PARACOCCIDIOIDES-BRASILIENSIS ANTIGEN BATCHES FROM THE SAME ISOLATE SHOW IMMUNOLOGICAL AND BIOCHEMICAL DIFFERENCES

We investigated the occurrence of antigenic and biochemical variabilit y among Paracoccidioides brasiliensis antigen batches prepared accordi ng to the same protocol. Initially (experiment #1), we analyzed two an tigen lots of two human isolates (Bt1 & Bt2), cultured in two media (P YG: bactopeptone, yeast extract, glucose; MMM: McVeigh & Morton medium ) in SDS-PAGE and in two immunological tests (imunodiffusion-ID and fo otpad swelling test-FPT). Afterwards (experiment #2), we compared the antigenic profile of three antigen batches from three human isolates ( Bt1, Bt2 & Bt3) by two-dimensional immunoelectrophoresis (2D-IEP) agai nst a reference system for Il brasiliensis antigens. In experiment #1, there were important intra- and inter-strain antigenic differences be tween batches of the fungal isolates cultured on both media. The block titration of the antigen batches for the immunological tests revealed correlation between protein concentration and biological activity in ID and no correlation in FPT. In experiment #2, the reference system f or P. brasiliensis showed 26 antigen peaks. There were important diffe rences between batches prepared from the same isolate and between batc hes from different isolates. Our data suggested the occurrence of inst ability in the synthesis of antigenic components by a same P. brasilie nsis isolate, under controlled incubation conditions.