Profiling of cellular immune responses to Mycoplasma pulmonis infection in C57BL/6 and DBA/2 mice

Area of Science:

• Immunology
• Microbiology
• Infectious Diseases

Background:

• Mycoplasma infections cause significant respiratory issues globally in humans and animals.
• Murine respiratory mycoplasmosis is a common disease model, with varying susceptibility observed in different mouse strains.
• Understanding strain-specific immune responses is crucial for managing Mycoplasma pulmonis (M. pulmonis) infections.

Purpose of the Study:

• To compare cellular immune responses between resistant C57BL/6NCrSlc (B6) and susceptible DBA/2CrSlc (D2) mice following M. pulmonis infection.
• To elucidate the immunological basis for differential susceptibility to murine respiratory mycoplasmosis.

Main Methods:

• Infection of B6 and D2 mice with M. pulmonis.
• Quantification of bacterial load in lung tissue.
• Analysis of pulmonary immune cell infiltration (neutrophils, macrophages, lymphocytes).
• Measurement of pro-inflammatory cytokines (IL-1β, IL-6, IL-17A, TNF-α) in bronchoalveolar lavage fluid.

Main Results:

• DBA/2 mice displayed significantly higher bacterial proliferation in the lungs compared to B6 mice.
• Increased infiltration of neutrophils, macrophages, and lymphocytes was observed in the lungs of D2 mice.
• Elevated levels of IL-1β, IL-6, IL-17A, and TNF-α were detected in bronchoalveolar lavage fluid from D2 mice.

Conclusions:

• DBA/2 mice are more susceptible to M. pulmonis infection than B6 mice.
• A hyper-inflammatory immune response characterized by elevated cytokine production and immune cell infiltration contributes to the susceptibility of D2 mice.
• These findings highlight the role of host immune response in the pathogenesis of murine respiratory mycoplasmosis.