The Mouse T Lymphocyte Subset Antibody Cocktail is a three-color reagent designed to identify major subsets of T lymphocytes by direct immunofluorescent staining with flow cytometric analysis. The 145-2C11 antibody reacts with the 25-kDa å chain of the T-cell receptor-associated CD3 complex, which is expressed on thymocytes, mature T lymphocytes, and NK-T cells of all mouse strains tested.1,2 The RM4-5 antibody recognizes CD4 (L3T4), a differentiation antigen expressed on most thymocytes, subpopulations of mature T lymphocytes (ie, MHC class IIrestricted T cells, including most T-helper cells and immunosuppressive regulatory T cells), and a subset of NK-T cells in all mouse strains tested.3,4,5 CD4 has also been detected on pluripotent hematopoietic stem cells, bone-marrow myeloid and B-lymphocyte precursors, intrathymic lymphoid precursors, and a subset of splenic dendritic cells.6,7,8,9,10,11,12 The 53-6.7 antibody reacts with the 38-kDa á and 34-kDa á' chains of the CD8 differentiation antigen (Ly-2 or Lyt-2) expressed on most thymocytes, subpopulations of mature T lymphocytes (including MHC class I-restricted T suppressor/cytotoxic cells and subsets of ãä TCR-bearing cells and intestinal intraepithelial lymphocytes) of all mouse strains tested.13,14,15,16,17,18 CD8a is also expressed on a subset of dendritic cells.19 The three antibodies have been titrated and pre-diluted, mixed together, and formulated for optimal staining performance. The Mouse T Lymphocyte Subset Isotype Control contains equivalent concentrations of fluorochrome- and isotype-matched negative-control immunoglobulin.

The use of three different fluorochromes for the labeling of the three different antibodies permits the recognition of each of the three antigens on each cell in a sample. The levels of expression of the three antigens distinguish the major subpopulations of developing and peripheral T lymphocytes.

Additional fluorochrome-labeled reagents may be combined with the Mouse T Lymphocyte Subset Antibody Cocktail, and the Mouse T Lymphocyte Subset Isotype Control, to further characterize T-cell subpopulations.