Phenotypic and functional study of natural killer cells in tuberculous pleurisy patients

The phenotypic and functional characteristics of the cells that mediate "natural killer" (NK) cytolysis were examined by using anti-Leu 7 monoclonal antibody specific for NK cell in peripheral blood mononuclear cells (PMC) and pleural effusion mononuclear cells (PEMNC) from the tuberculous pleurisy patients. The proportion of Leu 7+ cells in PEMNC was observed significantly lower than in PMC, whether the patients were treated or not. Before treatment NK cell activity, precisely cytotoxicity against K 562, in PEMNC was apparently higher than in PMC. There was little relationship between proportion of leu 7+ cells and NK cell activity. Further, the mechanism of high NK cell activity in PEMNC was analysed by coculture with a healthy control's PMC and a tuberculous pleural effusion. The NK cell activity of Leu 7+ cells was augmented by low molecular soluble factor(s).