ARTICLE | doi:10.20944/preprints202208.0338.v1
Subject: Life Sciences, Virology Keywords: migratory birds; Newcastle disease virus-GVII; poultry; phylogenetics; sequence-independent; sin-gle-primer amplification (SISPA); velogenic; whole genome sequencing (WGS)
Online: 18 August 2022 (10:40:10 CEST)
Newcastle disease virus (NDV) genotype VII is a highly pathogenic Orthoavulavirus that has caused multiple outbreaks among poultry in Egypt since 2011. This study aimed to investigate the genetic diversity of NDV prevailing in domestic and wild birds in Egyptian governorates. A total of 37 oropharyngeal swabs from wild birds and 101 swabs from domestic bird flocks including chickens, ducks, turkeys, and swans were collected from different geographic regions within 13 governorates during 2019-2020. Virus isolation and propagation via embryonated eggs revealed 91 swab samples produced allantoic fluid containing hemagglutination activity, suggestive of virus presence. The use of RT-PCR targeted to F gene successfully detected NDV in 85 samples. The geographical prevalence of NDV spread to 12 governorates in domestic birds, migratory and non-migratory wild birds. Following whole genome sequencing, we assembled six NDV genome sequences (70 - 99% of genome coverage), including five full F gene sequences. All NDV strains carried high virulence, based on the presence of polybasic amino acids (RRQRF) at the F gene cleavage site. Phylogenetic analysis revealed that the NDV strains belonged to class II within genotype VII.1.1. The presence of genetically similar virulent NDV in wild birds further highlights their role in the dissemination of NDV in poultry populations across Egypt. Continued genomic surveillance in both wild birds and poultry would be necessary for monitoring NDV incursions and genetic diversification.
REVIEW | doi:10.20944/preprints202004.0449.v2
Subject: Keywords: SARS-CoV-2; Covid-19; pandemic; primer; India; mortality rate; evolution; updated primer; evolving pandemic
Online: 1 June 2020 (11:08:03 CEST)
In this paper we first provide a primer on SARS-CoV-2 and Covid-19 delineating the etiopathogenesis, epidemiology, clinical manifestations and the natural history of the disease. We then trace the evolution of the Covid-19 pandemic highlighting the characteristics of the epidemic in China where the pandemic originated, select countries of Europe which peaked during April, and Brazil, US and India where the pandemic has taken serious turns recently. We also project some possible trajectories for the mega cities of India based on the demographic characteristics of these cities in comparison to New York city. This is an updated version of the article from mid-April published online.
COMMUNICATION | doi:10.20944/preprints201806.0203.v1
Subject: Materials Science, Biomaterials Keywords: Zirconia; primer; priming; bonding; catechol; dental; prosthodontics
Online: 13 June 2018 (06:06:31 CEST)
Zirconia has recently become one of the most popular dental materials in prosthodontics being used in crowns, bridges, and to implants. However, weak bonding strength of dental adhesives and resins to zirconia surface has been a grand challenge in dentistry, thus finding a better adhesion to zirconia is urgently required. Marine sessile organisms such as mussels use a unique priming strategy to produce a strong bonding to wet mineral surfaces; one of the distinctive chemical features in the mussel’s adhesive primer proteins is high catechol contents among others. In this study, we pursued a bioinspired adhesion strategy, using a synthetic catechol primer applied to dental zirconia surfaces to study the effect of catecholic priming to shear bonding strength. Catechol priming provided a statistically significant enhancement (P < 0.05) in shear bonding strength compared to the bonding strength without priming, and relatively stronger bonding than commercially available zirconia priming techniques. This new bioinspired dental priming approach can be an excellent addition to the practitioner’s toolkit to improve dental bonding to zirconia.
ARTICLE | doi:10.20944/preprints201805.0466.v2
Subject: Life Sciences, Immunology Keywords: influenza; serum; IgG; humoral antibody; original antigenic sin; hemagglutinin
Online: 6 July 2018 (07:53:32 CEST)
The first exposure to influenza is thought to impact subsequent immune responses later in life. The consequences of this can be seen during influenza epidemics and pandemics with differences in morbidity and mortality for different birth cohorts. There is a need for better understanding of how vaccine responses are affected by early exposures to influenza viruses. In this analysis of hemagglutination inhibition (HI) antibody responses in two cohorts of military personnel we noticed differences related to age, sex, prior vaccination, deployment and birth year. These data suggest that HI antibody production, in response to influenza vaccination, is affected by these factors. The magnitude of this antibody response is associated with, among other factors, the influenza strain that circulated following birth.
HYPOTHESIS | doi:10.20944/preprints202108.0270.v1
Subject: Biology, Other Keywords: T helper differentiation; T helper polarization; Cross-reactivity; Regulatory T cells; Microbiota; Original Antigenic Sin
Online: 12 August 2021 (08:46:55 CEST)
Naive CD4+ T cells engage cognate peptide MHC-II complexes (pMHC-IIs) to differentiate and acquire one of several T helper (Th) fates whose specific trajectories are guided by a dynamic cytokine milieu that develops in response to antigenic entity. This physiological process is often erroneously conflated with a pathological one termed Th polarization. Using the SPIRAL model, we argue here that unlike Th fate choice, innate signaling alone is insufficient to initiate Th polarization in naive CD4+ T cells, that it instead develops from pre-existing memory CD4+ T cells that express cross-reactive TCRs, and that it inevitably leads to immunopathology.
REVIEW | doi:10.20944/preprints201909.0306.v1
Subject: Life Sciences, Immunology Keywords: influenza virus; humoral response; hemagglutinin (HA) of influenza virus; broad neutralizing antibody(bnAb); heterosubtypic immunity of influenza; original antigenic sin "OAS"; "universal" influenza vaccine; protein microarray assay; mPLEX-Flu assay; multiple dimensional assays (MDA))
Online: 27 September 2019 (08:34:56 CEST)
The human antibody response to influenza virus infection or vaccination is as complicated as it is essential for protection against flu. The constant antigenic changes of the virus to escape human herd immunity hinder the yearly selection of vaccine strains since it is hard to predict which virus strains will circulate for the coming flu season. A "universal" influenza vaccine that could induce broad cross-influenza subtype protection would help to alleviate this burden. However, the human antibody response is intricate and often obscure, with factors like antigenic seniority or original antigenic sin "OAS", and back-boosting ensuring that each person mounts a unique immune response to infection or vaccination with any new influenza virus strain. Notably, the effects of existing antibodies on cross-protective immunity after repeated vaccinations are unclear. More research is needed to characterize the mechanisms at play, but traditional assays such as hemagglutinin inhibition (HAI) and microneutralization (MN) are excessively limited in scope and too resource-intensive to effectively meet this challenge. In the past ten years, new multiple dimensional assays (MDAs) have been developed to help overcome these problems by simultaneously measuring antibodies against a large panel of influenza hemagglutinin (HA) proteins with a minimal amount of sample in a high throughput way. MDAs will likely be a powerful tool for accelerating the study of the humoral immune response to influenza vaccination and the development of a universal influenza vaccine.