Antigénspecifikusság

Antigénspecifikusság refers to the ability of the immune system, particularly its adaptive components like T cells and B cells, to recognize and respond to specific molecular targets called antigens. Antigens are typically foreign substances, such as parts of bacteria, viruses, or allergens, that can trigger an immune response. This specificity is crucial for effective immunity, as it ensures that the immune system mounts a targeted attack against a particular pathogen without unnecessarily harming the body's own tissues.

The mechanism behind antigénspecifikusság lies in the presence of unique receptors on the surface of immune cells. T cells possess T cell receptors (TCRs) and B cells have B cell receptors (BCRs) which are highly diverse and can bind to specific epitopes, the precise molecular shapes on an antigen. This binding initiates a cascade of events leading to the activation and proliferation of antigen-specific lymphocytes. For instance, a T cell receptor might recognize a specific peptide fragment presented by an infected cell, while a B cell receptor can bind to an intact antigen on the surface of a pathogen.

This specificity is established during the development of lymphocytes in primary lymphoid organs. Through a process of genetic recombination, a vast repertoire of TCRs and BCRs is generated, ensuring that the immune system is equipped to recognize almost any potential antigen it may encounter. Without antigénspecifikusság, the immune system would be unable to differentiate between harmful invaders and harmless molecules, leading to uncontrolled inflammation or ineffective responses. This principle is also fundamental to vaccination, which exploits antigénspecifikusság to prime the immune system against future infections.