were mounted in Gelvato 20/30 (Monsanto, Springfield, Mass.) and viewed on a Leitz Orthoplan microscope with epifluorescence attachment.

4. Immunocytochemical examination of cell lines. Cells from the carcinoma lines were grown on glass slides. They were washed 3 times in PBS-A and then stained either live or after fixation in acetone for 10 min.

5. Controls. Immunohistochemical staining was controlled by the use of nonhybridoma tissue culture medium (RPMI 1640 with 10% FCS) as the primary layer. In addition, for immunoperoxidase staining the second antibody-enzyme conjugate and diaminobenzidine solution were also used individually. For immunofluorescence the FITC-conjugated rabbit anti-mouse IgG was used alone. Non-specific staining by these reagents was not observed.

Assessment of colorectal tumours

The colorectal adenocarcinomas were graded histologically by the criteria of Blenkinsopp et al. (1981) using sections stained with haematoxylin and eosin. For each antibody tumours were assessed as "negative" (no reactive cells), "heterogeneous" (some reactive cells) or "positive" (all cells reactive). Variations in the staining intensity between different cells of the same tumour or between tumour cells and the adjacent normal epithelium were sometimes seen but not quantitated.

Antibodies are screened by indirect immunofluorescent assays using CEA-positive cells air-dried and acetone-fixed on to cover slips. Also, whole cells or tissue sections carrying CEA are used and detection is by ELISA or radioimmunoassay (RIA).

Antibodies which are positive for CEA-expressing cell lines, negative for BGP- and NCA-expressing cell lines, and negative for BGP-CEA B3-expressing and BGP-CEA B3-BGPTM-expressing cell lines comprise antibodies of the invention.

To prepare monospecific polyclonal antibodies reactive against CEA a suitable animal (rabbit, goat or the like) is immunized with hybrid BGP-CEA B3-GPI. The antisera so produced is then absorbed with purified BGP or cells expressing BGP to remove BGP-reactive antibodies and to leave the CEA reactive antibodies of the invention.

Antibodies are used in RIS as described by Granowska et al (1989) in Nuclear Medicine, trends and possibilities in nuclear medicine, pp. 531-534 Schmidt & Buraggi (eds.), Schattauer, N.Y. A monoclonal antibody obtained by the method of Example 2 is labelled with indium-111 using the bifunctional chelate method of Hnatovich et al (1987). Imaging is undertaken using a Siemans 75 tube digitrac rotating gamma camera set with a medium energy parallel hole `gallium` collimator and linked to a Nodecrest V77 computer. The camera is peaked to the two energies of In-111 with 15% and 20% windows and the counts are summed. Images are displayed on transparent film and in colour on the visual display unit of the computer.

Patients with primary or suspected recurrent colorectal cancer are selected by the surgeons and presented for RIS. The study is approved by the Administration of Radioactive Substances Advisory Committee of the Department of Health. Signed informed consent is obtained from each patient. Patients with a history of allergy to foreign proteins or with a positive skin test to the antibody are to be excluded. Patients with low rectal tumours were studied using multiple per rectal submucosal injection of antibody to undertake lymphoscintigraphy.

After the injection of 2-3 mCi (80-120 MBq) of a known amount of activity, imaging was performed immediately, sometimes at 4 hours, at 24 hours with emission tomography, and at 48, 72 or 96 hours. Anterior and posterior views of the lower chest and upper abdomen, and lower abdomen and pelvis are obtained, together with images of six radioactive marker sources set on the bone land-marks to check repositioning of the patient and the image at each time point. Gamma camera images are also made of the excised surgical specimen. The histological staging and grading of the tumour is undertaken. Specimens of the tumour, nearby mucosa and lymph nodes known to be involved or not involved with tumour are selected and counted, together with standards and appropriate background samples. Serial blood and urine samples are also assayed.

Blood clearance at 24 hours averages 51%; at 48 hours 33% and at 72 hours 27% of the injected dose taking the 5 minute sample volume as 100 percent. Urine output is less than 3%.

Images of primary and recurrent colorectal cancer are of high quality. Tumour sites are clearly identified in the abdomen and pelvis often as early as 4 hours. Liver metastases are identified as focal defects on the early images which took up activity progressively with time. There is appreciably less normal bowel uptake than we are accustomed to with In-111 anti CEA (that is, anti-CEA antibodies that do not recognise the epitope recognised by PR1A3). Marrow and liver uptakes are similar. No false positive or false negative results are obtained. Single photon emission tomography is of no particular benefit since the planar images were so good.

Imaging of a surgical specimens shows that tumours and polyps have high uptake and that, unlike with other anti CEA antibodies (that do not recognise the epitope recognised by PR1A3) normal nodes are not visualised. The tumour to mucosa ratios are high ranging up to 47:1. Poorly differentiated tumours take up the antibody reasonably well and, on average, better than with In-111 anti CEA (that do not recognise the epitope recognised by PR1A3).

Complementary DNAs (cDNAs) encoding the variable regions of the monoclonal antibody were cloned and sequenced. Primers used for PCR cloning of the heavy chain V-region were from Orlandi et al (1989) and for the light chain V-region were from Jones & Bendig (1991). In each instance two sequences were given, one each for the parental NS1 light and heavy chains and unique sequences for a heavy chain and a light chain.

To confirm the specificity of the unique sequences they were expressed as a human-mouse chimaeric antibody where the mouse antibody V-regions were fused to human constant regions. The mouse antibody V.sub.H -region clone was linked to a cDNA clone of the C-regions of the human IgG.sub.1 heavy chain NEWM (Kabat et al (1991) supra) by PCR techniques (see FIG. 1). The mouse antibody V.sub.L -region was linked to a cDNA clone of the human kappa light chain REI (Kabat et al (1991) supra) by PCR techniques (see FIG. 2).

The NEWM sequence is disclosed in Poljak et al (1977) Biochemistry 16, 3412-3420 and the REI sequence is disclosed in Palm & Hilschmann (1973) Z. Physiol. Chem. 354, 1651-1654 both incorporated herein by reference.

The chimaeric light and heavy chains were then inserted into the expression vector pCDM8 and the two plasmids co-transfected into COS cells. After eight days of culture antibody levels of approximately 1 .mu.g/ml were determined in a human IgG Fc specific ELISA and the chimaeric antibody gave a positive immunofluorescent staining on MKN45 cells, a human gastric carcinoma cell line that carries the determinant identified by PR1A3.

The DNA sequences of the V-regions were used to design humanised antibody. Analysis of the database allowed the selection of a human antibody with similarity to the mouse antibody (about 75% homology). This human antibody sequence was used as the template to design a humanised antibody sequence which was constructed from overlapping oligonucleotides and PCR and then linked to the cDNA of NEWM heavy chain.

The murine light chain had a homology of 70% to the human light chain. The light chain was then used as the template to construct humanised PR1A3 light chain using oligonucleotides and PCR by the method of Lewis & Crowe (1991).

Methods

Heavy Chain (see FIG. 6)

Synthetic oligonucleotides, 1-6, code for the variable region of the heavy chain of the monoclonal antibody. These oligonucleotides (90mers) coded alternatively for the sense or the antisense strand of DNA, with 12 base pair overlaps between each sequential oligonucleotide. Primer dimer formation between pairs of oligonucleotides occurs, followed by PCR amplification.

The constant region was primed from a human heavy chain sequence contained within a plasmid. Incorporated into these primers was a 5' overlap with the 3' end of the variable region and a cloning site at the extreme 3' end of the gene.

PCR Conditions 95.degree. C./1 min .rarw. add Taq DNA polymerase 60.degree. C./2 min 72.degree. C./2 min .times.30 95.degree. C./1 min 60.degree. C./2 min 72.degree. C./7 min ______________________________________

Light Chain (see FIG. 7)

The light chain was constructed in a similar manner to the heavy chain. Primers 1+2, 3+4, 5+6, 7+8 were PCR-amplified to produce overlapping fragments. The programme used was the same as for the heavy chain. The fragments were then joined using the following PCR programme.

Initially only the fragments are added. Initially only the fragments are added. 93.degree. C./1.5 min 37.degree. C./1.0 min .times.7 72.degree. C./2.0 min Outside primers are added. 93.degree. C./1.5 min 37.degree. C./1.0 min .times.25 72.degree. C./2.0 min 93.degree. C./1.5 min 37.degree. C./1.0 min 72.degree. C./10.0 min ______________________________________

The template for this construct was a human light chain sequence contained within a plasmid. Primers (20-30 mers) were designed to have a 3' region which was complementary to the human framework and a foreign 5' region (either restriction enzyme sites or partial monoclonal antibody CDRs). The frameworks were amplified and the 5' foreign sequences were incorporated during this amplification. The individual fragments overlaps at the ends and were joined by overlapping PCR to form the complete gene.

Light and heavy chains have been inserted into the expression vector pCDM8 and antibody is being expressed in COS cells and its binding activity to MKN45 cells confirmed by immunofluorescence.

The V-regions of PR1A3 have been modelled using co-ordinates from structures of antibodies known from X-ray crystallographic studies. The complementarity determining regions (CDRs) were fitted to the framework structures using the canonical loop structures derived from Chothia et al (1992). Prominent features of the model include an additional residue, a tyrosine, in CDR3 of the light chain, and two glutamic acid residues, one in CDR2 of the heavy chain, and the other in CDR3 of the heavy chain. The two glutamic acids are unusual in that they are unpaired charges, but the additional tyrosine in CDR3-L causes this loop to kink and allows salt bridges to form between the two tyrosines in the CDR3-L loop and the unpaired glutamic acids of VH to stabilise the structure. The presence of these features is strongly suggestive that they are key to antigen recognition and that the epitope is positively charged.

Sequencing the V-region of the mouse PR1A3 heavy chains has consistently given a choice of two residues for the first amino acid of CDR1-H, both valine and glutamine have been found. Chimaeric antibodies of both isotypes are equally active in immunofluorescent studies with MKN45 cells and modelling allows both amino acids to be positioned with no constraints being imposed on the structure.

Cell suspensions, approximately 10.sup.5 cells/ml in phosphate-buffered saline (PBS), were dropped onto microscope slides and allowed to dry, then immersed in acetone for 10 minutes and rinsed in PBS. Alternatively, coverslips were placed into a Petri dish containing culture medium such as RPMI 1640 containing 10% foetal calf serum, and cells seeded on to the coverslips. The Petri dishes were then incubated for between 48 and 72 hours at 37.degree. C., and then were removed from the Petri dish, rinsed in PBS, immersed in acetone 10 minutes and then rinsed in PBS. The slides or coverslips were then incubated with the appropriate test antibody and washed. The test antibody either bound to or did not bind to the cell.

In order to detect binding of the test antibody, an anti-species antibody, labelled with fluorescein isothiocyanate (FITC), is added and then the cells washed. Binding is determined by measuring the fluorescence.

When mouse IgG is the test antibody FITC-conjugated sheep anti-mouse antibody (Sigma Chemical Co, Poole, Dorset, UK) is used as the probe.

The cells used for binding studies are the colon carcinoma cell line HT-29 (ATCC HTB 38); COS-7 cells transfected with CEA cDNA; and COS-7 cells transfected with any of the DNA chimaeric constructs described in Example 1.

Transfection of the COS-7 cells is by electroporation.

Electroporation: 200 .mu.g of plasmid DNA were mixed with 0.8 ml of cells in PBS, at a concentration of .sub.10.sup.7 -10.sup.8 cells/ml. Cells were pulsed with 1 kv, 25 .mu.FD capacitance using a Bio-Rod Gene Pulser. Cells were then placed on ice for at least 10 minutes before transfer to culture medium. Following overnight incubation at 37.degree. C. fresh medium was added to the cells.

The variable region of the murine monoclonal antibody was amplified by PCR using primers which added a HindIII restriction site to the 5' end of the sequence and the 3' end was designed to have a region of overlap with the 5' end of the constant domain of the kappa chain of the human antibody REI. This was amplified using standard amplification procedures (95.degree. C. for 1 minute followed by 30 cycles of 95.degree. C. for 1 minute, 60.degree. C. for 2 minutes and 72.degree. C. for 2 minutes with a final 72.degree. C. for 10 minutes). The REI kappa constant fragment was amplified under the same conditions, with the primers adding a 5' overlap with the 3' end of the monoclonal antibody kappa variable and a 3' XbaI site. These fragments were joined and extended by mutually primed synthesis to produce a sequence containing the variable region of the kappa chain of the murine monoclonal antibody and the constant domain from the kappa chain of the human antibody REI. PCR condition were 7 rounds of amplification, in a reaction containing both fragments, of 95.degree. C. for 2 minutes and 72.degree. C. for 4 minutes after which the outside primers were added and subjected to standard amplification procedures.

The heavy chain was constructed in a similar manner using the variable region of the heavy chain of the murine monoclonal antibody and the constant domains from the human heavy chain of NEWM.

These fragments were removed by restriction endonuclease digestion with HindIII and XbaI. They were placed independently into the vectors pCDM8 and co-transfected into COS cells. The chimeric antibody was secreted into the medium and when tested by immunofluorescence against CEA expressed on the surface of MKN45 cells, exhibited all the characteristics of the construct which was murine in origin. tumour cells in vitro, pp. 115-141, Plenum Press, New York. #             SEQUENCE LISTING - (1) GENERAL INFORMATION: -    (iii) NUMBER OF SEQUENCES: 40 - (2) INFORMATION FOR SEQ ID NO: 1: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 121 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -      (v) FRAGMENT TYPE: internal -     (vi) ORIGINAL SOURCE: (A) ORGANISM: VH chain #1:   (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Gln Val Lys Leu Gln Gln Ser Gly Pro Glu Le - #u Lys Lys Pro Gly Glu #                15 - Thr Val Lys Ile Ser Cys Lys Ala Ser Gly Ty - #r Thr Phe Thr Val Phe #            30 - Gly Met Asn Trp Val Lys Gln Ala Pro Gly Ly - #s Gly Leu Lys Trp Met #        45 - Gly Trp Ile Asn Thr Lys Thr Gly Glu Ala Th - #r Tyr Val Glu Glu Phe #    60 - Lys Gly Arg Phe Ala Phe Ser Leu Glu Thr Se - #r Ala Thr Thr Ala Tyr #80 - Leu Gln Ile Asn Asn Leu Lys Asn Glu Asp Th - #r Ala Lys Tyr Phe Cys #                95 - Ala Arg Trp Asp Phe Tyr Asp Tyr Val Glu Al - #a Met Asp Tyr Trp Gly #           110 - Gln Gly Thr Thr Val Thr Val Ser Ser #       120 - (2) INFORMATION FOR SEQ ID NO: 2: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 110 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -      (v) FRAGMENT TYPE: internal -     (vi) ORIGINAL SOURCE: (A) ORGANISM: VL chain #2:   (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Gly Asp Ile Val Met Thr Gln Ser Gln Arg Ph - #e Met Ser Thr Ser Val #                15 - Gly Asp Arg Val Ser Val Thr Cys Lys Ala Se - #r Gln Asn Val Gly Thr #            30 - Asn Val Ala Trp Tyr Gln Gln Lys Pro Gly Gl - #n Ser Pro Lys Ala Leu #        45 - Ile Tyr Ser Ala Ser Tyr Arg Tyr Ser Gly Va - #l Pro Asp Arg Phe Thr #    60 - Gly Ser Gly Ser Gly Thr Asp Phe Thr Leu Th - #r Ile Ser Asn Val Gln #80 - Ser Glu Asp Leu Ala Glu Tyr Phe Cys His Gl - #n Tyr Tyr Thr Tyr Pro #                95 - Leu Phe Thr Phe Gly Ser Gly Thr Lys Leu Gl - #u Met Lys Arg #           110 - (2) INFORMATION FOR SEQ ID NO: 3: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 5 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -      (v) FRAGMENT TYPE: internal -     (vi) ORIGINAL SOURCE: #CDR1     (A) ORGANISM: VH chain #3:   (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Val Phe Gly Met Asn 1               5 - (2) INFORMATION FOR SEQ ID NO: 4: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 17 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -      (v) FRAGMENT TYPE: internal -     (vi) ORIGINAL SOURCE: (A) ORGANISM: VH CDR2 #4:   (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Trp Ile Asn Thr Lys Thr Gly Glu Ala Thr Ty - #r Val Glu Glu Phe Lys #                15 - Gly - (2) INFORMATION FOR SEQ ID NO: 5: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 12 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -      (v) FRAGMENT TYPE: internal -     (vi) ORIGINAL SOURCE: #CDR3     (A) ORGANISM: VH chain #5:   (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Trp Asp Phe Tyr Asp Tyr Val Glu Ala Met As - #p Tyr #                10 - (2) INFORMATION FOR SEQ ID NO: 6: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 11 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -      (v) FRAGMENT TYPE: internal -     (vi) ORIGINAL SOURCE: #CDR1     (A) ORGANISM: VL chain #6:   (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Lys Ala Ser Gln Asn Val Gly Thr Asn Val Al - #a #                10 - (2) INFORMATION FOR SEQ ID NO: 7: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 7 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -      (v) FRAGMENT TYPE: internal -     (vi) ORIGINAL SOURCE: #CDR2     (A) ORGANISM: VL chain #7:   (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Ser Ala Ser Tyr Arg Tyr Ser 1               5 - (2) INFORMATION FOR SEQ ID NO: 8: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 10 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -      (v) FRAGMENT TYPE: internal -     (vi) ORIGINAL SOURCE: #CDR3     (A) ORGANISM: VL chain #8:   (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - His Gln Tyr Tyr Thr Tyr Pro Leu Phe Thr #                10 - (2) INFORMATION FOR SEQ ID NO: 9: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 21 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: BGP prime - #r #9:   (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #21                ACCT C - (2) INFORMATION FOR SEQ ID NO: 10: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 23 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: BGP prime - #r #10:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #                23TTGG TTG - (2) INFORMATION FOR SEQ ID NO: 11: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 21 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: CEA prime - #r #11:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #21                CTCC C - (2) INFORMATION FOR SEQ ID NO: 12: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 23 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: CEA prime - #r #12:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #                23GAGC AAC - (2) INFORMATION FOR SEQ ID NO: 13: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 20 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: #primer   (A) ORGANISM: Chimaera #13:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: # 20               GGTT - (2) INFORMATION FOR SEQ ID NO: 14: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 21 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: #primer   (A) ORGANISM: Chimaera #14:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #21                AGGC T - (2) INFORMATION FOR SEQ ID NO: 15: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 23 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: #primer   (A) ORGANISM: Chimaera #15:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #                23GAGC AAC - (2) INFORMATION FOR SEQ ID NO: 16: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 23 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: #primer   (A) ORGANISM: Chimaera #16:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #                23CAGA GAC - (2) INFORMATION FOR SEQ ID NO: 17: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 27 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: #primer   (A) ORGANISM: Chimaera #17:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #             27   CACC TGGGGCC - (2) INFORMATION FOR SEQ ID NO: 18: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 27 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: #primer   (A) ORGANISM: Chimaera #18:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #             27   CCAG ATGCAGA - (2) INFORMATION FOR SEQ ID NO: 19: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 24 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: #primer   (A) ORGANISM: Chimaera #19:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #                24AAAA TGGC - (2) INFORMATION FOR SEQ ID NO: 20: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 24 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: #primer   (A) ORGANISM: Chimaera #20:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #                24GAGA CTGT - (2) INFORMATION FOR SEQ ID NO: 21: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 15 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: CEA parti - #al sequence #21:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #    15 - (2) INFORMATION FOR SEQ ID NO: 22: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 15 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: #primer   (A) ORGANISM: Mutagenic #22:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #    15 - (2) INFORMATION FOR SEQ ID NO: 23: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 15 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: CEA parti - #al sequence #23:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #    15 - (2) INFORMATION FOR SEQ ID NO: 24: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 15 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: #primer   (A) ORGANISM: Mutagenic #24:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #    15 - (2) INFORMATION FOR SEQ ID NO: 25: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 15 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: CEA parti - #al sequence #25:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #    15 - (2) INFORMATION FOR SEQ ID NO: 26: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 15 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: #primer   (A) ORGANISM: Mutagenic #26:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: #    15 - (2) INFORMATION FOR SEQ ID NO: 27: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 120 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -    (iii) ANTI-SENSE: NO -      (v) FRAGMENT TYPE: N-terminal -     (vi) ORIGINAL SOURCE: (A) ORGANISM: Human RF- - #TS3 heavy chain #27:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Gln Val Gln Leu Val Gln Ser Gly Ser Glu Le - #u Lys Lys Pro Gly Ala #                15 - Ser Val Lys Val Ser Cys Lys Ala Ser Gly Ty - #r Thr Phe Thr Ser Tyr #            30 - Ala Met Asn Trp Val Arg Gln Ala Pro Gly Gl - #n Gly Leu Glu Trp Met #        45 - Gly Trp Ile Asn Thr Asn Thr Gly Asn Pro Th - #r Tyr Ala Gln Gly Phe #    60 - Thr Gly Arg Phe Val Phe Ser Leu Asp Thr Se - #r Val Ser Thr Ala Tyr #80 - Leu Gln Ile Ser Ser Leu Lys Ala Asp Asp Th - #r Ala Val Tyr Tyr Cys #                95 - Ala Arg Glu Asp Ser Asn Gly Tyr Leu Ile Ph - #e Asp Tyr Trp Asp Gln #           110 - Gly Thr Leu Val Ile Val Ser Ser #       120 - (2) INFORMATION FOR SEQ ID NO: 28: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 121 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -      (v) FRAGMENT TYPE: N-terminal -     (vi) ORIGINAL SOURCE: #heavy chain) ORGANISM: Humanised #28:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Gln Val Gln Leu Val Gln Ser Gly Ser Glu Le - #u Lys Lys Pro Gly Ala #                15 - Ser Val Lys Val Ser Cys Lys Ala Ser Gly Ty - #r Thr Phe Thr Val Phe #            30 - Gly Met Asn Trp Val Arg Gln Ala Pro Gly Gl - #n Gly Leu Glu Trp Met #        45 - Gly Trp Ile Asn Thr Lys Thr Gly Glu Ala Th - #r Tyr Val Glu Glu Phe #    60 - Lys Gly Arg Phe Val Phe Ser Leu Asp Thr Se - #r Val Ser Thr Ala Tyr #80 - Leu Gln Ile Ser Ser Leu Lys Ala Asp Asp Th - #r Ala Val Tyr Tyr Cys #                95 - Ala Arg Trp Asp Phe Tyr Asp Tyr Val Glu Al - #a Met Asp Tyr Trp Gly #           110 - Gln Gly Thr Thr Val Thr Val Ser Ser #       120 - (2) INFORMATION FOR SEQ ID NO: 29: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 108 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -      (v) FRAGMENT TYPE: N-terminal -     (vi) ORIGINAL SOURCE: (A) ORGANISM: Hukan REI - # light chain #29:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Asp Ile Gln Met Thr Gln Ser Pro Ser Ser Le - #u Ser Ala Ser Val Gly #                15 - Asp Arg Val Thr Ile Thr Cys Gln Ala Ser Gl - #n Asp Ile Ile Lys Tyr #            30 - Leu Ala Trp Tyr Gln Gln Thr Pro Gly Lys Al - #a Pro Lys Leu Leu Ile #        45 - Tyr Glu Ala Ser Asn Leu Gln Ala Gly Val Pr - #o Ser Arg Phe Ser Gly #    60 - Ser Gly Ser Gly Thr Asp Tyr Thr Phe Thr Il - #e Ser Ser Leu Gln Pro #80 - Glu Asp Ile Ala Thr Tyr Tyr Cys Gln Gln Ty - #r Gln Ser Leu Pro Tyr #                95 - Thr Phe Gly Gln Gly Thr Lys Ile Glu Ile Th - #r Arg #           105 - (2) INFORMATION FOR SEQ ID NO: 30: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 109 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: peptide -    (iii) HYPOTHETICAL: NO -      (v) FRAGMENT TYPE: N-terminal -     (vi) ORIGINAL SOURCE: #kappa light chainNISM: Humanised #30:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Asp Ile Gln Met Thr Gln Ser Pro Ser Ser Le - #u Ser Ala Ser Val Gly #                15 - Asp Arg Val Thr Ile Thr Cys Lys Ala Ser Gl - #n Asn Val Gly Thr Asn #            30 - Val Ala Trp Tyr Gln Gln Lys Pro Gly Lys Al - #a Pro Lys Leu Leu Ile #        45 - Tyr Ser Ala Ser Tyr Arg Tyr Ser Gly Val Pr - #o Ser Arg Phe Ser Gly #    60 - Ser Gly Ser Gly Thr Asp Phe Thr Phe Thr Il - #e Ser Ser Leu Gln Pro #80 - Glu Asp Ile Ala Thr Tyr Tyr Cys His Gln Ty - #r Tyr Thr Tyr Pro Leu #                95 - Phe Thr Phe Gly Gln Gly Thr Lys Val Glu Il - #e Lys Arg #           105 - (2) INFORMATION FOR SEQ ID NO: 31: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 1473 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: Human bil - #iary glycoprotein -     (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..1392 #31:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - ATG GGG CAC CTC TCA GCC CCA CTT CAC AGA GT - #G CGT GTA CCC TGG CAG 48 Met Gly His Leu Ser Ala Pro Leu His Arg Va - #l Arg Val Pro Trp Gln #                 15 - GGG CTT CTG CTC ACA GCC TCA CTT CTA ACC TT - #C TGG AAC CCG CCC ACC 96 Gly Leu Leu Leu Thr Ala Ser Leu Leu Thr Ph - #e Trp Asn Pro Pro Thr #             30 - ACT GCC CAG CTC ACT ACT GAA TCC ATG CCA TT - #C AAT GTT GCA GAG GGG 144 Thr Ala Gln Leu Thr Thr Glu Ser Met Pro Ph - #e Asn Val Ala Glu Gly #         45 - AAG GAG GTT CTT CTC CTT GTC CAC AAT CTG CC - #C CAG CAA CTT TTT GGC 192 Lys Glu Val Leu Leu Leu Val His Asn Leu Pr - #o Gln Gln Leu Phe Gly #     60 - TAC AGC TGG TAC AAA GGG GAA AGA GTG GAT GG - #C AAC CGT CAA ATT GTA 240 Tyr Ser Trp Tyr Lys Gly Glu Arg Val Asp Gl - #y Asn Arg Gln Ile Val # 80 - GGA TAT GCA ATA GGA ACT CAA CAA GCT ACC CC - #A GGG CCC GCA AAC AGC 288 Gly Tyr Ala Ile Gly Thr Gln Gln Ala Thr Pr - #o Gly Pro Ala Asn Ser #                 95 - GGT CGA GAG ACA ATA TAC CCC AAT GCA TCC CT - #G CTG ATC CAG AAC GTC 336 Gly Arg Glu Thr Ile Tyr Pro Asn Ala Ser Le - #u Leu Ile Gln Asn Val #           110 - ACC CAG AAT GAC ACA GGA TTC TAC ACC CTA CA - #A GTC ATA AAG TCA GAT 384 Thr Gln Asn Asp Thr Gly Phe Tyr Thr Leu Gl - #n Val Ile Lys Ser Asp #       125 - CTT GTG AAT GAA GAA GCA ACT GGA CAG TTC CA - #T GTA TAC CCG GAG CTG 432 Leu Val Asn Glu Glu Ala Thr Gly Gln Phe Hi - #s Val Tyr Pro Glu Leu #   140 - CCC AAG CCC TCC ATC TCC AGC AAC AAC TCC AA - #C CCT GTG GAG GAC AAG 480 Pro Lys Pro Ser Ile Ser Ser Asn Asn Ser As - #n Pro Val Glu Asp Lys 145                 1 - #50                 1 - #55                 1 - #60 - GAT GCT GTG GCC TTC ACC TGT GAA CCT GAG AC - #T CAG GAC ACA ACC TAC 528 Asp Ala Val Ala Phe Thr Cys Glu Pro Glu Th - #r Gln Asp Thr Thr Tyr #               175 - CTG TGG TGG ATA AAC AAT CAG AGC CTC CCG GT - #C AGT CCC AGG CTG CAG 576 Leu Trp Trp Ile Asn Asn Gln Ser Leu Pro Va - #l Ser Pro Arg Leu Gln #           190 - CTG TCC AAT GGC AAC AGG ACC CTC ACT CTA CT - #C AGT GTC ACA AGG AAT 624 Leu Ser Asn Gly Asn Arg Thr Leu Thr Leu Le - #u Ser Val Thr Arg Asn #       205 - GAC ACA GGA CCC TAT GAG TGT GAA ATA CAG AA - #C CCA GTG AGT GCG AAC 672 Asp Thr Gly Pro Tyr Glu Cys Glu Ile Gln As - #n Pro Val Ser Ala Asn #   220 - CGC AGT GAC CCA GTC ACC TTG AAT GTC ACC TA - #T GGC CCG GAC ACC CCC 720 Arg Ser Asp Pro Val Thr Leu Asn Val Thr Ty - #r Gly Pro Asp Thr Pro 225                 2 - #30                 2 - #35                 2 - #40 - ACC ATT TCC CCT TCA GAC ACC TAT TAC CGT CC - #A GGG GCA AAC CTC AGC 768 Thr Ile Ser Pro Ser Asp Thr Tyr Tyr Arg Pr - #o Gly Ala Asn Leu Ser #               255 - CTC TCC TGC TAT GCA GCC TCT AAC CCA CCT GC - #A CAG TAC TCC TGG CTT 816 Leu Ser Cys Tyr Ala Ala Ser Asn Pro Pro Al - #a Gln Tyr Ser Trp Leu #           270 - ATC AAT GGA ACA TTC CAG CAA AGC ACA CAA GA - #G CTC TTT ATC CCT AAC 864 Ile Asn Gly Thr Phe Gln Gln Ser Thr Gln Gl - #u Leu Phe Ile Pro Asn #       285 - ATC ACT GTG AAT AAT AGT GGA TCC TAT ACC TG - #C CAC GCC AAT AAC TCA 912 Ile Thr Val Asn Asn Ser Gly Ser Tyr Thr Cy - #s His Ala Asn Asn Ser #   300 - GTC ACT GGC TGC AAC AGG ACC ACA GTC AAG AC - #G ATC ATA GTC ACT GAG 960 Val Thr Gly Cys Asn Arg Thr Thr Val Lys Th - #r Ile Ile Val Thr Glu 305                 3 - #10                 3 - #15                 3 - #20 - CTA AGT CCA GTA GTA GCA AAG CCC CAA ATC AA - #A GCC AGC AAG ACC ACA 1008 Leu Ser Pro Val Val Ala Lys Pro Gln Ile Ly - #s Ala Ser Lys Thr Thr #               335 - GTC ACA GGA GAT AAG GAC TCT GTG AAC CTG AC - #C TGC TCC ACA AAT GAC 1056 Val Thr Gly Asp Lys Asp Ser Val Asn Leu Th - #r Cys Ser Thr Asn Asp #           350 - ACT GGA ATC TCC ATC CGT TGG TTC TTC AAA AA - #C CAG AGT CTC CCG TCC 1104 Thr Gly Ile Ser Ile Arg Trp Phe Phe Lys As - #n Gln Ser Leu Pro Ser #       365 - TCG GAG AGG ATG AAG CTG TCC CAG GGC AAC AC - #C ACC CTC AGC ATA AAC 1152 Ser Glu Arg Met Lys Leu Ser Gln Gly Asn Th - #r Thr Leu Ser Ile Asn #   380 - CCT GTC AAG AGG GAG GAT GCT GGG ACG TAT TG - #G TGT GAG GTC TTC AAC 1200 Pro Val Lys Arg Glu Asp Ala Gly Thr Tyr Tr - #p Cys Glu Val Phe Asn 385                 3 - #90                 3 - #95                 4 - #00 - CCA ATC AGT AAG AAC CAA AGC GAC CCC ATC AT - #G CTG AAC GTA AAC TAT 1248 Pro Ile Ser Lys Asn Gln Ser Asp Pro Ile Me - #t Leu Asn Val Asn Tyr #               415 - AAT GCT CTA CCA CAA GAA AAT GGC CTC TCA CC - #T GGG GCC ATT GCT GGC 1296 Asn Ala Leu Pro Gln Glu Asn Gly Leu Ser Pr - #o Gly Ala Ile Ala Gly #           430 - ATT GTG ATT GGA GTA GTG GCC CTG GTT GCT CT - #G ATA GCA GTA GCC CTG 1344 Ile Val Ile Gly Val Val Ala Leu Val Ala Le - #u Ile Ala Val Ala Leu #       445 - GCA TGT TTT CTG CAT TTC GGG AAG ACC GGC AG - #C TCA GGA CCA CTC CAA 1392 Ala Cys Phe Leu His Phe Gly Lys Thr Gly Se - #r Ser Gly Pro Leu Gln #   460 - TGACCCACCT AACAAGATGA ATGAAGTTAC TTATCTACCC TGAACTTTGA AG - #CCCAGCAA 1452 #                1473CT T - (2) INFORMATION FOR SEQ ID NO: 32: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 464 amino (B) TYPE: amino acid (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: protein #32:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Met Gly His Leu Ser Ala Pro Leu His Arg Va - #l Arg Val Pro Trp Gln #                 15 - Gly Leu Leu Leu Thr Ala Ser Leu Leu Thr Ph - #e Trp Asn Pro Pro Thr #             30 - Thr Ala Gln Leu Thr Thr Glu Ser Met Pro Ph - #e Asn Val Ala Glu Gly #         45 - Lys Glu Val Leu Leu Leu Val His Asn Leu Pr - #o Gln Gln Leu Phe Gly #     60 - Tyr Ser Trp Tyr Lys Gly Glu Arg Val Asp Gl - #y Asn Arg Gln Ile Val # 80 - Gly Tyr Ala Ile Gly Thr Gln Gln Ala Thr Pr - #o Gly Pro Ala Asn Ser #                 95 - Gly Arg Glu Thr Ile Tyr Pro Asn Ala Ser Le - #u Leu Ile Gln Asn Val #           110 - Thr Gln Asn Asp Thr Gly Phe Tyr Thr Leu Gl - #n Val Ile Lys Ser Asp #       125 - Leu Val Asn Glu Glu Ala Thr Gly Gln Phe Hi - #s Val Tyr Pro Glu Leu #   140 - Pro Lys Pro Ser Ile Ser Ser Asn Asn Ser As - #n Pro Val Glu Asp Lys 145                 1 - #50                 1 - #55                 1 - #60 - Asp Ala Val Ala Phe Thr Cys Glu Pro Glu Th - #r Gln Asp Thr Thr Tyr #               175 - Leu Trp Trp Ile Asn Asn Gln Ser Leu Pro Va - #l Ser Pro Arg Leu Gln #           190 - Leu Ser Asn Gly Asn Arg Thr Leu Thr Leu Le - #u Ser Val Thr Arg Asn #       205 - Asp Thr Gly Pro Tyr Glu Cys Glu Ile Gln As - #n Pro Val Ser Ala Asn #   220 - Arg Ser Asp Pro Val Thr Leu Asn Val Thr Ty - #r Gly Pro Asp Thr Pro 225                 2 - #30                 2 - #35                 2 - #40 - Thr Ile Ser Pro Ser Asp Thr Tyr Tyr Arg Pr - #o Gly Ala Asn Leu Ser #               255 - Leu Ser Cys Tyr Ala Ala Ser Asn Pro Pro Al - #a Gln Tyr Ser Trp Leu #           270 - Ile Asn Gly Thr Phe Gln Gln Ser Thr Gln Gl - #u Leu Phe Ile Pro Asn #       285 - Ile Thr Val Asn Asn Ser Gly Ser Tyr Thr Cy - #s His Ala Asn Asn Ser #   300 - Val Thr Gly Cys Asn Arg Thr Thr Val Lys Th - #r Ile Ile Val Thr Glu 305                 3 - #10                 3 - #15                 3 - #20 - Leu Ser Pro Val Val Ala Lys Pro Gln Ile Ly - #s Ala Ser Lys Thr Thr #               335 - Val Thr Gly Asp Lys Asp Ser Val Asn Leu Th - #r Cys Ser Thr Asn Asp #           350 - Thr Gly Ile Ser Ile Arg Trp Phe Phe Lys As - #n Gln Ser Leu Pro Ser #       365 - Ser Glu Arg Met Lys Leu Ser Gln Gly Asn Th - #r Thr Leu Ser Ile Asn #   380 - Pro Val Lys Arg Glu Asp Ala Gly Thr Tyr Tr - #p Cys Glu Val Phe Asn 385                 3 - #90                 3 - #95                 4 - #00 - Pro Ile Ser Lys Asn Gln Ser Asp Pro Ile Me - #t Leu Asn Val Asn Tyr #               415 - Asn Ala Leu Pro Gln Glu Asn Gly Leu Ser Pr - #o Gly Ala Ile Ala Gly #           430 - Ile Val Ile Gly Val Val Ala Leu Val Ala Le - #u Ile Ala Val Ala Leu #       445 - Ala Cys Phe Leu His Phe Gly Lys Thr Gly Se - #r Ser Gly Pro Leu Gln #   460 - (2) INFORMATION FOR SEQ ID NO: 33: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 1103 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: Human non - #-specific cross reacting antigen -     (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..1032 #33:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - ATG GGA CCC CCC TCA GCC CCT CCC TGC AGA TT - #G CAT GTC CCC TGG AAG 48 Met Gly Pro Pro Ser Ala Pro Pro Cys Arg Le - #u His Val Pro Trp Lys #                 15 - GAG GTC CTG CTC ACA GCC TCA CTT CTA ACC TT - #C TGG AAC CCA CCC ACC 96 Glu Val Leu Leu Thr Ala Ser Leu Leu Thr Ph - #e Trp Asn Pro Pro Thr #             30 - ACT GCC AAG CTC ACT ATT GAA TCC ACG CCA TT - #C AAT GTC GCA GAG GGG 144 Thr Ala Lys Leu Thr Ile Glu Ser Thr Pro Ph - #e Asn Val Ala Glu Gly #         45 - AAG GAG GTT CTT CTA CTC GCC CAC AAC CTG CC - #C CAG AAT CGT ATT GGT 192 Lys Glu Val Leu Leu Leu Ala His Asn Leu Pr - #o Gln Asn Arg Ile Gly #     60 - TAC AGC TGG TAC AAA GCG GAA AGA GTG GAT GG - #C AAC AGT CTA ATT GTA 240 Tyr Ser Trp Tyr Lys Ala Glu Arg Val Asp Gl - #y Asn Ser Leu Ile Val # 80 - GGA TAT GTA ATA GGA ACT CAA CAA GCT ACC CC - #A GGG CCC GCA TAC AGT 288 Gly Tyr Val Ile Gly Thr Gln Gln Ala Thr Pr - #o Gly Pro Ala Tyr Ser #                 95 - GGT CGA GAG ACA ATA TAC CCC AAT GCA TCC CT - #G CTG ATC CAG AAC GTC 336 Gly Arg Glu Thr Ile Tyr Pro Asn Ala Ser Le - #u Leu Ile Gln Asn Val #           110 - ACC CAG ATT GAC ACA GGA TTC TAT ACC CTA CA - #A GTC ATA AAG TCA GAT 384 Thr Gln Ile Asp Thr Gly Phe Tyr Thr Leu Gl - #n Val Ile Lys Ser Asp #       125 - CTT GTG AAT GAA GAA GCA ACC GGA CAG TTC CA - #T GTA TAC CCG GAG CTG 432 Leu Val Asn Glu Glu Ala Thr Gly Gln Phe Hi - #s Val Tyr Pro Glu Leu #   140 - CCC AAG CCC TCC ATC TCC AGC AAC AAC TCC AA - #C CCC GTG GAG GAC AAG 480 Pro Lys Pro Ser Ile Ser Ser Asn Asn Ser As - #n Pro Val Glu Asp Lys 145                 1 - #50                 1 - #55                 1 - #60 - GAT GCT GTG GCC TTC ACC TGT GAA CCT GAG GT - #T CAG AAC ACA ACC TAC 528 Asp Ala Val Ala Phe Thr Cys Glu Pro Glu Va - #l Gln Asn Thr Thr Tyr #               175 - GTC TGG TGG GTA AAT GGT CAG AGC CTC CCG GT - #C AGT CCC AGG CTG CAG 576 Val Trp Trp Val Asn Gly Gln Ser Leu Pro Va - #l Ser Pro Arg Leu Gln #           190 - CTG TCC AAT GGC AAC ATG ACC CTC ACT CTA CT - #C AGC GTC AAA AGG AAC 624 Leu Ser Asn Gly Asn Met Thr Leu Thr Leu Le - #u Ser Val Lys Arg Asn #       205 - GAT GCA GGA TCC TAT GAA TGT GAA ATA CAG AA - #C CCA GCG AGT GCC AAC 672 Asp Ala Gly Ser Tyr Glu Cys Glu Ile Gln As - #n Pro Ala Ser Ala Asn #   220 - CGC AGT GAC CCA GTC ACC CTG AAT GTC CTC TA - #T GGC CCA GAT GGC CCC 720 Arg Ser Asp Pro Val Thr Leu Asn Val Leu Ty - #r Gly Pro Asp Gly Pro 225                 2 - #30                 2 - #35                 2 - #40 - ACC ATT TCC CCC TCA AAG GCC AAT TAC CGT CC - #A GGG GAA AAT CTG AAC 768 Thr Ile Ser Pro Ser Lys Ala Asn Tyr Arg Pr - #o Gly Glu Asn Leu Asn #               255 - CTC TCC TCG CAC GCA GCC TCT AAC CCA CCT GC - #A CAG TAC TCT TGG TTT 816 Leu Ser Ser His Ala Ala Ser Asn Pro Pro Al - #a Gln Tyr Ser Trp Phe #           270 - ATC AAT GGG ACG TTC CAG CAA TCC ACA CAA GA - #G CTC TTT ATC CCC AAC 864 Ile Asn Gly Thr Phe Gln Gln Ser Thr Gln Gl - #u Leu Phe Ile Pro Asn #       285 - ATC ACT GTG AAT AAT AGC GGA TCC TAT ATG TG - #C CAA GCC CAT AAC TCA 912 Ile Thr Val Asn Asn Ser Gly Ser Tyr Met Cy - #s Gln Ala His Asn Ser #   300 - GCC ACT GGC CTC AAT AGG ACC ACA GTC ACG AT - #G ATC ACA GTC TCT GGA 960 Ala Thr Gly Leu Asn Arg Thr Thr Val Thr Me - #t Ile Thr Val Ser Gly 305                 3 - #10                 3 - #15                 3 - #20 - AGT GCT CCT GTC CTC TCA GCT GTG GCC ACC GT - #C GGC ATC ACG ATT GGA 1008 Ser Ala Pro Val Leu Ser Ala Val Ala Thr Va - #l Gly Ile Thr Ile Gly #               335 - GTG CTG GCC AGG GTC GCT CTG ATA TAGCAGCCCT GG - #TGTATTTT CGATATTTCA 1062 Val Leu Ala Arg Val Ala Leu Ile 340 # 1103             GGAC CAGACCCTGA ATTCTTCTAG C - (2) INFORMATION FOR SEQ ID NO: 34: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 344 amino (B) TYPE: amino acid (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: protein #34:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Met Gly Pro Pro Ser Ala Pro Pro Cys Arg Le - #u His Val Pro Trp Lys #                 15 - Glu Val Leu Leu Thr Ala Ser Leu Leu Thr Ph - #e Trp Asn Pro Pro Thr #             30 - Thr Ala Lys Leu Thr Ile Glu Ser Thr Pro Ph - #e Asn Val Ala Glu Gly #         45 - Lys Glu Val Leu Leu Leu Ala His Asn Leu Pr - #o Gln Asn Arg Ile Gly #     60 - Tyr Ser Trp Tyr Lys Ala Glu Arg Val Asp Gl - #y Asn Ser Leu Ile Val # 80 - Gly Tyr Val Ile Gly Thr Gln Gln Ala Thr Pr - #o Gly Pro Ala Tyr Ser #                 95 - Gly Arg Glu Thr Ile Tyr Pro Asn Ala Ser Le - #u Leu Ile Gln Asn Val #           110 - Thr Gln Ile Asp Thr Gly Phe Tyr Thr Leu Gl - #n Val Ile Lys Ser Asp #       125 - Leu Val Asn Glu Glu Ala Thr Gly Gln Phe Hi - #s Val Tyr Pro Glu Leu #   140 - Pro Lys Pro Ser Ile Ser Ser Asn Asn Ser As - #n Pro Val Glu Asp Lys 145                 1 - #50                 1 - #55                 1 - #60 - Asp Ala Val Ala Phe Thr Cys Glu Pro Glu Va - #l Gln Asn Thr Thr Tyr #               175 - Val Trp Trp Val Asn Gly Gln Ser Leu Pro Va - #l Ser Pro Arg Leu Gln #           190 - Leu Ser Asn Gly Asn Met Thr Leu Thr Leu Le - #u Ser Val Lys Arg Asn #       205 - Asp Ala Gly Ser Tyr Glu Cys Glu Ile Gln As - #n Pro Ala Ser Ala Asn #   220 - Arg Ser Asp Pro Val Thr Leu Asn Val Leu Ty - #r Gly Pro Asp Gly Pro 225                 2 - #30                 2 - #35                 2 - #40 - Thr Ile Ser Pro Ser Lys Ala Asn Tyr Arg Pr - #o Gly Glu Asn Leu Asn #               255 - Leu Ser Ser His Ala Ala Ser Asn Pro Pro Al - #a Gln Tyr Ser Trp Phe #           270 - Ile Asn Gly Thr Phe Gln Gln Ser Thr Gln Gl - #u Leu Phe Ile Pro Asn #       285 - Ile Thr Val Asn Asn Ser Gly Ser Tyr Met Cy - #s Gln Ala His Asn Ser #   300 - Ala Thr Gly Leu Asn Arg Thr Thr Val Thr Me - #t Ile Thr Val Ser Gly 305                 3 - #10                 3 - #15                 3 - #20 - Ser Ala Pro Val Leu Ser Ala Val Ala Thr Va - #l Gly Ile Thr Ile Gly #               335 - Val Leu Ala Arg Val Ala Leu Ile 340 - (2) INFORMATION FOR SEQ ID NO: 35: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 2097 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: Human car - #cinoembryonic antigen -     (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..2094 #35:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - TCG GCC CCT CCC CAC AGA TGG TGC ATC CCC TG - #G CAG AGG CTC CTG CTC 48 Ser Ala Pro Pro His Arg Trp Cys Ile Pro Tr - #p Gln Arg Leu Leu Leu #                 15 - ACA GCC TCA CTT CTA ACC TTC TGG AAC CCG CC - #C ACC ACT GCC AAG CTC 96 Thr Ala Ser Leu Leu Thr Phe Trp Asn Pro Pr - #o Thr Thr Ala Lys Leu #             30 - ACT ATT GAA TCC ACG CCG TTC AAT GTC GCA GA - #G GGG AAG GAG GTG CTT 144 Thr Ile Glu Ser Thr Pro Phe Asn Val Ala Gl - #u Gly Lys Glu Val Leu #         45 - CTA CTT GTC CAC AAT CTG CCC CAG CAT CTT TT - #T GGC TAC AGC TGG TAC 192 Leu Leu Val His Asn Leu Pro Gln His Leu Ph - #e Gly Tyr Ser Trp Tyr #     60 - AAA GGT GAA AGA GTG GAT GGC AAC CGT CAA AT - #T ATA GGA TAT GTA ATA 240 Lys Gly Glu Arg Val Asp Gly Asn Arg Gln Il - #e Ile Gly Tyr Val Ile # 80 - GGA ACT CAA CAA GCT ACC CCA GGG CCC GCA TA - #C AGT GGT CGA GAG ATA 288 Gly Thr Gln Gln Ala Thr Pro Gly Pro Ala Ty - #r Ser Gly Arg Glu Ile #                 95 - ATA TAC CCC AAT GCA TCC CTG CTG ATC CAG AA - #C ATC ATC CAG AAT GAC 336 Ile Tyr Pro Asn Ala Ser Leu Leu Ile Gln As - #n Ile Ile Gln Asn Asp #           110 - ACA GGA TTC TAC ACC CTA CAC GTC ATA AAG TC - #A GAT CTT GTG AAT GAA 384 Thr Gly Phe Tyr Thr Leu His Val Ile Lys Se - #r Asp Leu Val Asn Glu #       125 - GAA GCA ACT GGC CAG TTC CGG GTA TAC CCG GA - #G CTG CCC AAG CCC TCC 432 Glu Ala Thr Gly Gln Phe Arg Val Tyr Pro Gl - #u Leu Pro Lys Pro Ser #   140 - ATC TCC AGC AAC AAC TCC AAA CCC GTG GAG GA - #C AAG GAT GCT GTG GCC 480 Ile Ser Ser Asn Asn Ser Lys Pro Val Glu As - #p Lys Asp Ala Val Ala 145                 1 - #50                 1 - #55                 1 - #60 - TTC ACC TGT GAA CCT GAG ACT CAG GAC GCA AC - #C TAC CTG TGG TGG GTA 528 Phe Thr Cys Glu Pro Glu Thr Gln Asp Ala Th - #r Tyr Leu Trp Trp Val #               175 - AAC AAT CAG AGC CTC CCG GTC AGT CCC AGG CT - #G CAG CTG TCC AAT GGC 576 Asn Asn Gln Ser Leu Pro Val Ser Pro Arg Le - #u Gln Leu Ser Asn Gly #           190 - AAC AGG ACC CTC ACT CTA TTC AAT GTC ACA AG - #A AAT GAC ACA GCA AGC 624 Asn Arg Thr Leu Thr Leu Phe Asn Val Thr Ar - #g Asn Asp Thr Ala Ser #       205 - TAC AAA TGT GAA ACC CAG AAC CCA GTG AGT GC - #C AGG CGC AGT GAT TCA 672 Tyr Lys Cys Glu Thr Gln Asn Pro Val Ser Al - #a Arg Arg Ser Asp Ser #   220 - GTC ATC CTG AAT GTC CTC TAT GGC CCG GAT GC - #C CCC ACC ATT TCC CCT 720 Val Ile Leu Asn Val Leu Tyr Gly Pro Asp Al - #a Pro Thr Ile Ser Pro 225                 2 - #30                 2 - #35                 2 - #40 - CTA AAC ACA TCT TAC AGA TCA GGG GAA AAT CT - #G AAC CTC TCC TGC CAC 768 Leu Asn Thr Ser Tyr Arg Ser Gly Glu Asn Le - #u Asn Leu Ser Cys His #               255 - GCA GCC TCT AAC CCA CCT GCA CAG TAC TCT TG - #G TTT GTC AAT GGG ACT 816 Ala Ala Ser Asn Pro Pro Ala Gln Tyr Ser Tr - #p Phe Val Asn Gly Thr #           270 - TTC CAG CAA TCC ACC CAA GAG CTC TTT ATC CC - #C AAC ATC ACT GTG AAT 864 Phe Gln Gln Ser Thr Gln Glu Leu Phe Ile Pr - #o Asn Ile Thr Val Asn #       285 - AAT AGT GGA TCC TAT ACG TGC CAA GCC CAT AA - #C TCA GAC ACT GGC CTC 912 Asn Ser Gly Ser Tyr Thr Cys Gln Ala His As - #n Ser Asp Thr Gly Leu #   300 - AAT AGG ACC ACA GTC ACG ACG ATC ACA GTC TA - #T GCA GAG CCA CCC AAA 960 Asn Arg Thr Thr Val Thr Thr Ile Thr Val Ty - #r Ala Glu Pro Pro Lys 305                 3 - #10                 3 - #15                 3 - #20 - CCC TTC ATC ACC AGC AAC AAC TCC AAC CCC GT - #G GAG GAT GAG GAT GCT 1008 Pro Phe Ile Thr Ser Asn Asn Ser Asn Pro Va - #l Glu Asp Glu Asp Ala #               335 - GTA GCC TTA ACC TGT GAA CCT GAG ATT CAG AA - #C ACA ACC TAC CTG TGG 1056 Val Ala Leu Thr Cys Glu Pro Glu Ile Gln As - #n Thr Thr Tyr Leu Trp #           350 - TGG GTA AAT AAT CAG AGC CTC CCG GTC AGT CC - #C AGG CTG CAG CTG TCC 1104 Trp Val Asn Asn Gln Ser Leu Pro Val Ser Pr - #o Arg Leu Gln Leu Ser #       365 - AAT GAC AAC AGG ACC CTC ACT CTA CTC AGT GT - #C ACA AGG AAT GAT GTA 1152 Asn Asp Asn Arg Thr Leu Thr Leu Leu Ser Va - #l Thr Arg Asn Asp Val #   380 - GGA CCC TAT GAG TGT GGA ATC CAG AAC GAA TT - #A AGT GTT GAC CAC AGC 1200 Gly Pro Tyr Glu Cys Gly Ile Gln Asn Glu Le - #u Ser Val Asp His Ser 385                 3 - #90                 3 - #95                 4 - #00 - GAC CCA GTC ATC CTG AAT GTC CTC TAT GGC CC - #A GAC GAC CCC ACC ATT 1248 Asp Pro Val Ile Leu Asn Val Leu Tyr Gly Pr - #o Asp Asp Pro Thr Ile #               415 - TCC CCC TCA TAC ACC TAT TAC CGT CCA GGG GT - #G AAC CTC AGC CTC TCC 1296 Ser Pro Ser Tyr Thr Tyr Tyr Arg Pro Gly Va - #l Asn Leu Ser Leu Ser #           430 - TGC CAT GCA GCC TCT AAC CCA CCT GCA CAG TA - #T TCT TGG CTG ATT GAT 1344 Cys His Ala Ala Ser Asn Pro Pro Ala Gln Ty - #r Ser Trp Leu Ile Asp #       445 - GGG AAC ATC CAG CAA CAC ACA CAA GAG CTC TT - #T ATC TCC AAC ATC ACT 1392 Gly Asn Ile Gln Gln His Thr Gln Glu Leu Ph - #e Ile Ser Asn Ile Thr #   460 - GAG AAG AAC AGC GGA CTC TAT ACC TGC CAG GC - #C AAT AAC TCA GCC AGT 1440 Glu Lys Asn Ser Gly Leu Tyr Thr Cys Gln Al - #a Asn Asn Ser Ala Ser 465                 4 - #70                 4 - #75                 4 - #80 - GGC CAC AGC AGG ACT ACA GTC AAG ACA ATC AC - #A GTC TCT GCG GAG CTG 1488 Gly His Ser Arg Thr Thr Val Lys Thr Ile Th - #r Val Ser Ala Glu Leu #               495 - CCC AAG CCC TCC ATC TCC AGC AAC AAC TCC AA - #A CCC GTG GAG GAC AAG 1536 Pro Lys Pro Ser Ile Ser Ser Asn Asn Ser Ly - #s Pro Val Glu Asp Lys #           510 - GAT GCT GTG GCC TTC ACC TGT GAA CCT GAG GC - #T CAG AAC ACA ACC TAC 1584 Asp Ala Val Ala Phe Thr Cys Glu Pro Glu Al - #a Gln Asn Thr Thr Tyr #       525 - CTG TGG TGG GTA AAT GGT CAG AGC CTC CCA GT - #C AGT CCC AGG CTG CAG 1632 Leu Trp Trp Val Asn Gly Gln Ser Leu Pro Va - #l Ser Pro Arg Leu Gln #   540 - CTG TCC AAT GGC AAC AGG ACC CTC ACT CTA TT - #C AAT GTC ACA AGA AAT 1680 Leu Ser Asn Gly Asn Arg Thr Leu Thr Leu Ph - #e Asn Val Thr Arg Asn 545                 5 - #50                 5 - #55                 5 - #60 - GAC GCA AGA GCC TAT GTA TGT GGA ATC CAG AA - #C TCA GTG AGT GCA AAC 1728 Asp Ala Arg Ala Tyr Val Cys Gly Ile Gln As - #n Ser Val Ser Ala Asn #               575 - CGC AGT GAC CCA GTC ACC CTG GAT GTC CTC TA - #T GGG CCG GAC ACC CCC 1776 Arg Ser Asp Pro Val Thr Leu Asp Val Leu Ty - #r Gly Pro Asp Thr Pro #           590 - ATC ATT TCC CCC CCA GAC TCG TCT TAC CTT TC - #G GGA GCG AAC CTC AAC 1824 Ile Ile Ser Pro Pro Asp Ser Ser Tyr Leu Se - #r Gly Ala Asn Leu Asn #       605 - CTC TCC TGC CAC TCG GCC TCT AAC CCA TCC CC - #G CAG TAT TCT TGG CGT 1872 Leu Ser Cys His Ser Ala Ser Asn Pro Ser Pr - #o Gln Tyr Ser Trp Arg #   620 - ATC AAT GGG ATA CCG CAG CAA CAC ACA CAA GT - #T CTC TTT ATC GCC AAA 1920 Ile Asn Gly Ile Pro Gln Gln His Thr Gln Va - #l Leu Phe Ile Ala Lys 625                 6 - #30                 6 - #35                 6 - #40 - ATC ACG CCA AAT AAT AAC GGG ACC TAT GCC TG - #T TTT GTC TCT AAC TTG 1968 Ile Thr Pro Asn Asn Asn Gly Thr Tyr Ala Cy - #s Phe Val Ser Asn Leu #               655 - GCT ACT GGC CGC AAT AAT TCC ATA GTC AAG AG - #C ATC ACA GTC TCT GCA 2016 Ala Thr Gly Arg Asn Asn Ser Ile Val Lys Se - #r Ile Thr Val Ser Ala #           670 - TCT GGA ACT TCT CCT GGT CTC TCA GCT GGG GC - #C ACT GTC GGC ATC ATG 2064 Ser Gly Thr Ser Pro Gly Leu Ser Ala Gly Al - #a Thr Val Gly Ile Met #       685 #       2097G CTG GTT GGG GTT GCT CTG ATA TA - #G Ile Gly Val Leu Val Gly Val Ala Leu Ile #   695 - (2) INFORMATION FOR SEQ ID NO: 36: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 698 amino (B) TYPE: amino acid (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: protein #36:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Ser Ala Pro Pro His Arg Trp Cys Ile Pro Tr - #p Gln Arg Leu Leu Leu #                 15 - Thr Ala Ser Leu Leu Thr Phe Trp Asn Pro Pr - #o Thr Thr Ala Lys Leu #             30 - Thr Ile Glu Ser Thr Pro Phe Asn Val Ala Gl - #u Gly Lys Glu Val Leu #         45 - Leu Leu Val His Asn Leu Pro Gln His Leu Ph - #e Gly Tyr Ser Trp Tyr #     60 - Lys Gly Glu Arg Val Asp Gly Asn Arg Gln Il - #e Ile Gly Tyr Val Ile # 80 - Gly Thr Gln Gln Ala Thr Pro Gly Pro Ala Ty - #r Ser Gly Arg Glu Ile #                 95 - Ile Tyr Pro Asn Ala Ser Leu Leu Ile Gln As - #n Ile Ile Gln Asn Asp #           110 - Thr Gly Phe Tyr Thr Leu His Val Ile Lys Se - #r Asp Leu Val Asn Glu #       125 - Glu Ala Thr Gly Gln Phe Arg Val Tyr Pro Gl - #u Leu Pro Lys Pro Ser #   140 - Ile Ser Ser Asn Asn Ser Lys Pro Val Glu As - #p Lys Asp Ala Val Ala 145                 1 - #50                 1 - #55                 1 - #60 - Phe Thr Cys Glu Pro Glu Thr Gln Asp Ala Th - #r Tyr Leu Trp Trp Val #               175 - Asn Asn Gln Ser Leu Pro Val Ser Pro Arg Le - #u Gln Leu Ser Asn Gly #           190 - Asn Arg Thr Leu Thr Leu Phe Asn Val Thr Ar - #g Asn Asp Thr Ala Ser #       205 - Tyr Lys Cys Glu Thr Gln Asn Pro Val Ser Al - #a Arg Arg Ser Asp Ser #   220 - Val Ile Leu Asn Val Leu Tyr Gly Pro Asp Al - #a Pro Thr Ile Ser Pro 225                 2 - #30                 2 - #35                 2 - #40 - Leu Asn Thr Ser Tyr Arg Ser Gly Glu Asn Le - #u Asn Leu Ser Cys His #               255 - Ala Ala Ser Asn Pro Pro Ala Gln Tyr Ser Tr - #p Phe Val Asn Gly Thr #           270 - Phe Gln Gln Ser Thr Gln Glu Leu Phe Ile Pr - #o Asn Ile Thr Val Asn #       285 - Asn Ser Gly Ser Tyr Thr Cys Gln Ala His As - #n Ser Asp Thr Gly Leu #   300 - Asn Arg Thr Thr Val Thr Thr Ile Thr Val Ty - #r Ala Glu Pro Pro Lys 305                 3 - #10                 3 - #15                 3 - #20 - Pro Phe Ile Thr Ser Asn Asn Ser Asn Pro Va - #l Glu Asp Glu Asp Ala #               335 - Val Ala Leu Thr Cys Glu Pro Glu Ile Gln As - #n Thr Thr Tyr Leu Trp #           350 - Trp Val Asn Asn Gln Ser Leu Pro Val Ser Pr - #o Arg Leu Gln Leu Ser #       365 - Asn Asp Asn Arg Thr Leu Thr Leu Leu Ser Va - #l Thr Arg Asn Asp Val #   380 - Gly Pro Tyr Glu Cys Gly Ile Gln Asn Glu Le - #u Ser Val Asp His Ser 385                 3 - #90                 3 - #95                 4 - #00 - Asp Pro Val Ile Leu Asn Val Leu Tyr Gly Pr - #o Asp Asp Pro Thr Ile #               415 - Ser Pro Ser Tyr Thr Tyr Tyr Arg Pro Gly Va - #l Asn Leu Ser Leu Ser #           430 - Cys His Ala Ala Ser Asn Pro Pro Ala Gln Ty - #r Ser Trp Leu Ile Asp #       445 - Gly Asn Ile Gln Gln His Thr Gln Glu Leu Ph - #e Ile Ser Asn Ile Thr #   460 - Glu Lys Asn Ser Gly Leu Tyr Thr Cys Gln Al - #a Asn Asn Ser Ala Ser 465                 4 - #70                 4 - #75                 4 - #80 - Gly His Ser Arg Thr Thr Val Lys Thr Ile Th - #r Val Ser Ala Glu Leu #               495 - Pro Lys Pro Ser Ile Ser Ser Asn Asn Ser Ly - #s Pro Val Glu Asp Lys #           510 - Asp Ala Val Ala Phe Thr Cys Glu Pro Glu Al - #a Gln Asn Thr Thr Tyr #       525 - Leu Trp Trp Val Asn Gly Gln Ser Leu Pro Va - #l Ser Pro Arg Leu Gln #   540 - Leu Ser Asn Gly Asn Arg Thr Leu Thr Leu Ph - #e Asn Val Thr Arg Asn 545                 5 - #50                 5 - #55                 5 - #60 - Asp Ala Arg Ala Tyr Val Cys Gly Ile Gln As - #n Ser Val Ser Ala Asn #               575 - Arg Ser Asp Pro Val Thr Leu Asp Val Leu Ty - #r Gly Pro Asp Thr Pro #           590 - Ile Ile Ser Pro Pro Asp Ser Ser Tyr Leu Se - #r Gly Ala Asn Leu Asn #       605 - Leu Ser Cys His Ser Ala Ser Asn Pro Ser Pr - #o Gln Tyr Ser Trp Arg #   620 - Ile Asn Gly Ile Pro Gln Gln His Thr Gln Va - #l Leu Phe Ile Ala Lys 625                 6 - #30                 6 - #35                 6 - #40 - Ile Thr Pro Asn Asn Asn Gly Thr Tyr Ala Cy - #s Phe Val Ser Asn Leu #               655 - Ala Thr Gly Arg Asn Asn Ser Ile Val Lys Se - #r Ile Thr Val Ser Ala #           670 - Ser Gly Thr Ser Pro Gly Leu Ser Ala Gly Al - #a Thr Val Gly Ile Met #       685 - Ile Gly Val Leu Val Gly Val Ala Leu Ile #   695 - (2) INFORMATION FOR SEQ ID NO: 37: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 396 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: Mouse PR1 - #A3 kappa light chain -     (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..396 #37:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - ATG GGC ATC AAG ATG GAG TCA CAT TCC CTG GT - #C TTT GTA TAC ATG TTG 48 Met Gly Ile Lys Met Glu Ser His Ser Leu Va - #l Phe Val Tyr Met Leu #                 15 - CTG TGG TTG TCT GGT GTT GAT GGA GAC ATT GT - #G ATG ACC CAG TCT CAA 96 Leu Trp Leu Ser Gly Val Asp Gly Asp Ile Va - #l Met Thr Gln Ser Gln #             30 - AGA TTC ATG TCC ACA TCA GTA GGA GAC AGG GT - #C AGC GTC ACC TGC AAG 144 Arg Phe Met Ser Thr Ser Val Gly Asp Arg Va - #l Ser Val Thr Cys Lys #         45 - GCC AGT CAG AAT GTG GGT ACT AAT GTT GCC TG - #G TAT CAA CAG AAA CCA 192 Ala Ser Gln Asn Val Gly Thr Asn Val Ala Tr - #p Tyr Gln Gln Lys Pro #     60 - GGA CAA TCC CCT AAA GCA CTG ATT TAC TCG GC - #A TCC TAC CGG TAC AGT 240 Gly Gln Ser Pro Lys Ala Leu Ile Tyr Ser Al - #a Ser Tyr Arg Tyr Ser # 80 - GGA GTC CCT GAT CGC TTC ACA GGC AGT GGA TC - #T GGG ACA GAT TTC ACT 288 Gly Val Pro Asp Arg Phe Thr Gly Ser Gly Se - #r Gly Thr Asp Phe Thr #                 95 - CTC ACC ATC AGC AAT GTA CAG TCT GAA GAC TT - #G GCG GAG TAT TTC TGT 336 Leu Thr Ile Ser Asn Val Gln Ser Glu Asp Le - #u Ala Glu Tyr Phe Cys #           110 - CAC CAA TAT TAC ACC TAT CCT CTA TTC ACG TT - #C GGC TCG GGG ACA AAG 384 His Gln Tyr Tyr Thr Tyr Pro Leu Phe Thr Ph - #e Gly Ser Gly Thr Lys #       125 #      396 Leu Glu Met Lys 130 - (2) INFORMATION FOR SEQ ID NO: 38: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 132 amino (B) TYPE: amino acid (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: protein #38:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Met Gly Ile Lys Met Glu Ser His Ser Leu Va - #l Phe Val Tyr Met Leu #                 15 - Leu Trp Leu Ser Gly Val Asp Gly Asp Ile Va - #l Met Thr Gln Ser Gln #             30 - Arg Phe Met Ser Thr Ser Val Gly Asp Arg Va - #l Ser Val Thr Cys Lys #         45 - Ala Ser Gln Asn Val Gly Thr Asn Val Ala Tr - #p Tyr Gln Gln Lys Pro #     60 - Gly Gln Ser Pro Lys Ala Leu Ile Tyr Ser Al - #a Ser Tyr Arg Tyr Ser # 80 - Gly Val Pro Asp Arg Phe Thr Gly Ser Gly Se - #r Gly Thr Asp Phe Thr #                 95 - Leu Thr Ile Ser Asn Val Gln Ser Glu Asp Le - #u Ala Glu Tyr Phe Cys #           110 - His Gln Tyr Tyr Thr Tyr Pro Leu Phe Thr Ph - #e Gly Ser Gly Thr Lys #       125 - Leu Glu Met Lys 130 - (2) INFORMATION FOR SEQ ID NO: 39: -      (i) SEQUENCE CHARACTERISTICS: #pairs    (A) LENGTH: 417 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: cDNA -    (iii) HYPOTHETICAL: NO -     (vi) ORIGINAL SOURCE: (A) ORGANISM: Mouse PR1 - #A3 heavy chain -     (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..417 #39:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - ATG GGA TGG AGC TGT ATC ATG CTC TTC TTG GC - #A GCA ACA GCT ACA GGT 48 Met Gly Trp Ser Cys Ile Met Leu Phe Leu Al - #a Ala Thr Ala Thr Gly #                 15 - GTC CAC TCC CAG GTG AAG CTG CAG CAG TCA GG - #A CCT GAG TTG AAG AAG 96 Val His Ser Gln Val Lys Leu Gln Gln Ser Gl - #y Pro Glu Leu Lys Lys #             30 - CCT GGA GAG ACA GTC AAG ATC TCC TGC AAG GC - #T TCT GGA TAT ACC TTC 144 Pro Gly Glu Thr Val Lys Ile Ser Cys Lys Al - #a Ser Gly Tyr Thr Phe #         45 - ACA GTG TTT GGA ATG AAC TGG GTG AAG CAG GC - #T CCT GGA AAG GGT TTA 192 Thr Val Phe Gly Met Asn Trp Val Lys Gln Al - #a Pro Gly Lys Gly Leu #     60 - AAG TGG ATG GGC TGG ATA AAC ACC AAA ACT GG - #A GAG GCA ACA TAT GTT 240 Lys Trp Met Gly Trp Ile Asn Thr Lys Thr Gl - #y Glu Ala Thr Tyr Val # 80 - GAA GAG TTT AAG GGA CGG TTT GCC TTC TCT TT - #G GAG ACC TCT GCC ACC 288 Glu Glu Phe Lys Gly Arg Phe Ala Phe Ser Le - #u Glu Thr Ser Ala Thr #                 95 - ACT GCC TAT TTG CAG ATC AAC AAC CTC AAA AA - #T GAG GAC ACG GCT AAA 336 Thr Ala Tyr Leu Gln Ile Asn Asn Leu Lys As - #n Glu Asp Thr Ala Lys #           110 - TAT TTC TGT GCA AGA TGG GAC TTC TAT GAT TA - #C GTG GAG GCT ATG GAC 384 Tyr Phe Cys Ala Arg Trp Asp Phe Tyr Asp Ty - #r Val Glu Ala Met Asp #       125 #        417C CAA GGG ACC ACG GTC ACC GTC TC - #C Tyr Trp Gly Gln Gly Thr Thr Val Thr Val Se - #r #   135 - (2) INFORMATION FOR SEQ ID NO: 40: -      (i) SEQUENCE CHARACTERISTICS: #acids    (A) LENGTH: 139 amino (B) TYPE: amino acid (D) TOPOLOGY: linear -     (ii) MOLECULE TYPE: protein #40:  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - Met Gly Trp Ser Cys Ile Met Leu Phe Leu Al - #a Ala Thr Ala Thr Gly #                 15 - Val His Ser Gln Val Lys Leu Gln Gln Ser Gl - #y Pro Glu Leu Lys Lys #             30 - Pro Gly Glu Thr Val Lys Ile Ser Cys Lys Al - #a Ser Gly Tyr Thr Phe #         45 - Thr Val Phe Gly Met Asn Trp Val Lys Gln Al - #a Pro Gly Lys Gly Leu #     60 - Lys Trp Met Gly Trp Ile Asn Thr Lys Thr Gl - #y Glu Ala Thr Tyr Val # 80 - Glu Glu Phe Lys Gly Arg Phe Ala Phe Ser Le - #u Glu Thr Ser Ala Thr #                 95 - Thr Ala Tyr Leu Gln Ile Asn Asn Leu Lys As - #n Glu Asp Thr Ala Lys #           110 - Tyr Phe Cys Ala Arg Trp Asp Phe Tyr Asp Ty - #r Val Glu Ala Met Asp #       125 - Tyr Trp Gly Gln Gly Thr Thr Val Thr Val Se - #r #   135 __________________________________________________________________________

## Claims

1. A molecule which (i) binds membrane-bound human carcinoembryonic antigen, and (ii) binds a hybrid polypeptide consisting of residues 1 to 314 of human biliary glycoprotein (SEQ ID NO: 32) and joined (N-C) to residues 490 to C-terminus of human carcino embryonic antigen (SEQ ID NO: 36), but (iii) does not bind to human biliary glycoprotein and (iv) does not bind a hybrid polypeptide consisting of residues 1 to 314 of human biliary glycoprotein joined (N-C) to residues 490 to 643 of human carcino embryonic antigen which is soluble and is secreted from a COS cell, but excluding an intact mouse monoclonal antibody comprising an IgG.sub.1 group IIA heavy chain and a kappa group V light chain wherein in the said intact mouse monoclonal antibody the sequence of the V.sub.H chain is (SEQ ID NO: 1) VKQAPGKGLKWMGWINTKTGEATYVEEFKGRFAFSLETSATTAYLQINNLK NEDTAKYFCARWDFYDYVEAMDYWGQGTTVTVSS, or wherein in the said intact mouse monoclonal antibody the sequence of the V.sub.H chain is as given immediately above but the first amino acid residue of the V.sub.H CDR1 is glutamine and in either case the sequence in the said intact monoclonal antibody of the V.sub.L chain is (SEQ ID NO: 2) YQQKPGQSPKALIYSASYRYSGVPDRFTGSGSGTDFTLTISNVQSEDLAEY FCHQYYTYPLFTFGSGTKLEMKR. -2. A molecule according to claim 1 wherein the molecule is a monospecific antibody. 3. A molecule according to claim 1 which is an antibody comprising a human framework region and at least the complementarity determining regions of the V.sub.H chain and V.sub.L chain as defined in claim 1 wherein for the V.sub.H chain CDR1 is VFGMN (SEQ ID NO: 3), CDR2 is WINTKTGEATYVEEFKG (SEQ ID NO: 4) AND CDR3 is WDFYDYVEAMDY (SEQ ID NO: 5) and for the V.sub.L chain CDR1 is KASQNVGTNVA (SEQ ID NO: 6), CDR2 is SASYRYS (SEQ ID NO: 7) and CDR3 is HQYYTYPLFT (SEQ ID NO: 8). 4. A molecule according to claim 3 wherein the antibody is a monoclonal antibody. 5. A molecule according to claim 1 further comprising a directly or indirectly cytotoxic moiety. 6. A molecule according to claim 1 further comprising a readily-detectable label. 7. A molecule according to claim 1 for use in medicine. 8. A medicament for diagnosing or treating colorectal carcinoma comprising a molecule according to claim 1. 9. A method for diagnosing or treating colorectal carcinoma comprising administering to a person a composition comprising the molecule according to claim 1 and, optionally, a non-pyrogenic diluent. 10. A process for making a monospecific antibody as defined in claim 2, the process comprising screening a pool of antibodies to select those monospecific antibodies which bind (i) human carcinoembryonic antigen, (ii) bind a hybrid polypeptide consisting of residues 1 to 314 of human biliary glycoprotein joined (N-C) to residues 490 to 668 of human carcinoembryonic antigen, but (iii) do not bind to human biliary glycoprotein. 11. A process according to claim 10 wherein the monospecific antibody is a monoclonal antibody and the pool of antibodies is a pool of monoclonal antibodies. 12. A process according to claim 10 wherein the antibodies within the pool comprise antibodies produced by recombinant DNA methods. 13. A process according to claim 12 wherein the binding sites of the antibodies are displayed on the surface of a replicating vector. 14. A process according to claim 13 wherein the replicating vector is a bacteriophage. 15. A monospecific antibody obtainable by the process of claim 10 but excluding an intact mouse monoclonal antibody comprising an IgG.sub.1 group IIA heavy chain and a kappa group V light chain wherein in the said intact mouse monoclonal antibody the sequence of the V.sub.H chain is (SEQ ID NO: 1) VKQAPGKGLKWMGWINTKTGEATYVEEFKGRFAFSLETSATTAYLQINNLK NEDTAKYFCARWDFYDYVEAMDYWGQGTTVTVSS, or wherein in the said intact mouse monoclonal antibody the sequence of the V.sub.H chain is as given immediately above but the first amino acid residue of the V.sub.H CDR1 is glutamine; and in either case the sequence in the said intact monoclonal antibody of the V.sub.L chain is (SEQ ID NO: 2) YQQKPGQSPKALIYSASYRYSGVPDRFTGSGSGTDFTLTISNVQSEDLAEY FCHQYYTYPLFTFGSGTKLEMKR. 16. A hybrid polypeptide consisting of residues 1 to 314 of human biliary glycoprotein joined (N-C) to residues 490 to 668 of human 17. A hybrid polypeptide consisting of residues 1 to 314 of human biliary glycoprotein joined (N-C) to residues 490 to 643 of human carcinoembryonic antigen. 18. A hybrid polypeptide consisting of residues 1 to 314 of human biliary glycoprotein joined (N-C) to residues 490 to 644 of human carcinoembryonic antigen joined (N-C) to residues 391 to 430 of human biliary glycoprotein. 19. A hybrid polypeptide consisting of residues 1 to 314 of human biliary glycoprotein joined (N-C) to residues 490 to 642 of human carcinoembryonic antigen joined (N-C) to residues 387 to 430 of human biliary glycoprotein.