The recruitment of peripheral blood leukocytes to the brain is delayed in susceptible BALB/c compared to resistant C57BL/6 mice during herpes simplex virus encephalitis

AbstractThe cerebral immune response induced by herpes simplex virus (HSV) encephalitis (HSE) was evaluated in susceptible BALB/c and resistant C57BL/6 mice. BALB/c and C57BL/6 (named C57BL/6-high) mice were respectively infected intranasally with 1  × 103 and 5  × 105 plaque-forming units (PFUs) of HSV-1. C57BL/6 mice (named C57BL/6-low) infected with a low inoculum (1  × 103 PFUs) of HSV-1 were tested in parallel. Mice were monitored for weight loss, sickness signs, and survival for 21  days. The viral load, infectious titers, cytokine/chemokine levels, and peripheral leukocyte infiltration were determined in brain homogenates on days 0 (non-infected), 4, 6, and 8 post-infection (p.i.) by qPCR, plaque assay, ELISA/Luminex™, and flow cytometry, respectively. Our results showed t hat the mortality of BALB/c mice (67%) was higher compared to those of C57BL/6-low (0%;P ≤ 0.01) and C57BL/6-high (20%;P ≤ 0.05) animals. This higher mortality was associated with increased infectious titers and cytokine/chemokine levels in the brains of BALB/c compared to C57BL/6 mice. Recruitment of inflammatory monocytes, dendritic cells, natural killer, and natural killer T cells to the brain was higher in C57BL/6-high compared to BALB/c animals on day 4 p.i. Infiltration of inflammatory monocytes and T cells in the brain of BALB/c mice was seen on day 6 p.i. Our data suggest that a rapid, sustained, and coordinated recruitment of peripheral leukocytes to the brain o...
Source: Journal of NeuroVirology - Category: Neurology Source Type: research