Comparative analysis of natural killer function in lung, spleen, and peripheral blood lymphocytes: evidence of differential characteristics.

Organ associated as well as systemic natural killer (NK) activity play an important role in host defense. It is likely that tissue NK cells exhibit some specific characteristics resulting from their local environment. The purpose of the present study was to compare NK cell function of rat lung to that of spleen and blood in terms of magnitude of NK activity, NK cell number, and response to biological response modifiers (BRM). Lung interstitial lymphocytes (LL) were found to display significant cytotoxicity which was selective for YAC-1 tumor cells and abolished by treatment with antiasialo GM-1 serum and L-leucine methyl ester. In addition, LL were more effective than peripheral blood lymphocytes (PBL) and spleen lymphocytes (SL), although LL contained the same proportion of NK 3.2.3 positive cells than the spleen. Furthermore, the in vitro response to BRM varied both with BRM used and effector cell origin. Human recombinant interleukin 2 (rIL-2) increased NK activity of LL and PBL to a similar extent, whereas SL were more responsive to such treatment. Interferon alpha/beta (IFN-alpha/beta) increased NK activity in all three compartments with PBL being less responsive. By contrast, rat recombinant interferon gamma (rIFN-gamma) failed to augment LL or SL NK activity but did result in a significant enhancement of PBL activity. Together these data indicate that the lung contains comparable numbers of NK cells to that of spleen but which display higher specific activity. Furthermore, NK cell response to BRM vary with tissue origin, suggesting that tissue specific response may be an important determinant for the effective use of BRM.