antigenic efficiency of intact virus was found to result from the attachment of virus to sialic acid residues on the surface of the antigen-presenting cell since spikeless viral particles lacking the hemagglutinin molecule were much less efficient antigens for helper t cells and continuous presence of hemagglutination-inhibiting antihemagglutinin antibodies reduced efficiency of stimulation by intact virus approximately 100-fold for both hemagglutinin and internal virion proteins .
C0003342
antigenic
C0003320
antigens