Résumé
ObJective To locate the cysteine-rich domains(CRD) of murine 4-1BB binding to its natural ligand. Methods A serial soluble extracellular CRDs of routine 4-1BB and 4-1BBL fusion proteins was constructed and prepared. The binding of purified 4-1BB-Igs to 4-1BBL and 4-1BB monoclonal antibody were tested using ELISA assay and Western blot analysis. Blocking experiment with 4-1BBL and 4-1BB mon-oclonal antibody was performed by ELISA assay. Results All truncated overlapped proteins containing ex-tracellular CRD Ⅱ of murine 4-1BB were able to bind to 4-1BBL by ELISA assay, excepting the CRD Ⅰ do-main alone. A 4-1BB monoclonal antibody proved to block the interaction of 4-1BB and 4-1BBI, was also able to bind to CRD Ⅱ. Conclusion Murine 4-1BBL whose specificity was mapped to CRD Ⅱ of 4-1BB ex-tracellular region with a possible conformational structure.
Résumé
Objective Protein N-SRCR derived from salivary agglutinin (SAG) inhibits HIV-1 infection.An N-SRCR monoclonal antibody was prepared for the study of the interaction between N-SRCR and HIV-1 envelop glycoprotein (gp120).Methods The purified recombinant N-SRCR expressed by 293 cells was used to immunize four weeks old BALB/c mice.After the final boost,the mouse spleen cells were isolated and fused with mouse myeloma cell line SP2/0-Ag-14,and the resulting hybridomas were screened for the production of N-SRCR-specific antibodies by ELISA assay.The monoclonal antibody against N-SRCR was purified by HiTrap Protein G kit,the purity determined by SDS-PAGE and the antibody titers by ELISA.The antibody specificity.was charqacterized by western blotting.Results A strain of hybridoma cell clones stably secreting N-SRCR antibody,named 1D6,was obtained.The high purity of the IgG was demonstrated by SDS-PAGE,and the ELISA titers of 1D6 was more than 100?25.Conclusion A monoclonal antibody against N-SRCR was successfully prepared,which laid the ground for further studies on the biological function of N-SRCR and the interactions between SRCR domains and HIV-1 Env gp120.