<i>i</i>NKT cell-dependent protective activity of C24:1 gangliosides on respiratory bacterial infection.

(A) Lung iNKT cells from α-GalCer- or ganglioside-treated mice (12 h) were screened for intracellular IFNγ and IL-17 production. The ratio IFNγ-:IL-17A-producing iNKT cells is shown in the right panel. Lung γδT (B) and NK (C) cells were evaluated for intracellular IFNγ and IL-17 production as in Fig 7A. (D) Frequency of lung neutrophils (Live CD45+ Siglec F- CD11b+ Ly6G+) in treated or untreated animals is shown. Individual values and means ± SEM of two independent experiments are shown (6–15 mice/group) for panel (A–D). (E) Levels of cytokines in response to C24:1 GM3 were measured in lung homogenates from WT or Cd1d1−/− mice. Means ± SEM of two experiments are shown (4 mice/group). (F) Mice were pretreated with α-GalCer or gangliosides by the IN route one day prior to S. pneumoniae infection and monitored daily for survival (7–10 mice/group). ***P P P S1 Data. α-GalCer, α-galactosylceramide; γδT, gamma delta T; IFNγ, interferon gamma; IL-17, interleukin-17; IN, intranasal; iNKT, invariant natural killer T; NK, natural killer; WT, wild-type.