Final answer:
A superantigen is a class of toxins that cause an uncontrolled activation of T cells leading to a dangerous systemic inflammatory response, often resulting in life-threatening conditions.
Step-by-step explanation:
A superantigen is a class of potent toxins produced by some bacterial and viral pathogens. They lead to a highly immunogenic response by causing an unregulated, nonspecific activation of T cells, which results in a massive cytokine release known as a cytokine storm. This can cause severe immune reactions, including potentially life-threatening conditions such as toxic shock syndrome, fevers, low blood pressure, multi-organ failure, and shock.
The mechanism of action for superantigens involves the binding to Major Histocompatibility Complex (MHC) II molecules on antigen-presenting cells and the variable region of the T cell receptor (TCR) ß chain, without the need for specific foreign epitope recognition. This inappropriate activation can have dire consequences due to the overwhelming inflammatory response it induces.