Antigens of diagnostic value in three isolates of Paracoccidioides brasiliensis

Yeast cellular extracts of three isolates of Paracoccidioides brasiliensis were tested by the Western-blot technique against 53 sera from patients with paracoccidioidomycosis (PCM). Numerous antigens were recognized by the sera but only five were specific for (58, 57, 48, 44 and 23 kDa). These specific antigens had the same relative molecular mass in the different isolates but their reactivity with sera from PCM patients was variable. An antigen in isolate 688, which was specific for PCM, had an apparent molecular mass of 48 kDa. Although a 48 kDa antigen was also present in isolates B339 and 1789.88 it was not specific for PCM, demonstrating antigenic variability among isolates. The 44 kDa antigen in isolate B339 and the 44 and 48 kDa antigens in isolate 688 reacted with a rabbit antiserum raised against a 43 kDa glycoprotein, a specific antigen used in the diagnosis of PCM. There was no correlation between the specific antigen(s) detected and the clinical form of the disease.