Bovine herpesvirus-5 infection in a rabbit experimental model: Immunohistochemical study of the cellular response in the CNS

Abstract

Since little information is available regarding cellular antigen mapping and the involvement of non-neuronal cells in the pathogenesis of bovine herpesvirus type 5 (BHV-5) infection, it were determined the BHV-5 distribution, the astrocytic reactivity, the involvement of lymphocytes and the presence of matrix metalloproteinase (MMP)-9 in the brain of rabbits experimentally infected with BHV-5. Twelve New Zealand rabbits that were seronegative for BHV-5 were used for virus inoculation, and five rabbits were used as mock-infected controls. The rabbits were kept in separate areas and were inoculated intranasally with 500 μl of virus suspension (EVI 88 Brazilian isolate) into each nostril (virus titer, 10(7.5) TCID50). Control rabbits were inoculated with the same volume of minimum essential medium. Five days before virus inoculation, the rabbits were submitted to daily administration of dexamethasone. After virus inoculation, the rabbits were monitored clinically on a daily basis. Seven rabbits showed respiratory symptoms and four animals exhibited neurological symptoms. Tissue sections were collected for histological examination and immunohistochemistry to examine BHV-5 antigens, astrocytes, T and B lymphocytes and MMP-9. By means of immunohistochemical and PCR methods, BHV-5 was detected in the entire brain of the animals which presented with neurological symptoms, especially in the trigeminal ganglion and cerebral cortices. Furthermore, BHV-5 antigens were detected in neurons and/or other non-neural cells. In addition to the neurons, most infiltrating CD3 T lymphocytes observed in these areas were positive for MMP-9 and also for BHV-5 antigen. These infected cells might contribute to the spread of the virus to the rabbit brain along the trigeminal ganglia and olfactory nerve pathways.

RETRACTED ARTICLE: Comparative analysis of the replication of bovine herpesvirus 1 (BHV1) and BHV5 in bovine-derived neuron-like cells

“…This in vitro model presents ethical and economic advantages over in vivo models [18,25]. For this purpose, suitable in vitro systems resembling in vivo situations and implementing the ''Three Rs Principle'' of Russell and Burch [?REFERENCE?]…”

Isolation and characterization of bovine herpes virus 5 (BHV5) from cattle in India

“…Besides, we could not detect evidence of BHV1 infection also in the farm. Although reproducing clinical BHV5 disease under experimental conditions is a tedious task, some laboratories have developed a rabbit model of encephalitits [34–38]. Although the isolated virus in our study was ~99% identical with the Brazilian BHV5 strains, its complete genetic characterization (whole genome sequencing) as well as its ability to produces encephalitis in natural host and/or in rabbits needs to be elucidated which is beyond the scope of this manuscript.…”

NTPDase and 5′-nucleotidase activities in synaptosomes of rabbits experimentally infected with BoHV-5

“…Seizures are a classical and severe clinical sign observed in animals with herpetic meningoencephalitis (Meyer et al 1996;Chowdhury et al 1997;Silva et al 1999;Dezengrini et al 2009;Machado et al 2013) and have been related to deficiency of some ectonucleotidase activities (Trams and Lauter 1978;Nagy et al 1990Nagy et al , 1997Young and Dragunow 1994). Furthermore, several studies showed that the stimulation of A1 receptors, induced by ADO, results in anticonvulsant effects (Chin 1989;Young and Dragunow 1994;Glass et al 1996).…”

“…On this early stage of infection, an elevated adenosine production may facilitate the entry of the virus into the target cell and the viral spread, once adenosine has anti-inflammatory properties. The difference in the activity of ectonucleotidases between the cerebral cortex and hippocampus can be related to the difference in the BoHV-5 infectivity, once the viral antigen and histological changes can be detected primarily in cortical neurons (Machado et al 2013;Dezengrini et al 2009) and the hippocampus and thalamus are described as the last brain regions to be affected during the BoHV-5 neuroinvasion (Dezengrini et al 2009). Also, it is suggested that the increased activity in hippocampus may be associated to granular cells found in this area and to the presence of axons from the dentate granule cells that synapse on pyramidal cells of CA3 hippocampal neurons and contains high levels of Zn 2 (Crawford and Connor 1972) that can increase the NTPDase activity (unpublished results of Handa and Guidotti cited by Wang and Guidotti 1998).…”

“…The main macroscopic lesions reported in the brain after BoHV-5 infection consists of parenchymal tissue softening and focal meningeal hemorrhages in the frontal and ventral areas (Carrillo et al 1983;Perez et al 2002;Dezengrini et al 2009). In the microscopic examination of brain regions, histological changes such as the presence of perivascular cuffs, neuronophagia, reactive astrocytes, astrogliosis, hemorrhages, neuronal degeneration, and necrosis can be observed in several brain structures, but mainly in the anterior and parietal cortex (Bagust and Clark 1972;Belknap et al 1994;Meyer et al 1996;Perez et al 2002;Dezengrini et al 2009;Machado et al 2013).…”