Enrichment of natural killer cells by negative selection: comparison to Percoll gradient separation method.

A method is described for the preparation of human peripheral blood mononuclear cell (PBMC) suspensions containing highly enriched natural killer (NK) cell cytotoxicity. The technique involved the negative selection of OKM1+ cells by the selective removal of nylon wool nonadherent PBMC which are reactive with the Leu-1 monoclonal antibody. The Leu-1+ cells are removed by subsequent rosette formation with anti-mouse IgG coated bovine erythrocytes. The resultant OKM1+ cell suspension had a greater number of large granular lymphocytes, K562 target binding effector cells, and lytic activity than concomitantly prepared fractions of Percoll gradients.