Combined NKT cell activation and influenza virus vaccination boosts memory CTL generation and protective immunity
Abstract
Current influenza A virus vaccines do not generate significant immunity against serologically distinct influenza A virus subtypes and would thus be ineffective in the face of a pandemic caused by a novel variant emerging from, say, a wildlife reservoir. One possible solution would be to modify these vaccines so that they prime cross-reactive CD8+ cytotoxic T lymphocytes (CTL) cell-mediated immunity directed at conserved viral epitopes. A further strategy is to use novel adjuvants, such as the immunomodulatory glycolipid α-galactosylceramide (α-GalCer). We show here that giving α-GalCer with an inactivated influenza A virus has the paradoxical effect of diminishing acute CTL immunity via natural killer T (NKT) cell-dependent expression of indoleamine 2,3-dioxygenase (IDO), an important mediator of immune suppression, while at the same time promoting the survival of long-lived memory CTL populations capable of boosting protection against heterologous influenza A virus challenge. This enhancement of memory was likely due to the α-GalCer-induced upregulation of prosurvival genes, such as bcl-2, and points to the potential of α-GalCer as an adjuvant for promoting optimal, vaccine-induced CD8+ T cell memory.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- March 2009
- DOI:
- 10.1073/pnas.0813309106
- Bibcode:
- 2009PNAS..106.3330G
- Keywords:
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- T cell memory;
- viral immunity;
- vaccine;
- adjuvant;
- Biological Sciences:Immunology