Virus Growth In Culture Research Articles

Rapid Antigen and Antibody Microfluidic Immunofluorescence Assays Compared to Culture, PCR, and Laboratory Reference Tests: Performance in a Longitudinal Cohort.

We evaluated the performance of rapid antigen (RAg) and antibody (RAb) microfluidic diagnostics with serial sampling of 71 participants at 6 visits over 2 months following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Rapid tests showed strong agreement with laboratory references (κAg = 81.0%; κAb = 87.8%). RAg showed substantial concordance to both virus growth in culture and PCR positivity 0-5 days since symptom onset (κAg-culture = 60.1% and κAg-PCR = 87.1%). PCR concordance to virus growth in culture was similar (κPCR-culture = 70.0%), although agreement between RAg and culture was better overall (κAg-culture = 45.5% vs κPCR-culture = 10.0%). Rapid antigen and antibody testing by microfluidic immunofluorescence platform are highly accurate for characterization of acute infection.

Repeated Coronavirus Disease 2019 Molecular Testing: Correlation of Severe Acute Respiratory Syndrome Coronavirus 2 Culture With Molecular Assays and Cycle Thresholds.

BackgroundRepeated coronavirus disease 2019 (COVID-19) molecular testing can lead to positive test results after negative results and to multiple positive results over time. The association between positive test results and infectious virus is important to quantify.MethodsA 2-month cohort of retrospective data and consecutively collected specimens from patients with COVID-19 or patients under investigation were used to understand the correlation between prolonged viral RNA positive test results, cycle threshold (Ct) values and growth of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in cell culture. Whole-genome sequencing was used to confirm virus genotype in patients with prolonged viral RNA detection. Droplet digital polymerase chain reaction was used to assess the rate of false-negative COVID-19 diagnostic test results.ResultsIn 2 months, 29 686 specimens were tested and 2194 patients underwent repeated testing. Virus recovery in cell culture was noted in specimens with a mean Ct value of 18.8 (3.4) for SARS-CoV-2 target genes. Prolonged viral RNA shedding was associated with positive virus growth in culture in specimens collected up to 21 days after the first positive result but mostly in individuals symptomatic at the time of sample collection. Whole-genome sequencing provided evidence the same virus was carried over time. Positive test results following negative results had Ct values >29.5 and were not associated with virus culture. Droplet digital polymerase chain reaction results were positive in 5.6% of negative specimens collected from patients with confirmed or clinically suspected COVID-19.ConclusionsLow Ct values in SARS-CoV-2 diagnostic tests were associated with virus growth in cell culture. Symptomatic patients with prolonged viral RNA shedding can also be infectious.

Localization and Importance of the Adenovirus E4orf4 Protein during Lytic Infection

The human adenovirus type 5 (Ad5) E4orf4 product has been studied extensively although in most cases as expressed from vectors in the absence of other viral products. Thus, relatively little is known about its role in the context of an adenovirus infection. Although considerable earlier work had indicated that the E4orf4 protein is not essential for replication, a recent study using dl359, an Ad5 mutant believed to produce a nonfunctional E4orf4 protein, suggested that E4orf4 is essential for virus growth in primary small-airway epithelial cells (C. O'Shea, et al., EMBO J. 24:1211-1221, 2005). Hence, to examine further the role of E4orf4 during virus infection, we generated for the first time a set of E4orf4 virus mutants in a common Ad5 genetic background. Such mutant viruses included those that express E4orf4 proteins containing various individual point mutations, those defective entirely in E4orf4 expression, and a mutant expressing wild-type E4orf4 fused to the green fluorescent protein. E4orf4 protein was found to localize primarily in nuclear structures shown to be viral replication centers, in nucleoli, and in perinuclear bodies. Importantly, E4orf4 was shown not to be essential for virus growth in either human tumor or primary cells, at least in tissue culture. Unlike E4orf4-null virus, mutant dl359 appeared to exhibit a gain-of-function phenotype that impairs virus growth. The dl359 E4orf4 protein, which contains a large in-frame internal deletion, clustered in aggregates enriched in Hsp70 and proteasome components. In addition, the late viral mRNAs produced by dl359 accumulated abnormally in a nuclear punctate pattern. Altogether, our results indicate that E4orf4 protein is not essential for virus growth in culture and that expression of the dl359 E4orf4 product interferes with viral replication, presumably through interactions with structures in the nucleus.

Primary subtype C HIV-1 infection in Harare, Zimbabwe.

Heterosexual transmission of HIV-1 is widespread in Southern Africa. Heteroduplex mobility assays (HMA) and phylogenetic analyses of V3-V5 envelope (env) gene sequences demonstrate that subtype C predominates in Zimbabwe. To elucidate factors contributing to the epidemic in Zimbabwe, clinical and virologic characteristics of recently acquired subtype C HIV-1 infection among 21 men and 1 woman were determined. In 12 of 19 men providing clinical histories, a sexually transmitted infection preceded serologic evidence of HIV-1, and 14 of 19 men complained of rash or fever before seroconversion. Quantitative p24 antigen levels, reverse transcriptase activity, and HIV RNA levels of 22 viral isolates correlated with in vitro infectivity in peripheral blood mononuclear cells (p < .05). Biologic phenotype assessed in MT-2 cells demonstrated that 3 of 22 isolates (14%) were syncytia inducing (SI) and the remaining 19 nonsyncytium inducing (NSI). Early growth of virus in culture was associated with increased plasma HIV RNA levels, decreased CD4 cell levels, and SI virus. Recent subtype C HIV-1 infection through heterosexual transmission in Zimbabwe demonstrated clinical and virologic features consistent with reports of seroconversion to subtype B viruses.

Sensitivity of subgroup F adenoviruses to interferon.

The subgroup F adenoviruses were tested for their ability to induce interferon in semi-permissive human cells (Chang conjunctiva) and non-permissive cells (HEF, human embryo lung fibroblasts). These cells did not produce interferon spontaneously or in response to infection by either of these adenoviruses. It was concluded that interferon induction in response to subgroup F adenovirus infection is not a likely explanation of limited virus growth in culture. Adenovirus 40 and Ad41, unlike Ad2, were found to be sensitive to human lymphoblastoid interferon in Chang conjunctival cells. The addition of Ad2 to cells before pretreatment with interferon resulted in the partial and complete abrogation of Ad40 and Ad41 interferon sensitivity, respectively. The suppressive effect of Ad2 on the inhibitory action of interferon and the modulatory function of Ad2 in mixed infection with either Ad40 or Ad41 suggests the inadequate functioning of a subgroup F adenovirus gene product or products involved in suppression of the interferon-induced antiviral state.

Effect of ribavirin on hepatitis A virus replication in vitro.

The effect of ribavirin on fetal Rhesus monkey kidney cells (FRhK-4) acutely or chronically infected with hepatitis A virus was studied. The effect of ribavirin on hepatitis A virus yield as detected by radioimmunoassay in acutely infected FRhK-4 cells was dependent on hepatitis A virus inoculum dose. Treatment with 100 μg/mL ribavirin completely inhibited hepatitis A virus growth in cultures infected with 100 to 800 tissue culture infectious dose 50 (TCID(50)) hepatitis A virus, but inocula of 800 to 1600 TCID(50) resulted in limited production of virus. The effect was time dependent and required more than 96 h of treatment to inhibit the virus completely. Ribavirin was less effective in treating cells persistently infected with hepatitis A virus, although there was significant inhibition of hepatitis A virus (82%) in persistently infected cells as well. Ribavirin had some inhibitory effect on cell growth; treatment with 25, 50 or 100 μg/mL ribavirin reduced cell growth by approximately 0, 20 and 40%, respectively.

Effect of interferon on Sindbis virus growth in chick embryo cell cultures.

A study of the effect of interferon on the growth of Sindbis virus in cultures of chick-embryo cells has shown that interferon forms an association with cells (uptake) and that the action of interferon is concentration rather than amount dependent. Evidence has also been obtained that interferon acts to reduce the yield of virus from cells, but does not reduce the number of cells synthesizing virus (all or none effect).

Efficiency of the synergistic infection of L cells by groups of damaged vaccinia virus particles, MR.

Abstract Suspensions of high passage vaccinia virus have been partially inactivated by methyl methanesulfonate, ultraviolet rays, and heat at 56°. Groups of virus particles, whether present before treatment or formed subsequently, are shown to be 10 to several thousand times more likely to make plaques than single particles. This synergistic effect of MMS and UV is stronger than after heating. It closely resembles the multiplicity reactivation previously shown with X-rays, 137 Cs γ-rays, nitrogen mustard, and formaldehyde. It is demonstrated also in terms of more rapid growth of virus in cultures inoculated with aggregated preparations of virus treated with several of these agents. The probability of plaque formation has been computed for single particles and groups of 2, 3, 4 … from aggregation analyses by electron microscopy. The values, at equivalent dosages, are remarkably similar for all agents except heat.

Cultivation of Avian Encephalomyelitis Virus in vitro. 1. In Chick Embryo Neuroglial Cell Culture

To date there have been no reports of the successful propagation of avian encephalomyelitis (AE) virus in vitro although the virus has been propagated in 5-to-7-day-old embryonated chicken eggs inoculated via the yolk sac as described by Wills and Moulthrop (5). Adams (1) has outlined the successful cultivation of chicken neuroglial cells in tissue culture using roller tubes, Leighton tubes, and roller-tube coverslips. He trypsinized brains from 2-to-8week-old chickens and employed Scherer's maintenance solution with 10% inactivated calf serum and 20% tryptose phosphate broth as the growth medium. His report indicated that small pieces of tissue debris were necessary for successful cultivation of glial cells. Adams (2) later described the growth of Rous sarcoma virus in cultures of chicken neuroglial cells. The infected cells were morphologically identical to the control cells. This report describes the cultivation of AE virus in chicken neuroglial cell culture. It also presents a modification of Adams' (1) method of growing glial cells in vitro.

Characteristics of Growth of Encephalomyocarditis Virus in Cultures of Mouse Muscle.

Conclusions1. Encephalomyocarditis virus grows readily in cultures of abdominal muscle of mice. 2. A characteristic cytopathic effect is produced; complete destruction of cultures occurs in about 72 hours. 3. The cellular changes are not due to activation of a virus latent in mouse muscle but to the agent of encephalomyocarditis.

Experiments with the virus of infectious ectromelia. The action of immune serum in vivo and on the growth of virus in culture

The Journal of Pathology and BacteriologyVolume 40, Issue 2 p. 297-310 Article Experiments with the virus of infectious ectromelia. The action of immune serum in vivo and on the growth of virus in culture A. W. Downie, A. W. Downie Department of Bacteriology and Preventive Medicine, University of ManchesterSearch for more papers by this authorC. A. McGaughey, C. A. McGaughey Department of Bacteriology and Preventive Medicine, University of ManchesterSearch for more papers by this author A. W. Downie, A. W. Downie Department of Bacteriology and Preventive Medicine, University of ManchesterSearch for more papers by this authorC. A. McGaughey, C. A. McGaughey Department of Bacteriology and Preventive Medicine, University of ManchesterSearch for more papers by this author First published: March 1935 https://doi.org/10.1002/path.1700400209Citations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume40, Issue2March 1935Pages 297-310 RelatedInformation