IMMUNOFLUORESCENCE AND GLUTARALDEHYDE FIXATION - A NEW PROCEDURE BASED ON THE SCHIFF-QUENCHING METHOD

The immunofluorescence technique is one of the most useful methods for localizing antigens in several tissues, including the central nervous system. For immunohistochemical procedures, especially immunofluoresc ence methods, formaldehyde is commonly used as a fixative agent. But f or some protocols, mainly in neurobiology, glutaraldehyde is necessary to recognize a number of small molecules (haptens) whose antisera hav e been raised using glutaraldehyde as the cross-linking agent. This is a severe limitation because glutaraldehyde gives rise to a strong aut ofluorescence on tissue that precludes the observation of specific imm unofluorescence staining. In this paper we present a new method that a llows the use of immunofluorescence techniques on glutaraldehyde-fixed tissues. The new method consists of a treatment of tissue sections wi th the Schiffs reagent (leucobasic fuchsin) followed by a reduction of the Schiff-dye with sodium borohydride. This reduced dye produces a q uenching of glutaraldehyde-induced fluorescence on the tissue. The goa l of the new method is to make possible the use of a great number of a vailable glutaraldehyde-raised antisera for immunofluorescence techniq ues, a useful tool in both basic and clinical research. (C) 1997 Elsev ier Science B.V.