An antigen is a molecular structure or substance that is recognized by the immune system as foreign or non-self. It triggers an immune response, leading to the production of antibodies or activation of immune cells. Antigens can be proteins, peptides, carbohydrates, or other biomolecules found on the surface of pathogens, cells, or foreign particles.
T cells are another type of white blood cell involved in the immune response. There are two main types: helper T cells and cytotoxic T cells. Helper T cells assist B cells and other immune cells, while cytotoxic T cells directly attack and destroy infected or abnormal cells
MHC molecules are proteins found on the surface of cells that present antigens to T cells. They play a crucial role in the immune system’s ability to distinguish self from non-self. MHC molecules help activate T cells by presenting antigens derived from pathogens or abnormal cells.
Adaptive immunity refers to the body’s ability to recognize and remember specific pathogens, providing a targeted and more efficient response upon subsequent exposure. B and T cells are key players in adaptive immunity, contributing to immunological memory.
Innate immunity is the body’s immediate, non-specific defense mechanism against pathogens. It includes physical barriers, such as the skin, and cellular components like phagocytes that engulf and destroy foreign particles. Innate immunity provides rapid but generalized protection.
Autoimmunity occurs when the immune system mistakenly targets and attacks the body’s own cells and tissues. This can result in autoimmune diseases, where the immune response becomes detrimental rather than protective.