Identification and quantification of immune precipitates adsorbed on solid surfaces

Identification of immunoprecipitates in gels is done mainly by comparing their interference reactions with those of other (known) precipitates. In this investigation an alternative approach for identification of precipitates is described, which involves interaction with antigen coated solid surfaces. Immunoprecipitates formed in a gel adsorbed immunospecifically on an antigen‐coated solid surface. A precipitate adsorption (PAS) phenomenon on the surface could be detected after removal of the gel, by means of ellipsometry. The PAS‐technique was used for identification of precipitates in a multiprecipitating system consisting of human serum (HS) and anti‐HS, and was found to be very simple to use and the results easy to interpret. It was also found that the amount of adsorbed precipitate was quantitatively related to the amount of antigen coating on the silicon surfaces. Adsorbed precipitates could subsequently be dissolved by incubation in excess of soluble antigen. This high degree of reversibility of the antigen‐antibody interaction within the precipitate was not found for a single layer of antibodies adsorbed on top of a single layer of antigen.

Key words:

• identification
• antigen antibody precipitate
• ellipsometry