Antigenic peptide

Antigenic peptides are **short sequences of amino acids derived from larger proteins or antigens that stimulate the adaptive immune response**[1]. These peptides are recognized by T-cell receptors or antibodies, triggering T cells (and sometimes B cells) to expand and mediate immune responses. Antigenic peptides originate from pathogens, tumor cells, or self-proteins (in autoimmunity), and are processed and presented on cell surfaces by major histocompatibility complexes (MHC class I or II)[1][3][5][7][8]. They can be designed synthetically for use in **peptide vaccines**, cancer immunotherapies, and tolerance-inducing therapies for autoimmune diseases[2][4][8][9]. Their specificity and immunogenicity are highly dependent on both their amino acid sequence and the MHC alleles of the host[1][2][3][6][8]. The concept is important in immunology, vaccine design, and disease research, but refers to a class of molecules rather than a unique drug target or receptor. Note: For drug targeting, the relevant molecules are usually the **MHC molecules** (which present antigenic peptides) or the **T-cell receptors** (which recognize them), rather than the peptides themselves[3][6][8].

Other names

Immunogenic peptideEpitope (when referring to the specific region recognized by immune receptors)Antigenic determinantVaccine peptide (in context of immunization)

Immune stimulation via MHC presentation (antigenic peptides are processed by antigen-presenting cells, loaded onto MHC molecules, and stimulate T cells) Induction of antibody response (especially if B-cell epitopes) Immune tolerance induction (for tolerogenic peptides in autoimmune therapy)