In order to identify tumor associated antigen (TAA) on the cell surface of transitional cell carcinoma (TCC) of the bladder, monoclonal antibodies (Mabs) to the established cell line KU-1, derived from transitional cell carcinoma of the bladder, was produced. Cell fusion technique, utilizing spleen cells of immunized Balb/c mouse and SP-2 cells of mouse myeloma cell line, was applied in the present study.
Identification and quantification of cell surface antigen of KU-1 cells and another established cell line derived from bladder carcinoma KU-7 cells were attempted by determining reactivity of the cell surface antigens with thus produced Mabs utilizing enzyme linked immunosorbent assay (ELISA).
Immunohistochemical study demonstrated the cell surface antigen on these two cell lines and surgically removed fresh specimens of TCC of the bladder, using indirect immunofluorescence technique.
Two distinct Mabs (TBSN-1 and TBSN-2) were obtained. TBSN-1 diluted ten fold was observed to be reactive with KU-1 cells but not with KU-7 cells. TBSN-2 diluted twenty fold showed reactivity with KU-7 cells but not with KU-1 cells.
Complement mediated cytotoxicity of these two Mabs against these two cell lines showed higher cytotoxicity of TBSN-1 against KU-7 cells (97.3±15.1% at 1:1 relative concentration of complement) as compared with its cytotoxicity against KU-1 cells (54.2±5.1%). Correlation between complement dose and cytotoxicity of TBSN-1 was statistically significant. TBSN-2 showed markedly higher cytotoxicity against KU-1 cells (57.8±10.5%) than against KU-7 cells (22.2±3.7%), however there was no correlation between complement dose and cytotoxicity of TBSN-2.
Cross reactivity of the Mabs showed higher specificity of TBSN-2 to TCC of the bladder.
The present study disclosed the presence of specific Mab (TBSN-2) to TCC of the bladder. In spite of different histopathological grade of the original tumors, both KU-1 and KU-7 had tumor associated antigen capable of binding with TBSN-2.
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