Superantigens

Definition

Superantigens are a class of antigens that result in excessive activation of the immune system by non-specifically binding to T-cell receptors and major histocompatibility complex molecules. This leads to a massive release of cytokines, causing severe inflammatory responses.

5 Must Know Facts For Your Next Test

1. Superantigens can bypass the normal antigen processing pathway and directly link T-cells with MHC molecules.
2. They can activate up to 20% of the body's T-cells at once, compared to less than 0.01% by typical antigens.
3. The excessive cytokine release triggered by superantigens is known as a cytokine storm, which can lead to toxic shock syndrome.
4. Common examples of bacteria producing superantigens include Staphylococcus aureus and Streptococcus pyogenes.
5. Superantigen-mediated diseases are often characterized by high fever, rash, hypotension, and multi-organ failure.

Review Questions

Related terms

Cytokine Storm:

A severe immune reaction where the body releases too many cytokines into the blood too quickly.

T-Cell Receptor (TCR): A molecule found on the surface of T-cells that helps recognize foreign antigens presented by MHC molecules.

Major Histocompatibility Complex (MHC):

Proteins on cell surfaces that help display antigens for recognition by T-cells.