P05: A novel dual-labelling technique for the immuno-histochemical demonstration of T-lymphocyte subsets in FFPE rat lymphoid tissue

Abstract

Immunotoxicology has developed into an integral regulatory requirement of the toxicological assessment of xenobiotics. Enhanced pathological assessment of tissues can provide genuine insight into perturbations of lymphoid cell populations. To facilitate this we have endeavoured to develop a panel of immunohistochemical techniques to demonstrate T-cells and T-cell subsets in formalin-fixed paraffin-embedded rat lymphoid tissues. We were successful in developing methods for CD3 and CD8 but failed to arrive at a satisfactory technique for the direct demonstration of CD4 in these tissues. Taking the assumption that the majority of mature T-cells are either CD4+ or CD8+ we have combined our methods for CD3 and CD8 in a novel dual-labelling IHC method to simultaneously demonstrate CD3, CD8 and, by implication, CD4.