Staphylococcus aureus and Streptococcus pyogenes colonize mucosal surfaces of the human body to cause disease. A group of virulence factors known as superantigens are produced by both of these organisms that allows them to cause serious diseases from the vaginal (staphylococci) or oral mucosa (streptococci) of the body. Superantigens interact with T cells and APCs to cause massive cytokine rele...

Amongst the many ploys used by microbial pathogens to interfere with host immune responses is the production of proteins with the properties of superantigens. These properties enable superantigens to interact with conserved variable region framework subdomains of the antigen receptors of lymphocytes rather than the complementarity determining region involved in the binding of conventional antig...

We investigated whether mouse mammary tumor virus (MMTV) favors preactivated or naive B cells as targets for efficient infection. We have demonstrated previously that MMTV activates B cells upon infection. Here, we show that polyclonal activation of B cells leads instead to lower infection levels and attenuated superantigen-specific T-cell responses in vivo. This indicates that naive small rest...