Assessment of the human cellular immune response to T27K, a coccidioidal antigen preparation, by flow cytometry of whole blood

Whole blood flow cytometry was performed among donors with various clinical forms of coccidioidomycosis using T27K, a coccidioidal antigen preparation protective in mice but not previously studied in humans. The median percen t of CD3+ lymphocytes (CD3+) producing intracellular interferon-gamma (FFN- gamma) among healthy immune donors was 0.43%, significantly above that for non-immune donors (0.01%) and greater than that for subjects with other for ms of coccidioidomycosis, including chronic pulmonary (0.11%), disseminated (0.09%) and concomitant human immunodeficiency virus (HIV) infection (0.07 %) (P<0.002 for all). No increase in intracellular interleukin (IL)-10 prod uction or apoptosis was noted in samples incubated with T27K. Among 14 HIV- infected patients with concomitant coccidioidomycosis, seven of eight patie nts whose peripheral blood CD4 concentration was >200 cells mul(-1) had >0. 06% of CD3+ produce intracellular IFN-gamma, compared to none of six whose peripheral blood CD4+ lymphocyte concentration was less than or equal to 20 0 cells mul(-1) (P=0.005). These data indicate that there is a specific hum an cellular immune response to T27K as a coccidioidal antigen and that this response can be categorized based on the clinical status of the coccidioid ally infected patient.