MHC class II genes refer to a group of genes that are part of the major histocompatibility complex (MHC) in humans and other vertebrates. The MHC class II genes play a crucial role in the immune system by encoding proteins known as major histocompatibility complex class II molecules.
These molecules are found on the surface of certain immune cells, including dendritic cells, macrophages, and B cells. They act as a communication platform, presenting antigens (foreign substances) to specific immune cells called T cells. This antigen presentation is crucial for the activation of the adaptive immune response and the subsequent elimination of pathogens.
MHC class II genes are highly polymorphic, meaning they exist in multiple variant forms within a population. This polymorphism allows for a wide range of pathogen recognition and ensures greater immune protection by enhancing the ability to recognize diverse infectious agents. The diversity in MHC class II genes is a result of evolutionary pressure from pathogen-driven selection.
These genes are vital in determining the compatibility and success of organ transplantation, as they influence the recognition and acceptance of transplanted tissues or organs by the recipient's immune system. MHC class II genes also play a role in autoimmune diseases and genetic susceptibility to certain conditions, as certain variants can contribute to the development or progression of these disorders.
In summary, MHC class II genes are a group of genes within the MHC that encode proteins involved in antigen presentation and immune response regulation, playing a pivotal role in immune surveillance, pathogen recognition, and organ transplantation compatibility.
