Cytochemistry of Human T‐Cell Subpopulations

Acid phosphatase and esterase cytochemistry performed on purified normal human T-cell populations showed that both methods produced distinctive localized dot patterns of reactivity in 60-70% of cells. By examination of rosette preparations formed with ox erythrocytes coated with IgM (EAM), with IgG (EAG), or anti-human kappa and lambda light chains, it was shown that this pattern of reactivity was largely restricted to small T lymphocytes possessing receptors for the Fc of IgM (T mu cells). In addition, both B lymphocytes and T cells with receptors for the Fc of IgG (T gamma cells) were larger lymphocytes with more abundant cytoplasm and usually displayed scattered granular acid phosphatase activity; in esterase preparations both cell types were either negative or possessed similar scattered granular positivity. As compared with T mu cells, T gamma cells were seen to form loose spontaneous rosettes with sheep erythrocytes. Combined esterase and acid phosphatase staining showed that both enzyme activities in the T mu cells are localized in the same area, and ultrastructural acid phosphatase cytochemistry established that this was in distinctive lysosomal structures. T mu staining by both esterase and acid phosphatase cytochemistry was greatly reduced after rosetting with EAG, but not after rosette formation with EAM or sheep erythrocytes.