Susceptibility of BALB/c-nu/nu Mice and BALB/c Mice to Equine Herpesvirus 9 Infection

Abstract

This study aimed to clarify the timing and infectivity of equine herpesvirus 9 (EHV-9) infection in BALB/c-nu/nu mice and their immunocompetent counterpart (BALB/c). Following intranasal inoculation with 10(5) PFU of EHV-9, specimens from 8 mice per group were collected at different times postinoculation (PI) and assessed using histopathology, immunohistochemistry for viral antigen, and quantitative real-time polymerase chain reaction for ORF30 gene expression. In BALB/c-nu/nu mice, EHV-9 antigen was abundant in olfactory epithelia of all inoculated animals, and in the olfactory bulb of 1 animal. In contrast, only 1 BALB/c mouse per time point had rhinitis, with mild to moderate immunopositivity starting from 12 to 48 h PI, followed by a gradual virus clearance at 72 h PI. Statistically, significant differences were noted in the immunohistochemistry reactions between the 2 mouse strains, indicating that BALB/c-nu/nu is more susceptible to infection. Relative expression levels of ORF30 gene in olfactory epithelia were significantly different between the 2 groups, with the exception of 12 h PI, when BALB/c-nu/nu animals showed dramatic increases in ORF30 gene expression level until 48 h PI, followed by a decline in expression level until the end of experiment. In contrast, the expression level in brains showed no differences between mouse strain except at 96 h PI. In both strains, the highest messenger RNA expression was detected at 48 h PI, followed by a decline in BALB/c mice, proving a rapid clearance of virus in BALB/c and a gradual slowing down of the increased expression levels in BALB/c-nu/nu.

Evaluation of Viral Migration of Different Variants of Equid Alphaherpesvirus 1 in the Central Nervous System of Hamsters by Immunohistochemistry

“…EHV-9 viral antigens were detected in the olfactory epithelium, nerve and bulb in the first 48 hours post inoculation, while in the cerebral cortex and areas such as those connecting the trigeminal sensory nerve root to the brain stem, pons and medulla oblongata, positive detection was found at 60h PI [29]. Recent studies in mice have shown the EHV-1 and 9 migration from the olfactory epithelium to the olfactory bulb on day 3 post inoculation, but without viral migration to other areas of the CNS, probably due to the higher susceptibility to infection of the hamster in comparison to mice [16,45].…”

Characterizing the Pathogenesis and Immune Response of Equine Herpesvirus 8 Infection in Lung of Mice

“…We also investigated the host’s viral behavior and immune response [ 21 , 22 ]. Several reports have indicated that mice can serve as animal models for EHVs infection [ 12 , 19 , 23 , 24 ]. However, the pathogenicity and immune response of EHV-8 in mice is still unknown.…”

“…In the current study, the pathological findings of EHV-8 were interstitial pneumonia in the lung of BALB/c mice, which was similar to results observed for EHV-1 infection in a previous study [ 25 , 26 , 27 ]. However, the infection of EHV-9 in BALB/c mice develops necrosis of the olfactory epithelium [ 24 ]. Notably, the EHV-8 ORF70 gene was detected in the brain, which was closely related to viral encephalitis in mice in a previous study [ 12 ].…”

Application Route and Immune Status of the Host Determine Safety and Oncolytic Activity of Oncolytic Coxsackievirus B3 Variant PD-H

“…Animals used in CT-26Luc and Colon-26 cancer models had an intact immune system with an efficient T cell immune response that is lacking in nude mice [39]. It enables a more efficient clearance of virus and less severe illness, compared to immunodeficient mice [40][41][42]. Conceivably, virus mutants may be cleared before they manage to spread within the host.…”