Objective To identify molecules that modulate T-cell functions and serve the studies on T-cell mediated 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 results indicate that the anti-CD45 mAb can effectively suppress T-cell proliferation, and is promising to be used in the prevention and treatment of T-cell mediated autoimmune diseases in the future.