Wednesday, October 10, 2007

TAP-1 indirectly regulates CD4+ T cell priming in Toxo infection

J Exp Med. 2007 Oct 8; [Epub ahead of print]

TAP-1 indirectly regulates CD4+ T cell priming in Toxoplasma gondii infection by controlling NK cell IFN-{gamma} production

Goldszmid RS, Bafica A, Jankovic D, Feng CG, Caspar P, Winkler-Pickett R, Trinchieri G, Sher A

Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD 20892.

To investigate if transporter associated with antigen processing (TAP)-1 is required for CD8(+) T cell-mediated control of Toxoplasma gondii in vivo, we compared the resistance of TAP-1(-/-), CD8(-/-), and wild-type (WT) mice to infection with the parasite. Unexpectedly, TAP-1(-/-) mice displayed greater susceptibility than CD8(-/-), beta(2)-microglobulin(-/-) (beta(2)m(-/-)), or WT mice to infection with an avirulent parasite strain. The decreased resistance of the TAP-1(-/-) mice correlated with a reduction in the frequency of activated (CD62L(low) CD44(hi)) and interferon (IFN)-gamma-producing CD4(+) T cells. Interestingly, infected TAP-1(-/-) mice also showed reduced numbers of IFN-gamma-producing natural killer (NK) cells relative to WT, CD8(-/-), or beta(2)m(-/-) mice, and after NK cell depletion both CD8(-/-) and WT mice succumbed to infection with the same kinetics as TAP-1(-/-) animals and displayed impaired CD4(+) T cell IFN-gamma responses. Moreover, adoptive transfer of NK cells obtained from IFN-gamma(+/+), but not IFN-gamma(-/-), animals restored the CD4(+) T cell response of infected TAP-1(-/-) mice to normal levels. These results reveal a role for TAP-1 in the induction of IFN-gamma-producing NK cells and demonstrate that NK cell licensing can influence host resistance to infection through its effect on cytokine production in addition to its role in cytotoxicity.

PMID: 17923502 [PubMed - as supplied by publisher]

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