Natural Killer cell function during foot-and-mouth disease virus infection (46.19)

Abstract

Abstract Foot-and-mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals. Immunological knowledge to assess more rapid acting vaccines against FMDV is presently limited. We examined the reactivity of swine and cattle NK cells following infection for their capability to express intracellular perforin, to kill a human tumor cell line target in vitro, and to secret IFN gamma. The cytotoxicity of NK cells from non-infected animals against the K562 cells is low with baseline levels at 5–15% in swine and 15–20% in cattle. Stimulation with rhIL-2 or rhIL-12 plus rhIL-15, increased the lytic activity against K562 cells. Infection with FMDV inhibited swine NK cell lytic activity but did not significantly increase IFN gamma secretion during the acute infection. Perforin expression increased but this did not correlate with the killing capability of the swine NK cells. Infection of cattle with FMDV initially activated the NK cells to increase target cell lysis. NK cell IFN gamma secretion and perforin expression were slightly elevated upon infection and coincided with the lytic activity in cattle. These results are a further indication of immune evasion by FMDV by inhibiting or limiting NK cell function. The potential to manipulate the innate immune response to block this evasion is discussed in the context of designing rapid acting vaccines for foot-and-mouth disease.