Objective To identify molecules that modulate T-cell functions and serve the studies on T-cell media-ted autoimmune diseases.Methods Bone marrow-derived dentritic cells were collected from BALB/c mice to immunize Wistar rats, and to establish many hybridoma cell lines.Many hybridoma cell lines which could modulate T-cell functions were obtained.One of the cell lines, most actively inhibiting T-cell proliferation, was further studied.Results The anti-CD45 mAb recognized CD45 and significantly suppressed T-cell proliferation in proliferation assays.Conclusions Our re-sults indicate that the anti-CD45 mAb can effectively suppress T-cell proliferation, and is promising to be used in the pre-vention and treatment of T-cell mediated autoimmune diseases in the future.