Question

Superantigens: Which of the following statements is true about superantigens?

1) They do not cause pathology.
2) They are not mitogenic for T-cells.
3) They bind to MHC class III.
4) They bind to all members of a given V-region T cell receptor family.
5) They have to be processed before recognition by the T-cell.

Answer 1

The correct statement about superantigens is that they bind to all members of a given V-region T cell receptor family, triggering a nonspecific immune activation and a potentially dangerous cytokine storm.

Step-by-step explanation:

The true statement about superantigens among the given options is that they bind to all members of a given V-region T cell receptor family. This occurs because superantigens are capable of simultaneously binding to MHC class II molecules on Antigen-Presenting Cells (APCs) and the variable region of the TCR β chain on T cells. This binding is not dependent on the antigen being presented within the MHC's peptide-binding cleft. Therefore, unlike regular antigens that need to be processed for recognition by T cells, superantigens can directly cross-link the TCR and MHC class II. This nonspecific activation leads to a massive release of cytokines, also known as a cytokine storm, which can cause severe immune responses including shock and multi-organ failure.