{"title":"Development of a multiplex droplet digital PCR method for detection and differentiation of mpox virus clades","authors":"Xiaoyue Chu , Hailong Chen , Rui Wu , Linghao Zhang , Yong Zhang , Hua Xu , Chaofeng Ma","doi":"10.1016/j.jviromet.2024.115078","DOIUrl":"10.1016/j.jviromet.2024.115078","url":null,"abstract":"<div><h3>Background</h3><div>The current outbreak of mpox has been declared a public health emergency of international concern by the World Health Organization. However, distinguishing symptoms of mpox virus (MPXV) infection from other orthopoxviruses is atypical, necessitating laboratory confirmatory tests to aid in clinical diagnosis. Therefore, rapid and accurate detection and differentiation of various clades of MPXV are imperative.</div></div><div><h3>Objective</h3><div>A multiplex droplet digital PCR (ddPCR) method was developed to detect and differentiate various clades of MPXV with subsequent evaluation of its sensitivity and accessibility through the analysis of 17 clinical samples.</div></div><div><h3>Methods</h3><div>Primers and probes for multiple ddPCR were designed by comparing multiple complete genomes of orthopoxviruses. Primer and probe concentrations, reaction conditions were tentatively optimized on the Biorad QX200 platform. Seventeen clinical samples of MPXV were detected and verified by Sanger sequencing.</div></div><div><h3>Results</h3><div>The established ddPCR method could detect and differentiate MPXV, and the results were consistent with those of Sanger sequencing.</div></div><div><h3>Conclusion</h3><div>Multiplex ddPCR could be used to detect and distinguish different clades of MPXV rapidly and accurately.</div></div>","PeriodicalId":17663,"journal":{"name":"Journal of virological methods","volume":"332 ","pages":"Article 115078"},"PeriodicalIF":2.2,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142739966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sung-Sil Moon , Houping Wang , Kimberly Brown , Yuhuan Wang , Theresa Bessy , Harry B. Greenberg , Baoming Jiang
{"title":"Development and validation of a VP7-specific EIA for determining the potency and stability of inactivated rotavirus vaccine","authors":"Sung-Sil Moon , Houping Wang , Kimberly Brown , Yuhuan Wang , Theresa Bessy , Harry B. Greenberg , Baoming Jiang","doi":"10.1016/j.jviromet.2024.115079","DOIUrl":"10.1016/j.jviromet.2024.115079","url":null,"abstract":"<div><div>To determine the potency of the inactivated rotavirus vaccine (IRV), we developed an enzyme immunoassay (EIA) using a biotin-conjugated RV VP7-specific monoclonal antibody. RV VP7, a pivotal structural protein in the outer capsid layer, governs RV G genotypes and prompts host immune responses, including neutralizing antibodies. This EIA showed high specificity, good linearity, high precision, and high accuracy, with a low limit of detection (LOD) and a limit of quantitation (LOQ) of 0.037 µg/ml RV antigen. The EIA was evaluated and proved suitable for establishing the long-term stability of IRV drug substance (DS) and aluminum-formulated drug product (DP) when stored at −70±10°C and 5±3 °C, respectively. Our results support the use of this EIA to examine the stability and determine the potency, antigen dose, lot-to-lot consistency, and lot release of IRV products. This RV potency assay may serve as an alternative to <em>in vivo</em> potency tests, making it suitable for quality control tests of cGMP IRV lots in clinical trials.</div></div>","PeriodicalId":17663,"journal":{"name":"Journal of virological methods","volume":"332 ","pages":"Article 115079"},"PeriodicalIF":2.2,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Florence C.H. Lee , Frankie T. Sitam , Lu Ping Tan
{"title":"Little influence of DNA quality on the direct sequencing output of non-human primates’ faecal samples","authors":"Florence C.H. Lee , Frankie T. Sitam , Lu Ping Tan","doi":"10.1016/j.jviromet.2024.115074","DOIUrl":"10.1016/j.jviromet.2024.115074","url":null,"abstract":"<div><div>DNA samples selected for long read sequencing (LRS) are routinely required to be ‘pure’ with high DNA concentration. Hence the usefulness of samples with substandard DNA quality for LRS is unknown. We aim to perform de-novo assembly of Adenovirus sequenced from non-human primate (NHP) faeces using the Oxford Nanopore technologies (ONT), an LRS platform. Guided by initial conventional PCR screening, we performed ONT sequencing on 34 Adenovirus positive DNA samples, without prior selection based on faeces freshness level or DNA quality. Non-parametric correlation analysis showed that ONT sequencing outputs is not significantly associated (<em>p</em> > 0.05) with DNA concentrations, faeces freshness levels and the OD ratios of A260/A280 and A260/A230. This indicated that conventional DNA quality parameters may not be the most critical factors in determining the suitability of samples for ONT sequencing. A total of 61.76 % (21/34) of the positive-by-PCR-screening samples yielded Adenovirus reads while 38.24 % (13/34) did not in the PCR-free ONT workflow, although rarefaction analysis showed that sequencing saturation was achieved by all samples. Among the 21 samples with adenovirus reads, ten resulted in at least one Adenovirus contig by the Flye assembler while nine did not and two samples had only a single Adenovirus read. Identity similarity above 90 % in conventional PCR screening may help in selecting ONT positive samples.</div></div>","PeriodicalId":17663,"journal":{"name":"Journal of virological methods","volume":"332 ","pages":"Article 115074"},"PeriodicalIF":2.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142695379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Developing and validating a multiplex hydrolysis probe-based quantitative PCR assay for the detection of four pathogens in chelonians","authors":"Maris J. Daleo , Matthew C. Allender","doi":"10.1016/j.jviromet.2024.115077","DOIUrl":"10.1016/j.jviromet.2024.115077","url":null,"abstract":"<div><div>Many wildlife conservation efforts focus on the effects of one pathogen, but for many conservation efforts to be successful, researchers require an understanding of ecological processes that may include multiple co-occurring pathogens. We developed a multiplex quantitative PCR (qPCR) assay to detect four pathogens in eastern box turtles (<em>Terrapene carolina carolina</em>), including frog virus 3 (FV3), <em>Terrapene</em> herpesvirus 1 (TerHV1), box turtle <em>Mycoplasma</em> sp. (BTMyco), and <em>Terrapene</em> adenovirus (TerAdv). TaqMan™ primer probes were designed using previously published assays with four different fluorophores. Multiplex Cq values plotted against singleplex Cq values demonstrated slopes of 0.967, 1.00, 0.980, and 0.973 for TerHV1, TerAdv, FV3, and BTMyco, respectively, and R<sup>2</sup> values of 0.999 for all four pathogens. The assay was highly consistent with the intra-assay variation of all four pathogen targets, ranging from 0.05–1.826 % across all concentrations, while inter-assay variation ranged from 0.031–4.569 % among all four targets at all concentrations. Clinical samples were tested using previously collected samples from eastern box turtles and red-eared sliders (<em>Trachemys scripta elegans</em>) and performed similarly to singleplex assays. This multiplex assay is an effective, time-efficient diagnostic tool to quickly monitor chelonian pathogens by detecting FV3, TerHV1, BTMyco, and TerAdv within a single reaction. A validated and clinically utilized multiplex assay will be beneficial to characterizing a more complex pathogen profile for future chelonian epidemiological studies to better describe pathogen dynamics and their impacts on individual and population health.</div></div>","PeriodicalId":17663,"journal":{"name":"Journal of virological methods","volume":"332 ","pages":"Article 115077"},"PeriodicalIF":2.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142695337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development of a novel multiplex digital PCR-based method for the detection of HTLV-1 proviral deletion","authors":"Kou Hiraga , Kenta Tezuka , Koh Nagata , Ki-Ryang Koh , Hitomi Nakamura , Yasuko Sagara , Rieko Sobata , Masahiro Satake , Michikazu Tanio , Hiroo Hasegawa , Masumichi Saito , Kiyonori Miura , Takuo Mizukami , Isao Hamaguchi , Madoka Kuramitsu","doi":"10.1016/j.jviromet.2024.115071","DOIUrl":"10.1016/j.jviromet.2024.115071","url":null,"abstract":"<div><div>The human T-cell leukemia virus type 1 (HTLV-1), a retrovirus, integrates into host DNA and causes adult T-cell leukemia/lymphoma (ATL) in some individuals. Two types of defective proviruses, Type 1 and Type 2, are often observed in ATL cells. Here, we developed a 3-plex digital PCR (dPCR) method to detect HTLV-1 proviral deletions by comparing the ratios of copy numbers quantified using specific primer-probes for the LTR, pol, and pX regions. We analyzed HTLV-1-positive asymptomatic carriers (ACs) and AC samples at high risk for developing ATL due to high proviral load (ATL high-risk (HR) ACs) using dPCR. Deletions were identified in 11.8 % (4/34, all Type 1) of ACs and 33.3 % (7/21, Type 1:1, Type 2:6) of ATL HR ACs. dPCR analysis revealed that in three ATL samples, all exhibited Type 1 defective characteristics, and two showed extremely low ratios in the pol region. Clonality analysis of these two samples revealed high monoclonality, indicating monoclonal expansion of ATL cells with defective proviruses. These findings demonstrate that our method effectively detects defective proviruses in both ACs and ATL, providing a valuable tool for understanding the genomic characteristics of proviruses in these conditions.</div></div>","PeriodicalId":17663,"journal":{"name":"Journal of virological methods","volume":"332 ","pages":"Article 115071"},"PeriodicalIF":2.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142693053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Crystal M. Gigante , Vaughn Wicker , Kimberly Wilkins , Melanie Seiders , Hui Zhao , Puja Patel , Lillian Orciari , Rene Edgar Condori , Lisa Dettinger , Pamela Yager , Dongxiang Xia , Yu Li
{"title":"Optimization of pan-lyssavirus LN34 assay for streamlined rabies diagnostics by real-time RT-PCR","authors":"Crystal M. Gigante , Vaughn Wicker , Kimberly Wilkins , Melanie Seiders , Hui Zhao , Puja Patel , Lillian Orciari , Rene Edgar Condori , Lisa Dettinger , Pamela Yager , Dongxiang Xia , Yu Li","doi":"10.1016/j.jviromet.2024.115070","DOIUrl":"10.1016/j.jviromet.2024.115070","url":null,"abstract":"<div><div>Reliable, validated diagnostic tests are critical for rabies control in animals and prevention in people. We present a performance assessment and updates to the LN34 real-time RT-PCR assay for rabies diagnosis in postmortem animal brain samples. In two U.S. laboratories during 2017–2022, routine used of the LN34 assay produced excellent diagnostic sensitivity (99.72–100 %) and specificity (99.99–100 %) compared to the direct fluorescence antibody test (DFA). Almost all (>90 %) DFA indeterminate results caused by non-specific or atypical fluorescence were negative by LN34 testing, representing up to 111 cases where unnecessary post-exposure prophylaxis could be avoided. LN34 assay original primer sequences showed low sensitivity for some rare lyssaviruses. Increased primer concentration combined with new primer formulation showed improved performance for impacted lyssaviruses with no loss in performance across diverse rabies virus variants from clinical samples. The updated LN34 and internal control assays were combined into a single-well LN34 multiplexed (LN34M) format, run at half reagent volumes. The LN34M assay showed similar detection of rabies virus to the singleplexed assay with simplified assay set-up, lower cost, and improved quality controls.</div></div>","PeriodicalId":17663,"journal":{"name":"Journal of virological methods","volume":"333 ","pages":"Article 115070"},"PeriodicalIF":2.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142695431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Accurate vector copy number determination in gammaretroviral vector producer cell clones using triplex digital droplet PCR","authors":"Tomomine Iida , Yoshiki Nakamura , Katsuhiko Yamamoto , Eiki Maeda , Yukihiro Ikeda","doi":"10.1016/j.jviromet.2024.115075","DOIUrl":"10.1016/j.jviromet.2024.115075","url":null,"abstract":"<div><div>Gammaretroviral vectors are widely used in cellular and gene therapy products because of the availability of stable vector producer cells. Accurately assessing vector copy number (VCN) is critical for selecting appropriate clones to avoid the risks of homologous recombination and complications in mutation detection. Traditional methods such as quantitative polymerase chain reaction (PCR) and Southern blotting have limitations in accuracy and throughput. This study presents a triplex droplet digital PCR (ddPCR) method for analyzing the VCN in gammaretroviral vector producer cells. We designed a universal primer– probe set targeting the packaging signal sequence common to murine leukemia virus– and murine stem cell virus– based gammaretroviral vectors. Two reference genes were selected after karyotyping the PG13 gammaretroviral vector packaging cell line to identify stable chromosomes. The triplex ddPCR assay was optimized and verified using PG13 cells transduced with constructs of different transgene and vector backbones. The assay showed high concordance with Southern blot. Using multiple reference genes ensures accurate and robust VCN assessment, especially in cell lines with chromosomal instability. This method improves the clone selection process for gammaretroviral vector producer cells, accelerates the development of novel cellular and gene therapy products, and ensures their rapid delivery to patients.</div></div>","PeriodicalId":17663,"journal":{"name":"Journal of virological methods","volume":"332 ","pages":"Article 115075"},"PeriodicalIF":2.2,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142682056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anaïs Scohy , Maria A. Argudín , Florence Kabera , Nathalie Olive , Benoît Kabamba Mukadi
{"title":"Evaluation of the Alinity m CMV assay for detecting and quantifying cytomegalovirus DNA in non-plasma samples","authors":"Anaïs Scohy , Maria A. Argudín , Florence Kabera , Nathalie Olive , Benoît Kabamba Mukadi","doi":"10.1016/j.jviromet.2024.115069","DOIUrl":"10.1016/j.jviromet.2024.115069","url":null,"abstract":"<div><div>CMV infection remains a well-recognized threat in immunocompromised patients and is a major cause of congenital infection. If plasma and whole blood are routinely used as clinical samples for detection of CMV infection and disease, CMV laboratory testing in non-blood samples is becoming more and more relevant to support the diagnosis, prognosis and management of CMV infection. Accurate CMV viral load assessment in various body fluids is therefore essential. We evaluated the performance of the Alinity m CMV assay for detecting and quantifying CMV in plasma, amniotic fluid, bronchoalveolar lavage, cerebrospinal fluid, saliva and urine. Using a commercially available CMV reference panel and CMV culture supernatant, we assessed the linearity and accuracy of the Alinity m CMV assay across the different sample types. Excellent linear correlations (r values > 0.98) and a good accuracy (bias < ± 0.50 Log<sub>10</sub> IU/mL and SD < 0.23) were observed. In conclusion, the Alinity m CMV assay is suitable to detect and quantify CMV DNA in plasma but also in all non-plasma samples tested. Random and continuous access capabilities of the Alinity m enable rapid and efficient laboratory detection and quantification of CMV DNA.</div></div>","PeriodicalId":17663,"journal":{"name":"Journal of virological methods","volume":"332 ","pages":"Article 115069"},"PeriodicalIF":2.2,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142687357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Azzania Fibriani, Katerina Naisanu, Nicholas Yamahoki, Denti Rizki Kinanti
{"title":"Development of polyclonal chicken egg yolk immunoglobulin Y (IgY) antibodies targeting SARS-CoV-2 multi-epitope antigen","authors":"Azzania Fibriani, Katerina Naisanu, Nicholas Yamahoki, Denti Rizki Kinanti","doi":"10.1016/j.jviromet.2024.115062","DOIUrl":"10.1016/j.jviromet.2024.115062","url":null,"abstract":"<div><div>Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is the primary cause of the Coronavirus disease 2019 (COVID-19) pandemic, which affects millions of people worldwide with high levels of infectivity and mortality. However, the antibodies developed for COVID-19 research and diagnostics are still limited. Therefore, in this study, we developed polyclonal immunoglobulin (IgY) antibodies from chicken egg yolk targeting multi-epitope antigen of SARS-CoV-2. After immunizing hens with a SARS-CoV-2 multi-epitope peptide, IgY antibodies were isolated from chicken eggs and further characterized using SDS-PAGE and ELISA. The results showed that the IgY antibodies were successfully isolated from egg yolks. The sandwich ELISA results demonstrated that the isolated IgYs could bind to SARS-CoV-2 antigens, both the multi-epitope peptide and the trimeric Spike. Furthermore, the developed polyclonal antibodies could recognize SARS-CoV-2 in human nasopharyngeal swab samples, even at the lowest concentration (dilution at 1:10000). Thus, it can be concluded that the developed polyclonal IgYs were successfully produced and have the potential to be applied in the development of COVID-19 diagnostics.</div></div>","PeriodicalId":17663,"journal":{"name":"Journal of virological methods","volume":"331 ","pages":"Article 115062"},"PeriodicalIF":2.2,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Caroline L. Ashley , Malik Bloul , Sibel Alca , Lachlan Smith , Wang Jin , David Khoury , Claudio Counoupas , Miles Davenport , James A. Triccas , Megan Steain
{"title":"Optimisation of a multiplexed, high throughput assay to measure neutralising antibodies against SARS-CoV-2 variants","authors":"Caroline L. Ashley , Malik Bloul , Sibel Alca , Lachlan Smith , Wang Jin , David Khoury , Claudio Counoupas , Miles Davenport , James A. Triccas , Megan Steain","doi":"10.1016/j.jviromet.2024.115073","DOIUrl":"10.1016/j.jviromet.2024.115073","url":null,"abstract":"<div><div>A multiplexed, lentivirus-based pseudovirus neutralisation assay (pVNT) was developed for high-throughput measurement of neutralising antibodies (nAbs) against three distinct SARS-CoV-2 spike variants. Intra-assay variability was minimised by optimising the plate layout and determining an optimal percentage transduction for the pseudovirus inoculum. Comparison of EC<sub>50</sub> titres between single and multiplexed pVNT assays showed no significant differences, indicating reliability of the multiplexed assay. Evaluation of convalescent human sera confirmed assay robustness, with consistent EC<sub>50</sub> titres for variant pseudoviruses relative to the ancestral strain observed across single and multiplexed assays. This multiplexed pVNT provides a reliable tool for assessing nAb responses against SARS-CoV-2 variants and could be used to accelerate preclinical vaccine assessment in preparation for the next coronavirus pandemic.</div></div>","PeriodicalId":17663,"journal":{"name":"Journal of virological methods","volume":"332 ","pages":"Article 115073"},"PeriodicalIF":2.2,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142668436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}