[Inducibility of tumor necrosis factor alpha to peritoneal macrophages and lethality to mice of clinical isolates of Staphylococcus aureus].

When murine resident peritoneal macrophages were treated in vitro with overnight culture supernatants of clinical isolates of S. aureus (21 strains)(S. aureus-CS) for 4 hrs at 37 degrees C in a 5% CO2-air humidified incubator, TNF alpha induction from the treated cells was observed in 20/21 strains. The amount of TNF alpha dispersed from 88.4 to 1726.5 pg/ml but more or less amount of TNF alpha did not relate with the presence of TSST-1 and enterotoxin production of S. aureus. Recombinant protein A induced TNF alpha production by macrophages dose-dependently, but the relationship between the amount of protein A in each S. aureus CS and that of TNF alpha induced from macrophages treated with them were not satisfactory (r = 0.69). When each strain was injected (X10(9) bacterial cells) interperitonealy to mice, 13/21 strains indicated lethal activity. Relation between TNF alpha inducibility in vitro and lethal activity, however, was not found (r = 0.4). These results suggest that TNF alpha inducibility is the basic biological activity of S. aureus, although there is a difference in the induction amount and in component(s) to induce TNF alpha on each strain, and then because the strain is strong in TNF alpha inducibility, it does not necessarily follow that pathogenicity is strong.