Endogenous gamma interferon and interleukin-10 in Brucella abortus 2308 infection in mice.

CD-1 mice intravenously infected with the virulent Brucella abortus 2308 strain simultaneously produce significant levels of gamma interferon (IFN-gamma) and interleukin-10 (IL-10) in their spleens between the second and eighth day post-infection with no production of interleukin-4 (IL-4). Endogenous synthesis of IL-10 does not affect the production of IFN-gamma in this organ, while the production of both cytokines during this period of time is accompanied by a statistically significant increase (P < 0.001) in the number of colony forming units (cfu) of B. abortus 2308 present in the organ. These findings suggest that although the endogenous synthesis of IL-10 apparently does not affect IFN-gamma production, it may affect the effector functions of macrophages to control intracellular brucellae. Production of the Th1 cytokine IFN-gamma during B. abortus 2308 infection is also associated with a specific IgG3 and IgG2a response against the B. abortus 2308 lipopolysaccharide (S-LPS) antigen.