Quantitative Radial Immunodiffusion

Abstract

Mancini et al. (1965) developed a very simple method to quantitate antigens using gel diffusion. The principle is this: The antigen is placed in a well punched into an agar layer. The agar was mixed while melted at 45{\textdegree}-50{\textdegree}C with the corresponding antibody. The antigen will diffuse into the agar and will form a radial precipitate around the well with the antibody already in the agar. The more antigen we put into the well, the further it will diffuse into the agar and the greater will be the diameter of the circular precipitin zone. Keeping the antibody concentration in the gel and the volume of antigen solution pipetted into the well constant, the amount of antigen in the solution can be determined by measuring the diamter of the precipitation ring, This Exercise describes the procedure for quantitative determination of complement C3 components in sera based on the publications of Fahey and McKelvey (1965) as well as Shanbrom et al. (1967).