Aim: To prepare an anti-human 4-1BB functional monoclonal antibody and to characterize its biological activities.
Methods: A stable human 4-1BB molecule transfected cell line 293T/4-1BB was used as an antigen to immunize BALB/c mice. By means of the cell fusion by hybridoma technique and multiple cell subcloning and repeated screening with 293T/4-1BB as the antibody screening positive cell while 293T/mock as the negative cell. The hybridoma cell lines specifically secreting anti-4-1BB monoclonal antibodies were selected. Then their characteristics and its biological activities were investigated by Western blot, fast-strip routine Ig subclass typing method, indirect immunofluorescence, competitive inhibition test, (3);H-TdR and cell apoptosis analysis.
Results: Three hybridoma cell lines 1G5, 4B11 and 9F11 with the property of secreting specific anti-4-1BB monoclonal antibody continuously and steadily were successfully obtained. These monoclonal antibodies could bind to human 4-1BB epitopes on activated T cells and monocytoes and DC. Additionally, mAb 4B11 could promote T proliferation and enhance the growth and maturation of Mo-DC.
Conclusion: Three hybridoma cell lines which secrete anti-4-1BB monoclonal antibodies steadily have been established. These monoclonal antibodies could specifically recognize 4-1BB molecule and mAb 4B11 had a potent function to promote T proliferation cell as well as to enhance the growth and maturation of Mo-DC in vitro.