Immunogenicity

Subject: Science and technology

Context: The term has been news for vaccines for Covid-19 being approved and these being tested for immunogenicity as well.

Concept:

Immunogenicity is the ability of a foreign substance, such as an antigen, to provoke an immune response in the body of a human or other animal.
It results from biomaterial being detected by the body’s immune system as a foreign object.
A biochemical cascade then occurs, whereby T-helper cells (these are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses) migrate towards the biomaterial. This immune response can result in rejection of the biomaterial, and non-union between the biomaterial and the wound site.
It is of two types:

1. Wanted immunogenicity: It is used in case of vaccines, where the injection of an antigen (the vaccine) provokes an immune response against the pathogen (virus, bacteria), protecting the organism from future exposure.
2. Unwanted immunogenicity: It 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.