No discrete molecular drug target – immunogen

No discrete molecular drug target – immunogen is a classification used in pharmacological databases to describe therapeutic agents, primarily vaccines and certain immunotherapies, that do not function by binding to a specific endogenous protein or receptor (DrugBank, 2024). Instead, these agents act as immunogens—substances capable of inducing a specific immune response (Janeway et al., 2001). When introduced into the body, these antigens are captured by antigen-presenting cells (APCs), processed, and displayed on MHC molecules to activate T-cells and B-cells (CDC, 2023). This orchestration leads to the production of antibodies and the establishment of immunological memory, providing protection against future encounters with a pathogen. Because the target is the entire immune system's capacity for recognition rather than a single molecular entity, the term is used to denote the absence of a traditional drug-receptor interaction. This category encompasses a wide range of biologicals, including toxoids, recombinant proteins, and attenuated viruses used in the prevention of infectious diseases and the treatment of certain malignancies.

Other names

ImmunogenAntigenVaccine antigenImmunogenic agent

The mechanism involves the presentation of the immunogen to the host immune system, triggering the activation of innate and adaptive immune pathways, resulting in the generation of antigen-specific antibodies and memory lymphocytes (WHO, 2023).