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Reproduction of vaccine and virulent Rickectsia prow azeki strains in continuous cell lines at different temperatures
Abstract:
The features of intracellular development of the virulent Breinl strain and 3 vaccine E strains of Rickettsia prowazeki have been followed in continuous FL, McCoy, and B cell cultures at temperatures of 30, 35, 37, 38.5 and 40 degrees C. The virulent Breinl strain multiplied well at these temperatures in McCoy and B cells but in had been gradually lost when cultured at 40 degrees C in FL cells. In contrast to the virulent Breinl strain the vaccine E strains have lost their capacity of long term reproduction at 38.5 degrees C. At 40 degrees C the E strains did not multiply in and had been eliminated from the McCoy and B cells; thus the vaccine E strains revealed a ts-phenotype and, accordingly, it was found to represent a ts-mutant.
Insights
Vaccine strains of Rickettsia prowazeki showed temperature sensitivity (ts-phenotype), losing reproductive capacity at higher temperatures. This suggests these vaccine strains are ts-mutants, impacting their use in certain conditions.
Area of Science:
- Microbiology
- Cell Biology
- Virology
Background:
- Rickettsia prowazeki causes epidemic typhus.
- Understanding vaccine strain behavior is crucial for efficacy and safety.
Purpose of the Study:
- To investigate the intracellular development of virulent and vaccine strains of Rickettsia prowazeki.
- To determine the effect of temperature on the growth and viability of these strains in cell cultures.
Main Methods:
- Culturing virulent (Breinl) and vaccine (E) strains of Rickettsia prowazeki.
- Utilizing FL, McCoy, and B cell lines.
- Incubating cultures at various temperatures (30, 35, 37, 38.5, and 40°C).
Main Results:
- The virulent Breinl strain multiplied well in McCoy and B cells across tested temperatures, but showed reduced growth in FL cells at 40°C.
- Vaccine E strains lost long-term reproductive capacity at 38.5°C.
- At 40°C, vaccine E strains failed to multiply and were eliminated from McCoy and B cells, indicating a ts-phenotype.
Conclusions:
- Vaccine E strains of Rickettsia prowazeki exhibit temperature sensitivity (ts-phenotype).
- These strains are identified as temperature-sensitive mutants (ts-mutants).
- Findings suggest potential limitations for vaccine E strain use at elevated temperatures.