The hapten definition refers to small molecules that elicit immune responses when conjugated to carriers. Understanding the hapten definition helps design vaccines and allergy diagnostics. By binding to proteins, haptens trigger antibody formation, illustrating fundamental antigen recognition and immune system mechanisms in immunological research and therapy development. https://www.betalifesci.com/blogs/news/antibody-vs-antigen-vs-epitope-vs-hapten-vs-immunogen