Identification and characterization of a cell-surface molecule that is selectively induced on rat lymphokine-activated killer cells

We have identified a 40- to 45-kDa cell-surface molecule designated gp42, that is expressed in high levels by rat lymphokine-activated killer (LAK) cells of NK cell origin. gp42 cannot be detected on the precursors of LAK cells and is not present on resting or activated T cells. Rather, expression of gp42 is selectively induced on NK cells by the high concentrations of rIL-2 that are required for the induction of LAK activity. Although the function of gp42 is not known, the selective nature of its expression suggests a role for this molecule in regulating responses that are unique to IL-2-activated NK cells.