Immunosuppressive factor in cow follicular fluid

The activity of the immunosuppressive fraction and proteinase inhibitor isolated from cow follicular fluid was investigated. The immunosuppressive factor was separated from the accompanying proteinase inhibitor by Sepharose 6B and Sephacryl S-200 column chromatography. In vitro, the fraction significantly reduced mitogen-induced lymphocyte proliferation. In vivo, the fraction inhibited mouse plaque formation. However, the factor had no effect on the development of intact or zona free embryos. The active components have a molecular mass of about 110,000.