Immunobiological Reactions

IMMUNOBIOLOGICAL REACTIONS, are based on the interaction of antigen and antibody present in immune serum (according to Ehrlich's views) or of antigen and specifically altered serum under the influence of immunizing irritation (according to newer views). The most important I. reactions are agglutination, precipitation, bacteriolysis, complement deviation reaction, and a reaction based on the action of opsonins. Agglutination and precipitation occur upon the meeting of antigen and corresponding antibody; for the realization of bacteriolysis, the complement deviation reaction, and others, in addition to antigen and antibody, the participation of complement is also required. The significance of I. reactions is twofold. With their help, one can establish the diagnosis of a certain infectious disease by bringing the serum of the patient into contact with the microbe, the causative agent of the suspected infection (Widal reaction in typhoid fever and paratyphoid, complement deviation reaction in various infections). On the other hand, having serum immune to a certain infection, it is possible to identify the microbe whose nature is unknown. Precipitation also has significance in sanitary-hygienic and judicial-medical practice, allowing the determination of the species to which the examined material belongs.