Virus-infected fruit bats showed no signs of clinical infection.

Nine isolates of Canine parvovirus (CPV) were obtained from Vietnamese dogs and cats. One canine isolate showed a unique antigenic property which indicates a novel antigenic variant of CPV-2b when examined with hemagglutination inhibition tests using our monoclonal antibodies, 21C3 and 19D7, which were recently developed. This isolate had an amino acid substitution of residue 426, Asp to Glu, and the same substitution has recently been found in CPV from Italian dogs. This study first showed that such substitution caused an antigenic difference demonstrable by monoclonal antibodies and that a similar evolution may have occurred in CPV in Vietnam.

The life cycle of calicivirus is not fully understood because most of the viruses cannot be propagated in tissue culture cells. We studied the mechanism of calicivirus entry into cells using feline calicivirus (FCV) The family Caliciviridae comprises a diversity of pathogens in humans and animals. Studies of the life cycle of the virus have been quite limited because of the lack of cell culture methods for most caliciviruses (13). Porcine enteric calicivirus in the genus Sapovirus is known to propagate in vitro with the addition of an intestinal content fluid filtrate, and Chang et al. (6) recently identified bile acids as molecules responsible for culture in cells. Studies with virus-like particles showed that ABH histo-blood group antigens are ligands of noroviruses belonging to the genus Norovirus (24). Studies in vivo also showed that these antigens are critical for human susceptibility to norovirus infection (17,22). Because noroviruses are not cultivable in cell culture (9), it has not been established whether ABH histo-blood antigens function as receptors for them.,Feline calicivirus (FCV) is a member of the genus Vesivirus and causes upper respiratory tract disease and acute mouth ulceration, occasionally associated with chronic stomatitis and acute arthritis in cats (15,21). It is comparatively easy to study the life cycle of FCV, because the virus replicates efficiently in cell culture without specific supplementation. Kreutz et al. (20) investigated the binding of FCV to feline and nonfeline cells.They reported that FCV bound to feline cells but also showed poor binding ability to nonfeline cells. It was also demonstrated that when nonfeline cells were transfected with genomic RNA of FCV, infectious virus could be recovered from the cells (20). These data suggest that FCV host specificity is restricted in the early stage of FCV infection in cells.In this study, to elucidate the cellular determinant(s) of FCV host specificity, we applied an improved expression cloning method (28,29) to identify cell surface molecules that interact with FCV. As a result, feline junctional adhesion molecule 1 (JAM-1) was identified as a binding receptor for FCV. JAM-1 is a member of the immunoglobulin (Ig) superfamily expressed by various cells and is involved in regulation of cell-cell interactions in the immune system and apical tight junction formation (10, 23). We here demonstrate that feline JAM-1 (fJAM-1) possesses the characteristics required of a functional receptor for FCV. MATERIALS AND METHODS Cells.Crandell-Rees feline kidney (CRFK) cells and human embryonic kidney 293T cells were cultured in Dulbecco's modified Eagle's medium (DMEM; Sigma, St. Louis, MO) supplemented with 10% fetal calf serum (FCS). Nonpermissive hamster lung (HmLu-1) cells and African green monkey kidney (Vero) cells were cultured in DMEM with 5% FCS. Murine myeloma P3X63Ag8U.1 (P3U1) cells were grown in RPMI 1640 medium (Sigma) with 10% FCS. Plat-E cells, a 293T-derived murine leukemia virus-based packaging cell line (25), were kindly pr...

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Tannins, plant-derived polyphenols and other related compounds, have been utilized for a long time in many fields such as the food industry and manufacturing. In this study, we investigated the anti-viral effects of tannins on 12 different viruses including both enveloped viruses (influenza virus H3N2, H5N3, herpes simplex virus-1, vesicular stomatitis virus, Sendai virus and Newcastle disease virus) and non-enveloped viruses (poliovirus, coxsachievirus, adenovirus, rotavirus, feline calicivirus and mouse norovirus). We found that extracts from persimmon (Diospyros kaki), which contains ca. 22% of persimmon tannin, reduced viral infectivity in more than 4-log scale against all of the viruses tested, showing strong anti-viral effects against a broad range of viruses. Other tannins derived from green tea, acacia and gallnuts were effective for some of the viruses, while the coffee extracts were not effective for any of the virus. We then investigated the mechanism of the anti-viral effects of persimmon extracts by using mainly influenza virus. Persimmon extracts were effective within 30 seconds at a concentration of 0.25% and inhibited attachment of the virus to cells. Pretreatment of cells with the persimmon extracts before virus infection or post-treatment after virus infection did not inhibit virus replication. Protein aggregation seems to be a fundamental mechanism underlying the anti-viral effect of persimmon tannin, since viral proteins formed aggregates when purified virions were treated with the persimmon extracts and since the anti-viral effect was competitively inhibited by a non-specific protein, bovine serum albumin. Considering that persimmon tannin is a food supplement, it has a potential to be utilized as a safe and highly effective anti-viral reagent against pathogenic viruses.

Since the emergence of Canine parvovirus (CPV-2) in the late 1970s, CPV-2 has evolved consecutively new antigenic types, CPV-2a and 2b. Although CPV-2 did not have a feline host range, CPV-2a and 2b appear to have gained the ability to replicate in cats. Recent investigations demonstrate the prevalence of CPV-2a and 2b infection in a wide range of cat populations. We illustrate the pathogenic potential of CPV in cats and assesses the risk caused by CPV variants.

ABSTRACT. Fifty-five canine parvovirus type 2 (CPV) samples, 12 fecal specimens and 43 cell culture isolates, were examined for their genetic characteristics of VP2 gene. They were collected from the diseased dogs at various districts of Japan during 27 years from 1980 to 2006. A fragment of VP2 gene was analyzed by restriction fragment length polymorphism assay and DNA sequencing. The original antigenic type 2 of CPV (CPV-2) was no longer found in the samples since 1984, and two antigenic variants CPV-2a and CPV-2b replaced CPV-2 as predominant types for about 5 years from 1982. A new genetic variant of prototype CPV-2a with non-synonymous substitution at the VP2 amino acid residue 297 from Ser to Ala was first detected in 1987. New CPV-2b with the same amino acid substitution at position 297 as new CPV-2a was also detected from the samples collected in 1997. Since then new CPV-2b has been the predominant CPV over the field of Japan. Several additional amino acid substitutions were detected in the VP2 gene of some recent CPV strains. Neither CPV-2c(a), CPV-2c(b), nor "Glu-426" of the antigenic variants previously found outside the country was detected in any samples tested. Reactivity of new CPV-2a and 2b variants against antibodies produced by the current vaccine products was determined by a cross hemagglutination-inhibition test. The recent field CPV isolates reacted more efficiently to the antibodies produced in dogs vaccinated with the new CPV-2b vaccine strain than the conventional CPV-2 vaccine strain.

Interleukin-2 dependent feline T-lymphoblastoid cells designated as MYA-1 cells were established. The cells were free from exogenous retroviruses and sensitive for replication of feline immunodeficiency virus (FIV). FIV can grow more efficiently in MYA-1 cells than in feline primary peripheral blood mononuclear cells. This line of cells will be useful not only for isolation and propagation of FIV, but also for further investigation of properties of FIV.