Staphylococcus aureus and Staphylococcus epidermidis strains differ in interleukin 2 inducing activity.

Heat-killed preparations of different Staphylococcus aureus and Staphylococcus epidermidis strains were compared for interleukin 2 (IL-2) inducing activity in cultures of human mononuclear cells (MNC). S. aureus strains exhibited a strong individual variation, but they induced considerably more IL-2 than did S. epidermidis strains. Enterotoxin production, coagulase production, pigment formation and the phage type of the staphylococci showed no strict correlation of any of these properties with the IL-2 inducer activity. The results indicate that the IL-2 inducing activity may be a differential feature of S. aureus and S. epidermidis.