Abstract
Humoral response of paracoccidioidomycosis sera in hamsters with different Venezuelan isolates. Paracoccidioidomycosis (PCM) is a progressive systemic mycosis caused by the fungus Paraccocidioides brasiliensis (Pb), endemic to Venezuela and Latin America. In this study, eight different Venezuelan isolates obtained from patients with PCM, were inoculated intraperitoneally in Syrian hamsters (Cricetus auratus) and studied by immune-serum. Each strain was collected by gently scraping the surface of the culture medium (Sabouraud Dextrose Agar) and suspended in 3 ml of 0.15 M phosphate-buffered saline. The antigen obtained was called Paraccocidioides brasiliensis Crude Antigen (CAP). Immunoblotting results showed that the immune-sera from hamsters recognized at least 3 bands: one over 200 kDa, and two of 80 and 15-20 kDa. This study suggests that IgG anti-CAP can reveal a significant variability in the eight Venezuelan isolates. Sera from 88 infected hamsters were evaluated by ELISA with eight different CAPs and Western blot with CAP 37383. ELISA results showed that, the antigen of the virulent isolate 37383 had the highest percentage (38%) of positivity, while the nonvirulent isolate 1458 had the lowest one (13.6%). Furthermore, scanning densitometry revealed that the isolate 37383 had less bands than the non-virulent isolates. These results suggest that the ELISA test with CAP 37383 can detect circulating antibodies, and that this virulent isolate may be useful for the diagnosis of PCM, and to monitor disease responses to treatments.
Highlights
Paracoccidioidiomycosis (PCM) has been recognized as a public health problem in Latin America, being the most prevalent human deep mycosis in the region. It is a progressive systemic granulomatous disease caused by the fungus Paraccocidioides brasiliensis (Pb) (Brummer et al 1993)
We evaluated the cross reactivity with an isolated of H. capsulatum (10023) as antigen and obtained 22% of the cross-reaction with sera from hamsters infected with different isolated of P. brasiliensis by the Enzyme-linked Immunosorbent Assay (ELISA) test
This study showed that CAPs preparations from eight different isolates were useful in ELISA test to evaluate the humural responses in hamsters with PCM infection
Summary
Paracoccidioidiomycosis (PCM) has been recognized as a public health problem in Latin America, being the most prevalent human deep mycosis in the region. It is a progressive systemic granulomatous disease caused by the fungus Paraccocidioides brasiliensis (Pb) (Brummer et al 1993). Serology has become a vital instrument for the diagnosis of PCM infection and the identification of antibody response has proven to be very useful. Several authors have reported different recognition patterns by the antibodies in immunoblotting assays using low virulent and virulent isolates (Camargo et al 1991, Casotto et al 1991, Blotta & Camargo 1993, Vaz et al 1992). The concentration was adjusted to 1.4 x 106 CFU of fungal elements per ml of suspension
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