HC enhances the expression of IL-2/IL15Rβ– and γ-chains in CD56⁺CD3^– cells. Purified CD56⁺ cells activated with IL-15 in the absence or presence of HC, at concentrations of 10^–6 M and 10^–4 M, for 10 to 15 days, were extensively washed and cultured for an additional 8-hour period in the absence of IL-15 and HC and tested for surface β- (CD122) and γ-chain (CD132) expression by FACS analysis on gated CD3^– and CD3⁺ cells. (A,B; left) □ indicates absence of HC; ▨, 10^–6 M HC; and ▪, 10^–4 M HC. (A) CD122⁺ and (B) CD132⁺ MESF values (mean ± SD from the pooled data with 3 different healthy donors). (A,B; right) Dotted curve indicates isotype control; filled curve, absence of HC; light gray curve, 10^–6 M HC; and dark gray curve, 10^–4 M HC. Histogram plots from a representative donor are presented.