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Role of gamma-delta T cells in murine Chlamydia trachomatis infection
D M Williams1, B G Grubbs, K Kelly
1Division of Infectious Diseases, Audie L. Murphy Memorial Veterans Hospital, San Antonio, Texas, USA.
Abstract:
The role of gamma-delta T cells in host resistance to Chlamydia trachomatis was characterized by using a murine model of pneumonia caused by the mouse pneumonitis agent (MoPn), murine C. trachomatis. At days 3 and 7 after infection, gamma-delta T-cell-deficient knockout mice had significantly higher levels of MoPn in the lungs than did immunologically intact controls. At day 20, paradoxically, gamma-delta T-cell-deficient mice were more resistant to MoPn than were controls. This increased resistance was not due to an increased production of toxic cytokines or interleukin-10 in controls on that day. Gamma-delta T cells play a role in protection early in MoPn infection, but they may be deleterious later in infection, as has been observed in models of salmonella and trypanosome infection.
Insights
Gamma-delta T cells aid early Chlamydia trachomatis lung infection clearance but may hinder host resistance later. This study reveals their dual role in host defense against this bacterial pneumonia.
Area of Science:
- Immunology
- Microbiology
- Infectious Diseases
Background:
- Chlamydia trachomatis causes pneumonia.
- Gamma-delta T cells are immune cells with diverse functions.
- Their specific role in Chlamydia trachomatis infection is not fully understood.
Purpose of the Study:
- To investigate the role of gamma-delta T cells in host resistance to Chlamydia trachomatis pneumonia.
- To characterize the impact of gamma-delta T cell deficiency on Chlamydia trachomatis infection dynamics and outcomes.
Main Methods:
- Utilized a murine model of pneumonia caused by the mouse pneumonitis agent (MoPn), a strain of C. trachomatis.
- Compared MoPn lung burden and host resistance in gamma-delta T-cell-deficient knockout mice versus immunologically intact controls at different time points post-infection.
Main Results:
- Gamma-delta T-cell-deficient mice exhibited significantly higher MoPn levels in the lungs at early infection stages (days 3 and 7).
- Paradoxically, these deficient mice showed increased resistance to MoPn by day 20 post-infection.
- This later-stage resistance was not attributed to increased toxic cytokine or interleukin-10 production in control mice.
Conclusions:
- Gamma-delta T cells play a protective role during the early phase of MoPn infection.
- Conversely, gamma-delta T cells may have a detrimental or deleterious effect later in the course of infection.
- These findings suggest a complex, time-dependent role for gamma-delta T cells in host defense against Chlamydia trachomatis, similar to observations in other infections.