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Dengue Fever: A Viral Hemorrhagic Fever of Global Concern
Published in Jagriti Narang, Manika Khanuja, Small Bite, Big Threat, 2020
Bennet Angel, Neelam Yadav, Jagriti Narang, Annette Angel, Vinod Joshi
Plaque reduction neutralization test (PRNT): The test enables detection of antibodies in the patient’s serum sample. The antibodies are allowed to react and then inoculated into Vero cell lines. The obtained suspension was then covered by a layer of carboxy methyl cellulose (CMC), which eventually leads to the formation of plaque and is counted under microscope. Staining can also be done in order to expedíate the cell counting process (Guzman and Kouri, 1996; Russell et al., 1967).
New and Emerging Pathogens
Published in Thomas T. Yoshikawa, Shobita Rajagopalan, Antibiotic Therapy for Geriatric Patients, 2005
The diagnosis of WNV infection is usually made using serology. Acute infection is diagnosed by detecting IgM antibody in serum or cerebrospinal fluid (CSF) using an enzyme-linked immunosorbent assay. The presence of IgM antibodies in the CSF indicates infection of the CNS. False-positive WT^JV IgM antibody results can occur from recent infection with another flavivirus such as dengue. Confirmation of an acute WNV infection is done using a plaque reduction neutralization test. It is important to note that IgM antibodies can persist for over a year, so that a positive IgM test may be unrelated to current illness under investigation (25).
Dengue and zika seropositivity, burden, endemicity, and cocirculation antibodies in Nigeria
Published in Annals of Medicine, 2023
Peter Asaga Mac, Markos Tadele, Philomena E. Airiohuodion, Thilini Nisansala, Shaistha Zubair, Jude Aigohbahi, Chukwuma Anyaike, Raman Velayudha, Axel Kroeger, Marcus Panning
This study had several significant limitations. The cross-reactivity of IgG antibodies between flaviviruses and other alphaviruses is well established and a confounding factor for serological studies investigating the seropositivity of arboviruses. All serum samples that were seropositive for both DENV and ZIKV, or both, were classified as flavivirus-positive. Because of the large sample size, it was impractical to conduct additional testing using techniques such as the plaque reduction neutralization test (PRNT), other sero-neutralization tests, and PCR. The current study was conducted in tertiary hospitals in three regions of Nigeria; therefore, it may not be representative of true dengue and Zika seropositivity. Additionally, we did not perform plaque reduction neutralization tests (PRNT) or PCR to confirm DENV and ZIKV, and there is a likelihood of false negatives or positives due to cross-reactivity and arboviral vaccines. There were more females than males, which may have led to bias and confounding variables, as well as age.
Rapid discovery of diverse neutralizing SARS-CoV-2 antibodies from large-scale synthetic phage libraries
Published in mAbs, 2022
Tom Z. Yuan, Pankaj Garg, Linya Wang, Jordan R. Willis, Eric Kwan, Ana G Lujan Hernandez, Emily Tuscano, Emily N. Sever, Erica Keane, Cinque Soto, Eric M. Mucker, Mallorie E. Fouch, Edgar Davidson, Benjamin J. Doranz, Shweta Kailasan, M. Javad Aman, Haoyang Li, Jay W. Hooper, Erica Ollmann Saphire, James E. Crowe, Qiang Liu, Fumiko Axelrod, Aaron K. Sato
Plaque-reduction neutralization testing (PRNT) were performed as described previously (Brocato 2020).31 Briefly, an equal volume of complete media (EMEM containing 10% heat-inactivated FBS, 1% Pen/Strep, 0.1% Gentamycin, 0.2% Fungizone, cEMEM) containing SARS-CoV-2 USA-WA-1/2020 was combined with antibodies serial diluted twofold in cEMEM. The virus/antibody mixture was incubated at 37°C in a 5% CO2 for 1 hour and then added to 6-well plates containing 3-day old, ATCC Vero 76 monolayers. After a 1-hour incubation at 37°C, 5% CO2 incubator a 3 mL per well of agarose overlay (0.6% SeaKem ME agarose, EBME with HEPES, 10% heat-inactivated FBS, 100X NEAA, 1% Pen/Strep, 0.1% Gentamycin and 0.2% Fungizone) was added. The plates were placed in a 37°C, 5% CO2 incubator for 2 days and then stained with neutral red. PRNT80 titers are the reciprocal of the highest dilution that results in an 80% reduction in the number of plaques relative to the number of plaques visualized in the cEMEM alone (no antibody) wells.
Dengue virus 4: the ‘black sheep’ of the family?
Published in Expert Review of Vaccines, 2020
Regarding the other two clinical trials, conducted in Asian Pacific and Latin America, averaged results evidenced the highest efficacy for DENV-4 (76.9%), followed by DENV-3 (71.6%) and DENV-1 (54.7%), with the lowest efficacy against DENV-2 (43.0%). Again, the neutralizing antibody response after the third dose did not correlate with the efficacy and the lowest titers were detected against DENV-4 (Table 1) [10,26]. These observations cast doubt on whether the plaque reduction neutralization test is a good assay for predicting the efficacy of a vaccine candidate. Noteworthy, they also suggest that DENV-2 component needs to induce very high titers relative to the other serotypes, in order to provide an acceptable efficacy; In the case of DENV-4 not-so-high neutralizing antibody titers may be necessary to counteracting infection with this serotype.