Chemotaxis of large granular lymphocytes.

Abstract

The hypothesis that large granular lymphocytes (LGL) are capable of directed locomotion (chemotaxis) was tested. A population of LGL isolated from discontinuous Percoll gradients migrated along concentration gradients of N-formyl-methionyl-leucyl-phenylalanine (f-MLP), casein, and C5a, well known chemoattractants for polymorphonuclear leukocytes and monocytes, as well as interferon-beta and colony-stimulating factor. Interleukin 2, tuftsin, platelet-derived growth factor, and fibronectin were inactive. Migratory responses were greater in Percoll fractions with the highest lytic activity and HNK-1+ cells. The chemotactic response to f-MLP, casein, and C5a was always greater when the chemoattractant was present in greater concentration in the lower compartment of the Boyden chamber. Optimum chemotaxis was observed after a 1 hr incubation that made use of 12 micron nitrocellulose filters. LGL exhibited a high degree of nondirected locomotion when allowed to migrate for longer periods (greater than 2 hr), and when cultured in vitro for 24 to 72 hr in the presence or absence of IL 2 containing phytohemagluttinin-conditioned medium. The chemotactic LGL was HNK-1+, OKT11+ or HNK-1+, OKT11- on the basis of monoclonal antibody and complement depletion. They did not bear either T cell or monocyte cell surface markers, exhibiting an OKT3-, OKT4-, OKT8-, OKM1-, and MO2- phenotype, and did not form E rosettes at 29 degrees C, which is characteristic of lytic NK cells in contrast to T cells. Furthermore, a rat LGL leukemia (RNK) exhibited a chemotactic response to both f-MLP and casein. LGL chemotaxis to f-MLP could be inhibited in a dose-dependent manner by the inactive structural analog CBZ-phe-met, and the RNK tumor line specifically bound f-ML[3H]P, suggesting that LGL bear receptors for the chemotactic peptide.