Influence of prior cellular immunity on the in vitro lymphocyte response to virus antigens after influenza vaccination.

The in vitro peripheral blood lymphocyte response to specific influenza virus antigens was studied before and 2 weeks after trivalent influenza vaccination of 16 healthy persons. Changes in serum hemagglutination inhibition antibody titers were also determined. An inverse correlation was found between the prevaccination antibody titers and the log2 mean-fold increase in antibody titers after vaccination (r = -0.86, P less than 0.01). An inverse correlation was also found between the prevaccination stimulation index and the ratio of postvaccination to prevaccination stimulation index for each virus strain (A/Victoria, r = -0.48, P less than 0.05; A/USSR, r = -0.55, P less than 0.02; and B/Hong Kong, r = -0.55, P less than 0.02). Similar negative correlations were not consistently found with the nonspecific mitogens phytohemagglutinin, pokeweed mitogen, and concanavalin A. These results suggest that the state of cellular as well as humoral immunity to virus antigens before vaccination influence the magnitude of response after vaccination and that antigen-specific suppressor cell activity may be stimulated by vaccination.