Ouchterlony
Introduction
Immunoprecipitaton is an immunological phenomenon that results from the reaction of a soluble antibody and soluble antigen. Together, this complex may or may not form an insoluble immunoncomplex known as a precipitate1. A way to observe this reaction is through the method of Ouchterlony. The Ouchterlony method is when antigens and antibodies are placed into adjacent wells within an agar gel. Being a double diffusion reaction, both the antigens and antibodies are able to diffuse through the gel. When the reactants diffuse towards each other, and an optimum zone of equivalence is reached whereby the ratio of antigen: antibody is equal, a precipitin line will become visible.
The precipitin lines formed could be of 3 results-…show more content… This could be due the antigen concentration. Being a relatively low concentration having been diluted, there would have been an excess of IgG antibody present resulting in the Prozone phase of the precipitin curve. Antigen-antibody complexes do occur in this phase however there is insufficient antigen to form a bigger immune complex and cross linking and therefore there are free antibodies and so no precipitin line is formed3. Well 8 did show a slight precipitation with the rabbit anti-human serum but due to the disproportion of the antigen to antibody, the precipitin line was only faint. This proved that the two antibodies had different zones of equivalence.
Overall, the Ouchterlony procedure was successful in providing both qualitative and quantitative results. It demonstrated antigen: antibody interactions through the precipitation lines that were formed and helped better understand the mechanisms behind it.
Application of test
Ouchterlony was clinically used to identify the presence of some autoimmune antibodies within patients. Such antibodies included those against the Smith (Sm) antigen and ribonucleic protein (RNP) 1. These antibodies were originally found to reside it the sera of patients with Systemic Lupus Erythematosus4. Ouchterlony is a low-cost, simple procedure to undertake. It is a method that is rarely used in the present time due to its lack of instantaneous results, mechanical errors, bacterial contamination and difficulty of