Interleukin 12 in part regulates gamma interferon release in human whole blood stimulated with Leptospira interrogans.

Heat-killed pathogenic Leptospira interrogans serovar rachmati induced the production of gamma interferon (IFN-gamma) and the IFN-gamma-inducing cytokines interleukin-12p40 (IL-12p40) and tumor necrosis factor alpha in human whole blood in vitro. The production of IFN-gamma was largely dependent on IL-12. These data establish that pathogenic leptospires can stimulate the production of type I cytokines involved in cellular immunity.