T. Kogure et al., Killer-cell inhibitory receptors, CD158a/b, are upregulated by interleukin-2, but not interferon-gamma or interleukin-4, MEDIAT INFL, 8(6), 1999, pp. 313-318
ALTHOUGH it is now accepted that killer-cell inhibitory receptors (KIRs), w
hich were molecularly cloned in 1995, deliver negative signals to natural k
iller (NK) cells regarding the recognition of target cells, it is still unc
lear how the expression of these receptors on lymphocytes is regulated. The
refore, we investigated the regulation of expression of representative KIRs
, CD158a and CD158b, by cytokines such as interleukin-a (IL-2), IL-4 and in
terferon-gamma (IFN-gamma). Neither IL-4 nor IFN-gamma affected the express
ion of CD158a/b, but incubation for 48 h with IL-2, which enhances the kill
er activity of Mt cells, upregulated the expression of the KIRs, This upreg
ulation by IL-2 was also observed in CD16-positive cells sorted from total
lymphocytes. In contrast, IL-4, which is a down-regulator of IL-2-induced k
iller responses, did not change the level of CD158a/b expression when added
after the IL-2 treatment. These findings suggest that IL-2 plays an import
ant role in the regulation of CD158a/b expression, and might be involved in
controlling NK activity via regulating expression of these molecules.