CYCLOACTIVE, ANEUGENIC AND CLASTOGENIC EFFECTS OF PARACOCCIDIOIDES-BRASILIENSIS EXOANTIGEN IN HUMAN LYMPHOCYTE-CULTURES

The in vitro effect of Paracoccidioides brasiliensis exoantigen on the human lymphocytes cell cycle and chromosomes was studied. Human perip heral blood lymphocyte cultures from ten healthy, white, non-smoking, non-related adult males (mean age 31.3 +/- 8.2 years) were studied. Bl ood cultures were treated with three exoantigen concentrations (0.25, 2.50 and 10.00 mu g ml(-1)). At least 1000 metaphases were analysed at each concentration, for evaluation of numerical and structural chromo some aberrations (CA) and 30 000 for mitotic index (MI). Among the tre ated cultures, statistically significant differences in the frequencie s of MI and CA were not observed. Nevertheless, when compared with con trol cultures, they all showed a significantly lower frequency of MI a nd higher frequency of CA. It is suggested that the detected alteratio ns were caused by the exoantigen, its fractions or its metabolites.