A Study Of Murine Monoclonal Antibodies To Human Hepatoma

A new ELISA to screen MAbs against cellular antigens has been established. The assay is specific, sensitive and well reproduc -tive. It is a useful method to screen large scale spant supernatant of hybridomas and ascites at less expense and time. On the other hand, this method can be used to detect cellular antigens with either MAbs or conventional antibodies.Several libraries of monoclonal antibodies(KAbs) reactive with human hepatorma cells were generated following immunization of BABL/c mice with intact human hepatoma cell lines PUMC-H1 or PUMC -H3. The reactivity of 9 MAbs to 23 human cell lines and 6 MAbs to human tissue frozen sections were measured by ELISA or IF respectively. According to their reactivity, 3 groups of MAbs can be defined. Group 1 includes those which recognize tumor associa -ted antigen(TAA) of cell lines and tissue sections originated from one germ layer such as endoderm. MAb D5(IgG1) belongs to the group, which only reacts with hepatoma and lung carcinoma. MAb A24(IgG1) is possible to be the group too, which reacts with hepatoma, lung carcinoma and pancreatic carcinoma. Group 2 are those which react with TAAs of cell lines or tissue sections from two germ layers such as ectoderm and endoderm. MAbs A25(IgG1) A29, B1 (IgM) and D3(IgG2a) belong to the group. Grcup 3 are those which react with TAAs of cell lines and tissue sections from three germ layers including ectoderm, endoderm and mesoderm. MAb B2 (IgG2a), C7(IgM) and D9 belong to this group. In combination with three groups of MAbs, several phenotypes of hepatoma can be defined, which might be useful in tumor pathology for diagnosis and typing of hepatoma after the relation between the phenotypes and other references such as morphology and genotypes is well understood.MAb A25 and A24 densely stained the plasma membrane of H1 cells by indirect immunofluorescence. A25 precipitated H1 cell surface protein of 200K, 125K and 110K-mol wt, on the other hand the antigen which A24 recognizes has not yet precipitated. KAb B1 and D3 also stained the plasma membrane of H1 cells, the former recog nized a 60K-mol wt protein by western blot but the antigen recog nized by the later has not been determined by both immunoprecipi tation and western blot. MAb D5 recognized the antigenic deter minant in nucleic membrane and cytoplasm, which was secreted to the supernatant of H1 cells. D5 precipitated the secreted protein of 67K and 42-46K-mol wt. D5 and A25 did not react with AFP, fibronectin and CA19-9 by ELISA or RIA. B2 stained mainly the cytoplasm and reacted with a protein of 60K-mol wt by IF and western blot respectively.