The aim of this study was to analyze phenotypes of T cells activated by mitogen (PWM) and antigen (PPD) in the presence of FcR+ or FcR- monocytes. It was found that CD4+ and CD8+ lymphocytes are preferentially acitvated in the presence of different <monocyte> subpopulations. Expression of HLA-DR and CD25 on CD4+ lymphocytes was greater in cultures activated in the presence of FcR-. CD8+ lymphocytes were more efficiently activated (exprression of HLA-DR) when FcR+ monocytes were added to culture. In the presence of FcR+ monocytes an increased expression of CD45RA antigen on CD4+ cells was also observed. These data support our previous functional studies which showed that "suppressor" T cells of CD8+ phenotype are activated in the presence of FcR+ monocytes.