To begin to explore the relation between IFN-γ and IL-2 producing T cells in a recall antigen specific response, we measured memory IFN-γ and IL-2 producing CD4 and CD8 T cell frequencies in the periphery of healthy individuals previously exposed to mumps (by immunization), candida (usual cutaneous exposure), or viral antigen (seropositive for these antigens). This evidence concerns the gene CD4 and mumps infectious disease.