Regulatory roles of NKT cells in Anaplasma phagocytophilum infection

Choi, Kyoung-Seong; Chae, Joon-Seok

Korean Journal of Veterinary Research 2009;49(2):167-172.

¹College of Ecology and Environmental Sciences, Kyungpook National University
²College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University

Abstract

Human granulocytic anaplasmosis (HGA) is caused by the obligate intracellular bacterium Anaplasma (A.) phagocytophilum. Natural killer T (NKT) cells are key players in host defense against various microbial infections. We investigated the role of NKT cells in immune response to A. phagocytophilum infection using NKT-knockout ($Jalpha$18-/-) mice. $Jalpha$18-/- and wild-type (WT) mice were infected with low-passage A. phagocytophilum and assayed for hepatic histopathology and cytokine production during 7 days post-infection. Compared to WT controls, the infected $Jalpha$18 -/- mice had much less histopathologic lesions and less apoptosis through day 7, and lower concentrations of ${IFNgamma}$ and IL- 12, but not of IL-10. This result suggests that NKT cells are major components in the pathogenesis of HGA.

Key Words: Anaplasma phagocytophilum, human granulocytic anaplasmosis, NKT cells, NKT-knockout mice