PREPARATION AND CHARACTERIZATION OF MONOCLONAL ANTIBODY AGAINST HUMAN TELOMERASE REVERSE TRANSCRIPTASE

Objective. To develop monoclonal antibodies against the catalytic subunit of human telomerase reverse transcriptase (hTERT) for its expression detection of human tumors. Methods. A dominant epitope in hTERT (peptide hTERT7)was automatically synthesized based on Fmoc method, and was used to immunize Balb/c mice. Hybridomas were generated and screened by ELISA for specific monoclonal antibodies, and the characterization was performed by Western blotting and immunohistochemical staining. The heavy chain variable region of antibody was cloned by RT-PCR and sequenced. Results. Antigenic peptide hTERT7 was synthesized and confirmed by MALDI-TOF-MS and HPLC analysis. One hybridoma cell line secreting anti-hTERT7 antibodies designated as M2 was established after primary screening and consequent 3 rounds of limited dilution. M2 was IgG1 in isotyping. The competi tive assay showed that the M2 antibody was hTERT7 -specific, and the affinity constant was about 1×106 mol-1. The antibody reacted with cell extracts from HeLa cancer cells but not with those from normal 2BS cells in ELISA assay. For in situ staining of immunohistochemistry, the positive staining presented in the nuclear compartment of HeLa, while 2BS was negative. The heavy chain variable region from M2 re vealed that the monoclonal antibody was mouse origin. Conclusions. The developed mouse monoclonal antibody is hTERT-specific and able to recognize native cellular hTERT in ELISA and immunohistochemistry, which makes the immuno-detection of telom erase hTERT expression in cancer cells or tissues possible.