scholarly journals Development of a Western Blot Assay for Detection of Antibodies against Coronavirus Causing Severe Acute Respiratory Syndrome

2004 ◽  
Vol 11 (2) ◽  
pp. 417-422 ◽  
Author(s):  
Qigai He ◽  
Kooi Hoong Chong ◽  
Hiok Hee Chng ◽  
Bernard Leung ◽  
Ai Ee Ling ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Western Blot ◽  
Recombinant Proteins ◽  
Immunofluorescence Assay ◽  
Sars Coronavirus ◽  
Western Blot Assay ◽  
Nucleocapsid Gene ◽  
Specificity And Sensitivity ◽  
C Terminus ◽  
Coronavirus Infection

ABSTRACT To identify a major antigenic determinant for use in the development of a rapid serological diagnostic test for severe acute respiratory syndrome (SARS) coronavirus infection and to study the immune response during SARS coronavirus infection in humans, we cloned the full length and six truncated fragments of the nucleocapsid gene, expressed them, and purified them as glutathione S-transferase-tagged recombinant proteins. The reactivities of the recombinant proteins to a panel of antibodies containing 33 SARS coronavirus-positive sera and 66 negative sera and to antibodies against other animal coronaviruses were screened. A truncated 195-amino-acid fragment from the C terminus of the nucleocapsid protein (N195) was identified that had a strong ability to detect antibodies against SARS coronavirus. No cross-reaction was found between the N195 protein and antibodies against chicken, pig, and canine coronaviruses. The N195 protein was used to develop a Western blot assay to detect antibodies against SARS coronavirus in 274 clinically blinded samples. The specificity and sensitivity of this test were 98.3 and 90.9%, respectively. The correlation between our Western blotting assay and an immunofluorescence assay (IFA) was also analyzed. The results of our Western blot assay and IFA for the detection of SARS coronavirus-positive sera were the same. Thus, the N195 protein was identified as a suitable protein to be used as an antigen in Western blot and other possible assays for the detection of SARS coronavirus infection.

scholarly journals Severe Acute Respiratory Syndrome Coronavirus Infection of Mice Transgenic for the Human Angiotensin-Converting Enzyme 2 Virus Receptor

2006 ◽  
Vol 81 (3) ◽  
pp. 1162-1173 ◽  
Author(s):  
Chien-Te K. Tseng ◽  
Cheng Huang ◽  
Patrick Newman ◽  
Nan Wang ◽  
Krishna Narayanan ◽  
...  
Keyword(s):  
Weight Loss ◽  
Severe Acute Respiratory Syndrome ◽  
Transgenic Mice ◽  
Angiotensin Converting Enzyme ◽  
Virus Replication ◽  
Clinical Manifestations ◽  
Converting Enzyme ◽  
Sars Coronavirus ◽  
Angiotensin Converting Enzyme 2 ◽  
Coronavirus Infection

ABSTRACT Animal models for severe acute respiratory syndrome (SARS) coronavirus infection of humans are needed to elucidate SARS pathogenesis and develop vaccines and antivirals. We developed transgenic mice expressing human angiotensin-converting enzyme 2, a functional receptor for the virus, under the regulation of a global promoter. A transgenic lineage, designated AC70, was among the best characterized against SARS coronavirus infection, showing weight loss and other clinical manifestations before reaching 100% mortality within 8 days after intranasal infection. High virus titers were detected in the lungs and brains of transgene-positive (Tg+) mice on days 1 and 3 after infection. Inflammatory mediators were also detected in these tissues, coinciding with high levels of virus replication. Lower virus titers were also detected in other tissues, including blood. In contrast, infected transgene-negative (Tg−) mice survived without showing any clinical illness. Pathologic examination suggests that the extensive involvement of the central nervous system likely contributed to the death of Tg+ mice, even though viral pneumonia was present. Preliminary studies with mice of a second lineage, AC63, in which the transgene expression was considerably less abundant than that in the AC70 line, revealed that virus replication was largely restricted to the lungs but not the brain. Importantly, despite significant weight loss, infected Tg+ AC63 mice eventually recovered from the illness without any mortality. The severity of the disease that developed in these transgenic mice—AC70 in particular—makes these mouse models valuable not only for evaluating the efficacy of antivirals and vaccines, but also for studying SARS coronavirus pathogenesis.

scholarly journals Longitudinal Profile of Immunoglobulin G (IgG), IgM, and IgA Antibodies against the Severe Acute Respiratory Syndrome (SARS) Coronavirus Nucleocapsid Protein in Patients with Pneumonia Due to the SARS Coronavirus

2004 ◽  
Vol 11 (4) ◽  
pp. 665-668 ◽  
Author(s):  
Patrick C. Y. Woo ◽  
Susanna K. P. Lau ◽  
Beatrice H. L. Wong ◽  
Kwok-hung Chan ◽  
Chung-ming Chu ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Indirect Immunofluorescence ◽  
Immunoglobulin G ◽  
Nucleocapsid Protein ◽  
Baseline Level ◽  
Immunofluorescence Assay ◽  
Indirect Immunofluorescence Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sars Coronavirus ◽  
Iga Antibodies

ABSTRACT By using a recombinant severe acute respiratory syndrome coronavirus (SARS-CoV) nucleocapsid protein-based enzyme-linked immunosorbent assay (ELISA) and serum specimens serially collected (from day 0 to day 240 after symptom onset) from patients with pneumonia due to SARS-CoV, we analyzed the longitudinal profiles of immunoglobulin G (IgG), IgM, and IgA antibodies against the SARS-CoV nucleocapsid protein in patients with pneumonia due to SARS-CoV. For IgG, the median optical density at 450 nm (OD450) turned positive at day 17 and a biphasic response was observed. At day 240, all patients were still positive for anti-nucleocapsid protein IgG antibody. For IgM, the median OD450 turned positive at day 20.5, peaked at about day 80, and fell to below the baseline level at about day 180. At day 240, 36% of the patients were still positive for anti-nucleocapsid protein IgM antibody. For IgA, the median OD450 turned positive at day 17, peaked at about day 50, and fell to below the baseline level at about day 180. At day 240, 36% of the patients were still positive for anti-nucleocapsid protein IgA antibody. The time of seroconversion detected by the recombinant SARS-CoV nucleocapsid protein-based ELISA and that detected by indirect immunofluorescence assay were similar. The median times of seroconversion for IgG, IgM, and IgA detected by the indirect immunofluorescence assay were 17 days (17 days by ELISA), 16.5 days (20.5 days by ELISA), and 17.5 days (17 days by ELISA), respectively, after disease onset. One, four, and one of the six patients who died did not produce any IgG, IgM, and IgA antibodies against the nucleocapsid protein of SARS-CoV, respectively, although these antibodies were detected in all six patients by the indirect immunofluorescence assay. Further studies should be performed to see whether SARS-CoV nucleocapsid protein antibody positivity has any prognostic significance.

scholarly journals False-Positive Results in a Recombinant Severe Acute Respiratory Syndrome-Associated Coronavirus (SARS-CoV) Nucleocapsid-Based Western Blot Assay Were Rectified by the Use of Two Subunits (S1 and S2) of Spike for Detection of Antibody to SARS-CoV

2006 ◽  
Vol 13 (3) ◽  
pp. 409-414 ◽  
Author(s):  
Mimoun Maache ◽  
Florence Komurian-Pradel ◽  
Alain Rajoharison ◽  
Magali Perret ◽  
Jean-Luc Berland ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Western Blot ◽  
False Positive ◽  
High Sensitivity ◽  
Cross Reactivity ◽  
Serum Samples ◽  
Western Blot Assay ◽  
N Protein ◽  
False Positive Diagnosis ◽  
Healthy Donors

ABSTRACT To evaluate the reactivity of the recombinant proteins expressed in Escherichia coli strain BL21(DE3), a Western blot assay was performed by using a panel of 78 serum samples obtained, respectively, from convalescent-phase patients infected with severe acute respiratory syndrome-associated coronavirus (SARS-CoV) (30 samples) and from healthy donors (48 samples). As antigen for detection of SARS-CoV, the nucleocapsid protein (N) showed high sensitivity and strong reactivity with all samples from SARS-CoV patients and cross-reacted with all serum samples from healthy subjects, with either those obtained from China (10 samples) or those obtained from France (38 serum samples), giving then a significant rate of false positives. Specifically, our data indicated that the two subunits, S1 (residues 14 to 760) and S2 (residues 761 to 1190), resulted from the divided spike reacted with all samples from SARS-CoV patients and without any cross-reactivity with any of the healthy serum samples. Consequently, these data revealed the nonspecific nature of N protein in serodiagnosis of SARS-CoV compared with the S1 and S2, where the specificity is of 100%. Moreover, the reported results indicated that the use of one single protein as a detection antigen of SARS-CoV infection may lead to false-positive diagnosis. These may be rectified by using more than one protein for the serodiagnosis of SARS-CoV.

scholarly journals Kinetics of Severe Acute Respiratory Syndrome (SARS) Coronavirus-Specific Antibodies in 271 Laboratory-Confirmed Cases of SARS

2004 ◽  
Vol 11 (4) ◽  
pp. 792-794 ◽  
Author(s):  
Zhongping He ◽  
Qingming Dong ◽  
Hui Zhuang ◽  
Shujing Song ◽  
Guoai Peng ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Enzyme Immunoassay ◽  
Immunoglobulin G ◽  
Immunofluorescence Assay ◽  
Sars Coronavirus ◽  
Specific Antibodies ◽  
Kinetics Of

ABSTRACT The sensitivities and specificities of an immunofluorescence assay and an enzyme immunoassay for detection of antibodies specific for severe acute respiratory syndrome coronavirus (SARS-CoV) were compared for 148 laboratory-confirmed SARS cases. The appearance and persistence of SARS-CoV-specific antibodies were assessed, with immunoglobulin G detected in 59% of samples collected within 14 days and persisting for 60 to 95 days after the onset of illness.

The Anti-tumor Activity and Mechanisms of rLj-RGD3 on Human Laryngeal Squamous Carcinoma Hep2 Cells

2020 ◽  
Vol 19 (17) ◽  
pp. 2108-2119
Author(s):  
Yang Jin ◽  
Li Lv ◽  
Shu-Xiang Ning ◽  
Ji-Hong Wang ◽  
Rong Xiao
Keyword(s):  
Wound Healing ◽  
Western Blot ◽  
Morphological Changes ◽  
In Vivo Studies ◽  
Migration And Invasion ◽  
Tunel Staining ◽  
Dna Ladder ◽  
Western Blot Assay

Background: Laryngeal Squamous Cell Carcinoma (LSCC) is a malignant epithelial tumor with poor prognosis and its incidence rate increased recently. rLj-RGD3, a recombinant protein cloned from the buccal gland of Lampetra japonica, contains three RGD motifs that could bind to integrins on the tumor cells. Methods: MTT assay was used to detect the inhibitory rate of viability. Giemsa’s staining assay was used to observe the morphological changes of cells. Hoechst 33258 and TUNEL staining assay, DNA ladder assay were used to examine the apoptotic. Western blot assay was applied to detect the change of the integrin signal pathway. Wound-healing assay, migration, and invasion assay were used to detect the mobility of Hep2 cells. H&E staining assay was used to show the arrangement of the Hep2 cells in the solid tumor tissues. Results: In the present study, rLj-RGD3 was shown to inhibit the viability of LSCC Hep2 cells in vitro by inducing apoptosis with an IC50 of 1.23µM. Western blot showed that the apoptosis of Hep2 cells induced by rLj- RGD3 was dependent on the integrin-FAK-Akt pathway. Wound healing, transwells, and western blot assays in vitro showed that rLj-RGD3 suppressed the migration and invasion of Hep2 cells by integrin-FAKpaxillin/ PLC pathway which could also affect the cytoskeleton arrangement in Hep2 cells. In in vivo studies, rLj-RGD3 inhibited the growth, tumor volume, and weight, as well as disturbed the tissue structure of the solid tumors in xenograft models of BALB/c nude mice without reducing their body weights. Conclusion: hese results suggested that rLj-RGD3 is an effective and safe suppressor on the growth and metastasis of LSCC Hep2 cells from both in vitro and in vivo experiments. rLj-RGD3 might be expected to become a novel anti-tumor drug to treat LSCC patients in the near future.

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