Unique subpopulations of CD56(+) NK and NK-T peripheral blood lymphocytes identified by chemokine receptor expression repertoire

CD56, an adhesion molecule closely related to neual cell adhesion molecule, is an immunophenotypic marker for several unique populations of PBLs. Alth ough CD56(+) cells derive from multiple lymphocyte lineages, they share a r ole in immunosurveillance and antitumor responses. We have studied the chem okine receptor expression patterns and functional migratory responses of th ree distinct CD56(+) populations from human peripheral blood. NK-T cells we re found to differ greatly from NK cells, and CD16(+) NK cells from CD16(-) NK cells. CD16(+) NK cells were the predominant population responding to I L-8 and fractalkine, whereas NK-T cells were the predominant population res ponding to the CCR5 ligand macrophage-inflammatory protein-1 beta. CD16(-) NK cells were the only CD56(+) population that uniformly expressed traffick ing molecules necessary for homing into secondary lymphoid organs through h igh endothelial venule. These findings describe a diverse population of cel ls that may have trafficking patterns entirely different from each other, a nd from other lymphocyte types.