The low efficiency of dendritic cells and macrophages from mice susceptible to Paracoccidioides brasiliensis in inducing a Th1 response

In the present study we evaluated T cell proliferation and Th lymphokine pa tterns in response to gp43 from Paracoccidioides brasiliensis presented by isolated dendritic cells from susceptible and resistant mice. T cell prolif eration assays showed that dendritic cells from susceptible mice were less efficient than those from resistant mice, The pattern of T cell lymphokines stimulated by dendritic cells was always Th1, although the levels of IL-2 and IFN-gamma were lower in T cell cultures from susceptible mice. To deter mie whether different antigen-pressenting cells such as macrophages and den dritic cells stimulated different concentrations of Th1 lymphokines, the pr oduction of IFN-gamma and IL-2 was measured, It was observed that dendritic cells were more efficient than macrophages in stimulating lymphoproliferat ion in resistant mice. However, no significant difference was observed for IFN-gamma or IL-2 production. When cells from susceptible mice were used, m acrophages were more efficient in stimulating lymphoproliferation than dend ritic cells, but no difference was observed in the production of Th1 cytoki ne. Taken together, these results suggest the lower efficiency of dendritic cells and macrophages from B10.A mice in stimulating T cells that secrete Th1 lymphokines in vitro, an effect that may be involved in the progression of the disease in vivo.