Immunochemistry is a branch of chemistry that involves the study of the molecular mechanisms underlying the function of the immune system, especially the nature of antibodies, antigens and their interactions.
Various methods in immunochemistry have been developed and refined, and been used in scientific study, from virology to molecular evolution.
One of the earliest examples of immunochemistry is the Wasserman test to detect Syphilis. Svante Arrhenius was also one of the pioneers in the field; he published Immunochemistry in 1907 which described the application of the methods of physical chemistry to the study of the theory of toxins and antitoxins.
Immunochemistry is also studied from the aspect of using antibodies to label epitopes of interest in cells (immunocytochemistry) or tissues (immunohistochemistry)