Determination of the position of electroimmune precipitates of antigen--antibody systems on their respective quantitative precipitation curves.

Using corresponding monospecific antisera from the rabbit, the precipitation curves for albumin, alpha-1-antitrypsin, haptoglobin 1-1 and fibrinogen were produced. In parallel, four different dilutions of these antigens were examined by line immmunoelectrophoresis, employing the same antisera. The distance of the resulting line immune precipitates from the start served to calculate the amount of antigen-antiserum reacting with each other. After converting these values to the amount of antiserum used for producing the precipitation curves, the 'line antigen/antibody ratios' were drawn into the appropriate precipitation curves. All electroimmune precipitates (in this case, the 'line immune precipitates') were found to be located on the side of antigen excess of their corresponding precipitation curve.