Secretion of immunoglobulins by human lymphocytes after infection with influenza virus

The biosynthesis of IgM by the Epstein-Barr virus-negative RAMOS lymphoblastoid cell line infected with an influenza A virus, fowl plague virus Dobson strain (FPV-B), was investigated. The results show that FPV infection of RAMOS cells slightly inhibited overall cellular protein synthesis only at 24 h after infection, despite the synthesis of FPV-specific proteins. However, even at this time, the synthesis and secretion of IgM were not affected by virus infection. Secreted IgM contained a reduced amount of sialic acid. The quantity of the asialylated IgM increased proportionally to the amount of enzymically active neuraminidase, suggesting that the asialylation of IgM is due to the action of virus neuraminidase. No such asialylated IgM was observed in RAMOS cells infected with measles virus, which does not possess neuraminidase. These results, together with a previous observation of ours that asialylated immunoglobulins acquire an altered antigenicity, suggest that the modulation of enzyme activities in B lymphocytes in response to an exogenous aggression may lead to disturbances in the structure and in the antigenic properties of immunoglobulins.