CHARACTERIZATION OF NATURAL-KILLER-CELL ACTIVITY IN MACACA-NEMESTRINA

Natural killer (NK) cell activity was evaluated in three groups of Mac aca nemestrina that varied with respect to SAIDS D retrovirus serotype 2 (SRV-2/W) and viremic status. Target cells used were Raji and K562 cells. No significant differences (ANOVA) in mean NK activity were det ected among the three groups of animals studied. Using Raji targets, m ean LU(30)/10(6)+/-SEM was 6.3+/-1.6 for seronegative (V-Ab-) animals, 7.3+/-1.5 for seropositive (V-Ab+) animals, and 10.2+/-3.5 for persis tently viremic (V+Ab-) animals. Using K562 targets, mean LU(30)/10(6) was 7.6+/-1.7 for seronegative (V-Ab-) animals, 6.5+/-2.5 for seroposi tive (V-Ab+) animals, and 5.1+/-1.9 for persistently viremic (V+Ab-) a nimals. Percentage blood CD16(+) and CD8(+) cells also were not differ ent in the three groups of animals. NK activity did not always correla te with percentage of CD16(+) or CD8(+) cells in peripheral blood at t he time the assays were done. In persistently viremic animals, there w as a strong positive correlation between percent CD16(+) and CD8(+) ce lls and NK activity using K562 cells but not Raji cells. Depletion exp eriments indicated that lysis was mediated by both CD8(+) and CD16(+) cells with both Raji and K562 cells. However, Raji targets were a bett er indicator of killing mediated by CD16(+) cells. Our studies indicat e that M. nemestrina may be classified as high or low responders with regard to NK activity, and there was no correlation with SRV-2/W viral or antibody status. Additionally, our results suggested that group ho using of M. nemestrina was usually associated with increased NK activi ty. In conclusion, studies of NK activity in M. nemestrina should cons ider target cells used, phenotype of effecters, endogenous (high or lo w) levels of NK activity in individual animals, and housing conditions . (C) 1996 Wiley-Liss, Inc.