Submitted to: Parasite Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2005
Publication Date: 4/15/2006
Citation: Goff, W.L., Storset, A.K., Johnson, W.C., Brown, W.C. 2006. Bovine splenic NK cells synthesize IFN-gamma in response to IL-12-containing supernatants from Babesia bovis-exposed monocyte cultures. Parasite Immunology. 28:221-228.
Interpretive Summary: Babesiosis is a tick-borne disease responsible for significant economic impact on the cattle industry throughout the world. Babesia bovis is one of three important species affecting cattle, and the subject of research into immunological responses of cattle after exposure. The first immune response is referred to as innate and involves a complex series of molecular and cellular activities resulting in some degree of control of the infection. Studies have identified the important factors contributing to this protective control and the study reported here describes the type of cells responsible for producing the mediating factors.
Technical Abstract: The spleen is a critical effector organ functioning in hemoparasitic diseases like babesiosis, to destroy the pathogen and clear the host of infected erythrocytes. It has an important role in both innate and adaptive immune responses. Young calves demonstrate a strong spleen-dependent innate response to an initial infection with Babesia bovis involving the type-1 regulatory cytokines interleukin-12 and interferon-gamma. However, the specific splenic cell types that produce interferon gamma in response to infection and the cellular factors that regulate the induction have not been fully determined. Splenic NKp46+ NK cells were identified and purified. They consisted of CD3-, CD2+/-, and CD8+/- populations. NK cells responded to exogenous interleukin-12 and interleukin-18 with the production of interferon-gamma. Functionally, interleukin-18 served as a potent costimulant with interleukin-12 for interferon-gamma production. Finally, innate interferon-gamma production was induced in splenic NK cells in the presence of supernatants from B. bovis merozoite-exposed monocytes in an interleukin-12 pathway-dependent manner.