Characterisation of the swine swC1 antigen.

Some biochemical and functional characteristics of the swine swC1 antigen, determined by the use of the authors' swC1-specific monoclonal antibody (mAb) 335-2, are reported. The molecular weight of the antigen was determined by immunoprecipitation. The swC1 antigen has 41 and approx. 15 kD components under reducing conditions. It is sensitive to proteolytic enzymes such as bromelain or trypsin, but not to papain. Phosphatidylinositol-specific phospholipase C treatment diminished the expression of swC1 on the surface of leukocytes. Cross-linking of swC1 on the cell surface did not influence the proliferation of mitogen-activated mononuclear cells and had no mitogenic activity by itself. During 48 h of mitogen activation its surface expression did not change significantly. Possible relationships of swC1 to human CD antigens are discussed in the light of the results obtained.