Gallus gallus coxsackievirus and adenovirus receptor facilitates the binding of fowl adenovirus serotype 1 in chickens

Coxsackievirus and adenovirus receptor (CXADR) is an integral membrane protein that serves as a receptor for coxsackie B viruses and adenovirus types 2 and 5. Previous studies demonstrated that Fowl adenovirus (FAV) can also utilize Homo sapiens CXADR to infect cells. FAV is a double-stranded DNA virus of the family Adenoviridae. FAV causes inclusion body hepatitis and hydropericardium syndrome in chickens. In addition, FAV serotypes 1 and 8 have recently been shown to cause gizzard erosion in chickens. These chicken diseases and growth insufficiency caused by FAV infection result in great economic loss. Thus, identifying and characterizing the viral receptor would further enhance our understanding of the mechanisms underlying virus infection and histocompatibility. Here, in order to determine the FAV receptor in chickens, we investigated the effect of the recently identified Gallus gallus CXADR (ggCXADR) on FAV infection. Overexpression of ggCXADR in CHO cells resulted in increased FAV binding and expression of early FAV genes. However, the propagation of infectious viruses in CHO cells expressing ggCXADR was not detected. These findings provide the basis for further studies aimed at elucidating the infection mechanism of FAV. Further research is required to characterize the additional host factors involved in FAV infection and life cycle

A new method for the detection of neutralizing antibodies against mumps virus.

Neutralization test is the most reliable method of evaluating immunity against viral diseases but there is no standard procedure for mumps virus, with tests differing in the infectivity of the challenge virus, 50% plaque reduction or complete inhibition of cytopathic effects (CPE), and usage of complement. A reliable, easy, and simple neutralization test for mumps virus was developed in this study. A recombinant mumps virus expressing GFP was generated as a challenge virus. Complement was added to the neutralizing mixture at 1∶200 when stocked serum samples were used. Neutralizing antibody titers were expressed as the reciprocal of the highest dilution that did not exceed two-fold of FU values (GFP expression) of the cell control wells. A total of 1,452 serum samples were assayed by inhibition of GFP expression in comparison with those examined by conventional 100% inhibition of CPE. 1,367 (94.1%) showed similar neutralizing antibody titers when examined by both methods. The GFP expression inhibition assay, using a recombinant mumps virus expressing GFP, is a simple and time- saving method

Rapid Diagnostic Method for Detection of Mumps Virus Genome by Loop-Mediated Isothermal Amplification

Most mumps patients are clinically diagnosed without any virological examinations, but some diagnosed cases of mumps may be caused by other pathogens or secondary vaccine failure (SVF). To clarify these issues, a sensitive, specific, and rapid diagnostic method is required. We obtained 60 salivary swabs from 34 patients with natural infection during the course of the illness, 10 samples from patients with vaccine-associated parotitis, and 5 samples from patients with SVF. Total RNA was extracted and subjected to reverse transcription-PCR (RT-PCR) and loop-mediated isothermal amplification (LAMP) for genome amplification. We detected mumps virus RNA corresponding to 0.1 PFU by LAMP within 60 min after RNA extraction, with the same sensitivity as RT-nested PCR. Mumps virus was isolated in 30 of 33 samples within day 2, and mumps virus genome was amplified by LAMP in 32 of them. The quantity of virus titer was calculated by monitoring the time to reach the threshold of turbidity. The viral load decreased after day 3 and was lower in patients serologically diagnosed as having SVF with milder illness. Accuracy of LAMP for the detection of mumps virus genome was confirmed; furthermore, it is of benefit for calculating the viral load, which reflects disease pathogenesis

Genome construction of the recombinant mumps Hoshino strain expressing GFP and expression of GFP.

<p>Vero cells were infected with GFP Hoshino mumps strain at m.o.i. = 0.02 and subjected to experiments for GFP expression with fluoro EIA and microscopic examination on day 1, 3 and 5 of infection in comparison with mock-infection. Infectivity was assayed in culture supernatants on day 1, 3, and 5 of infection.</p

Effect of the addition of complement in 21 fresh and 227 stocked serum samples.

<p>Distribution of serum samples is shown for neutralizing antibody titers assayed without inactivation and for those assayed after inactivation with the addition of complement, using 21fresh serum samples (left panel). 227 stocked serum samples were assayed in a similar manner (right panel).</p