Spontaneous Cell-Mediated Cytotoxicity (SCMC) Associated with Lymphocytes Negative for Acid α-Naphthyl Acetate Esterase (ANAE) Activity

A modified histochemical procedure for nonspecific acid α-naphthyl acetate esterase (ANAE) activity in human lymphocytes was used to identify a subpopulation of E-rosette forming cells. Performing a one hour reaction at pH 6.5 the distinct dot-like staining pattern was almost exclusively observed on high affinity E-rosettes which sedimented readily in a regular Ficoll-Metrizoate gradient. By combining latex phagocytosis with staining for ANAE activity, a clear-cut distinction between mononuclear phagocytes and lymphocytes could be made. An attempt was undertaken to relate the ANAE marker on human lymphocytes to their functional capacity in spontaneous cell-mediated cytotoxicity (SCMC) reactions. Using as targets two allogeneic (K562,IGR3) and a xenogeneic cell line (L1210) it could be clearly demonstrated that high SCMC activity is mediated by ANAE negative mononuclear cells, whereas enrichment for ANAE positive lymphocytes resulted in a loss of SCMC.