Immunohistochemical localization of IgA antigens in sections embedded in epoxy resin.

Abstract

Antigenic determinants for H and L chains of Ig[immunoglobulin]A in [rat] immunocytes and lysozyme in Paneth cells were successfully identified by immunohistochemistry in sections of tissue embedded in epoxy resin. Successful staining for Ig and lysozyme required removal of the epoxy resin prior to application of the immunochemical reagents and was independent of the type of epoxy resin employed. Localization of Ig antigens depended upon the utilization of chemical fixation other than glutaraldehyde or physical fixation by freeze-drying. Lysozyme was detected regardless of the fixation process used. Optimal preservation of antigenicity for Ig and lysozyme was obtained with physical fixation by freeze-drying. Incubation of the etched tissue sections with oxidizing agents such as periodic acid diminished or eliminated immunoreactivity of Ig antigenic determinants. Ig antigenicity is not inactivated by embedment in epoxy resins, Ig can be localized after removal of epoxy resin and immunoreactivity of these antigenic determinants can be diminished by oxidizing agents often used to suppress endogenous peroxidase activity.