The Immunopathologic Effects of Mycoplasma pneumoniae and Community-acquired Respiratory Distress Syndrome Toxin. A
Diego J Maselli1, Jorge L Medina2,3, Edward G Brooks3,4
11 Division of Pulmonary Diseases and Critical Care Medicine, Department of Medicine.
Abstract:
Mycoplasma pneumoniae infection has been linked to poor asthma outcomes. M. pneumoniae produces an ADP-ribosylating and vacuolating toxin called community-acquired respiratory distress syndrome (CARDS) toxin that has a major role in inflammation and airway dysfunction. The objective was to evaluate the immunopathological effects in primates exposed to M. pneumoniae or CARDS toxin. A total of 13 baboons were exposed to M. pneumoniae or CARDS toxin. At Days 7 and 14, BAL fluid was collected and analyzed for cell count, percent of each type of cell, CARDS toxin by PCR, CARDS toxin by antigen capture, eosinophilic cationic protein, and cytokine profiles. Serum IgM, IgG, and IgE responses to CARDS toxin were measured. All animals had a necropsy for analysis of the histopathological changes on lungs. No animal developed signs of infection. The serological responses to CARDS toxin were variable. At Day 14, four of seven animals exposed to M. pneumoniae and all four animals exposed to CARDS toxin developed histological "asthma-like" changes. T cell intracellular cytokine analysis revealed an increasing ratio of IL-4/IFN-γ over time. Both M. pneumoniae and CARDS toxin exposure resulted in similar histopathological pulmonary changes, suggesting that CARDS toxin plays a major role in the inflammatory response.
Insights
Mycoplasma pneumoniae and its CARDS toxin cause asthma-like lung changes in primates. The toxin is a key driver of airway inflammation and dysfunction, impacting asthma outcomes.
Area of Science:
- Pulmonary immunology
- Microbial pathogenesis
Background:
- Mycoplasma pneumoniae infection is associated with adverse asthma outcomes.
- The bacterium produces the community-acquired respiratory distress syndrome (CARDS) toxin, implicated in airway inflammation and dysfunction.
Purpose of the Study:
- To investigate the immunopathological effects of M. pneumoniae and CARDS toxin exposure in a primate model.
- To evaluate the role of CARDS toxin in mediating inflammation and airway changes.
Main Methods:
- 13 baboons were exposed to M. pneumoniae or CARDS toxin.
- Bronchoalveolar lavage (BAL) fluid and serum were analyzed for cellular, molecular, and serological markers.
- Pulmonary histopathology was assessed post-necropsy.
Main Results:
- Histological "asthma-like" changes were observed in animals exposed to M. pneumoniae and CARDS toxin by Day 14.
- An increased IL-4/IFN-γ ratio was noted in T cells over time.
- CARDS toxin exposure alone induced pulmonary changes similar to those seen with M. pneumoniae infection.
Conclusions:
- CARDS toxin plays a significant role in the pulmonary inflammatory response associated with M. pneumoniae infection.
- The findings suggest CARDS toxin as a potential therapeutic target for mitigating M. pneumoniae-induced airway dysfunction.
More Related Videos
09:17A Robust Pneumonia Model in Immunocompetent Rodents to Evaluate Antibacterial Efficacy against S. pneumoniae, H. influenzae, K. pneumoniae, P. aeruginosa or A. baumannii
Published on: January 2, 2017
09:49Experimental Model to Evaluate Resolution of Pneumonia
Published on: February 17, 2023
