Related Experiment Videos
Neuraminidase activity and antigenicity of the egg adapted strains of mumps virus
Abstract:
Two freshly isolated mumps virus strains were adapted to embryonated eggs. The activity of their neuraminidase (NA) and their antigenicity were examined in the 5th, 10th and 15th passages. The NA was characterized by estimation of the Michaelis constant, while the antigenicity of virus strains was assessed by induction of antibodies as detected in complement fixation (CF) tests. The KM value for strain Berlin 9/76 NA in its 15th passage was 5.65 mmol/l and exceeded 4.2 times that of strain Berlin 1/76 (KM = 1.31 mmol/l). The KM values of both strains increased in the course of passaging by 55 or 260%, respectively. The antigenicity of both egg passaged strains remained unchanged. Under the same conditions, the Jeryl Lynn vaccine strain revealed a seroconversion rate of 44%; the KM value of the NA from this strain was closely similar to that of Berlin 1/76 virus in the 15th passage (= 1.34 mmol/l).
Insights
Mumps virus neuraminidase (NA) activity increased with egg adaptation, but antigenicity remained stable. This adaptation did not affect the virus
Area of Science:
- Virology
- Biochemistry
Background:
- Mumps virus adaptation to embryonated eggs is a common method for vaccine strain development.
- Understanding changes in viral enzyme activity and antigenicity during adaptation is crucial for vaccine efficacy.
Purpose of the Study:
- To investigate the impact of embryonated egg adaptation on the neuraminidase (NA) activity and antigenicity of two freshly isolated mumps virus strains.
- To compare the characteristics of adapted strains with a known vaccine strain.
Main Methods:
- Adaptation of mumps virus strains to embryonated eggs through serial passaging.
- Characterization of neuraminidase (NA) activity by determining Michaelis constant (KM) values.
- Assessment of viral antigenicity using complement fixation (CF) tests to detect antibody induction.
Main Results:
- Neuraminidase (NA) Michaelis constant (KM) values increased significantly with serial passaging for both mumps virus strains (55% and 260%).
- The antigenicity of the egg-passaged mumps virus strains remained unchanged throughout the passaging process.
- The Jeryl Lynn vaccine strain exhibited a KM value similar to one of the adapted strains and a 44% seroconversion rate.
Conclusions:
- Embryonated egg adaptation enhances mumps virus neuraminidase (NA) activity without altering its antigenicity.
- These findings suggest that NA activity changes during adaptation may not impact the immunogenicity of mumps virus vaccines.
- Further research is warranted to fully elucidate the implications of NA activity modulation on vaccine effectiveness.