Antigener

Antigener is the plural form used in some languages for antigens. In immunology, antigener are substances capable of eliciting an adaptive immune response and, at the same time, being recognized specifically by antibodies or by receptors on T cells. They are typically foreign macromolecules or parts of macromolecules.

An antigen can be a protein, polysaccharide, lipid, or nucleic acid. The immune system often recognizes specific regions of an antigener called antigenic determinants or epitopes. Epitopes can be linear (a sequence of amino acids or nucleotides) or conformational (dependent on the three‑dimensional folding of the molecule). B cells commonly recognize surface-exposed epitopes on intact antigener, while T cells recognize peptide fragments presented by major histocompatibility complex (MHC) molecules.

Haptens are small molecules that are not immunogenic by themselves but can become antigener when attached to a larger carrier protein, enabling the immune system to respond to the hapten.

Antigenicity and immunogenicity are related but distinct concepts. Antigenicity is the ability of an antigener to bind specifically to antibodies or T cell receptors. Immunogenicity is the capacity to provoke a measurable immune response. Many factors influence immunogenicity, including molecular size and complexity, foreignness to the host, route of exposure, and the presence of adjuvants.

Clinical relevance includes vaccines, which present antigener to stimulate protective immunity, and diagnostic tests that detect antigener to identify infections or immune conditions. Understanding antigener and their epitopes aids in vaccine design, allergy research, and immunotherapy.