THE COMBINATION OF HIGH-ACCELERATOR EPOXY-RESIN AND ANTIGEN RETRIEVALTO OBTAIN MORE INTENSE IMMUNOLABELING ON EPOXY SECTIONS THAN ON LR-WHITE SECTIONS FOR LARGE PROTEINS

The purpose of this study was to examine how antigen retrieval affecte d the yield of immunogold labeling on epoxy sections based on embeddin g with different amounts of accelerator. The concentration of accelera tor DMP-30 (tri(dimethyl amino methyl) phenol) was varied in the range of 0-8% in the processing of the tissue for epoxy embedding. Immunogo ld labeling was performed on epoxy sections and LR-White sections of f ibrin clots and renal tissue with IgG-deposits, and the antibodies use d were anti-fibrinogen anti-IgG and, respectively. For some of the sec tions antigen retrieval was performed by healing the sections in citra te buffer. In all cases, the yield of immunogold labeling increased fo llowing antigen retrieval. The increase (%) in the yield of immunogold labeling as a result of antigen retrieval was larger for epoxy sectio ns than for LR-White sections. The immunolabeling on high-accelerator epoxy sections exposed to antigen retrieval was about 20% more intense than on untreated LR-White sections both for IgG and fibrinogen. In a ddition to breaking fixations bonds introduced by the chemical fixatio n, we believe that the antigen retrieval also breaks bonds between the epoxy resin and the embedded tissue. The combination of increased amo unt of accelerator during tissue processing for epoxy embedding and an tigen retrieval by heating in citrate buffer is a potent method for in creasing specific immunolabeling on epoxy sections. (C) 1998 Elsevier Science Ltd. All rights reserved.