Rapid identification of T helper and T cytotoxic/suppressor lymphocytes with an oxazine dye.

Peripheral blood lymphocytes displayed a plurality of sizes and colors when exposed first to a methanolic solution of C.I. basic blue 141, then to an aqueous alkaline solution of the same dye and rinsed in a neutral HEPES buffer containing trace amounts of various salts. As confirmed with purified lymphocyte subpopulations obtained with a cell sorter, T helper cells (CD4) were small and their nuclei and cytoplasm stained deep blue. T cytotoxic/suppressor cells (CD 8) were larger than T helper cells, their nuclei stained pale green or blue green and their cytoplasm contained a cluster of magenta colored granules. From start to finish, the stain takes 15 min to perform. Used in the manner described, basic blue 141 holds promise as a rapid means of identifying and differentiating CD4 and CD8 cells under the ordinary light microscope without using monoclonal antibodies or fluorescence.