Paracoccidioides restrepiensis B339 (PS3) and P. lutzii LDR2 yeast cells and soluble components display in vitro hemolytic and hemagglutinating activities on human erythrocytes

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by thermally dimorphic fungi of the Paracoccidioides species complex. Several pathogenic fungi produce hemagglutinins and hemolysins, which are virulence factors involved in adhesion of pathogens to host tissues or cells and in destruction of erythrocytes. The present research investigated hemolytic and hemagglutinating activities of yeast cells and soluble components from P. restrepiensis (PS3; formerly P. brasiliensis B339) and P. lutzii (LDR2). Different concentrations of live and heat‐killed yeast cells and soluble components from a cell free antigen preparation (native or heated, 56°C or 100°C, 30 min) were mixed with 1% human erythrocyte suspensions. Yeast cells from both species caused hemolysis, P. lutzii LDR2 being more strongly hemolytic than P. restrepiensis B339, whereas the opposite phenomena occurred with soluble components in most conditions. Live or heat‐killed yeast cells of both fungi agglutinated erythrocytes, but only heated soluble components from P. restrepiensis B339 showed hemagglutinating activity. In conclusion, yeast cells of P. restrepiensis B339 and P. lutzii LDR2 produce hemolysins and hemagglutinins, which are most likely predominantly restricted to yeast cells in P. lutzii LDR2 and predominantly released in soluble form by P. restrepiensis B339, requiring further study.