Superantigen

Definition

Superantigen is a class of antigens that result in excessive activation of the immune system, specifically T-cells. They bypass normal antigen processing, leading to massive cytokine release and potentially severe immune responses.

5 Must Know Facts For Your Next Test

1. Superantigens can trigger up to 20% of the body's T-cells simultaneously, compared to the typical 0.01-0.1%.
2. Common superantigen-producing bacteria include Staphylococcus aureus and Streptococcus pyogenes.
3. Diseases associated with superantigens include Toxic Shock Syndrome (TSS) and certain types of food poisoning.
4. Superantigens bind directly to MHC class II molecules on antigen-presenting cells and T-cell receptors, bypassing regular antigen presentation pathways.
5. The massive cytokine release caused by superantigens can lead to symptoms such as fever, rash, low blood pressure, and multi-organ failure.

Review Questions

Related terms

Toxic Shock Syndrome (TSS): A severe illness caused by toxins produced by certain strains of bacteria, often linked with superantigens.

Cytokine Storm:

An excessive and uncontrolled release of pro-inflammatory cytokines that can be triggered by infections or other conditions.

Antigen-Presenting Cells (APCs):

Immune cells that process and present antigens to T-cells, crucial for initiating specific immune responses.