Recombinant rabies virus vaccine strain SAD-L16 inoculated intracerebrally in young mice produces a severe encephalitis with extensive neuronal apoptosis

Department of Microbiology and Immunology, Queen's University, Kingston, Ontario.
Canadian journal of veterinary research = Revue canadienne de recherche vétérinaire (Impact Factor: 1.02). 05/2005; 69(2):100-5.
Source: PubMed


Seven-day-old ICR mice were infected by intracerebral inoculation with recombinant rabies virus vaccine strain SAD-L16. Infected mice developed severe and fatal encephalitis with rabies virus-infected neurons in widespread regions of the brain. There was extensive neuronal death with predominant features of apoptosis, as assessed by light and electron microscopy, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining, and immunohistochemical staining for activated caspase-3. Although SAD-L16 is a neuroattenuated rabies virus, it is fully capable of spreading efficiently and inducing widespread neuronal apoptosis in the immature mouse brain.

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    • "Previously, SAD B19 strain of RV was mainly and successfully used as a seed for the construction of viral vectors for generating live vaccines for HIV/SIV, HCV or SARS-CoV (Faber et al., 2005b; Faul et al., 2009; McKenna et al., 2003; Siler et al., 2002) and delivering cytokines as chemokines, cytochrome C, TNF-␣ and IFN-␤ (Pulmanausahakul et al., 2001; Faber et al., 2005a; Faul et al., 2008; Zhao et al., 2009; Kuang et al., 2009). However, since even SAD B19 and its derivate SAD I16 were pathogenic when inoculated directly into mouse brains, further efforts to attenuate the virus are necessary (Vos et al., 1999; Mebatsion, 2001; Rasalingam et al., 2005). Therefore, in this report, the highly attenuated Chinese human RV vaccine strain CTN181 (Du et al., 2008) is recommended as a more suitable candidate seed strain for development of new viral vectors. "
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    ABSTRACT: The recombinant rabies virus (RV) vectors encoding the secreted gene marker Gaussia luciferase (Gluc) were generated based on Chinese vaccine strain CTN181. Vectors included replication competent CTN-Gluc, CTN/G(Q333R)-Gluc, in which the amino acid in position 333 of glycoprotein was mutated from glutamine (Q) to arginine (R), and replication constrained CTNΔG-Gluc, in which the glycoprotein encoding gene (G) was deleted. The growth of recombinant RVs in transfected cells was confirmed through biochemical assays of Gluc activities. Gluc expression in recombinant CTNΔG-Gluc virus was highest while that in CTN/G(Q333R)-Gluc virus was lowest. The optimal time to harvest recombinant RVs was determined and the function of pathogenic and nonpathogenic rabies glycoprotein in virus recovery was examined. The addition of glycoprotein was slightly beneficial for virus recovery and the titer of rescued virus was lowered even when the amino acid in G333 position of glycoprotein was mutated from nonpathogenic Gln to pathogenic Arg. Conclusions: Viral vectors based on a human rabies vaccine strain CTN181 were successful. Gluc was useful as an in vitro gene marker for monitoring the growth of recombinant RVs iteratively in cell culture.
    Full-text · Article · May 2011 · Virus Research
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    • "The occurrence of neuronal death after encephalitis induced by rhabdoviruses remains controversial [41], [42], [43], [44], but in general, when it is unequivocally detected, it seems to be a microglial-mediated event (e.g. [45],[46]). "
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    Full-text · Article · Jan 2011 · PLoS ONE
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    • "96611) at a 1:200 dilution using a standard avidinbiotin complex ABC technique, as previously described (Rasalingam et al, 2005). Using the same methodology, we previously demonstrated specific caspase-3 immunostaining in many apoptotic brain neurons in an experimental model of rabies in mice (Rasalingam et al, 2005). Immunoperoxidase staining for the monocyte/macrophage marker CD68 (mouse monoclonal M0814, clone KP1, DAKO, at a 1:100 dilution) was also performed on selected serial sections of brain that showed positive staining for caspase-3. "
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    ABSTRACT: It is generally accepted that there are not prominent features of neuronal cell death in rabies encephalitis. However, Hemachudha and coworkers recently reported widespread apoptosis in the central nervous system of several human rabies cases (BMC Infect Dis 5: 104, 2005). In this study we have evaluated morphological features and markers of neuronal apoptosis in postmortem brain tissue from 12 cases of human rabies who died in four different countries. Histopathological analysis, TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling) staining, and immunostaining for cleaved (activated) caspase-3 were performed on paraffin-embedded tissues from the cerebral cortex, hippocampus, and brainstem, and additional regional areas from one of the cases. We did not find morphological evidence of neuronal apoptosis or TUNEL staining in any of the cases of rabies encephalitis. Similarly, immunostained cleaved caspase-3 was not seen in neurons, but prominent staining was observed in microglial processes. We conclude that neuronal apoptosis does not play an important pathogenetic role in human rabies encephalitis.
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