| Abstract: | Studies were performed to determine if natural killer (NK) activity in the mononuclear cells harvested from infected lungs was dependent on local or systemic factors. Mice were inoculated by intratracheal (it), intraperitoneal (ip), or intravenous (iv) routes with (a LD50 dose of) influenza virus A PR/8/34. At various days postinoculation cells from lungs, spleens, and peripheral blood were assayed for NK activity, and lung wash, lung homogenates, and serum were assayed for interferon. After it inoculation there was three- to fourfold increase of NK activity in the lung with little or no increase in NK activity in spleens or peripheral blood. The local augmentation of NK activity in the lung correlated with an increase in interferon (IFN) titer in the lung wash and lung homogenate of PR8 inoculated mice. The virus failed to induce IFN or augment NK activity when it was inoculated systemically. The observed local augmentation of NK activity and local induction of interferon production following it inoculation suggests that the NK population in the lung is capable of responding to locally derived regulatory factors. |
