Immunigenkänning

Immunigenkänning is a fundamental process in the adaptive immune system of vertebrates. It refers to the ability of immune cells to distinguish between foreign substances, known as antigens, and the body's own tissues. This recognition is crucial for mounting an effective immune response against pathogens like bacteria, viruses, and parasites, while simultaneously preventing autoimmune reactions where the immune system attacks healthy cells.

The primary cells involved in immunigenkänning are lymphocytes, specifically B cells and T cells. B cells recognize intact antigens through surface receptors called B cell receptors (BCRs). Upon activation, B cells differentiate into plasma cells that produce antibodies, which can neutralize or mark pathogens for destruction. T cells, on the other hand, recognize processed antigen fragments presented by other cells on major histocompatibility complex (MHC) molecules. There are different types of T cells, including helper T cells that coordinate immune responses and cytotoxic T cells that directly kill infected or cancerous cells.

The specificity of immunigenkänning is remarkable. Each lymphocyte expresses a unique BCR or T cell receptor (TCR) capable of binding to a specific antigen. This diversity is generated through a process of gene rearrangement during lymphocyte development, ensuring that the immune system can recognize a vast array of potential threats. Failure in immunigenkänning can lead to immunodeficiency disorders, where the body is unable to fight off infections, or autoimmune diseases, where the immune system mistakenly targets self-antigens.