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Characterization of a human lung fibroblast receptor site for Mycoplasma pneumoniae
1Bionique Laboratories, Inc., Saranac Lake, NY 12983.
Abstract:
Mycoplasma pneumoniae, a respiratory pathogen of humans, is the etiologic agent of primary atypical pneumonia. The mycoplasma attaches to the host cell by means of a specialized terminal structure. This structure binds the organism to the corresponding receptor site on the host cell. A glycoprotein receptor site for M. pneumoniae was isolated from MRC-5 human lung fibroblasts. It was isolated from a Triton X-100 extract by column affinity chromatography, utilizing wheat germ agglutinin bound sepharose 6MB. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed it to have an MW of approximately 100 kilodaltons (kDa) and to be composed of subunits of approximately 21 kDa. At a concentration of 56 micrograms/ml, the receptor inhibited the binding of 14C-labeled M. pneumoniae to MRC-5 fibroblasts by 77%. Chemical analysis determined that it does not contain any detectable sialic acid. Knowledge of the biochemical and immunological characteristics of the receptor site are essential to understand the attachment phase of the pathogenic process and to further the development of effective prophylaxis.
Insights
Researchers identified a specific glycoprotein receptor on human lung cells that Mycoplasma pneumoniae uses for attachment. This finding is crucial for understanding and preventing this respiratory pathogen.
Area of Science:
- Microbiology
- Cell Biology
- Biochemistry
Background:
- Mycoplasma pneumoniae is a significant cause of human respiratory infections, specifically primary atypical pneumonia.
- The pathogen utilizes a specialized terminal structure to adhere to host cells.
- Understanding the host cell receptor is key to elucidating the attachment mechanism.
Purpose of the Study:
- To isolate and characterize the specific host cell receptor for Mycoplasma pneumoniae.
- To investigate the biochemical properties of the identified receptor.
- To assess the receptor's role in M. pneumoniae attachment to host cells.
Main Methods:
- Isolation of the receptor from MRC-5 human lung fibroblasts using Triton X-100 extraction and affinity chromatography with wheat germ agglutinin.
- Analysis of the receptor's molecular weight and subunit composition using SDS-PAGE.
- Inhibition assays to quantify the receptor's effect on M. pneumoniae binding.
Main Results:
- A glycoprotein receptor with an approximate molecular weight of 100 kDa, composed of 21 kDa subunits, was isolated.
- The receptor demonstrated no detectable sialic acid.
- At 56 µg/ml, the isolated receptor inhibited M. pneumoniae binding to fibroblasts by 77%.
Conclusions:
- A specific glycoprotein receptor on human lung fibroblasts mediates Mycoplasma pneumoniae attachment.
- The receptor's biochemical characteristics, including the absence of sialic acid, provide insights into the interaction.
- Further understanding of this receptor is vital for developing strategies against M. pneumoniae infections.