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Interaction of Mycoplasma pulmonis with mouse peritoneal macrophages and polymorphonuclear leucocytes
Abstract:
Mouse peritoneal macrophages and polymorphonuclear leucocytes were examined for their ability to kill Mycoplasma pulmonis in vitro. Killing of mycoplasmas was shown to require specific antibody, suggesting that antibody-dependent phagocytosis may be involved in resistance to infection. Convalescent mouse serum appeared to be less effective than rabbit antiserum in promoting the killing of mycoplasmas by phagocytic cells. Moreover, mycoplasmas recovered directly from the respiratory tract of infected mice were more resistant to killing by macrophage cultures than organisms grown in vitro. The possibility that these observations may contribute to an understanding of the persistent nature of M. pulmonis infections in mice is discussed.
Insights
Antibody-dependent phagocytosis aids in clearing Mycoplasma pulmonis. However, in vivo-grown Mycoplasma pulmonis exhibit increased resistance to phagocytic cells, potentially explaining persistent infections.
Area of Science:
- Immunology
- Microbiology
- Infectious Diseases
Background:
- Mycoplasma pulmonis is a common respiratory pathogen in mice.
- Understanding host-pathogen interactions is crucial for controlling Mycoplasma pulmonis infections.
Purpose of the Study:
- To investigate the mechanisms of Mycoplasma pulmonis killing by murine phagocytic cells.
- To explore factors influencing Mycoplasma pulmonis resistance to phagocytosis.
Main Methods:
- In vitro killing assays using mouse peritoneal macrophages and polymorphonuclear leucocytes.
- Comparison of killing efficacy using convalescent mouse serum versus rabbit antiserum.
- Assessment of the resistance of in vivo-passaged Mycoplasma pulmonis to phagocytic killing.
Main Results:
- Specific antibody is required for Mycoplasma pulmonis killing by phagocytic cells, indicating antibody-dependent phagocytosis.
- Rabbit antiserum was more effective than convalescent mouse serum in promoting mycoplasmal killing.
- Mycoplasma pulmonis recovered from infected mouse respiratory tracts were significantly more resistant to macrophage-mediated killing than in vitro-grown organisms.
Conclusions:
- Antibody-dependent phagocytosis plays a role in resistance to Mycoplasma pulmonis infection.
- In vivo adaptation may enhance Mycoplasma pulmonis survival against host immune defenses.
- Observed resistance mechanisms may contribute to the persistence of Mycoplasma pulmonis infections in mice.