Enhancement of the B-cell response to Staphylococcus aureus Cowan strain 1 by natural human gamma interferon.

The effects of interferon (IFN) on the B-cell response to Staphylococcus aureus Cowan strain 1 (SAC) were studied comparatively with natural human IFN-alpha, IFN-beta, and IFN-gamma, employing equal units of their anti-viral activity. First, the response was investigated in peripheral mononuclear cells obtained from healthy individuals, and next, confirmed in cultures employing B-cell enriched populations derived from tonsils obtained at tonsillectomy from patients with chronic tonsillitis. B cells were purified by rosetting out T cells with sheep red cells followed by the removal of adherent cells on a plastic surface. The results show that the SAC-stimulated lymphoproliferative response was enhanced in the presence of IFN-gamma in a dose-related manner, at concentrations ranging from 10 to 1000 IU/ml, both in peripheral mononuclear cells and tonsillar B-cell enriched fractions. In contrast, IFN-alpha and IFN-beta did not enhance or suppress SAC-stimulated blastogenesis in either lymphocyte preparation. The enhancing effects specific to IFN-gamma were more remarkable in cultures stimulated with a suboptimal dose (0.002%) of SAC than when the optimal dose (0.005%) was employed.