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Protection of mice against vaginal colonisation by Mycoplasma pulmonis
1Division of Sexually Transmitted Diseases, Clinical Research Centre, Harrow, Middlesex.
Abstract:
Resistance against vaginal colonisation by Mycoplasma pulmonis in strain TO mice after exposure to the mycoplasma was investigated. Eighteen mice from which M. pulmonis had been eliminated from the vagina, either naturally or by antibiotic therapy, were resistant to vaginal recolonisation. Specific antibody was measured by an indirect microimmunofluorescence technique and the geometric mean titre (GMT) for each group of mice is presented. Almost all of 31 mice that had developed circulating antibody (GMT 83) or local antibody (GMT 40), or both, after vaginal exposure were resistant to re-colonisation, as were those in which antibodies could not be detected. Seven other mice which had been colonised only in the oropharynx previously and which possessed antibody--circulating (GMT 64) or local (GMT 30), or both--were resistant to vaginal colonisation, but 13 mice with little or no antibody after lack of colonisation at either anatomical site were susceptible. All of 15 mice given killed M. pulmonis organisms intravenously, despite developing circulating antibody in high titre (GMT 122), were susceptible to vaginal colonisation, as were 14 of 15 mice that developed circulating (GMT 15) and local antibodies after being given killed organisms intravaginally. However, 25 mice with high titres of circulating (GMT 154-170) or local (GMT 20) antibody, or both, after receiving live organisms intravenously, were less susceptible to vaginal colonisation (17 becoming colonised) than were 21 non-immunised mice (all becoming colonised) and the organisms were eradicated more rapidly from the former. Despite this, the mice that were colonised following intravenous inoculation of live organisms had pre-challenge antibody titres that were as great as those that were not colonised.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Mice previously exposed to Mycoplasma pulmonis developed resistance to vaginal colonization. Antibody presence correlated with resistance, though not always definitively, suggesting complex immune responses to Mycoplasma pulmonis infection.
Area of Science:
- Immunology
- Microbiology
- Veterinary Science
Background:
- Mycoplasma pulmonis is a common respiratory pathogen in rodents.
- Vaginal colonization by M. pulmonis can lead to reproductive issues and chronic infections.
- Understanding host resistance mechanisms is crucial for controlling M. pulmonis spread.
Purpose of the Study:
- To investigate the development of resistance against vaginal colonization by Mycoplasma pulmonis in mice.
- To determine the role of specific antibodies in conferring protection against M. pulmonis vaginal recolonization.
Main Methods:
- Mice were exposed to live or killed M. pulmonis organisms via different routes (vaginal, intravenous).
- Vaginal colonization was assessed after challenge.
- Specific antibody titers (circulating and local) were measured using indirect microimmunofluorescence.
Main Results:
- Mice previously cleared of M. pulmonis were resistant to recolonization.
- Presence of circulating or local antibodies generally correlated with resistance to vaginal colonization.
- Mice immunized with killed M. pulmonis showed susceptibility, indicating limitations of killed vaccines.
- Mice receiving live M. pulmonis intravenously showed reduced susceptibility and faster clearance, despite some colonization.
Conclusions:
- Prior exposure and clearance of M. pulmonis can induce resistance to vaginal colonization.
- Humoral immunity plays a role in resistance, but its effectiveness varies depending on the immunization method.
- Live M. pulmonis challenge induces a more robust protective response than killed vaccines.