Lymphocyte emperipolesis revisited. II. Further characterization of the lymphocyte subpopulation involved.

We have previously shown that lymphocyte emperipolesis, the phenomenon whereby lymphocytes wander freely within the cytoplasm of larger host cells, is almost totally dependent on host cell pre-sensitization with IgG type antibody. In addition, the particular lymphocyte subpopulation involved was partially characterized as an Fc receptor bearing, non-T cell. In this study we have attempted to further define the emperipoletic lymphocyte subpopulation using cell fractionation procedures and correlation analysis. Significant correlation was found between emperipolesis and both Fc receptor bearing, surface immunoglobulin negative (Fc + SIg-) cells and antibody dependent lymphocyte mediated cytotoxicity; observations which suggest that the so-called K cells are the emperipoletic effector cells. The significance of these findings in relation to antibody dependent cytolysis is discussed.