Major histocompatibility complex

Definition

The Major Histocompatibility Complex (MHC) is a set of cell surface proteins essential for the acquired immune system to recognize foreign molecules in vertebrates. These proteins display antigen fragments to T cells, triggering an immune response.

5 Must Know Facts For Your Next Test

1. There are two main classes of MHC molecules: Class I and Class II.
2. MHC Class I molecules present antigens from intracellular pathogens to CD8+ T cells.
3. MHC Class II molecules present antigens derived from extracellular pathogens to CD4+ T cells.
4. Each individual has a unique set of MHC genes, making organ transplantation challenging due to potential immune rejection.
5. Antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells play a crucial role in presenting antigens via MHC molecules.

Review Questions

• What are the differences between MHC Class I and Class II molecules?
• How do MHC molecules contribute to the body's ability to recognize and respond to pathogens?
• Why is the uniqueness of MHC genes significant in organ transplantation?

Related terms

CD8+ T Cells: A type of lymphocyte that interacts with MHC Class I molecules and is responsible for killing infected or cancerous cells.

CD4+ T Cells: A type of lymphocyte that interacts with MHC Class II molecules and aids other immune cells by releasing cytokines.

Antigen-Presenting Cells (APCs):

Cells like dendritic cells, macrophages, and B cells that present antigens on their surface using MHC molecules.