Supplementary Material for: Bacillus Calmette-Guérin Confers Neuroprotection in a Murine Model of Japanese Encephalitis

Objective: Japanese encephalitis (JE) is a debilitating
disease caused by infection with the JE virus (JEV; family:
Flaviviridae), which leaves neurological sequelae in survivors but more
often leads to mortality. Neurodegeneration caused by inflammation is
the primary pathology behind the clinical manifestation of encephalitis
caused by JEV. Bacillus Calmette-Guérin (BCG) has been used in
immunoprophylaxis for tuberculosis and in the adjuvant therapy of many
malignancies, and has exhibited neuroprotective activities in
experimental models of Parkinson and Alzheimer disease. This study aimed
at assessing the neuroprotective role of BCG in a murine model of JE. Methods: Suckling mice were inoculated with 106 CFU of BCG and at 18 days postinoculation were challenged with 100 LD50
of JEV. PBS-inoculated mice were used as controls. Mice were sacrificed
on days 2, 4, 6, and 8. Brain tissue was homogenized for RNA
extraction. One-step real-time RT-PCR was performed to assess the
relative gene expressions of TNF-α, IL-6, and iNOS. Results:
The BCG-inoculated (BCG+JEV) group exhibited a significant delay in the
presentation of neuropathological symptoms, longer survival, and a
downregulation in the expression of TNF-α, IL-6, and iNOS on days 2, 4,
and 6 post-JEV challenge compared to the JEV group. Conclusion:
These findings indicate that the administration of BCG offers
neuroprotection in the murine model of JE. BCG should therefore be
further investigated as an adjuvant in the management of JE. BCG is an
accepted vaccine for tuberculosis in many countries that are endemic for
JEV. This approach may have a significant impact on the public health
burden in these countries.