Immunity and retroviral superantigens in humans

Several studies have suggested that some viruses use superantigens to modulate immune responses in humans. However, the identification and characterization of putative viral superantigens has proven to be very difficult. Two recent papers confirm the presence of an endogenous retroviral superantigen in humans, and show that its expression can be induced by secondary viral infections. The up-regulation of expression of endogenous retroviral superantigens has substantial implications for understanding the pathology of virus infections and human disease.