A neonatal murine model for evaluation of enterovirus E HY12 virus infection and pathogenicity

Abstract

BackgroundsHY12 viruses are enteroviruses recently isolated from cattle characterized by severe respiratory and digestive disease with high morbidity and mortality in China. While the viruses exhibit unique biological and molecular characters distinct from known enterovirus E, the pathogenicity and viral pathogenesis remains largely unknown.MethodsNeonatal mice of Balb/C, ICR, and Kunming strain are infected with HY12 to determine the susceptible mouse strain. The minimal infection dose, the virus infection routes, the pathogenicity and tissue tropism for HY12 were determined by infecting susceptible mice with HY12 viruses, and confirmed by different approaches including virus isolation and recovery, virus detection, histopathology, and immunohistochemistry.ResultsA murine model for HY12 infection was successfully established and employed to investigate the pathogenicity of HY12 viruses. ICR mouse strain is the most susceptible strain for HY12 infection with a minimal infective dose as 2×106TCID50/mouse. HY12 viruses have the capability of infecting ICR suckling mice via all infection routes including intranasal administration, oral administration, intraperitoneal injection, subcutaneous injection, and intramuscular injection, which are confirmed by the isolation and recovery of viruses from HY12-infected mice; detection of viruses by RT-PCR; observations of pathological lesions and inflammatory cell infiltrations in the intestine, lung, liver, and brain; uncovering of HY12 virus antigens in majority of tissues, especially in intestine, lung, and infected brain of mice by immunohistochemistry assay.ConclusionsA neonatal murine model for HY12 infection is successfully established for determining the susceptible mouse strain, the minimal infective dose, the infection route, the viral pathogenicity and the tropism of HY12, thus providing an invaluable model system for elucidating the pathogenesis of HY12 viruses and the elicited immunity.

Unveiling of Evolution Pattern for HY12 Enterovirus Quasispecies and Pathogenicity Alteration

“…Pathogenicity for P2 and P40 HY12 virus was comparably determined using the established neonatal mouse model as described [46]. Three groups of neonatal ICR mice at the age of 3 days old were intraperitoneally inoculated with 10 8 TCID 50 of P2 and P40 HY12 virus.…”

“…Tissues collected from mice infected with P2 and P40 HY12 virus were processed in the procedure described previously [46]. Paraffin-embedded tissue blocks were sectioned at 5 µm using a microtome.…”

“…Paraffin-embedded tissue blocks were sectioned at 5 µm using a microtome. The ribbon sections were loaded to polylysine-coated glass slides, dried overnight at 42 • C, and stained using hematoxylin and eosin (H&E) staining as previously described [46]. Microscopic lesions were visualized and captured using a CCD camera mounted on a Nikon epifluorescence microscope (Nikon Instruments Co., Ltd., Shanghai, China).…”

Rescue and characterization of a recombinant HY12 bovine enterovirus carrying a foreign HA epitope in the 3A nonstructural protein

“…Twenty 4-week-old ICR mice were purchased from the Laboratory Animal Center of Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (Harbin, China). The mice were randomly divided into four test groups (n = 4) (groups A-C) and a parental virus group D. They were intramuscularly inoculated with 0.2 ml containing 10 8 TCID 50 of the parental rHY12 virus or one of the three recombinant marker viruses, which were emulsified with ISA 15 (Seppic, Castres, France) adjuvant [7]. Serum samples were collected and prepared from the mice in each group by tail bleeding at 7-day intervals until 42 days after immunization.…”

Molecular Identification of Enteroviruses from Cattle and Goat Feces and Environment in Thailand

“…In calves experimentally inoculated with an EV-E isolate, pathogenesis associated with an acute infection has been reported (25). Some studies have reported that the inoculation of experimental mice with particular strains of EV-E produced clinical symptoms as well as gross and microscopic lesions in the brain, respiratory system, and digestive system (2,26). EV-Gs are detected mainly in domestic pigs (EV-G1 to -4, -6, -8 to -15, and -17 to -19) (http://www.picornaviridae.com/enterovirus/ev-g/ev_g_seq.htm).…”