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Updated: Dec 23, 2025
Antigen-Capture Enzyme-Linked Immunosorbent Assay for Specific Detection of Mycoplasma pneumoniae
Published on: February 24, 2023
The Vsa shield of Mycoplasma pulmonis is antiphagocytic
Brandon M Shaw1, Warren L Simmons, Kevin Dybvig
1Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA.
Abstract:
The infection of mice with Mycoplasma pulmonis is a model for studying chronic mycoplasmal respiratory disease. Many in vivo and in vitro studies have used the organism to gain a better understanding of host-pathogen interactions in chronic respiratory infection. The organism's Vsa proteins contain an extensive tandem repeat region. The length of the tandem repeat unit varies from as few as 11 amino acids to as many as 19. The number of tandem repeats can be as high as 60. The number of repeats varies at a high frequency due to slipped-strand mispairing events that occur during DNA replication. When the number of repeats is high, e.g., 40, the mycoplasma is resistant to lysis by complement but does not form a robust biofilm. When the number of repeats is low, e.g., 5, the mycoplasma is killed by complement when the cells are dispersed but has the capacity to form a biofilm that resists complement. Here, we examine the role of the Vsa proteins in the avoidance of phagocytosis and find that cells producing a protein with many tandem repeats are relatively resistant to killing by macrophages. These results may be pertinent to understanding the functions of similar proteins that have extensive repeat regions in other microbes.
Insights
Mycoplasma pulmonis Vsa proteins with numerous tandem repeats help bacteria evade macrophage killing. This finding aids understanding of microbial protein repeat functions in chronic respiratory infections.
Area of Science:
- Microbiology
- Immunology
- Molecular Biology
Background:
- Mycoplasma pulmonis infection in mice models chronic respiratory disease.
- Vsa proteins in Mycoplasma pulmonis feature variable tandem repeat regions.
- Repeat number variation influences Mycoplasma pulmonis interactions with host immune components.
Purpose of the Study:
- To investigate the role of Vsa proteins in evading phagocytosis.
- To determine how tandem repeat length in Vsa proteins affects macrophage resistance.
Main Methods:
- Infection of mice with Mycoplasma pulmonis.
- In vitro and in vivo studies of host-pathogen interactions.
- Analysis of Vsa protein tandem repeat regions and their variation.
Main Results:
- High Vsa tandem repeat numbers confer resistance to complement-mediated lysis and promote biofilm formation.
- Low Vsa tandem repeat numbers lead to complement sensitivity but enhanced biofilm resistance.
- Mycoplasma pulmonis with numerous Vsa tandem repeats show increased resistance to macrophage killing.
Conclusions:
- Vsa protein tandem repeat variation is crucial for Mycoplasma pulmonis survival strategies.
- The Vsa protein's repeat region plays a significant role in evading phagocytosis.
- Findings offer insights into similar repeat-containing proteins in other microbial pathogens.
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