Further studies on the Mycoplasma pneumoniae extract: ciliostatic and cell recruitment activities
D K Chandler1, M W Grabowski, A S Rabson
1Mycoplasma Laboratory, Food and Drug Administration, Bethesda, MD 20205.
Abstract:
Since inactivated vaccines have proved disappointing in preventing Mycoplasma pneumoniae disease, we have initiated studies to identify protective immunogens as candidates for an acellular, purified component vaccine. A cell-free extract was prepared, and was shown to have hemagglutination, attachment inhibition, and ciliostasis activities. Ciliostatic activity in hamster tracheal organ cultures was dependent on the time of incubation and on the amount of added extract. The ciliostatic factor was resistant to boiling and to trypsin and chymotrypsin digestion. When administered intratracheally to Golden Syrian hamsters, the extract induced lung lesions with histopathologic characteristics similar to those caused by virulent M. pneumoniae infection. Thus, in addition to attachment and ciliostatic factors, the extract contains factors that induce inflammatory responses in hamster lungs and cause cytotoxic damage to lung tissues.
Insights
Researchers are developing a new Mycoplasma pneumoniae vaccine using purified components. A cell-free extract showed potential by inhibiting bacterial attachment and causing ciliostasis, indicating its promise for preventing respiratory disease.
Area of Science:
- Microbiology
- Vaccinology
- Immunology
Background:
- Inactivated vaccines for Mycoplasma pneumoniae have shown limited efficacy.
- There is a need for effective acellular, purified component vaccines against M. pneumoniae.
Purpose of the Study:
- To identify protective immunogens from Mycoplasma pneumoniae for vaccine development.
- To characterize the biological activities of a cell-free M. pneumoniae extract.
Main Methods:
- Preparation of a cell-free extract from M. pneumoniae.
- Assay of hemagglutination, attachment inhibition, and ciliostasis activities.
- Intratracheal administration of the extract to Golden Syrian hamsters.
Main Results:
- The cell-free extract exhibited hemagglutination, attachment inhibition, and ciliostasis.
- Ciliostatic activity was time and dose-dependent and resistant to heat and proteases.
- Intratracheal administration induced lung lesions similar to virulent M. pneumoniae infection.
Conclusions:
- The M. pneumoniae extract contains factors responsible for attachment inhibition and ciliostasis.
- The extract also contains factors that induce inflammatory responses and cytotoxic damage in hamster lungs.
- These findings support the development of an acellular vaccine targeting identified immunogens.
