What is "immunogenicity"

n. (context immunology English) The ability of a particular substance to provoke an immune response.

Immunogenicity is the ability of a particular substance, such as an antigen or epitope, to provoke an immune response in the body of a human or animal. In other words, immunogenicity is the ability to induce a humoral and/or cell-mediated immune responses.
Differentiation has to be made between wanted and unwanted immunogenicity.

• Wanted immunogenicity is typically related with vaccines, where the injection of an antigen (the vaccine) provokes an immune response against the pathogen (virus, bacteria...) aiming at protecting the organism. Vaccine development is a complex multistep process, immunogenicity being at the center of the vaccine efficiency.
• Unwanted immunogenicity is an immune response by an organism against a therapeutic antigen (ex. recombinant protein, or monoclonal antibody). This reaction leads to production of anti-drug-antibodies (ADAs) inactivating the therapeutic effects of the treatment and, in rare cases, inducing adverse effects. The prediction of the immunogenic potential of novel protein therapeutics is thus a challenge in biotherapy.