SELECTIVE LONG-TERM ELIMINATION OF NATURAL-KILLER-CELLS IN-VIVO BY ANANTI-INTERLEUKIN-2 RECEPTOR BETA-CHAIN MONOCLONAL-ANTIBODY IN MICE

The interleukin 2 receptor beta chain (IL-2Rbeta) is preferentially ex pressed in natural killer (NK) cells, but is not detected in a majorit y of resting T and B cells. We recently established a novel monoclonal antibody (mAb) to murine IL-2Rbeta and examined in vivo the effect of the mAb in mice. We found that intraperitoneal injection of the anti- IL-2Rbeta mAb into adult mice resulted in a selective in vivo eliminat ion of splenic NK function in various mouse strains. The reduction of NK cell function is associated with complete disappearance of NK1.1+ c ells in C57BL/6 mice. Other lymphocyte subsets in the thymus and splee n were uncompromised. T cell function was not affected by the mAb trea tment as judged by allogeneic cytotoxic T cell induction. The single i njection of anti-IL-2Rbeta mAb caused a long-term elimination of splen ic NK cells, lasting for at least 5 wk. We also found that NK and/or N K precursor cells become susceptible to the mAb treatment only after b irth, suggesting that functional maturation of NK cells in terms of IL -2Rbeta expression is a later event in the course of NK cell developme nt. The use of the anti-IL-2Rbeta mAb will be useful in defining the p hysiological role of NK cells in host defense as well as dissecting th eir developmental pathway in vivo.