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Antigenic differences within the species Mycoplasma hominis
Abstract:
Membrane and soluble fractions of one genital and two oral strains of Mycoplasma hominis were compared by immunodiffusion and polyacrylamide gel electrophoresis. Differences were demonstrated between the membrane antigens of the three strains by immunodiffusion, and the membrane proteins also gave dissimilar patterns in polyacrylamide gel electrophoresis. The soluble fractions gave identical lines in immunodiffusion tests and similar patterns in polyacrylamide gel electrophoresis.When the strains were cross-titrated in metabolic inhibition (MI) and indirect haemagglutination (IHA) tests, statistical analysis of the results revealed significant differences between the strains. Previously, growth-inhibition, MI and IHA activity was shown to be associated with the membrane antigens of M. hominis, so the intraspecies differences revealed by MI and IHA correlate with the differences in the membrane antigens demonstrated by immunodiffusion. Growth-inhibition tests, which might also have been expected to show intraspecies differences, did not do so, probably because of the insensitivity of the test. In contrast to MI and IHA, complement-fixation (CF) tests revealed a high degree of relatedness between the strains. This is consistent with the observation that the soluble antigens of M. hominis participate in the CF reaction, and that the soluble antigens of different strains are identical in immunodiffusion tests.
Insights
Mycoplasma hominis strains show significant differences in membrane antigens, correlating with metabolic inhibition and indirect hemagglutination tests. Soluble antigens, however, appear conserved across strains.
Area of Science:
- Microbiology
- Immunology
- Molecular Biology
Background:
- Mycoplasma hominis is a common human pathogen.
- Understanding intraspecies variation is crucial for diagnostics and treatment.
- Previous studies linked growth-inhibition, metabolic inhibition (MI), and indirect hemagglutination (IHA) activity to membrane antigens.
Purpose of the Study:
- To compare membrane and soluble antigens of different Mycoplasma hominis strains.
- To investigate the correlation between antigen profiles and serological test results.
Main Methods:
- Immunodiffusion and polyacrylamide gel electrophoresis (PAGE) were used to analyze membrane and soluble fractions.
- Cross-titration in metabolic inhibition (MI) and indirect hemagglutination (IHA) tests were performed.
- Complement-fixation (CF) tests were conducted to assess strain relatedness.
Main Results:
- Immunodiffusion and PAGE revealed distinct differences in membrane antigens among the three Mycoplasma hominis strains.
- Soluble fractions showed identical immunodiffusion lines and similar PAGE patterns.
- MI and IHA tests demonstrated significant intraspecies differences, correlating with membrane antigen variations.
- Complement-fixation (CF) tests indicated a high degree of relatedness, consistent with conserved soluble antigens.
Conclusions:
- Mycoplasma hominis exhibits significant intraspecies antigenic diversity primarily in its membrane components.
- Metabolic inhibition and indirect hemagglutination assays effectively detect these membrane-based antigenic differences.
- Soluble antigens are conserved and contribute to the high relatedness observed in complement-fixation tests.