A Quantitative Assay for Antibodies to Surface Antigens of Guinea Pig Testicular Cells and Spermatozoa

Abstract

A sensitive and reproducible cellular radioimmunobinding assay for quantitation of antibody to surface antigens of testicular cells and spermatozoa has been developed based on an autoantiserum to guinea pig spermatozoa. This antiserum reacts with cell surface and acrosomal antigens of guinea pig testicular cells and epididymal spermatozoa. To establish a standard curve, different dilutions of a pooled antisperm antiserum (standard) were incubated with guinea pig testicular cells dissociated by collagenase, trypsin and DNAase. The cell-bound immunoglobulin G (IgG) from the antiserum standard was then quantitated in a liquid phase radioimmunoassay for guinea pig IgG. In the cellular radioimmunobinding assay, unknown sera and different dilutions of the antisperm antiserum standard were incubated with guinea pig testicular cells and the cell-bound IgG was determined by further reaction of the testicular cells with [¹²⁵I]-labeled protein A. The amount of antibody IgG in the unknown sera was then determined from the standard curve. With this assay, as low as nanogram amounts of antibody IgG can be detected.