The exotoxin implicated in this patient's disease is unusual in that it is a superantigen. This means which of the following?
Both the staphylococcal toxic shock syndrome toxin-1 (TSST-1) and the streptococcal superantigen (SSA) are unusual in that they tend to trigger a massive release of cytokines in response to relatively small amounts of toxin. The reason is that, unlike normal antigens that bind inside the normal peptide grooves of the MHC class II molecule on the antigen presenting cell and the T cell receptor (TCR) molecule of the T lymphocyte, these antigens recognize sites outside the grooves on these two molecules. The result is that they can, in effect, "turn on" almost every T cell they find, thereby producing the massive release of cytokines. IgA, IgE, MHC class I molecules, and IgG are not involved in these processes. Ref: Levinson W. (2012). Chapter 58. Cellular Basis of the Immune Response. In W. Levinson (Ed), Review of Medical Microbiology & Immunology, 12e.
It can bind to the inside surfaces of the normal peptide grooves of both lgA and the TCR molecule
It can bind to the inside surfaces of the normal peptide grooves of both lgE and the TCR molecule
It can bind to the inside surfaces of the normal peptide grooves of both the MHC class l molecule and the TCR molecule
It can bind to the outside surfaces of the normal peptide grooves of both the MHC class ll molecule and the TCR molecule