Introduction: COVID-19 is an infectious disease caused by SARS-CoV-2, discovered in December 2019. Since then, this highly infectious coronavirus caused a world-wide emergency, with just over 1 year infected more than 100 million of people around the world with almost 2,5 million of deaths Until February 2021, Brazil is third in ranking of infected and second in number of deaths, with more than 9 million of infected and 240 thousand of deaths, respectively. Even with the start of vaccination, the development of therapeutic approaches aimed at reversing severe conditions in patients affected by COVID-19, besides new inputs for diagnosis. Therefore, neutralizing monoclonal antibodies have been emerging as an important alternative to treat cases, with the approval of some of them for emergency use.Objective: To select fragments of human antibodies from patients affected by SARS-COV-2, using the phage display technique.Methodology: Twenty-three individuals with confirmed SARS-CoV-2 were recruited for this study (CEP-CAAE 31368620.0.0000.5262). In order to build a human immune library of antibody fragments, peripheral blood mononuclear cells from donors were isolated by Ficoll gradient. From an RNA template, it was produced a pool of cDNA. Heavy and light chains regions were synthesized by PCR to construct scFv genes by overlaping PCR both with specific primers. The scFvlibrary genes were cloned into pCOMB3XSS vector and transformed into Escherichia coli XL1-blue. To recover scFv the culture was infected with helper phage VCSM13. To select the target, a recombinant protein was immobilized into 96 wells plate and we have obtained a pool of specific phage-scFvs, confirmed by ELISA. Furthermore, single cells were cultivated and the expression of each scFv was analyzed by dot blot and sequenced by SANGER to identify major prevalence of sequences and the most promising clone was assessed by ELISA against SARS-COV-2 antigens. Results:The PCR produced 400 bp amplicons for VH and 350 bp for VL and the overlap PCR generated a 800 bp product for scFvs and after four rounds of biopanning was performed and selected scFv against the target. The evaluation of specificity of scFvs was confirmed by high ODs obtained in ELISA tests using phage-scFv and purified scFv. After the evaluation by dot blot of single cells product, the better clone was sequenced and analysed the directly neutralizing activity by PRNT against virus inactivated particle, but was not show effective. However, the PRNT will be repeated using an approach to obtain a complete antibody from this clone. Conclusion:It was possible to obtain, in record time, an immune library for phage display selection of human fragments. Our panning methodology was successful in selecting specific scFvs fragments against our target, as well as, the whole virus, and could possibly become a tool for diagnosis and treatment for COVID-19

Introduction: Two most important forms of diagnostic testing available for SARS-CoV-2 are molecular and serological tests. Among those, the serum neutralization assay stands out as the gold standard for evaluation of the effectiveness of neutralizing antibodies (NAbs) against viral infections. In this regard, it is important the standardization of neutralization-based assay to validate the specificity and sensitivity of current immunoassays against SARS-CoV-2 to avoid bias outcomes.Objective: The present study aims to develop a test for the evaluation of NAbs against SARS-CoV-2 through universal serum neutralization platform by plaque reduction neutralization test (PRNT-SARS-CoV-2).Methodology: Briefly, 24-well plates were seeded with two different Vero cell concentrations (1.2 x 10 5 or 2 x 10 5 cells/well). In addition, dilutions were assessed with approximately 60-100 PFU of SARS-CoV-2 (PV004/20 CoV-2-P4; 1,71 X 10 6 TCID50/mL) per well, and plates with virus and serum as well as mock plates followed by incubation at 37°C for 1h. Thereafter, the supernatant was transferred to definitive plates with cell monolayers and incubated at 37°C for 1 h. After this time, media was discarded; cells were overlaid with 1 mL of E199 medium with 1.5 or 2% of CMC and incubated for 3 days at 37°C in 5% CO2. Cells were then fixed with 10% formalin, stained with crystal violet and plaques were counted. Neutralizing antibody titers were expressed by 50% or 90% of plaque reduction. Results:We found that 2 x 105 cells/well and 1.5% of CMC, besides the 1:12.000 of virus dilution revealed to be the better conditions to perform the assay. Our early results showed that the majority of specimens from COVID-19 positive donor presented low neutralizing antibodies levels (Median 1:36.5; titers calculated by reciprocal dilution). Conclusion:In perspective, this project aims to contribute to elucidate the role of NAb levels in the protection and/or severity of COVID-19. Considering that SARS-CoV-2 infection is a public health concern, besides the imminent vaccination, the available of a neutralization assay, standardized and validated, could help to answer important gaps related to epidemiologic perspective on surveillance policies. The authors thank the Multi-user Research Facility of Biosafety Platform NB3-

SARS-CoV-2 virus jumped the barrier between species and started to infect humans in Wuhan province, China. The disease has spread quickly and has caused thousands of deaths since the declaration of the Covid-19 pandemic by the WHO. In order to avoid the spread of the disease, mass diagnosis is essential as a strategy for public health, allowing immediate quarantine of infected people. Added to this, the discovery of an effective treatment brings hope to those currently infected. Herein we have developed antibodies against Spike and Nucleocapsid proteins of SARS-CoV-2 which could help the development of antigen capture point-of-care tests and treatment of this illness.

Introduction:The pandemic of SARS-CoV-2 brought interest to fabric industry to develop functional textiles formulated with antiviral and/or virucidal agents, able to inactivate virus and reduce risk of infection and transmission. The antiviral textiles could be use in production of individual protection equipment (IPE), but that fabrics need to be tested in many specific antiviral assays.Objective: This study aims to assess the antiviral efficacy of functional textiles using an antiviral activity evaluation platform, which uses as model viruses of respiratory transmission, such as Measles virus (Laboratory with Biosafety level 2 -NB-2) and/or SARS-CoV-2 virus (NB-3).Methodology: To meet this demand, it was designed a work plan, outlined a pricing strategy and developed a technical protocol adapted from ISO18184. Textile samples were analyzed at different steps: analysis of cytotoxicity in NB-2 and antiviral activity against the Measles virus (previous antiviral efficacy screening in NB-2) and/or against the SARS-CoV-2 virus in NB-3. Briefly, after cytotoxicity analysis approved, samples (20mm x 20mm) of control or formulated textiles were challenged with a virus suspension for 1 or 30 minutes (contact time/room temperature = Fabric plus Virus). Afterwards, washed out samples with recovered viruses were quantified by TCID50 method, using Vero CCL-81 cells to determine the virus infectivity titer. Likewise, antiviral samples submitted industrially washed were evaluated for wash-stable. The antiviral performance of products were measured and the differences among 2.0-3.0 (log TDID 50 /mL) or higher than 3.0 (log TDID50/mL) were considered as good or excellent effect, with antiviral efficacy higher than 99% or 99.9%, respectively.

, , , , , , , , , , , , , , , , , , ,