YopH inhibits early pro-inflammatory cytokine responses during plague pneumonia
1 Department of Microbiology and Immunology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX 78229, USA
2 Department of Biology, University of Texas at San Antonio, One UTSA circle, San Antonio, TX 78249, USA
BMC Immunology 2010, 11:29 doi:10.1186/1471-2172-11-29Published: 16 June 2010
Yersinia pestis is the causative agent of pneumonic plague; recently, we and others reported that during the first 24-36 hours after pulmonary infection with Y. pestis pro-inflammatory cytokine expression is undetectable in lung tissues.
Here, we report that, intranasal infection of mice with CO92 delta yopH mutant results in an early pro-inflammatory response in the lungs characterized by an increase in the pro-inflammatory cytokines Tumor Necrosis Factor-alpha and Interleukin one-beta 24 hours post-infection. CO92 delta yopH colonizes the lung but does not disseminate to the liver or spleen and is cleared from the host within 72 hours post-infection. This is different from what is observed in a wild-type CO92 infection, where pro-inflammatory cytokine expression and immune cell infiltration into the lungs is not detectable until 36-48 h post-infection. CO92 rapidly disseminates to the liver and spleen resulting in high bacterial burdens in these tissues ultimately cumulating in death 72-94 h post-infection. Mice deficient in TNF-alpha are more susceptible to CO92 delta yopH infection with 40% of the mice succumbing to infection.
Altogether, our results suggest that YopH can inhibit an early pro-inflammatory response in the lungs of mice and that this is an important step in the pathogenesis of infection.