Superantigen shock in mice with an inapparent viral infection.

Subclinical lymphocytic choriomeningitis virus infection primes mice expressing a V beta 8.1D beta 2J beta 2.3C beta 2 T cell receptor as a transgene for induction of fatal hematogenous shock after administration of a dose of staphylococcal enterotoxin B (SEB) that is tolerated by uninfected controls. The lethal effect is greatly diminished by prior depletion of the virus-primed CD4+ T cells. Evidence of transient tumor necrosis factor (TNF) secretion is detected in serum within 1 h of SEB administration, and massive amounts of interferon-gamma (IFN-gamma) and interleukin-6 (IL-6) are present within 4-6 h. Mice are partly protected by treatment with dimeric soluble TNF receptor-Fc fusion protein or the nitric oxide synthase inhibitor, aminoguanidine, neither of which blocks SEB-induced IFN-gamma or IL-6 production. Administration of a monoclonal antibody to IFN-gamma concomitant with SEB effectively neutralizes this cytokine but has no effect on survival.