Determination of antigen-specific immunoglobulin content in ascitic fluids and antisera

A rapid and sensitive method is described for the determination of the antigen-specific immunoglobulin contents of ascitic fluids and/or antisera. Immunoglobulins are quantitatively separated from the biological fluid by immunoaffinity chromatography on the insolubilized antigen using the Millipore Millititer filtration system to perform the simultaneous assay of multiple samples. The specific immunoglobulins are then eluted at acidic pH and their concentration is estimated by solid-phase competitive radioimmunoassay. Radioimmunoassay values, corrected for dilutions, give the antigen-specific immunoglobulin concentration of ascitic fluids and/or antisera.