PREFERENTIAL INDUCTION OF SEPTIC ARTHRITIS AND MORTALITY BY SUPERANTIGEN-PRODUCING STAPHYLOCOCCI

Staphylococcal enterotoxins A through D (SEA through SED) and toxic sh ock syndrome toxin-1 display superantigen properties, i.e., they stimu late a great fraction of T cells expressing certain T-cell receptor V beta sequences. Using a newly established rat model of septic Staphylo coccus aureus arthritis, we have recently shown that an S. aureus stra in producing SEA showed marked arthritogenic properties. In the presen t study we decided to employ another five S. aureus strains, each one producing a distinct exotoxin. Almost all rats injected with superanti gen-producing strains developed arthritis. In contrast, only 20% of ra ts injected with an S. aureus strain lacking superantigen production d isplayed mild and transient arthritis. Mortality was preferentially in duced among the rats inoculated with the S. aureus strains producing S EE and SED. This study emphasizes that superantigen production is an i mportant virulence factor in the development of septic S. aureus arthr itis. Differences concerning mortality between staphylococcal strains producing different exotoxins may be dependent on the degree of activa tion of the Immune system.