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Pathomorphologic characterization of CNS damage in monkeys infected with persistent variant of measles virus vaccine
O K Sharova1, N N Bogomolova, I B Koptyaeva
1Moscow Research Institute of Viral Preparations, U.S.S.R. Ministry of Health.
Abstract:
The lesions of CNS were examined in monkeys infected intracerebrally (i.c.) with a variant of measles virus vaccine strain L-16 isolated after prolonged persistence in human cell culture NEr-2. The persisting virus variant appeared pathogenic for monkeys. The changes which had developed in their CNS within 30 to 60 days post-infection (p.i.) were alike to acute measles encephalitis which was evidenced by giant cell formation at the injection site. Twenty-two months p.i. the chronic character of lesions was evident from the appearance of foci of neuron destruction. Based on morphologic findings it was suggested that strain L-16-H has acquired some properties characteristic of nonattenuated virus.
Insights
A measles virus vaccine strain, persisting in human cells, caused acute and chronic central nervous system (CNS) lesions in monkeys. This variant showed properties similar to non-attenuated measles virus, indicating potential pathogenicity.
Area of Science:
- Virology
- Neurology
- Pathology
Background:
- Measles virus vaccine strains are generally attenuated for safety.
- Virus variants can emerge after prolonged cell culture passage.
- Understanding virus behavior in vivo is crucial for vaccine safety and efficacy.
Purpose of the Study:
- To investigate the pathogenicity of a measles virus vaccine strain variant (L-16-H) after prolonged persistence in human cell culture.
- To characterize the central nervous system (CNS) lesions induced by this variant in a primate model.
Main Methods:
- Monkeys were inoculated intracerebrally with the measles virus variant L-16-H.
- Central nervous system (CNS) tissues were examined at 30-60 days and 22 months post-infection.
- Morphological analysis was used to identify pathological changes.
Main Results:
- The measles virus variant L-16-H induced acute CNS lesions resembling measles encephalitis, characterized by giant cell formation at the inoculation site.
- Chronic lesions, including foci of neuron destruction, were observed 22 months post-infection.
- The observed pathological changes suggest the variant retained or acquired properties of non-attenuated measles virus.
Conclusions:
- The measles virus vaccine strain variant L-16-H demonstrated pathogenicity in monkeys.
- The variant induced both acute and chronic CNS lesions, indicating a potential reversion to a more virulent phenotype.
- Morphological findings suggest that prolonged persistence in cell culture may alter the pathogenic potential of vaccine strains.