Induction of human immunoglobulin synthesis (IgG, IgA) by the novel, T cell independent mitogen Cytophaga allerginae endotoxin.

Cytophaga allerginae endotoxin (CAE) has been purified from C. allerginae, a newly discovered bacterial species isolated from a chilled water spray humidification system. The present study was undertaken in order to determine whether CAE can induce immunoglobulin synthesis by human peripheral blood lymphocytes (PBL) in culture. To this end, human PBL were purified and cultured with either pokeweed mitogen at 5 micrograms/ml, or CAE (at varying concentrations) for 6 days. The levels of IgG and IgA in the supernatants were determined by the particle concentration fluorescence immunoassay and the IgE levels were determined by the avidin-biotin enzyme-linked immunosorbent assay. Our results indicate that CAE added to cultures in vitro induces IgG and IgA synthesis. CAE is a T cell independent mitogen inasmuch as ciclosporin A does not inhibit CAE-stimulated immunoglobulin synthesis but does inhibit PWM-stimulated immunoglobulin synthesis. In addition, CAE causes human B cell differentiation through the B1 and the DR determinants. In summary, CAE is a novel mitogen which can be used to induce human IgG and IgA synthesis in a T cell independent manner.