Measles encephalitis in rodents: defective expression of viral proteins

Area of Science:

• Virology
• Neuroscience
• Immunology

Background:

• Measles virus (MeV) infection can cause neurological complications.
• Different MeV strains exhibit varying neurovirulence.
• Understanding viral protein synthesis is crucial for MeV pathogenesis.

Purpose of the Study:

• To investigate the synthesis of measles virus structural proteins in rodent brains and cell cultures infected with the hamster neurotropic (HNT) strain.
• To compare protein synthesis between the HNT strain and the LEC strain of measles virus.
• To explore potential mechanisms underlying restricted viral replication of the HNT strain.

Main Methods:

• Infection of adult BALB/C mice and suckling hamsters with HNT and LEC strains.
• Infection of Vero cell cultures with HNT and LEC strains.
• Detection of five measles virus structural proteins (NP, P, HA, M, N) using monoclonal antibodies.
• Histopathological examination of infected brain tissues.

Main Results:

• In HNT-infected adult mouse brains, only nucleocapsid (NP) and phosphoprotein (P) were detected.
• Suckling hamster brains infected with HNT showed NP, P, and hemagglutinin (HA) proteins.
• Vero cell cultures infected with HNT lacked matrix (M) protein expression.
• In contrast, all five structural proteins were detected in LEC strain-infected brains and cell cultures.
• HNT infection in adult mice showed minimal inflammation, with viral antigen in the cerebral cortex and selective hippocampal pyramidal cell necrosis.

Conclusions:

• Restricted replication of the HNT strain may stem from defective matrix (M) protein expression.
• Cellular suppression cannot be ruled out as a cause for restricted HNT replication.
• Hippocampal necrosis in HNT-infected mice did not correlate with observed virus replication levels.