MHC class II

MHC class II molecules are special proteins found on certain immune cells like macrophages and helper T cells. They act like display boards, showing pieces of proteins (antigens) from pathogens such as bacteria. This display helps other immune cells recognize and respond to infections. When an MHC class II presents an antigen, it alerts helper T cells to activate the immune response, leading to the production of antibodies and other defenses. Essentially, MHC class II molecules are crucial for identifying threats and coordinating the body's immune defense against infections.