Dendritic cells pulsed with Coccidioides immitis lysate induce antigen-specific naive T cell activation.

Coccidioidomycosis, an infection endemic to the southwestern United States, is caused by the fungus Coccidioides immitis. Coccidioidal infection is overcome by the development of cell-mediated immunity. This study evaluated the role of dendritic cells (DCs) in the initiation of coccidioidal immunity in nonimmune individuals. It was demonstrated that DCs pulsed with the coccidioidal antigen preparation, toluene spherule lysate (TSL), induce DC maturation, autologous lymphocyte proliferation, and antigen-specific lymphocyte responses from nonimmune donors. Furthermore, TSL-primed lymphocytes secreted interferon-gamma after restimulation with TSL or antigen 2/proline-rich antigen, a subcomponent of TSL, but they did not do so when restimulated with ovalbumin or unpulsed DCs. The results demonstrate that DCs generated from individuals not exposed to C. immitis can specifically prime lymphocytes for coccidioidal antigens and that the response generated by the lymphocytes is characteristic of a cellular immune response.