Author: Mx

A group from Fudan University, etc. has shown that Gallocatechin gallate (GCG), a polyphenol from green tea, inhibits SARS-CoV-2 replication efficiently.
https://www.nature.com/articles/s41467-021-22297-8

SARS-CoV-2 N protein is a structural protein binding to RNA, and form a shell embracing SARS-CoV-2 RNA. This is a typical example of so called Liquid-Liquid Phase Separation (LLPS) which is a mechanism in organizing macromolecules such as proteins and RNAs into membrane-less oil droplet like organelles.
Authors has shown that GCG could could inhibit N protein LLPS in the context of SARS-CoV-2 infection effectively. Since, the amino acid sequence shares ～90% homology among corona viruses, targeting N protein by GCG could be a novel drug candidate not only for SARS-CoV-2 but also for new coronaviruses in the future.

A group from University of Colorado Denver Anschutz Medical Campus has reported that IL-1R7 antibody would be effective in COVID-19 to suppress cytokine storms.
https://www.jbc.org/article/S0021-9258(21)00416-6/fulltext

Excessive inflammation observed in macrophage activation syndrome (MAS) results in severe diseases with high mortality. The cytokine storms observed in COVID-19 patients would be a typical example similar to MAS.
Interleukin-18 (IL-18), a proinflammatory cytokine belonging to the IL-1 family, is elevated in both MAS and COVID-19 patients, and its level is known to correlate with the severity of COVID-19 symptoms

IL-18 binds its specific receptor IL-1 Receptor 5 (IL-1R5, also known as IL-18 Receptor alpha chain), leading to the recruitment of the co-receptor, IL-1 Receptor 7 (IL-1R7, also known as IL-18 Receptor beta chain).

Authors found that the anti-IL-1R7 antibody significantly suppressed IL-18-mediated NFκB activation, IL-18-stimulated IFNγ production, and IL-6 production in human cell lines.

A group from Juntendo University Faculty of Medicine has reported seroprevalence of IgG and IgM antibodies in COVID-19 patients, although the cohort size was small including only 34 patients.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8023454/

Using a chemiluminescent microparticle immunoassay (CMIA)-based SARS-CoV-2 IgG test (cat. # 06R90, Abbott),
Severe/Critical cases：within a week after symptom onset＝40％、1～2 weeks＝88%、after two weeks＝100％,
Mild/Moderate cases：within a week after symptom onset＝0％、1～2 weeks＝38%、after two weeks＝100％.

Using an IC IgG antibody assay using the Anti-SARS-CoV-2 Rapid Test (cat. # RTA0203, AutoBio),
Severe/Critical cases：within a week after symptom onset＝60%、1～2 weeks＝63%、after two weeks＝100%,
Mild/Moderate cases：within a week after symptom onset＝17%、1～2 weeks＝63%、after two weeks＝100%.

In this study, IgG titers remained at significantly elevated levels for 2 months, regardless of disease severity. These results indicate that IgG serologic tests could be used as a complementary test to PCR to diagnose COVID-19 from 14 days after symptom onset. However, since this cohort is so small without including asymptomatic individuals, a larger scale cohort is needed to conclude final answer.
     

A group from University of Southampton, etc. has compared site-specific glycosylation of SARS-CoV-2 spike proteins (all recombinants) among five laboratories.
The cells used for Sproten expression were as follows.
HEK293： Amsterdam, Harvard,
HEK293F： Southampton/Texas,
HEK293T： Oxford,
CHO： Swiss,
It is celarly shown that site-specific glycosylation changes considerablly with reflecting differences in cells and culture conditions.
Fundamentally speaking, it is a mixture of oligo mannose and complex type N-glycans.

Blog admin is interested in how much these differences cause difference in the infectivity, how glycosylation changes with SARS-CoV-2 mutations, and how much the glycosylation changes due to mutations affect the infectivity.
https://www.biorxiv.org/content/10.1101/2021.03.08.433764v1.full

A group from German Primate Center, Göttingen, etc. has reported on the effectiveness of major monoclonal antibodies for COVID-19 (Casirivimab, Bamlanivimab, Imdevimab）against SARS-CoV-2 variants, that of a cocktail monoclonal antibody (REGN-COV2: consisting of Casirivimab and Imdevimab), and also that of Pfizer BNT162b2 vaccine against those variants.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7980144/

A cocktail monoclonal antibody (REGN-COV2）efficiently inhibited infection mediated by the S proteins of all variants (B.1.1.7, B.1.351, P.1). However, infection mediated by the S proteins of the B.1.351 and P.1 variant was completely resistant to REGN10989 and Bamlanivimab.

On the other hand, the Pfizer BNT162b2 vaccine is based on an mRNA that encodes for the SARS-CoV-2 S protein and is said to be highly protective against COVID-19. All sera from 15 donors immunized twice with BNT162b2 efficiently inhibited entry driven by the WT S protein and inhibition of entry driven by the S protein of the B.1.1.7 variant was only slightly reduced. However, 12 out of 15 sera showed a markedly reduced inhibition of entry driven by the S proteins of the B.1.351 and P.1 variants

A group from Sejong University, Seoul, etc. has reported on the accuracy of COVID-19 diagnosis in chest CT images with applying Deep Learning.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0249450

The neural network using in Deep Learning was composed of 20 stages, and convolution and pooling functions were incorporated. The resolution of the input images were (224 x 224, and the sizes of convolution were (3 x 3）and（5 x 5). The obtained overall accuracy was 99.83%（sensitivity＝0.9286, specificity＝0.99). In the future, it will be accelerate to adopt Deep Learning in diagnostic applications.