Impact of bacteria on the phenotype, functions, and therapeutic activities of invariant NKT cells in mice
Sungjune Kim, Saif Lalani, Vrajesh V. Parekh, Tiffaney L. Vincent, Lan Wu, Luc Van Kaer
Sungjune Kim, Saif Lalani, Vrajesh V. Parekh, Tiffaney L. Vincent, Lan Wu, Luc Van Kaer
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Research Article Immunology

Impact of bacteria on the phenotype, functions, and therapeutic activities of invariant NKT cells in mice

Abstract

Invariant NKT (iNKT) cells are innate-like lymphocytes that recognize glycolipid antigens in the context of the MHC class I–like antigen-presenting molecule CD1d. In vivo activation of mouse iNKT cells with the glycolipid α-galactosylceramide (α-GalCer) results in the acquisition of a hyporesponsive (anergic) phenotype by these cells. Because iNKT cells can become activated in the context of infectious agents, here we evaluated whether iNKT cell activation by microorganisms can influence subsequent responses of these cells to glycolipid antigen stimulation. We found that mouse iNKT cells activated in vivo by multiple bacterial microorganisms, or by bacterial LPS or flagellin, became unresponsive to subsequent activation with α-GalCer. This hyporesponsive phenotype of iNKT cells required IL-12 expression and was associated with changes in the surface phenotype of these cells, reduced severity of concanavalin A–induced hepatitis, and alterations in the therapeutic activities of α-GalCer. These findings may have important implications for the development of iNKT cell–based therapies.

Authors

Sungjune Kim, Saif Lalani, Vrajesh V. Parekh, Tiffaney L. Vincent, Lan Wu, Luc Van Kaer

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Figure 8

Bacteria-induced iNKT cell hyporesponsiveness is predominantly iNKT cell autonomous.

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Bacteria-induced iNKT cell hyporesponsiveness is predominantly iNKT cell...
(A) Mice were injected with α-GalCer or heat-killed E. coli and sacrificed at 3 weeks. DCs from the spleen and iNKT cells from the liver were then enriched as described in Methods. iNKT cells (1 × 105 per well) and DCs (5 × 104 per well) were then cultured in different combinations in the presence or absence of α-GalCer. Proliferation was assessed by [3H]thymidine incorporation, and IFN-γ and IL-4 levels in the supernatant were evaluated by ELISA. Data shown are the mean ± SD of 2 wells per group and representative of 2 independent experiments. (B) Mice were injected with α-GalCer or heat-killed E. coli and sacrificed at 3 weeks. DCs and iNKT cells were then MACS purified as described in Methods. DCs (2 × 104 per well) were loaded with α-GalCer and cultured with splenic CFSE-labeled iNKT cells (1 × 105 per well). Cells were harvested 3 days later, stained with anti-B220–PerCP, tetramer-allophycocyanin, and analyzed by flow cytometry. Data shown are CFSE staining on iNKT cells. Three mice per group were pooled for the experiment. (C) Mice were left untreated or injected with heat-killed E. coli or live L. monocytogenes. DCs were MACS purified from naive mice, pulsed with α-GalCer, washed, and then injected i.v. (2 × 105 DCs per mouse) into naive mice or mice treated 3 weeks earlier with the indicated bacteria. As a control, mice were also treated without DCs. Mice were sacrificed 3 days later, and splenocytes were stained with anti–TCR-β–FITC, anti-B220–PerCP, and tetramer-allophycocyanin and analyzed by flow cytometry. Data shown are representative of 2 mice per group.