Cytotoxic T-lymphocyte antigen 4 blockade augments the T-cell response primed by attenuated Listeria monocytogenes resulting in more rapid clearance of virulent bacterial challenge.
Immunology 2008;
128:e471-8. [PMID:
19191906 DOI:
10.1111/j.1365-2567.2008.03001.x]
[Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cytotoxic T-lymphocyte antigen 4 (CTLA-4) uniformly suppresses antigen-specific T cells during chronic infection with bacterial, parasitic or viral pathogens. However, the importance of CTLA-4 in controlling the T-cell response during acute infection or after priming with live attenuated vaccine vectors has not been well characterized. Since strategies aimed at blocking CTLA-4 are being actively developed to therapeutically augment T-cell-mediated immunity, the effects of CTLA-4 blockade on T-cell activation during these conditions need to be more clearly defined. We have examined the role of CTLA-4 in a prime-challenge model of acute bacterial infection using both attenuated and virulent strains of the intracellular bacterium Listeria monocytogenes. Although Foxp3(+) CD4(+) T cells are the predominant CTLA-4-expressing cell type in naïve mice, antigen-specific Foxp3(-) CD4(+) cells upregulate CTLA-4 expression after primary L. monocytogenes infection. Blockade of CTLA-4 results in increased numbers of L. monocytogenes-specific CD4 and CD8 T cells after primary infection with attenuated L. monocytogenes, and confers more rapid bacterial clearance after secondary challenge with virulent L. monocytogenes. Accordingly, CTLA-4 plays an important suppressive role in T-cell priming and protective immunity in a prime-challenge model of acute bacterial infection.
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