Britannica
Sources used in this answer
Which immune cells can display class II major histocompatibility complex molecules?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
immune system
Stimulation of immune response by activated helper T cells. Activated by complex interaction with molecules on the surface of a macrophage or some other antigen-presenting cell, a helper T cell proliferates into two general subtypes, TH1 and TH2. These in turn stimulate the complex pathways of the cell-mediated immune response and the humoral immune response, respectively.
Class II major histocompatibility complex (MHC) molecules are specialized proteins primarily restricted to the surfaces of specific immune cells. These cells, which function as antigen-presenting cells, include:
- Macrophages and macrophage-like cells12
- Most B cells2
- Some T cells2
These molecules play a critical role in the immune response by displaying peptide fragments of foreign substances to helper T cells, which recognize the antigen in association with the class II MHC molecule. While class I MHC molecules are found on nearly all nucleated cells in the body, the restricted expression of class II molecules ensures that specific immune cells can effectively coordinate the activation of the adaptive immune system.12