IMMUNOHISTOCHEMICAL DETECTION OF T-CELL SUBSETS AND OTHER LEUKOCYTES IN PARAFFIN-EMBEDDED RAT AND MOUSE-TISSUES WITH MONOCLONAL-ANTIBODIES

We describe a method for immunohistochemical localization of T-cells, CD4(+) T-cells, CD8(+) T-cells, B-cells, activated lymphocytes, major histocompatibility complex (MHC) class II antigens, macrophages, dendr itic cells, and granulocytes in rat and mouse tissue fixed in periodat e-lysine-paraformaldehyde (PLP) and embedded in paraffin, Rat and mous e spleen and eyes were fixed in PLP for 18-24 hr, rapidly dehydrated, infiltrated under vacuum with paraffim at 54 degrees C, sectioned, and stained with appropriate monodonal antibodies (MAbs), Sections of PLP -fixed, paraffin-embedded spleen were compared with acetone-fixed froz en spleen sections with respect to morphology and staining quality, Ni ne of 10 MAbs to rat antigens and eight of nine MAbs to mouse antigens stained paraffin sections equally or more intensely than frozen secti ons, The two MAbs that showed weaker staining still gave good staining on paraffin sections. Paraffin-embedded rat and mouse eyes were easie r to section serially than frozen eyes, showed superior morphology, an d individually stained cells were readily identified. Therefore, a com bination of PLP fixation and low-temperature paraffin embedding permit s detection of the major types of immune cell in rat and mouse tissues while maintaining good morphology, particularly in diseased, damaged, or delicate tissues.