Immunochemistry is a branch of chemistry that studies the immune system. This includes the body’s cellular and chemical responses to bacterial, fungal, and viral organisms. In the early 1900s, scientists Karl Landsteiner and Svante Arrhenius developed chemical methods of studying antibodies and their antitoxin response to toxins. These studies eventually led to the tests used to detect specific diseases and methods of treating different maladies.
Throughout human history, it has been understood that when an illness subsides, the individual who was ill is less likely to have a recurrence. In 1798, the English physician, Edward Jenner, tested a means of creating smallpox immunity by injecting another person with the contents of a cowpox lesion. The result was immunization against smallpox. Later scientists would discover the actions and components of the immune system.
During the early phases of immunochemistry, researchers formulated methods of observing immune responses outside of the body. These pioneers concluded that chemical reactions occurred but were unsure what exactly triggered a reaction or how to reproduce this reaction. Laboratory research revealed haptens, which are parts of antigens. Researchers eventually discovered that an immune response reaction occurred when antibodies contacted haptens that were attached to specific proteins. Using the combined substance, further testing indicated that an antigen reaction generally included the formation of a precipitate.
Continued evaluation of antibodies and reactants revealed that these immune system components distinguished between molecular structures with even the slightest difference. Certain substances produced a greater reaction than others. As an example, compounds containing a carboxylic group elicited a smaller response than substances containing a sulfuonic group. Advancements in immunochemistry eventually allowed researchers to study antibody binding and reacting properties by using luminescent molecules. Later research techniques usually involved electrophoresis.
At the beginning of the 20th century, scientists also developed the Wasserman test for syphilis. The test was commonly performed by combining a sample of blood or cerebrospinal fluid with a lipid from sheep. The antibodies combined with the lipid exhibited varying degrees of reaction, depending on the severity of the condition. This type of test was also effective for detecting malaria and tuberculosis. The tests were not fool proof, and false positives or negatives sometimes occurred. Currently laboratory technicians use more sophisticated methods of testing.
Virology, or the study of viruses, is also a branch of immunochemistry that classifies viruses, analyzes how infections are acquired, and develops methods of treatment. Molecular evolution usually involves the study microbiology at the level of deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and proteins. This includes immunochemistry when the study concerns disease processes and infection.