Histochemical localization of T-cells in tissue sections.

Utilizing the acid alpha-naphthyl acetate esterase histochemical staining technique, cells with established T-cell (thymus-derived) staining characteristics could be consistently demonstrated in the periarteriolar lymphatic sheaths of the spleen and the diffusely infiltrated area of the cloacal bursa. The same areas failed to stain positively in significant numbers following a preincubation period with a specific inhibitor for carboxyl esterase. Lymphoid cells in the thymus, the splenic follicles, and bursal follicles were mostly negative.