EVALUATION OF PARACOCCIDIOIDES-BRASILIENSIS EXOANTIGEN IN THE DETECTION OF DELAYED DERMAL HYPERSENSITIVITY IN EXPERIMENTAL AND HUMAN PARACOCCIDIOIDOMYCOSIS

The exoantigen of Paracoccidioides brasiliensis standardized by Camarg o et al. [1] (AgR) was used to evaluate the in vivo and in vitro cell immune response of experimental animals and of patients with paracocci dioidomycosis (PBM). Fava Netto antigen (AgF) was tested in parallel a s a control antigen. The study was conducted with mice and guinea pigs infected with P. brasiliensis or immunized with its fungal antigens, on patients with PBM and on their respective control groups. The cell immune response was analysed by skin tests, and by the macrophage and leucocyte migration inhibition tests (MMIT and LMIT) in the animals an d in the patients, respectively. The skin test with AgR as paracoccidi oidin was positive in infected or immunized mice and guinea pigs and n egative in control animals. The skin tests with AgR (24 h) showed 96.7 % positivity in patients with PBM and were negative in control individ uals. Histopathological study of the in vivo tests in the different ex perimental models was consistent with a delayed hypersensitivity respo nse (DHR). Immunohistochemical study of the skin tests of PBM patients demonstrated a predominance of T lymphocytes, confirming the nature o f a DHR to the fungal antigens. The in vitro cell immune response show ed variable results for the various experimental models, i.e. signific ant rates of MMIT in immunized mice, a tendency to positivity in infec ted guinea pigs, and the absence of migration inhibition in PBM patien ts. Taken together, the data indicate that the AgR is efficient as par acoccidioidin in the evaluation of DHR in PBM, with an optimum time of reading the test of 24 h.