NATURAL CYTOTOXICITY TOWARD K562 CELLS BY MACAQUE LYMPHOCYTES FROM INFANCY THROUGH PUBERTY - EFFECTS OF EARLY SOCIAL CHALLENGE

The consequences of a single maternal separation experience followed b y reunion at 6-7 months of age was studied in socially housed pigtail (Macaca nemestrina) and bonnet (Macaca radiata) macaques. At 15 months , these subjects were removed from their natal group and placed in sam e species social groups, consisting of other separated and matched con trol subjects. Some subjects were followed until they reached an avera ge age of 4 years while remaining in this group. Blood samples were dr awn to permit assessment of the ability of peripheral blood lymphocyte s to lyse, in vitro, K562 cells. Maternal separation failed to affect lysis of K562 cells acutely, although lysis by matched control subject s appeared to be transiently reduced 2 h after removal of the adult fe male. 4 longer-term influence was noted such that lysis of targets in previously separated subjects was greater than that in matched control s. Lysis rose over time regardless of species or experimental conditio n. A striking internal consistency in the lysis was also noted. Lysis was highly intercorrelated (r's > .60, p less than or equal to .005) w ithin subjects across time during baseline, separation, and reunion ph ases of the acute social challenge. In addition, there was a tendency for this correlation to hold over the longitudinal phases. Lysis of K5 62 targets by macaque lymphocytes would appear to possess trait-like s tability; however, the range of lysis may be modified by early experie nces. (C) 1996 Academic Press, Inc.