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2022 ◽  
Vol 12 ◽  
Author(s):  
Alexander Suvorov ◽  
Tatiana Gupalova ◽  
Yulia Desheva ◽  
Tatiana Kramskaya ◽  
Elena Bormotova ◽  
...  

Contemporary SARS-Cov-2 pandemic, besides its dramatic global influence on the human race including health care systems, economies, and political decisions, opened a window for the global experiment with human vaccination employing novel injectable vaccines providing predominantly specific IgG response with little knowledge of their impact on the mucosal immunity. However, it is widely accepted that protection against the pathogens at the gates of the infection - on mucosal surfaces—predominantly rely on an IgA response. Some genetically modified bacteria, including probiotics, represent attractive vehicles for oral or nasal mucosal delivery of therapeutic molecules. Probiotic-based vaccines for mucous membranes are easy to produce in large quantities; they have low cost, provide quite a long T-cell memory, and gut IgA response to oral vaccines is highly synchronized and strongly oligoclonal. Here we present a study demonstrating construction of the novel SARS-Cov-2 vaccine candidate employing the gene fragment of S1 SARS-Cov-2 gene. This DNA fragment was inserted in frame into major pili protein gene with d2 domain of enterococcal operon encoding for pili. The DNA sequencing proved the presence of the insert in enterococcal genome. RNA transcription, immunoprecipitation, and immune electron microscopy with human sera obtained from the SARS-Cov-2 patients demonstrated expression of SARS-Cov-2 antigens in bacteria. Taken together the data obtained allowed considering this genetically modified probiotic strain as an interesting candidate for vaccine against SARS-Cov-2.


2022 ◽  
Vol 12 ◽  
Author(s):  
Nathalie Vanderheijden ◽  
Annelies Stevaert ◽  
Jiexiong Xie ◽  
Xiaolei Ren ◽  
Cyril Barbezange ◽  
...  

To face the continuous emergence of SARS-CoV-2 variants, broadly protective therapeutic antibodies are highly needed. We here focused on the fusion peptide (FP) region of the viral spike antigen since it is highly conserved among alpha- and betacoronaviruses. First, we found that coronavirus cross-reactive antibodies are commonly formed during infection, being omnipresent in sera from COVID-19 patients, in ~50% of pre-pandemic human sera (rich in antibodies against endemic human coronaviruses), and even in feline coronavirus-infected cats. Pepscan analyses demonstrated that a confined N-terminal region of the FP is strongly immunogenic across diverse coronaviruses. Peptide-purified human antibodies targeting this conserved FP epitope exhibited broad binding of alpha- and betacoronaviruses, besides weak and transient SARS-CoV-2 neutralizing activity. Being frequently elicited by coronavirus infection, these FP-binding antibodies might potentially exhibit Fc-mediated effector functions and influence the kinetics or severity of coronavirus infection and disease.


2021 ◽  
Author(s):  
Alexander Muik ◽  
Bonny Gaby Lui ◽  
Ann-Kathrin Wallisch ◽  
Maren Bacher ◽  
Julia Muehl ◽  
...  

A new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineage, B.1.1.529, was recently detected in Botswana and South Africa and is now circulating globally. Just two days after it was first reported to the World Health Organization (WHO), this strain was classified as a variant of concern (VOC) and named Omicron. Omicron has an unusually large number of mutations, including up to 39 amino acid modifications in the spike (S) protein, raising concerns that its recognition by neutralizing antibodies from convalescent and vaccinated individuals may be severely compromised. In this study, we tested pseudoviruses carrying the SARS-CoV-2 spike glycoproteins of either the Wuhan reference strain, the Beta, the Delta or the Omicron variants of concern with sera of 51 participants that received two doses or a third dose (≥6 months after dose 2) of the mRNA-based COVID-19 vaccine BNT162b2. Immune sera from individuals who received two doses of BNT162b2 had more than 22-fold reduced neutralizing titers against the Omicron as compared to the Wuhan pseudovirus. One month after a third dose of BNT162b2, the neutralization titer against Omicron was increased 23-fold compared to two doses and antibody titers were similar to those observed against the Wuhan pseudovirus after two doses of BNT162b2. These data suggest that a third dose of BNT162b2 may protect against Omicron-mediated COVID-19, but further analyses of longer-term antibody persistence and real-world effectiveness data are needed.


2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Raquel Martínez-López ◽  
Catarina Vaz ◽  
Esther Redondo ◽  
Guillermo Calvo ◽  
María Luisa Hernáez ◽  
...  

The transition between yeast and hyphal morphologies plays a crucial role in the pathogenicity of Candida albicans. Recent studies have pointed out the great relevance of extracellular vesicles (EVs) secreted by microorganisms in a wide variety of biological processes including interaction with the host. Therefore, the main objective of this work was to compare the EVs secreted by yeast and hyphal forms to shed light on C. albicans-host interaction. EVs were obtained by ultracentrifugation of the culture medium supernatant and analysed by mass spectrometry. They were characterized by transmission electronic microscopy (TEM) and dynamic light scattering (DLS). DLS and TEM analysis showed that yeast EVs were significantly bigger than hyphal EVs, being most of them in the range between 400 to 500nm while hyphal EVs were ranged mostly around 100-200nm. Proteomic analysis showed greater protein diversity in hyphal EVs when compared to yeast EVs (up to 1700 different proteins identified versus 300), although less amount of total protein was obtained. Gene Ontology (GO) analysis showed that yeast EVs were enriched in surface proteins while hyphal EVs, although containing also most of these surface proteins, were also significantly and exclusively enriched in proteins involved in protein metabolism (ribosomal proteins, many aminoacid-pathway enzymes and proteasome) and cellular transport. The differences between YEVs and HEVs also prompted a different immune host response, as tested with macrophage cell cultures and human sera from patients with invasive candidiasis. All these differences point out a possible different biogenesis and roles of EVs secreted by both morphologies.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ilaria Varotto-Boccazzi ◽  
Alessandro Manenti ◽  
Francesca Dapporto ◽  
Louise J. Gourlay ◽  
Beatrice Bisaglia ◽  
...  

To detect and prevent emerging epidemics, discovery platforms are urgently needed, for the rapid development of diagnostic assays. Molecular diagnostic tests for COVID-19 were developed shortly after the isolation of SARS-CoV-2. However, serological tests based on antiviral antibody detection, revealing previous exposure to the virus, required longer testing phases, due to the need to obtain correctly folded and glycosylated antigens. The delay between the identification of a new virus and the development of reliable serodiagnostic tools limits our readiness to tackle future epidemics. We suggest that the protozoan Leishmania tarentolae can be used as an easy-to-handle microfactory for the rapid production of viral antigens to face emerging epidemics. We engineered L. tarentolae to express the SARS-CoV-2 receptor-binding domain (RBD) and we recorded the ability of the purified RBD antigen to detect SARS-CoV-2 infection in human sera, with a sensitivity and reproducibility comparable to that of a reference antigen produced in human cells. This is the first application of an antigen produced in L. tarentolae for the serodiagnosis of a Coronaviridae infection. On the basis of our results, we propose L. tarentolae as an effective system for viral antigen production, even in countries that lack high-technology cell factories.


2021 ◽  
Author(s):  
Maren Schubert ◽  
Federico Bertoglio ◽  
Stephan Steinke ◽  
Philip Alexander Heine ◽  
Mario Alberto Ynga-Durand ◽  
...  

Background The ongoing COVID-19 pandemic is caused by the beta coronavirus SARS-CoV-2. COVID-19 manifests itself from mild or even asymptomatic infections to severe forms of life-threatening pneumonia. At the end of November 2021, yet another novel SARS-CoV-2 variant named B.1.1.529 or Omicron was discovered and classified as a variant of concern (VoC) by the WHO. Omicron shows significantly more mutations in the amino acid (aa) sequence of its spike protein than any previous variant, with the majority of those concentrated in the receptor binding domain (RBD). In this work, the binding of the Omicron RBD to the human ACE2 receptor was experimentally analyzed in comparison to the original Wuhan SARS-CoV-2 virus, and the Beta and Delta variants. Moreover, we compared the ability of human sera from COVID-19 convalescent donors and persons fully vaccinated with BNT162b2 (Corminaty) or Ad26.COV2.S (Janssen COVID-19 vaccine) as well as individuals who had boost vaccine doses with BNT162b2 or mRNA-1273 (Spikevax) to bind the different RBDs variants. Methods The Omicron RBD with 15 aa mutations compared to the original Wuhan strain was produced baculovirus-free in insect cells. Binding of the produced Omicron RBD to hACE was analyzed by ELISA. Sera from 27 COVID-19 patients, of whom 21 were fully vaccinated and 16 booster recipients were titrated on the original Wuhan strain, Beta, Delta and Omicron RBD and compared to the first WHO International Standard for anti-SARS-CoV-2 immunoglobulin (human) using the original Wuhan strain as reference. Results The Omicron RBD showed a slightly reduced binding to ACE2 compared to the other RBDs. The serum of COVID-19 patients, BNT162b2 vaccinated and boost vaccinated persons showed a reduced binding to Omicron RBD in comparison to the original Wuhan strain, Beta und Delta RBDs. In this assay, the boost vaccination did not improve the RBD binding when compared to the BNT162b2 fully vaccinated group. The RBD binding of the Ad26.COV2.S serum group was lower at all compared to the other groups. Conclusions The reduced binding of human sera to Omicron RBD provides first hints that the current vaccinations using BNT162b2, mRNA-1273 and Ad26.COV2.S may be less efficient in preventing infections with the Omicron variant.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Fekadu Gutema Wegi ◽  
Kebede Amenu ◽  
Adugna Chalchisa ◽  
Gezahegne Mamo

Brucellosis is an important neglected zoonotic disease caused by infection with bacteria of the genus Brucella affecting different mammalian species including humans. A cross-sectional study was conducted to estimate the seroprevalence of brucellosis in camels and humans and its associated risk factors in Amibara District of Afar Region in Northeast Ethiopia, from October 2019 to May 2020. A total of 250 camel and 120 human sera were serially tested using the Rose Bengal plate test (RBPT) and complement fixation test (CFT). The overall seroprevalence of camel brucellosis in this study was 7.6% (95% CI: 4.9–11.56) by RBPT and 3.2% (95% CI: 1.63–6.2) by combined RBPT and CFT. In humans, twelve (10%) of the collected sera were positive by RBPT among which only four of them (3.33%) were positive by CFT. The risk factor analysis indicated that age, body condition, number of parity, and abortion history were significantly associated with Brucella seropositivity in camel ( P  ≤ 0.05). In humans, occupation and nonprotective handling of dystocia cases showed an apparent association with Brucella seropositivity. The results of this study indicated that brucellosis is a common health problem in camels and humans in Amibara District of Afar Region. The public health importance of this disease is associated with raw milk consumption and close contact with the animals having history of recent abortion. Therefore, controlling the risk factors, establishing Brucella diagnostic service in human clinics and hospitals, continuous social training with feedback assessments, and overall implementing of One Health approach framework to attain optimal health for people and domestic animals in area are recommended to safeguard the health of society.


2021 ◽  
Author(s):  
Yfat Yahalom-Ronen ◽  
Noam Erez ◽  
Morly Fisher ◽  
Hadas Tamir ◽  
Boaz Politi ◽  
...  

BriLife® (rVSV- ΔG-spike) is a SARS-CoV-2 vaccine candidate based on vesicular stomatitis virus (VSV) platform. We show that sera from BriLife® vaccinees maintain neutralization capacity against alpha, beta, gamma and delta SARS-CoV-2 variants. BriLife® spontaneously-acquired spike mutations, corresponding with key SARS-CoV-2 variants mutations, may contribute to its efficacy against SARS-CoV-2 variants.


2021 ◽  
Vol 12 ◽  
Author(s):  
Fan Zhou ◽  
Lena Hansen ◽  
Gabriel Pedersen ◽  
Gunnveig Grødeland ◽  
Rebecca Cox

The highly pathogenic avian influenza H5N1 viruses constantly evolve and give rise to novel variants that have caused widespread zoonotic outbreaks and sporadic human infections. Therefore, vaccines capable of eliciting broadly protective antibody responses are desired and under development. We here investigated the magnitude, kinetics and protective efficacy of the multi-faceted humoral immunity induced by vaccination in healthy adult volunteers with a Matrix M adjuvanted virosomal H5N1 vaccine. Vaccinees were given escalating doses of adjuvanted vaccine (1.5μg, 7.5μg, or 30μg), or a non-adjuvanted vaccine (30μg). An evaluation of sera from vaccinees against pseudotyped viruses covering all (sub)clades isolated from human H5N1 infections demonstrated that the adjuvanted vaccines (7.5μg and 30μg) could elicit rapid and robust increases of broadly cross-neutralizing antibodies against all clades. In addition, the adjuvanted vaccines also induced multifaceted antibody responses including hemagglutinin stalk domain specific, neuraminidase inhibiting, and antibody-dependent cellular cytotoxicity inducing antibodies. The lower adjuvanted dose (1.5µg) showed delayed kinetics, whilst the non-adjuvanted vaccine induced overall lower levels of antibody responses. Importantly, we demonstrate that human sera post vaccination with the adjuvanted (30μg) vaccine provided full protection against a lethal homologous virus challenge in mice. Of note, when combining our data from mice and humans we identified the neutralizing and neuraminidase inhibiting antibody titers as correlates of in vivo protection.


2021 ◽  
Vol 102 (11) ◽  
Author(s):  
Nazli Ayhan ◽  
Bulent Alten ◽  
Vladimir Ivovic ◽  
Aleksandar Cvetkovikj ◽  
Jovana Stefanovska ◽  
...  

Sandfly-borne phleboviruses are distributed widely throughout the Mediterranean Basin, presenting a threat to public health in areas where they circulate. However, the true diversity and distribution of pathogenic and apathogenic sandfly-borne phleboviruses remains a key issue to be studied. In the Balkans, most published data rely on serology-based studies although virus isolation has occasionally been reported. Here, we report the discovery of two novel sandfly-borne phleboviruses, provisionally named Zaba virus (ZABAV) and Bregalaka virus (BREV), which were isolated in Croatia and North Macedonia, respectively. This constitutes the first isolation of phleboviruses in both countries. Genetic analysis based on complete coding sequences indicated that ZABAV and BREV are distinct from each other and belong to the genus Phlebovirus, family Phenuiviridae. Phylogenetic and amino acid modelling of viral polymerase shows that ZABAV and BREV are new members of the Salehabad phlebovirus species and the Adana phlebovirus species, respectively. Moreover, sequence-based vector identification suggests that ZABAV is mainly transmitted by Phlebotomus neglectus and BREV is mainly transmitted by Phlebotomus perfiliewi. BREV neutralizing antibodies were detected in 3.3% of human sera with rates up to 16.7% in certain districts, demonstrating that BREV frequently infects humans in North Macedonia. In vitro viral growth kinetics experiments demonstrated viral replication of both viruses in mammalian and mosquito cells. In vivo experimental studies in mice suggest that ZABAV and BREV exhibit characteristics making them possible human pathogens.


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