Chlamydia-specific CD4 T cell clones control Chlamydia muridarum replication in epithelial cells by nitric oxide-dependent and -independent mechanisms

J Immunol. 2010 Dec 1;185(11):6911-20. doi: 10.4049/jimmunol.1002596. Epub 2010 Oct 29.

Abstract

Chlamydia trachomatis serovars D-K are sexually transmitted intracellular bacterial pathogens that replicate in epithelial cells lining the human reproductive tract. It is clear from knockout mice and T cell depletion studies using Chlamydia muridarum that MHC class II and CD4 T cells are critical for clearing bacteria from the murine genital tract. It is not clear how CD4 T cells interact with infected epithelial cells to mediate bacterial clearance in vivo. Previous work using an epithelial tumor cell line showed that a Chlamydia-specific CD4 T cell clone was able to inhibit C. muridarum replication in vitro via induction of epithelial NO production. We have previously shown that Chlamydia-specific CD4 T cell clones can recognize and be activated by infected reproductive tract epithelial cells and block Chlamydia replication in them. We extend those observations by investigating the mechanism used by a panel of CD4 T cell clones to control Chlamydia replication in epithelial cells. We found that Chlamydia-specific CD4 T cell clones were cytolytic, but that cytolysis was not likely critical for controlling C. muridarum replication. For one, CD4 T cell clone-induced epithelial NO production was critical for controlling replication; however, the most potent CD4 T cell clones were dependent on T cell degranulation for replication control with only a minor additional contribution from NO production. We discuss our data as they relate to existing knockout mouse studies addressing mechanisms of T cell-mediated control of Chlamydia replication and their implications for intracellular epithelial pathogens in mouse models.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • CD4-Positive T-Lymphocytes / drug effects
  • CD4-Positive T-Lymphocytes / immunology*
  • CD4-Positive T-Lymphocytes / metabolism
  • CD4-Positive T-Lymphocytes / microbiology*
  • Cell Line
  • Chlamydia Infections / immunology
  • Chlamydia Infections / microbiology
  • Chlamydia muridarum / growth & development
  • Chlamydia muridarum / immunology*
  • Clone Cells
  • Epithelial Cells / immunology*
  • Epithelial Cells / metabolism
  • Epithelial Cells / microbiology*
  • Female
  • Genital Diseases, Female / immunology
  • Genital Diseases, Female / microbiology
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Nitric Oxide / biosynthesis
  • Nitric Oxide / pharmacology
  • Nitric Oxide / physiology*

Substances

  • Nitric Oxide