Question

Many bacteria cause disease by secreting proteins called bacterial toxins, which damage or disrupt the function of the host's cells. Most toxins are active at nanomolar concentrations; for example, a single molecule of diphtheria toxin can kill a cell. To have an effect, a toxin must interact with a specific molecule that serves as a receptor on the surface of the target cell. The erythrogenic/pyrogenic toxins A and C of Streptococcus pyogenes, staphylococcal enterotoxins, and staphylococcal toxic shock syndrome toxin are examples of what?

Immunotoxins
Superantigens
Immunophilins
Toxoids
RTX toxins

Answer 1

Examples of the erythrogenic/pyrogenic toxins A and C of Streptococcus pyogenes, as well as staphylococcal enterotoxins and toxic shock syndrome toxin, are superantigens. These toxins cause a massive, unregulated immune response that can lead to severe systemic effects, unlike the more targeted action of A-B toxins such as the diphtheria toxin.

Step-by-step explanation:

The erythrogenic/pyrogenic toxins A and C of Streptococcus pyogenes, staphylococcal enterotoxins, and staphylococcal toxic shock syndrome toxin are examples of superantigens. Superantigens are a class of exotoxins that prompt a significant, unregulated stimulation of immune cells leading them to secrete large amounts of cytokines.

This unregulated secretion can result in serious systemic effects including high fevers, low blood pressure, and potentially life-threatening conditions such as shock and multi-organ failure. Superantigens differ from other exotoxins, such as A-B toxins like diphtheria and botulinum toxins, in their mechanism of action.

While A-B toxins typically have specific cellular targets and interfere with cellular processes such as protein synthesis, superantigens bypass normal immune specificity and activate a large proportion of T cells without the need for antigen processing, leading to a cytokine storm and related symptoms.