Antigenic peptide ()

Molecular Classification

Other (antigenic peptides are not receptors, enzymes, transporters, or transcription factors; they are short peptides derived from protein antigens), Peptide (short amino acid sequence), Epitope (functional domain)

Other Names

Immunogenic peptide, Epitope (when referring to the specific region recognized by immune receptors), Antigenic determinant, Vaccine peptide (in context of immunization)

Disease Roles

Infection (derived from infectious agents and recognized by the immune system)Autoimmune diseases (misrecognition of self-peptides as antigens)Cancer (tumor-associated antigens used for immunotherapy)

Antigenic peptide Overview

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].

Mechanism of Action

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)

Biological Functions

Immune response (stimulate T-cell or antibody-mediated response)

Antigen presentation (presented by major histocompatibility complex molecules)

Vaccine development (serve as immunogens in peptide vaccines)

Autoimmune response (can drive autoimmunity if derived from self-protein)

Tumor immune recognition (identification of tumor-associated antigenic peptides in cancer immunotherapy)

Disease Associations

Infection (derived from infectious agents and recognized by the immune system)

Autoimmune diseases (misrecognition of self-peptides as antigens)

Cancer (tumor-associated antigens used for immunotherapy)

Other (not directly associated with specific cardiovascular, neurodegenerative roles but relevant where immune response is pathogenic or therapeutic)

Safety Considerations

Limited specificity (wrong peptide may not induce desired immune response)
Potential for autoimmunity (if self-peptides are presented)
Immune escape (mutations in pathogens or tumor cells may render antigenic peptides non-recognizable)
Allergic reactions (rarely, unexpected immune activation)

Interacting Drugs

Peptide vaccines (synthetic or recombinant antigenic peptides used for immunization)

Tolerogenic peptides (therapies designed to reduce autoimmune responses)

Adjuvants (used in vaccine formulations to enhance the immune response to antigenic peptides)

Associated Biomarkers

Biomarker
Detection of antigenic peptides in patient samples (used for infection or cancer diagnosis)
ELISPOT or tetramer assays tracking T cell responses specific for a peptide antigen (immunomonitoring)