RT Journal Article
SR Electronic
T1 Natural killer T cell activation increases iNOS<sup>+</sup>CD206<sup>-</sup> M1 macrophage and controls the growth of solid tumor
JF Journal for ImmunoTherapy of Cancer
JO J Immunother Cancer
FD BMJ Publishing Group Ltd
SP 208
DO 10.1186/s40425-019-0697-7
VO 7
IS 1
A1 Sourav Paul
A1 Sushanta Chhatar
A1 Amrita Mishra
A1 Girdhari Lal
YR 2019
UL http://jitc.bmj.com/content/7/1/208.abstract
AB Background NKT cells play an important role in anti-tumor immunity. Alpha-galactosylceramide (α-GalCer), a synthetic glycolipid is presented to natural killer T (NKT) cells by most antigen-presenting cells through CD1d molecules leading to activation of NKT cells. However, the precise mechanisms of how α-GalCer-activated NKT regulate the polarization of the macrophages and effector T cells in the solid tumor are not studied adequately.Methods We induced solid tumor in C57BL/6 mice by subcutaneous injection of B16F10 cell line (1 X 106 cells) and monitored the tumor growth. Animals were given an intraperitoneal injection of α-GalCer (2 μg/injection) in 200 μl PBS on day + 1, + 5, + 10, + 15, and + 20 (with respect to tumor cell injection). Immune cells were characterized using flow cytometry and immunofluorescence staining. NK cells, Gr1+ cells, and F4/80+ macrophages in the mice were depleted by intravenous injection of cell-specific antibodies. Statistical analysis was performed using Student’s t-test or one-way ANOVA.Results Our results showed that intratumoral NKT cells have a lower frequency of CD69, CD25, CD122, and IFN-γR expression; produced less inflammatory cytokines such as IFN-γ, TNF-α, and GM-CSF; higher frequency CD62L+ NKT cells; and also showed reduced proliferation as compared to the splenic NKT cells. Mice treated with α-GalCer showed a significantly increased frequency of IFN-γ-producing NKT cells, CD8+ T cells, and effector Th1 cells. Depletion of NK cells in α-GalCer-treated mice showed a lower frequency of IFN-γ-producing CD4+ and CD8+ T cells in the tumor and prevented the α-GalCer-induced tumor growth. NKT cell activation with α-GalCer treatment significantly increased the iNOS+CD206− M1-macrophages and reduced the iNOS−CD206+ M2-macrophages in the spleen and tumor, and depletion of F4/80+ macrophages prevented the α-GalCer-induced reduction in the tumor growth.Conclusions We showed that activation of NKT cell with α-GalCer modulates the frequency of M1-macrophages and effector Th1 cells in the secondary lymphoid tissues and tumor microenvironment and inhibit tumor growth. The finding suggests that activation of NKT cells with α-GalCer may provide an effective anti-cancer outcome.