Determination of IgG subclasses and Gm allotypes in culture supernatants of pokeweed mitogen-stimulated human blood lymphocytes.

Concentrations of the 4 IgG subclasses, of IgM, and of IgA were determined in culture supernatants of pokeweed mitogen-stimulated mononuclear cells isolated from human peripheral blood. Time-course studies showed cumulative secretion of IgM, IgA, and the subclasses IgG1, IgG2, and IgG3 but not of IgG4. In supernatants of 7-day cultures of unseparated mononuclear cells, IgG1 was predominant, followed by IgG2 and IgG3. Removal of most monocytes from the mononuclear cells resulted in an overall decrease of immunoglobulin production but had no influence on the relative IgG subclass distribution. In supernatants of T cell-enriched cultures, the synthesized IgG was deficient in IgG1. Likewise, in supernatants of B cell-enriched cultures, IgG2 exceeded IgG1 concentration. Elimination of the T gamma cells suggested some influence of this subset on IgG2 production. Gm allotypes determined in supernatants corresponded to those in serum of the blood donors.