Severe acute respiratory syndrome (SARS) was caused by a novel virus now known as SARS coronavirus (SARS-CoV). The discovery of SARS-CoV-like viruses in masked palm civets (Paguma larvata) raises the possibility that civets play a role in SARS-CoV transmission. To test the susceptibility of civets to experimental infection by different SARS-CoV isolates, 10 civets were inoculated with two human isolates of SARS-CoV, BJ01(with a 29-nucleotide deletion) and GZ01 (without the 29-nucleotide deletion). All inoculated animals displayed clinical symptoms, such as fever, lethargy, and loss of aggressiveness, and the infection was confirmed by virus isolation, detection of viral genomic RNA, and serum-neutralizing antibodies. Our data show that civets were equally susceptible to SARS-CoV isolates GZ01 and BJ01.Severe acute respiratory syndrome (SARS) first appeared in Guangdong, China, in November 2002, and it subsequently spread to many parts of the world, making it the first major infectious disease outbreak of the 21st century (8,13,19). The etiological agent was a newly emerged and previously unrecognized coronavirus, now known as SARS coronavirus (SARSCoV) (2,3,(5)(6)(7)12), which is classified within the order Nidovirales, family Coronaviridae, genus Coronavirus (9,14,15). Epidemiological data obtained from the early stage of the SARS outbreak suggest an animal origin for SARS-CoV, although the reservoir host has yet to be identified (11,(20)(21)(22). The isolation of SARS-CoV-like viruses in masked palm civets and the relationship of their genomic sequences with those of viruses isolated from humans (1, 4) raise the possibility that civets play a role in SARS-CoV transmission to the human population. A striking difference between the vast majority of SARS-CoV genomes from humans and those from civets is the presence in the latter of an additional 29-nucleotide (nt) sequence 246 nt upstream of the start codon of the N gene. Only human SARS-CoV isolated from the earliest stage of the outbreak contains this same 29-nt additional sequence (1). In other words, most human SARS-CoV isolates had a 29-nt deletion in this region of the genome. Thus, while it is clear that SARS-CoV with and without the 29-nt deletion can replicate in humans, the influence of the 29-nt deletion on the capacity of the virus to replicate in civets has not been determined. Here we show that civets are equally susceptible to experimental infection with two different human SARS-CoV isolates, one containing and the other lacking the 29-nt sequence, and that all animals display clinical signs during the early stage of infection.SARS-CoV isolates GZ01 and BJ01 used in this study were originally isolated in Vero E6 cells at the Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China, and were propagated in Vero E6 cells for two additional passages at our institute in Harbin to generate virus stocks with titers of 10 6 50% tissue culture infective doses (TCID 50 )/ml. BJ01 has the 29-nt deletion found in most hu...

West Nile virus (WNV) non-structural protein 1 (NS1) elicits protective immune responses during infection of animals. WNV NS1-specific antibody responses can provide the basis for serological diagnostic reagents, so the antigenic sites in NS1 that are targeted by host immune responses need to be identified and the conservation of these sites among the Japanese encephalitis virus (JEV) serocomplex members also needs to be defined. The present study describes the mapping of linear B-cell epitopes in WNV NS1. We screened eight NS1-specific mAbs and antisera (polyclonal antibodies; pAbs) from mice immunized with recombinant NS1 for reactivity against 35 partially overlapping peptides covering the entire WNV NS1. The screen using mAbs identified four WNV-specific (including Kunjin virus) epitopes, located at aa 21-36, 101-116, 191-206 and 261-276 in WNV NS1. However, using pAbs, only three WNV-specific epitopes were identified, located at positions 101-116, 191-206 and 231-246. Two of these epitopes (aa 21-36 and 261-276) had different reactivity with mAbs and pAbs. The knowledge and reagents generated in this study have potential applications in differential diagnostics and epitope-based marker vaccine development for WNV and viruses of the JEV serocomplex.

The full-length equine interferon-gamma (eIFN-gamma) cDNA, including the secretion signal peptide coding region, was recloned into baculovirus transfer vector pAcYM1. This vector was co-transfected with Autographa californica nuclear polyhedrosis virus DNA or hybrid nuclear polyhedrosis virus DNA into Spodoptera frugiperda cells. The recombinant viruses, named AcEIFN-gamma and HyEIFN-gamma, were then recovered. Recombinant eIFN-gamma (reIFN-gamma) was accumulated in the culture fluid of the AcEIFN-gamma or HyEIFN-gamma infected Tricoplusia ni -derived cell line, BTI TN 5B1-4, and hemolymph of HyEIFN-gamma infected silkworm larvae. These reIFN-gamma forms were shown to be 14, 16, 18 and 20kDa proteins, and glycosylated as confirmed by SDS-PAGE and tunicamycin treatment. Both reIFN-gamma proteins, showed high-level biological activities to vesicular stomatitis virus by cytopathic effect reduction assay, and MHC class II antigen induction on the equine fetal kidney-78 cell line.