Category Technology

A group from Perelman School of Medicine, University of Pennsylvania, etc. has reported a POCT biosensor (named RAPID) for SARS-CoV-2 based on electrochemical reading with quite high sensitivity and high detection speed.
https://pubmed.ncbi.nlm.nih.gov/33997767/

ACE2 was used as a probe detecting SARS-CoV-2 Spike protein. Enzyme immobilization on the electrode was done by cross-linking ACE2 using the bifunctional chemical cross-linker glutaraldehyde. BSA was used to block the electrode’s surface after immobilization of ACE2. Nafion was added to increase the sensitivity further.
The binding between two molecules (ACE2 and SARS-CoV-2 Spike protein) causes a change in interfacial electron transfer kinetics between the redox probe, ferricyanide/ferrocyanide in solution and the conducting electrode sites. This electrochemical change is then detectable by monitoring the charge-transfer resistance.

As a result, a linear concentration range from 10 fg/mL to 100 ng/mL was obtained (R2 = 0.993) and limits of detection (LOD) and quantification (LOQ) were calculated as 2.18 fg/mL on signal to noise ratios (S/N=3). With RAPID, result is obtained in 4 minutes (2 minutes of sample incubation + 2 minutes to perform the EIS analysis)..

In blinded tests using 139 nasopharyngeal swab samples, 109 of which were COVID-19 positive and 30 COVID-19 negative as determined by RT-qPCR, RAPID demonstrated high sensitivity, specificity and accuracy for nasopharyngeal (83.5%, 100% and 87.1%, respectively) and saliva (100%, 86.5% and 90.0%, respectively) samples.

A group from Arterra Bioscience SPA, Naples, Italy, etc. has reported that pomegranate peel extract (PPE) would be a promising source of novel anti-SARS-CoV-2 drugs.
https://www.frontiersin.org/articles/10.3389/fchem.2021.638187/full

Two major extracts from pomegranate peel are Punicalagin and Ellagitannins.

SARS-CoV-2 Spike/ACE2 binding was inhibited significantly in the presence of PPE as shown below. AC384 was used as a control, a monoclonal antibody that inhibited the binding between Spike and ACE2 by specifically recognizing ACE2 itself.

Infection experiments were done with using human kidney-2 cells (HK-2). The infection rate of lentivirus carrying SARS-CoV-2 Spike protein into was greatly reduced in the presence of PPE, and a lentivirus carrying vesicular stomatitis virus G (VSVG) protein was used as a control.

These in vitro experiments are quite reassuring to go to the next stage of the development of effective and innovative therapies using PPE.

A group from The First Affiliated Hospital of Anhui Medical University, Hefei, China, etc. has reported serum glycan biomarkers for Intracerebral hemorrhage (ICH).
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8105815/

The area under curve (AUC) were yielded as
0.93 for ConA (P<0.01), 0.95 for PNA (P<0.01), 0.67 for VVA (P=0.04), 0.92 for AAL (P<0.01), 0.86 for LTL (P<0.01), 0.84 for AIL (P<0.01). The sensitivity/specificity were as follows, 75.0%/95.8% for ConA, 100.0%/64.7% for PNA, 75.0%/58.3% for VVA, 100.0%/72.9% for AAL, 87.5%/79.2% for LTL, A68.8%/83.3% for AIL. As a result, α-Man/α-Glc (ConA) exhibited the best specificity. It is worthy to note that α-Man/α-Glc may be a potential biomarker with diagnostic and prognostic value in ICH and ConA will be a good probe for that.

There have been so many examples in using natural biomolecules extracted from Algae as antiviral therapeutics. A group from Zhengzhou University, China, etc. has summarized as a review paper.
https://www.mdpi.com/1420-3049/26/8/2134/htm

Carrageenan, Gaalactan, Chitosan, Agar, Fucoidan, Laminaran are so famous as algae-derived antiviral polysaccharides, and you might have heard about it once. The antiviral mechanisms of these polysaccharides underlie several processes, including the inhibition of viral absorption, the inhibition of virus transcription and replication, and the improvement of host antiviral immune responses. Since polysaccharides are water-soluble and vary safe, it would be quite easy to use as internal medicines. If you are interested in these polysaccharide in more detail, please refer to the original paper and its references.

As you know, since the viral envelop proteins are heavily glycosylated, lectins could be also used to inhibit virus adsorption onto host cells. There have been a number of such examples as shown below.

A past blog article summarizing how lectin-glycan interactions are to be used to combat COVID-19 would be a good reference from a view point of antiviral therapeutics. It would be a big challenge how side effects of using lectins as antiviral ones could be controlled.

A group from Mayo Clinic, etc. has reported a promising result of a phase 3 clinical trial of Lenzilumab against COVID-19.
https://pubmed.ncbi.nlm.nih.gov/33972949/

In COVID-19, it has been known that high levels of granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting T-cells are associated with disease severity, myeloid cell trafficking to the lungs, and ICU admission. GM-CSF is a kind of cytokine which activates differentiation of myeloid cells, leading to elevations of downstream inflammatory chemokines (MCP-1, IL-8, IP-10) and cytokines (IL-6, IL-1).

Lenzilumab is a novel anti-human GM-CSF monoclonal antibody that directly binds GM-CSF and prevents signaling through its receptor. It has high binding affinity (25 pM) for glycosylated human GM-CSF and a slow off-rate. A phase 3 randomized, double-blind, placebo-controlled clinical trial was designed to demonstrate the effectiveness of lenzilumab. The dose of lenzilumab was 600mg and administered 8hours apart for 28 days.

Lenzilumab could improve the likelihood of survival without ventilation (SWOV) through Day 28 by 54%. It should be noted that the improvement in SWOV was most evident in patients with CRP<150 mg/L who are less than 85 years of age.

CDC COVID-19 Response Team has reported about the vaccine effectiveness of Pfizer-BioNTech or Moderna vaccine.
https://www.cdc.gov/mmwr/volumes/70/wr/pdfs/mm7018e1-H.pdf

The team has reported that adjusted vaccine effectiveness for full vaccination using Pfizer-BioNTech or Moderna vaccine was 94% (95% CI = 49%–99%), and that for partial vaccination was 64% (95% CI = 28%–82%).
In this study, the vaccine effectiveness was assessed among 417 adults (including 187 case-patients and 230 controls) aged ≥65 years who admitted with COVID-19–like illness and confirmed by RT-PCR during January 1, 2021–March 26, 2021. Case-patients were those who received one or more positive test results for SARS-CoV-2. Patients meeting eligibility criteria who received negative SARS-CoV-2 RT-PCR test results served as controls. Participants in this study were considered to have received COVID-19 vaccine doses based on official CDC vaccination record card etc. and by plausible self-report.

It should be noted that there was no significant effect for receiving the first dose of a 2-dose COVID-19 vaccine series within 14 days before illness onset (adjusted vaccine effectiveness = 3%, 95% CI = −94%–51%)

A group from Universidade CEUMA, Brazil, etc. has reviewed past instances using lectin–glycan interactions to combat enveloped viruses, and mentioned about challenge to SARS-CoV-2.
https://academic.oup.com/glycob/article/31/4/358/5934657

The presence of glycoproteins in the viral envelope opens a wide range of possibilities for application of lectins to fight COVID-19. Lectins could be leading molecules for the development of new antiviral drugs due to their ability to inhibit viral entry into the host cell by binding to glycans expressed on he virus envelop.

The overall view of glycosylation profiles of SARS-CoV-2 is as follows. There are 22 N-glycosylation sites and 6 O-glycosylation sites on the spike protein.  The oligomannose-type glycans are predominant in two sites (N234 and N709). Complex-type glycans are predominantly expressed in 14 amino acid residues (N17, N74, N149, N165, N282, N331, N343, N616, N657, N1098, N1134, N1158, N1173 and N1194), while six sites show a mixture of oligomannose- and complex-type glycans (N61, N122, N603, N717, N801 and N1074). The most common configuration of oligomannose-type glycans was Man5GlcNAc2. The short O-glycans such as Tn and core 1  structures are mainly expressed in 6 sites (T73, T76, T478, T676, T678, T1076).

Typical lectins evaluated as antiviral drugs are explained in the review paper (FRAIL, GRFT, Cyanovirin-N, BanLec, MVN, and Avaren). All of these lectins have binding specificity to oligo and high mannose, probably because envelopes of targeted viruses in the past (e.g., HIV, HCV, influenza, and Ebora) were heavily mannosylated. In that sense, we can say that glycosylation profile of SARS-CoV-2 is somewhat different from other enveloped viruses, and therefore, there might be more suitable lectins for SARS-CoV-2 besides those lectins.

Anyhow, the major limitation in using lectins as therapeutic drugs is the possible binding of the lectin in unwanted glycosylated targets. For instance, the administration of lectins could result in the agglutination and proliferation of cells. Therefore, it is so important to modify lectins with using protein engineering to suppress such side effects and to extract only the antiviral property against SARS-CoV-2. Probably, the key word would be making fusion proteins, e.g., fusion to Fab, fusion to Fc, PEGylation, and so forth. 

A group from Israel Institute for Biological Research, etc. has reported on characteristics of 12 mAbs targeting to SARS-CoV-2 NTD.
https://pubmed.ncbi.nlm.nih.gov/33937725/

12 antibodies (from BLN1 to BLN14) targeting to SARS-CoV-2 NTD were able to efficiently neutralize SARS-CoV-2, exhibiting IC50 values ranging from 54.9 µg/ml for BLN8, to a highly potent values of 0.008 µg/ml for mAbs BLN1 and BLN12. All mAb specificity to NTD was confirmed with ELISA against NTD, and also in detail by an peptide array derived from the entire S1 protein. Then, the effects of glycan modification onto mAbs were investigate by using a glycan array and also with a competition assay adding glycans as inhibitors. While there was very low binding to most examined glycans, mAbs revealed a strong preference to LacNAc and its sialo-form suggesting that the interactions with the N-glycans are involved in the binding to NTD of BLN4 and BLN12 in particular.

It was recently reported that in addition to the “canonical” ACE2 receptor binding by RBD, SARS-CoV-2 NTD interacts with C-type lectin receptors, including L-SIGN and DC-SIGN as an alternative route for SARS-CoV-2 infection and entry into host cells. So, the ability of four representative mAbs to inhibit the interaction of the NTD with L-SIGN, was examined. In the presence of selected anti-NTD mAbs, inhibition efficiency ranged from approximately 25% binding inhibition by BLN14 to 50% inhibition by BLN4. It should be noted, that the observed binding inhibition may be the result of steric interference of L-SIGN binding to NTD, and not necessarily direct blocking of the NTD glycans, involved in binding to L-SIGN.

If L-SIGN and DC-SIGN are indeed alternative receptors for SARS-CoV-2 and mediate its infection of cells in many tissues lacking hACE2, it may be speculated that anti-NTD mAbs may also exert their therapeutic activity by limiting the spreading of the virus in the body. As a conclusion, BLN12 and BLN14 mAbs would represent excellent candidates for therapy of SARS-CoV-2, possibly in combination with anti-RBD mAbs as a cocktail mAb for SARS-CpoV-2. 

A group from University of Pisa, Italy, etc. has reported a new biomarker for ulcerative colitis.
https://www.frontiersin.org/articles/10.3389/fphar.2021.654319/full/

Ulcerative colitis (UC) is a chronic relapsing disease, characterized by an inflammation affecting the colon and the rectum with superficial mucosal ulceration, rectal bleeding, diarrhea and abdominal pain. Tumor necrosis factor (TNF) plays an important role in UC pathogenesis. Indeed, several immune cells produce high levels of TNF, and this cytokine is known to mediate several pro-inflammatory functions in the inflamed mucosa, promoting even tissue injury. On this basis, the monoclonal antibodies anti-TNF, like infliximab (IFX) and adalimumab (ADA), were developed for treatment of UC.

However, more than 30% of the UC patients receiving anti-TNF agents do not respond to treatment. Therefore, developing an early prediction method of therapeutic outcome is one of the most important challenges to optimize therapeutic management.
Authors has shown that Jacalin(JAC)-specific IgG glycosylation could be used as a biomarker of disease activity in UC, especially before starting an anti-TNF therapy. JAC is an O-glycan binder, and the putative role of JAC in predicting therapeutic effectiveness from the O-glycan point of view was not clearly demonstrated here, but it could be used as a good biomarker predicting therapeutic responses.

Many autoimmune diseases are associated with qualitative perturbations in circulating antibodies, and agalactosylated IgG is considered a marker of inflammatory condition. Agalactosylated IgG is capable to interact with FcγRIIa, induce macrophage activation and, subsequently, induce pro-inflammatory cytokines such as production of TNFα and IL6. Several studies showed that agalactosylation could be reverted in therapeutic conditions capable of ameliorating the inflammatory diseases. It has been known that in rheumatoid arthritis, steroid and anti-TNF therapy induce changes in IgG glycosylation from agalacto to sialo-complex-types.

A group from Medical University of Białystok, Poland, etc. has reported about therapeutic effects of Tocilizumab on COVID-19.
https://www.mdpi.com/2077-0383/10/8/1583/htm

In this clinical study with total 825 patients, Tocilizumab was administered to 170 patients and nothing was administered to 655 patients not only Tocilizumab but also any mAbs for cytokine receptors. The dose of Tocilizumab was 8mg/kg (the maximum dose =800mg) in a single dose.

In case of IL-6>100pg/mL, significant therapeutic effect of Tocilizumab was obtained (hazard ratio [HR]=0.21（95% confidence interval [CI]: 0.08–0.57). When IL-6>100pg/mL and either oxygen saturation <90% or requiring oxygen supplementation, HR decreased to 0.18. In addition, it was concluded that Tocilizumab has little therapeutic effect when IL-6<100pg/mL.
Anyhow, it is so great to know that Tocilizumab shows its therapeutic effect on what levels of serum IL-6 and how much dose is required for that.