A new role for NK cells in saliva-induced protection against Leishmania major transmitted by Phlebotomus duboscqi

Wednesday, October 26, 2011 — Poster Session IV
2:00 p.m. – 4:00 p.m.	Natcher Conference Center	NIAID	IMMUNO/INFLAM-28

Authors

• C Teixeira
• R Gomes
• LF Oliveira
• D Gilmore
• D Elnaiem
• C Meneses
• P Lawyer
• J Valenzuela
• S Kamhawi

Abstract

During blood feeding, the sand fly inoculates Leishmania parasites into the skin alongside saliva. Pre-exposure to sand fly saliva results in protection against vector-transmitted Leishmania major infection; however the initial immune response mediating this protection remains unclear. Here, we explore the early inflammatory response in the skin of exposed mice challenged with L. major-infected Phlebotomus duboscqi sand flies. The relative expression of cytokines and chemokines by skin cells was investigated 2-12 hours post-infection using a macroarray (Oligo GEArray®). Overall, a more rapid induction of inflammatory genes was observed in exposed compared to naïve mice. FACS analysis of the inflammatory infiltrate in the skin at six, 24, 48 hours and one week post-infection showed a significantly increased recruitment of neutrophils, NK cells, macrophages and CD4+ T cells in exposed mice. Relative to naïve mice, exposed mice also presented a higher frequency of IFN-gamma producing CD4+ T cells and NK cells after 24 hours and a threefold increase in the frequency of mature NK cells producing granzyme B 48 hours and one week after infection. This is the first report of the involvement of NK cells in saliva-induced immunity suggesting a role for these cells in Th1 priming and protection against leishmaniasis.

back to top