Inhibition of virus and T-haemagglutination by typhoid fever Vi-antigen.

This paper reports on tests of the effect of polysaccharide-lipid antigens of enteric bacteria and Rickettisa prowazekii antigen on virus and T-haemagglutination. It is shown that treatment of erythrocytes with typhoid Vi-antigen greatly reduces their agglutinability by myxoviruses or the Stewart-Eddy polyoma virus.Erythrocytes treated with typhoid antigen retained their capacity to adsorb and elute myxoviruses, although to a somewhat lesser degree than normal erythrocytes, and such treatment did not affect adsorption of the SE polyoma virus. The typhoid antigen does not fix or destroy the virus receptor of the erythrocyte.Adsorption of the typhoid antigen prevents T-agglutination of erythrocytes which have first been treated with receptor-destroying enzyme. On the surface of RDE-treated erythrocytes the typhoid antigen is fixed outside the T-antigen loci and does not block unmasked T-antigen. The general conclusion is that, in the systems reviewed, the Vi-antigen is able to increase the resistance of erythrocytes to agglutination.