The effects of enzymes on the blood factors associated with the FV system of bovine erythrocytes.

Treatment of cattle red cells (CRC) with proteases and neuraminidase revealed at least one trypsin- or pronase-sensitive type and a protease-resistant type of sialoglycoprotein. The antigen F itself and the antigen IM in the F/F and F/V type of CRC were associated with the protease-resistant glycoprotein. Moreover, they were demonstrable in the agglutination test, but only after treatment with proteases. The antigen V, allelic to F, was, however, associated with a pronase-sensitive protein and the antigen IM in the V/V type of CRC with a trypsin- or pronase-sensitive glycoprotein. The antigen N' was inactivated by chymotrypsin or pronase, irrespective of whether it was transmitted with the F or with the V. While the antigens IM, N' and the antigen reacting with rabbit serum, in addition to the antigen F in the F/F type of CRC, showed no or only very weak (titre 1:2) reactions, these same antigens, in addition to the antigen V in the V/V type of CRC, all showed high titres (1:32 to 1:128) in the anti-globulin test.