Prozone Effects in Indirect Immunofluorescence

It was concluded that the anti‐immunoglobulin conjugates were unable to reach antigenic determinants on tightly clustered immunoglobulins molecules, and prozone effects seem to depend primarily on the density of antigen determinants in the target tissues.

Abstract

A marked prozone effect was observed in indirect immunofluorescence (IFL) with rabbit antisera against rat renal proximal tubular epithelial brush border (BB) antigens: anti-BB antibodies were not detectable if used in high concentrations but were readily demonstrated if sufficiently diluted. The prozone effect occurred in spite of demonstrated binding of anti-BB antibodies to target antigens. No prozone was seen when direct IFL was used, and 'cross-reacting' antigens in small-intestinal epithelial brush border were detectable by indirect IFL without prozone. It was concluded that the anti-immunoglobulin conjugates were unable to reach antigenic determinants on tightly clustered immunoglobulin molecules. Thus prozone effects seem to depend primarily on the density of antigen determinants in the target tissues.