MODERN TECHNIQUES OF IMMUNOCHEMICAL ANALYSIS: INTEGRATION OF SENSITIVITY AND RAPIDITY

In course of accumulation of knowledge about antigen-antibody interaction as highly affine and highly specific reaction an interest to antibodies as the means for the detection of antigens of various chemical nature was growing. The history of immunoassay started from immune precipitating methods, in which after extended incubations visually detectable insoluble antigen-antibody aggregates were formed. Important is the possibility to carry out the immunoprecipitation with the use of unfractionated antiserums, containing antibodies to a defining compound, and various samples without their pre-processing (except for very turbid mediums). Such procedural simplicity, the initial reason of which was the absence of tools for more sensitive detection of immune complex, provided high viability of this approach, applied till the moment for the assay of many proteins and determination of blood-group specificity [1]. Maximal reduction of the determination duration was not demanded from immune precipitation; obtaining of the results of clinical test in 1–2 days after sampling was perceived as a norm several decades ago. More continuing incubation was not observed as a disadvantage of the procedure, but as a definite guarantee of greater reliability and reproducibility of the results due to achievement of final (equilibrium) stage by the immune-precipitating processes. An important, revolutionary progress within the development of immunoassay was the occurrence of analytical systems, in which one of implemented immune reagents was the complex with a marker, detected in extremely low concentrations. In the beginning of 1950-s such procedure was fulfilled for radio-active isotopic tags by Yalow and Berson [2], who were awarded for this development in 1977 with the Nobel Prize. A bit later the methods started developing with the use as the tags of enzymes, fluorophors, other compounds. New systems of detection were actively described, allowing to detect various compounds in the concentrations up to 10–10 M in several hours. Transfer to non-isotopic tags excluded the need in special equipment and safety measures and thus called even more wide spread of immune-diagnostics. The main area of its implementation was and remains to be medicine, which greatly exceeds in the scopes of commercialization the ecological monitoring, control of quality and safety of food products and agricultural raw materials, other areas, in which immunoassay is also actively used. UDK 57.083.3