Human Cytolytic T Cell Recognition of Yersinia pestis Virulence Proteins That Target Innate Immune Responses
1Department of Immunology, United States Army Medical Research Institute of Infectious Diseases, and 2Macromolecular Crystallography Laboratory, National Cancer Institute at Frederick, Frederick, Maryland
Cell contact by the plague bacterium Yersinia pestis initiates the injection of several virulence factors that target biochemical pathways critical for host clearance of bacteria. Despite this impairment of innate immunity, it is unclear whether antigen recognition by T cells is equally affected. We present evidence that human cytolytic T cells respond to Y. pestis virulence proteins presented by infected monocytes and dendritic cells. These T cell antigens consisted of a panel of proteins encoded by pCD1, a 70‐kDa plasmid that harbors virulence factors and transport proteins of the cell contact–dependent, type III secretion system. Infected cells retained the ability to process and present tetanus toxoid to T cells, which indicates that responses to unrelated antigens were also maintained. Our results indicate that T cell immunity remains functional during Y. pestis infection, which thus suggests the potential benefits of therapeutic vaccination and strategies that emphasize the inclusion of cytotoxic T lymphocyte responses.
Received 19 April 2006; accepted 13 July 2006; electronically published 2 November 2006.
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Online publication date: 1-Oct-2007.
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Potential conflicts of interest: none reported.
Financial support: Joint Science and Technology Office (grant 8.100205RDB to R.G.U.).
The views in the present article are those of the authors and do not purport to reflect official policy of the US Government.