Localizations of NS3 and E proteins in mouse brain infected with mutant strain of Japanese encephalitis virus

Area of Science:

• Virology
• Neuroscience
• Immunology

Background:

• Japanese encephalitis virus (JEV) causes significant neurological disease.
• Understanding JEV attenuation mechanisms is crucial for developing safer vaccines and therapeutics.
• Previous studies indicated varying neurovirulence among JEV strains.

Purpose of the Study:

• To investigate the cellular localization and intracellular behavior of JEV proteins in a less neurovirulent strain (RP-2ms).
• To elucidate the mechanisms underlying the reduced neurovirulence of the RP-2ms JEV strain.
• To compare the intracellular viral replication and protein distribution between JEV strains.

Main Methods:

• Infection of BALB/c mice and cultured cells with JEV strains.
• Immunocytochemistry to detect non-structural 3 (NS3) and envelope (E) proteins.
• Immunoelectron microscopy to visualize viral particles and protein localization within cellular structures.
• Comparative analysis of viral titers and protein distribution.

Main Results:

• The RP-2ms JEV strain exhibited reduced neurovirulence in mice compared to wild-type and RP-9 strains.
• Higher intracellular viral titers were observed in RP-2ms infected cultured cells.
• NS3 protein localized to specific neuronal populations in the cerebrum and cerebellum, sparing Purkinje cells.
• E and NS3 proteins were detected in JEV-induced membranous systems, including hypertrophic rough endoplasmic reticulum (rER) and membrane vesicle structures (MVS).
• Virus particles were found in the Golgi apparatus, rER, nuclear envelope, MVS, and cytoplasmic vacuoles.

Conclusions:

• The RP-2ms JEV strain demonstrates distinct intracellular localization patterns and trapping mechanisms.
• These unique intracellular mechanisms likely contribute to the attenuated neurovirulence of the RP-2ms JEV strain.
• Further research into these mechanisms could inform the development of JEV vaccines and antivirals.