Pathologic changes and immune responses against Coxiella burnetii in mice following infection via non-invasive intratracheal inoculation

PLoS One. 2019 Dec 5;14(12):e0225671. doi: 10.1371/journal.pone.0225671. eCollection 2019.

Abstract

Q fever is a worldwide zoonosis caused by Coxiella burnetii. Human Q fever is typically acquired through inhalation of contaminated aerosols, resulting in an initial pulmonary infection. In this study, BALB/c mice were infected with C. burnetii via an intratracheal (IT) route using a non-invasive aerosol pulmonary delivery device to directly place the living C. burnetii organisms into the lungs of the mice. The bacterial loads, pathological lesions, and antibody and cellular responses were analyzed and compared with those of mice infected via an intraperitoneal (IP) route. Compared with mice infected via an IP route, mice infected via an IT route exhibited a higher bacterial load and more severe pathological lesions in the heart and lungs at days 3 and 7 post-infection (pi). The levels of interferon-γ and IL-12p70 in the serum of mice infected via the IT route were significantly higher than those of mice infected via the IP route at day 3 pi. In conclusion, this murine model of acute C. burnetii infection via IT inoculation closely resembles the natural route of C. burnetii infection than that of IP injection. Thus, this newly developed model will be useful for investigating the pathogenesis and immunity of C. burnetii aerosol infection, as well as for the evaluation of therapeutic drugs and preventive vaccines of Q fever.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aerosols
  • Animals
  • Coxiella burnetii / immunology*
  • Disease Models, Animal
  • Female
  • Infusions, Parenteral
  • Interferon-gamma / immunology
  • Interleukin-12 / immunology
  • Lung / immunology
  • Mice
  • Mice, Inbred BALB C
  • Q Fever / immunology*
  • Q Fever / pathology*

Substances

  • Aerosols
  • Interleukin-12
  • Interferon-gamma

Grants and funding

This work was supported by the National Natural Science Foundation of China [31970178], State Key Laboratory of Pathogen and Biosecurity [SKLPBS1802] and the Beijing Nova Program [Z181100006218116]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript