In vitro antibody response to influenza virus. II. Specificity of helper T cells recognizing hemagglutinin

Abstract

Intraperitoneal immunization of mice with live influenza virus was shown to induce helper T (T(H)) cells with specificity for the hemagglutinin (HA). The interaction of virus-primed T(H) cells with purified HA was studied independently of B cell reactivity to the same antigen by using the generation of nonspecific help as an index of activation of HA-specific T(H) cells. T(H) cells from mice primed with any of the H3 viruses A/Aichi/68 x A/Bel/42 (H3N1), A/Memphis/102/72 x A/Bel/42 (H3N1) or A/Port Chalmers/73 (H3N2) were strongly cross-reactive towards HA of other strains within the 3 subtype. In addition, several examples of cross-reactivity towards HA of a different subtype were observed,..