Synergistic immunopotentiating effects induced by T-cell and B-cell superantigen in mice

Staphylococcal Enterotoxin-A(SEA), a 27kDa monomeric protein, produced by some strains of Staphylococcus aureus, is a prototype T-cell superantigen which causes proliferation of cytotoxic T-lymphocytes and produces cytokines like TNF-alpha and IFN-gamma. Recently Protein A (PA), a 42 kDa membrane protein of the Staphylococcus aureus Cowan-I strain, has been termed a B-cell super antigen. It has been shown to cause multiple immunological responses. In the present study we examined the effect of these two superantigens used separately as well as combination in a normal mouse system. It has been shown that combination treatment of PA and SEA is more effective than that of each individual one. FACS analyses of cell cycles showed that a finely turned cellular collaboration occurred in various phases of cell growth and proliferative response compared with controls (P<0.01). It has also been shown that the percentage of various cell types bearing different clusters of differentiation markers, e.g., CD8+, CD34+ increases considerably due to the combined effect of PA and SEA. We also observed that co-administration of both the elicits different soluble mediators like cytokines (TNF-alpha, INF-gamma, IL-1beta). No apoptotic phenomenon was observed (from the cell cycle analysis) for the dose of PA and SEA, used for the experiments, suggesting that these doses of PA and SEA should be non-toxic.