The effects of Staphylococcus aureus proteolytic enzymes on surface receptors of human lymphocytes were studied. Proteolytic activity was detected in 35 supernatants of 45 S. aureus strains. aur and sspA genes were detected by PCR in 43 strains. Incubation of lymphocytes showed reduced expression of receptors labeled with anti-CD8, anti-CD4, and anti-CD16 antibodies and no changes in the receptors labeled with anti-CD3 and anti-CD19 antibodies in comparison with the control (incubation with sterile nutrient medium). S. aureus enzymes can trigger in vivo one of the mechanisms of early death of lymphocyte subpopulations expressing these receptors.