Pathogenicity of antigenic variants of murine coronavirus JHM selected with monoclonal antibodies

Abstract

To analyze the pathogenesis of the neurotropic murine coronavirus JHMV, we used monoclonal antibodies to the E2 viral glycoprotein to select antigenic variant viruses. Monoclonal antibodies J.7.2 and J.2.2 were shown to bind to topographically distinct regions of the E2 molecule, and the variants selected with the two antibodies demonstrated very different disease pictures in mice. Variants selected with J.7.2 were, like the parental virus, highly virulent and caused an acute encephalitic illness. By contrast, J.2.2-selected variants predominantly caused a subacute paralytic disease clinically and extensive demyelination histologically. Antigenic differences among the variants and parental virus were readily demonstrable with anti-E2 monoclonal antibodies. However, no differences between the viruses could be shown in binding studies with monoclonal antibodies directed against either El or N, the other two JHMV structural proteins. Since only J.2.2 selected demyelinating variants with reduced neurovirulence, it is likely that this monoclonal antibody recognizes a subregion of the E2 molecule that is particularly important in JHMV pathogenesis.

IL-21 optimizes T cell and humoral responses in the central nervous system during viral encephalitis

“…All mice were housed under pathogen free conditions at an accredited facility at the Cleveland Clinic Lerner Research Institute. Mice were infected at 6-7 wks of age by intracranial injection with 1000 plaque forming units (PFU) of the J.2.2v-1 monoclonal antibody (mAb)-derived gliatropic JHMV variant (Fleming et al, 1986). Animals were scored for clinical signs of disease with: 0, healthy; 1, ruffled fur and hunched back; 2, hind limb paralysis or inability to turn to upright position; 3, complete hind limb paralysis and wasting; and 4, moribund or dead.…”

“…Virus titers within the CNS were determined in clarified supernatants by plaque assay using the murine delayed brain tumor (DBT) astrocytoma as detailed (Fleming et al, 1986). Plaques were counted after 48 h incubation at 37°C.…”

PKR mediated regulation of inflammation and IL-10 during viral encephalomyelitis

“…Based on the limited knowledge of PKR mediated regulation of innate and adaptive responses during viral CNS infection, the present study sets out to characterize in vivo effects of PKR on immune modulation following infection with the sublethal, demyelinating gliatropic coronavirus JHMV. JHMV infection is initiated in the brain and spreads to the spinal cord, where it preferentially persists in oligodendrocytes (Fleming et al, 1986;Kapil et al, 2012). In wt mice infectious virus peaks between days 3-5 post infection (p.i.)…”

IL-15 independent maintenance of virus-specific CD8+ T cells in the CNS during chronic infection

“…Mice were infected between 6 and 8 weeks of age. Infections were initiated by intracerebral injection of 250 PFU of the J.2.2v-1 monoclonal Ab (mAb) neutralization derived JHMV variant as described (Fleming et al, 1986). For each experiment, mice were both sex-and age-matched, and groups of at least 3 individuals were analyzed per time point.…”