Related Experiment Videos
Early stages in the interaction between Mycoplasma gallisepticum and the chick trachea, as related to pathogenicity
Abstract:
Mycoplasma strains, which occur naturally or as the result of laboratory manipulation, differ markedly in biological properties such as pathogenicity, infectivity, transmissibility, and immunogenicity. These properties are clinical expressions of a series of complex interactions between the mycoplasma organisms and the host. We have focused on the early interactions occurring at the level of the tracheal mucosa, with the intent of identifying Mycoplasma gallisepticum strains possessing a combination of properties suitable for use in a live vaccine. The ability of a strain to colonize the chick trachea was evaluated by reisolation from the infected organ, expressed as infective dose (ID50). In addition to studies in the live chick, we have employed an in vitro model system for the study of adherence of the mycoplasmas to human red blood cells (RBC). Several strains that colonized the chick trachea were studied, multiplying profusely in close proximity to the epithelial surface, but producing only moderate or transient tissue damage in vivo. Adherence in vivo occurred via the "bleb" region of the M. gallisepticum organisms. A serological response was elicited by colonizing pathogenic or nonpathogenic M. gallisepticum but not by strains that were found by other methods to be readily eliminated from the tracheal surface.
Insights
Researchers identified Mycoplasma gallisepticum strains for live vaccines by studying tracheal colonization in chicks. These strains adhere to the tracheal mucosa and elicit a serological response, indicating potential vaccine candidates.
Area of Science:
- Veterinary Microbiology
- Immunology
- Vaccine Development
Background:
- Mycoplasma strains exhibit diverse biological properties influencing host interactions.
- Understanding early host-pathogen interactions is crucial for vaccine design.
- Mycoplasma gallisepticum is a significant poultry pathogen.
Purpose of the Study:
- To identify Mycoplasma gallisepticum strains suitable for live vaccine development.
- To evaluate early interactions between M. gallisepticum and the chick tracheal mucosa.
- To assess strain colonization, adherence, and immunogenicity in vivo.
Main Methods:
- In vivo studies involving chick tracheal colonization and reisolation (ID50).
- In vitro adherence assays using human red blood cells (RBC).
- Evaluation of tissue damage and serological response post-infection.
Main Results:
- Several M. gallisepticum strains colonized the chick trachea, adhering via the "bleb" region.
- Colonizing strains multiplied near the epithelial surface with moderate or transient tissue damage.
- Both pathogenic and nonpathogenic M. gallisepticum elicited a serological response upon colonization.
Conclusions:
- M. gallisepticum strains capable of sustained tracheal colonization and eliciting an immune response are potential candidates for live vaccines.
- Adherence mechanisms and colonization efficiency are key factors for vaccine efficacy.
- Further research into specific strain properties can optimize vaccine development against Mycoplasma infections.