Influenza A2 inhibits murine in vitro antibody synthesis.

A2 influenza inhibited in a dose-dependent fashion the in vitro antibody-forming cell (AFC) response of CBA mouse spleen cells to sheep erythrocytes. The greatest amount of inhibition occurred if virus was added to the splenocytes on the day the cells were placed in culture. Inoculation of spleen cells with influenza on day 3 of culture or immediately before assay on day 4 had no effect on the AFC response. Experiments indicated that the inhibition could be transferred by adding viable, infected cells to uninfected spleen cultures. The origin of the cells that caused the suppression of AFC was not resolved; however, the data suggest that infected B or T cells were not solely responsible for the inhibition. Although infectious virus was most effective, inactivated influenza preparations also suppressed the AFC response. The possible in vivo significance of influenza's inhibitory effect on antibody synthesis is discussed.