Antigens are molecules or molecular structures that trigger the immune system's response. They are typically foreign substances, like proteins, carbohydrates, or chemicals, found on the surface of pathogens such as bacteria, viruses, and fungi. Antigens can also be present on non-pathogenic substances like pollen, allergens, or transplanted tissues. When the immune system encounters antigens, specialized cells, such as B cells and T cells, recognize and respond to them. B cells produce antibodies that can bind to and neutralize antigens, while T cells play roles in immune coordination and direct attacks on cells displaying antigens. Antigen recognition is fundamental to the immune system's ability to distinguish between self and non-self and mount targeted defenses.
Notes Credit : Bhumika Puri (B.Tech Biotechnology) 4th Year
