Specific anti-influenza virus antibody production in vitro by human peripheral blood mononuclear cells.

Cultures of human peripheral blood mononuclear cells stimulated in vitro with influenza virus were found to produce anti-influenza virus antibody. An enzyme-linked immunosorbent assay was used to measure cumulative antibody secretion into culture supernatants. Optimal antibody production was obtained with 2 x 10(6) peripheral blood mononuclear cells cultured in flat-bottomed wells for 12 days in 2 ml of RPMI 1640 medium supplemented with 10% fetal calf serum, antibiotics, and 4 mM L-glutamine. Antibody could be detected in cultures stimulated with live A/Hong Kong/68 (H3N2), purified formalin-inactivated A/Aichi/68 (H3N2), or live B/Hong Kong/68 influenza virus. Antibody of both IgG and IgM isotypes was produced. Under optimum conditions, the secreted IgG antibody was found to be directed preferentially at antigens on the stimulating virus. Antibody production was shown to require the cooperative interaction of B and T cells. Poisson analysis of B cell precursor frequency showed that approximately 1 in 40,000 B cells could be induced to produce IgG anti-influenza virus antibody in virus-stimulated cultures. Further investigation of this in vitro response should allow dissection of the cellular mechanisms involved in the regulation of antibody production in man.