Induction of Immunoglobulin Secretion in Cultured Human Lymphocytes by 4 Staphylococcus Aureus Strains and Their Extracts

Abstract

Human blood lymphocytes were stimulated in vitro by four Staphylococcus aureus strains. Activation of immunoglobulin‐secreting cells was determined by a reverse plaque forming cell (PFC) assay, and proliferation by quantitation of thymidine incorporation. Whole killed 5. aureus were slightly more efficient than water‐soluble preparations in the form of sonicated extracts and culture supernatants. Two S. aureus strains rich in protein A (Cowan I and E 2371) and one S. aureus strain deficient in protein A (E 1369) were potent B‐lymphocyte stimulators inducing maximal activity on day 6 of culture. Another S. aureus strain deficient in protein A (Wood 46) did not possess human lymphocyte stimulating capacity.