THE SUPERANTIGEN STAPHYLOCOCCUS ENTEROTOXIN-B INDUCES A STRONG AND ACCELERATED SECONDARY T-CELL RESPONSE RATHER THAN ANERGY

The primary and secondary immune response of V beta 8(+) T cells to th e bacterial superantigen Staphylococcus enterotoxin B was compared in BALB/c mice. Secondary responder T cells were found to up-regulate the expression of the adhesion molecule LFA-1 faster, and to enter the ce ll cycle earlier than primary responder T cells. Both, primary and sec ondary responder T cells up-regulate the expression of CD2 and CD25 an d turn into blast cells with superimposable time kinetics. Secondary r esponder T cells terminate DNA synthesis, blast formation and the up-r egulation of CD25 and CD2 expression earlier than primary responder T cells and become more rapidly deleted. Two days after superantigen cha llenge, when primary responder T cells reach peak activity in terms of DNA synthesis and blast formation, secondary responder T cells have r eturned to the size of microblasts and ceased to replicate their DNA. Whereas our results are consistent with the observations leading to th e concept of superantigen-induced T-cell anergy, they demonstrate, by revealing the accelerated vigorous secondary T-cell response to the su perantigen, that this concept requires reconsideration.