SARS-CoV-2 Neutralizing Antibody LY-CoV555 in Outpatients with Covid-19

COVID-19: from immune response to clinical intervention

The coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has highlighted the pivotal role of the immune response in determining the progression and severity of viral infections. In this paper, we review the most recent studies on the complicated dynamics between SARS-CoV-2 and the host immune system, highlight the importance of understanding these dynamics in developing effective treatments and formulate potent management strategies for COVID-19. We describe the activation of the host's innate immunity and the subsequent adaptive immune response following infection with SARS-CoV-2. In addition, the review emphasizes the immune evasion strategies of the SARS-CoV-2, including inhibition of interferon production and induction of cytokine storms, along with the resulting clinical outcomes. Finally, we assess the efficacy of current treatment strategies, including antiviral drugs, monoclonal antibodies, and anti-inflammatory treatments, and discuss their role in providing immunity and preventing severe disease.

Characterization of Treatment Resistance and Viral Kinetics in the Setting of Single-Active Versus Dual-Active Monoclonal Antibodies Against Severe Acute Respiratory Syndrome Coronavirus 2

BACKGROUND

Monoclonal antibodies (mAbs) represent a crucial antiviral strategy for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, but it is unclear whether combination mAbs offer a benefit over single-active mAb treatment. Amubarvimab and romlusevimab significantly reduced the risk of hospitalizations or death in the ACTIV-2/A5401 trial. Certain SARS-CoV-2 variants are intrinsically resistant against romlusevimab, leading to only single-active mAb therapy with amubarvimab in these variants. We evaluated virologic outcomes in individuals treated with single- versus dual-active mAbs.

METHODS

Participants were nonhospitalized adults at higher risk of clinical progression randomized to amubarvimab plus romlusevimab or placebo. Quantitative SARS-CoV-2 RNA levels and targeted S-gene next-generation sequencing was performed on anterior nasal samples. We compared viral load kinetics and resistance emergence between individuals treated with effective single- versus dual-active mAbs depending on the infecting variant.

RESULTS

Study participants receiving single- or dual-active mAbs had similar demographics, baseline nasal viral load, symptom score, and symptom duration. Compared with single-active mAb treatment, treatment with dual-active mAbs led to faster viral load decline at study days 3 (P < .001) and 7 (P < .01). Treatment-emergent resistance mutations were more likely to be detected after amubarvimab plus romlusevimab treatment than with placebo (2.6% vs 0%; P < .001) and were more frequently detected in the setting of single-active compared with dual-active mAb treatment (7.3% vs 1.1%; P < .01). Single-active and dual-active mAb treatment resulted in similar decrease in rates of hospitalizations or death.

CONCLUSIONS

Compared with single-active mAb therapy, dual-active mAbs led to similar clinical outcomes but significantly faster viral load decline and a lower risk of emergent resistance.

Clinical outcomes in patients with mild to moderate coronavirus disease 2019 treated with monoclonal antibody therapy versus an untreated control cohort

BACKGROUND

Monoclonal antibody therapy (MAT) received Food and Drug Administration (FDA) Emergency Use Authorization (EUA) for mild to moderate COVID-19 treatment in adults at a high-risk for progression to severe disease in November 2020. This study assessed the impact of MAT on clinical outcomes.

METHODS

We conducted a single-center, retrospective study comparing 30-day COVID-19-related emergency department (ED) visits, admissions, and mortality in patients receiving MAT (bamlanivimab, bamlanivimab-etesevimab, or casirivimab-imdevimab) between 16 November 2020 and 19 June 2021, compared to a control group of high-risk adults diagnosed with mild to moderate COVID-19 prior to MAT availability between 16 May 2020 and 15 November 2020. Statistical analysis used logistic regression analysis with backward selection to determine the odds ratios and 95% confidence interval evaluating the relationship between clinical characteristics and outcomes.

RESULTS

1187 patients who received MAT were compared to 1103 patients not treated with MAT. Multivariable regression model adjusted for possible confounders showed patients who received MAT had lower rates of ED visits (3.2% vs 7.4%, OR = 0.46, 95% CI = 0.31-0.70, p < .001) and hospital admissions (4.3% vs 7.8%, OR = 0.42, 95% CI = 0.29-0.62, p < .001) compared to the control group. After adjusting for confounders, MAT was associated with decreased mortality (OR = 0.36, p = .035). In the MAT group, those treated within 2 days of COVID-19 diagnosis had lower mortality than those treated more than 2 days post-diagnosis (unadjusted OR = 0.152, 95% CI = 0.031-0.734, p = .019).

CONCLUSIONS

Individuals treated with MAT had lower rates of 30-day COVID-19-related ED visits and hospital admissions compared to those not receiving MAT. Early MAT resulted in lower 30-day mortality compared to receipt >2 days post COVID-19 diagnosis.

Protective non-neutralizing SARS-CoV-2 monoclonal antibodies

Recent studies show an important role for non-neutralizing anti-spike antibodies, including monoclonal antibodies (mAbs), in robustly protecting against SARS-CoV-2 infection. These mAbs use Fc-mediated functions such as complement activation, phagocytosis, and cellular cytotoxicity. There is an untapped potential for using non-neutralizing mAbs in durable antibody treatments; because of their available conserved epitopes, they may not be as sensitive to virus mutations as neutralizing mAbs. Here, we discuss evidence of non-neutralizing mAb-mediated protection against SARS-CoV-2 infection. We explore how non-neutralizing mAb Fc-mediated functions can be enhanced via novel antibody-engineering techniques. Important questions remain to be answered regarding the characteristics of protective non-neutralizing mAbs, including the models and assays used for study, the risks of ensuing detrimental inflammation, as well as the durability and mechanisms of protection.

Enhanced Omicron Variant Neutralization by a Human Antibody Tailored to Wild-Type and Delta-Variant SARS-CoV-2 RBDs

Given the previous SARS-CoV-2 pandemic and the inherent unpredictability of viral antigenic drift and shift, preemptive development of diverse neutralizing antibodies targeting a broad spectrum of epitopes is essential to ensure immediate therapeutic and prophylactic interventions during emerging outbreaks. In this study, we present a monoclonal antibody engineered for cross-reactivity to both wild-type and Delta RBDs, which, surprisingly, demonstrates enhanced neutralizing activity against the Omicron variant despite a significant number of mutations. Using an Escherichia coli inner membrane display of a human naïve antibody library, we identified antibodies specific to the wild-type SARS-CoV-2 receptor binding domain (RBD). Subsequent directed evolution via yeast surface display yielded JS18.1, an antibody with high binding affinity for both the Delta and Kappa RBDs, as well as enhanced binding to other RBDs (wild-type, Alpha, Beta, Gamma, Kappa, and Mu). Notably, JS18.1 (engineered for wild-type and Delta RBDs) exhibits enhanced neutralizing capability against the Omicron variant and binds to RBDs noncompetitively with ACE2, distinguishing it from other previously reported antibodies. This underscores the potential of pre-existing antibodies to neutralize emerging SARS-CoV-2 strains and offers insights into strategies to combat emerging viruses.

Inhalable dry powders of a monoclonal antibody against SARS-CoV-2 virus made by thin-film freeze-drying

Monoclonal antibodies (mAbs) represent a promising modality for the prevention and treatment of viral infections. For infections that initiate from the respiratory tract, direct administration of specific neutralizing mAbs into lungs has advantages over systemic injection of the same mAbs. Herein, using AUG-3387, a human-derived mAb with high affinity to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its various variants, as a model mAb, we formulated the mAb into dry powders by thin-film freeze-drying, confirmed that the AUG-3387 mAb reconstituted from the dry powders retained their integrity, high affinity to the SARS-CoV-2 spike protein receptor binding domain (RBD), as well as ability to neutralize RBD-expressing pseudoviruses. Finally, we showed that one of the AUG-3387 mAb dry powders had desirable aerosol properties for pulmonary delivery into the lung. We concluded that thin-film freeze-drying represents a viable method to prepare inhalable powders of virus-neutralizing mAbs for pulmonary delivery into the lung.

Efficacy and safety of oral ivermectin in the treatment of mild to moderate Covid-19 patients: a multi-centre double-blind randomized controlled clinical trial

BACKGROUND

Evidence on ivermectin as a treatment for Covid-19 is controversial. A Cochrane review concluded that the efficacy and safety of ivermectin is uncertain (evidence up to April 2022) and WHO recommended its use only in the setting of clinical trials. This study aimed to assess the efficacy and safety of oral ivermectin in hospitalized patients with mild to moderate Covid-19.

TRIAL DESIGN AND METHODS

A double-blind, randomized placebo-controlled clinical trial was conducted among RT-PCR-confirmed, adults, hospitalised within the first four days of symptoms. Patients received oral ivermectin 24 mg or placebo daily for five days. RT-PCR was repeated on days five and ten. Clinical progression was monitored using the World Health Organization Clinical Progression Scale. Serum ivermectin levels were measured on days three, five, and seven. The primary outcome was the difference in the viral load between day zero and ten in the two groups.

RESULTS

Out of 1699 patients screened, 249 underwent randomization and 127 received ivermectin, and 122 placebo. D10 median viral load for E gene (IQR) was 2,000 copies/mL (100 - 20,500) with ivermectin (n = 80) and 4,100 copies/mL (1,000-65,600) with placebo (n = 81, p = 0.028), per protocol analysis. The difference in Log viral load between day zero and ten between ivermectin and placebo was 3.72 and 2.97 respectively (p = 0.022). There was no significant difference in the WHO clinical progression scale or the adverse effects. Ivermectin blood levels taken before or with meals were not significantly different. Only 7 and 17 patients achieved blood levels above 160ng/ML and 100ng/ML respectively and they did not achieve a significantly lower viral load.

CONCLUSION

Although ivermectin resulted in statistically significant lower viral load in patients with mild to moderate Covid-19, it had no significant effect on clinical symptoms.

TRIAL REGISTRATION NUMBER

SLCTR/2021/020, Sri Lanka Clinical Trials Registry. 19/07/2021.

Safety and Efficacy of SAB-185 for Non-hospitalized Adults with COVID-19: A Randomized Clinical Trial

BACKGROUND

To address the need for novel COVID-19 therapies, we evaluated the fully-human polyclonal antibody product SAB-185 in a phase 3 clinical trial.

METHODS

Non-hospitalized high-risk adults within 7 days of COVID-19 symptom onset were randomized 1:1 to open-label SAB-185 3,840 units/kg or casirivimab/imdevimab 1200 mg. Non-inferiority comparison was undertaken for the pre-Omicron population (casirivimab/imdevimab expected to be fully active) and superiority comparison for the Omicron population (casirivimab/imdevimab not expected to be active). Primary outcomes were the composite of all-cause hospitalizations/deaths and grade ≥3 treatment-emergent adverse events (TEAEs) through day 28. Secondary outcomes included time to sustained symptom improvement and resolution.

RESULTS

Enrollment was terminated early due to low hospitalization/death rates upon Omicron emergence. 733 adults were randomized, 255 included in pre-Omicron and 392 in Omicron analysis populations. Hospitalizations/deaths occurred in 6 (5.0%) and 3 (2.2%) of pre-Omicron SAB-185 and casirivimab/imdevimab arms, respectively (absolute difference [95% CI] 2.7% [-2.3%, 8.6%]), inconclusive for non-inferiority; and 5 (2.5%) versus 3 (1.5%) (absolute difference 1.0% [-2.3%, 4.5%]) for Omicron. Risk ratios for grade ≥3 TEAEs were 0.94 [0.52, 1.71] (pre-Omicron) and 1.71 [0.96, 3.07] (Omicron). Time to symptom improvement and resolution were shorter for SAB-185, median 11 vs 14 (pre-Omicron) and 11 vs 13 days (Omicron) (symptom improvement), and 16 vs 24 days and 18 vs >25 days (symptom resolution), p<0.05 for symptom resolution for Omicron only.

CONCLUSIONS

SAB-185 had an acceptable safety profile with faster symptom resolution in the Omicron population. Additional studies are needed to characterize its efficacy for COVID-19.

From bench to bedside: potential of translational research in COVID-19 and beyond

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease 2019 (COVID-19) have been around for more than 3 years now. However, due to constant viral evolution, novel variants are emerging, leaving old treatment protocols redundant. As treatment options dwindle, infection rates continue to rise and seasonal infection surges become progressively common across the world, rapid solutions are required. With genomic and proteomic methods generating enormous amounts of data to expand our understanding of SARS-CoV-2 biology, there is an urgent requirement for the development of novel therapeutic methods that can allow translational research to flourish. In this review, we highlight the current state of COVID-19 in the world and the effects of post-infection sequelae. We present the contribution of translational research in COVID-19, with various current and novel therapeutic approaches, including antivirals, monoclonal antibodies and vaccines, as well as alternate treatment methods such as immunomodulators, currently being studied and reiterate the importance of translational research in the development of various strategies to contain COVID-19.

Computational Insights into SARS-CoV-2 Main Protease Mutations and Nirmatrelvir Efficacy: The Effects of P132H and P132H-A173V

Nirmatrelvir, a pivotal component of the oral antiviral Paxlovid for COVID-19, targets the SARS-CoV-2 main protease (Mpro) as a covalent inhibitor. Here, we employed combined computational methods to explore how the prevalent Omicron variant mutation P132H, alone and in combination with A173V (P132H-A173V), affects nirmatrelvir's efficacy. Our findings suggest that P132H enhances the noncovalent binding affinity of Mpro for nirmatrelvir, whereas P132H-A173V diminishes it. Although both mutants catalyze the rate-limiting step more efficiently than the wild-type (WT) Mpro, P132H slows the overall rate of covalent bond formation, whereas P132H-A173V accelerates it. Comprehensive analysis of noncovalent and covalent contributions to the overall binding free energy of the covalent complex suggests that P132H likely enhances Mpro sensitivity to nirmatrelvir, while P132H-A173V may confer resistance. Per-residue decompositions of the binding and activation free energies pinpoint key residues that significantly affect the binding affinity and reaction rates, revealing how the mutations modulate these effects. The mutation-induced conformational perturbations alter drug-protein local contact intensities and the electrostatic preorganization of the protein, affecting noncovalent binding affinity and the stability of key reaction states, respectively. Our findings inform the mechanisms of nirmatrelvir resistance and sensitivity, facilitating improved drug design and the detection of resistant strains.

COVID-19 drug discovery and treatment options

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused substantial morbidity and mortality, and serious social and economic disruptions worldwide. Unvaccinated or incompletely vaccinated older individuals with underlying diseases are especially prone to severe disease. In patients with non-fatal disease, long COVID affecting multiple body systems may persist for months. Unlike SARS-CoV and Middle East respiratory syndrome coronavirus, which have either been mitigated or remained geographically restricted, SARS-CoV-2 has disseminated globally and is likely to continue circulating in humans with possible emergence of new variants that may render vaccines less effective. Thus, safe, effective and readily available COVID-19 therapeutics are urgently needed. In this Review, we summarize the major drug discovery approaches, preclinical antiviral evaluation models, representative virus-targeting and host-targeting therapeutic options, and key therapeutics currently in clinical use for COVID-19. Preparedness against future coronavirus pandemics relies not only on effective vaccines but also on broad-spectrum antivirals targeting conserved viral components or universal host targets, and new therapeutics that can precisely modulate the immune response during infection.

Neutralizing monoclonal antibodies for the prevention of severe COVID-19: a retrospective study during Omicron BA.1 variant surge

Among treatment options for Coronavirus disease 2019 (COVID-19), monoclonal antibodies (mAbs) showed to be effective in preventing disease progression, but real-world data during the Omicron variant surge are still lacking. Multicentre retrospective study evaluating the effectiveness of sotrovimab and casirivimab-imdevimab in fragile patients with mild SARS-CoV-2 infection between November 2021 and March 2022. Unfavourable outcome was defined as increased need for oxygen supplementation and/or death. Of 268 study-participants, 12 (4.48%) previously needed supplemental oxygen, while 6 (2.24%) had active solid neoplasia (2.24%); 186 (69%) have previously received SARS-CoV-2 vaccination. Overall, 22 (8%) had unfavourable outcomes (42% versus 6% of patients with and without previous oxygen need and 50% versus 7% of patients with and without active solid neoplasia). Both supplemental oxygen therapy before SARS-CoV-2 infection and solid malignant tumour have shown to be risk factors for treatment failure. Log-rank test did not identify differences between sotrovimab and casirivimab-imdevimab treatment. Despite diffusion of Omicron variant, the rate of unfavourable outcome was higher than expected. The presence of underlying risk factors, including solid cancer and previous oxygen therapy are independently associated with risk of COVID-19 progression, suggesting the need for antiviral treatments not limited to mAbs and implementation of vaccine campaign.

Efficacy and safety of casirivimab and imdevimab for preventing and treating COVID-19: a systematic review and meta-analysis

Background

The ongoing global epidemic of coronavirus disease 2019 (COVID-19) has created a serious public health problem. The selection of safe and effective therapeutic agents is of paramount importance. This systematic review aims to evaluate the efficacy and safety of the combination of casirivimab and imdevimab in the treatment of global cases of COVID-19.

Methods

To identify randomized controlled trials (RCTs) investigating the combined administration of casirivimab and imdevimab for COVID-19 management, a comprehensive search was conducted across multiple databases including PubMed, Web of Science, Embase, and the Cochrane Library from their inception to September 10, 2022. Data on the efficacy and safety of casirivimab and imdevimab were extracted. Subgroup analyses and sensitivity analyses were performed.

Results

A total of 851 articles were searched. Twelve studies were finally included in the meta-analysis, with 27,179 participants. Dichotomous and continuous variables were presented as odds ratios (ORs) and weighted mean differences (WMDs) with their 95% confidence intervals (CIs), respectively. Compared to placebo or alternative medications, the combination of casirivimab and imdevimab reduced viral load (WMD: -0.73, 95% CI: -1.09 to -0.38, P<0.01), all-cause mortality (OR =0.90, 95% CI: 0.82-0.99, P=0.03), the incidence of any serious adverse events (OR =0.80, 95% CI: 0.67-0.95, P=0.01), the incidence of Grade 3 or more severe adverse events (OR =0.76, 95% CI: 0.62-0.92, P=0.01), the likelihood of contracting COVID-19, the incidence of hospitalization, emergency room visits, and mortality (OR =0.54, 95% CI: 0.32-0.93, P=0.03).

Conclusions

The monoclonal antibody combination of casirivimab and imdevimab is effective in treating patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as they can reduce viral load, all-cause mortality, infection rates, and the incidence of clinical outcomes of special interest after treatment, while maintaining a favorable safety profile.

Infectious Diseases Society of America Guidelines on the Treatment and Management of Patients With COVID-19 (September 2022)

There are many pharmacologic therapies that are being used or considered for treatment of coronavirus disease 2019 (COVID-19), with rapidly changing efficacy and safety evidence from trials. The objective was to develop evidence-based, rapid, living guidelines intended to support patients, clinicians, and other healthcare professionals in their decisions about treatment and management of patients with COVID-19. In March 2020, the Infectious Diseases Society of America (IDSA) formed a multidisciplinary guideline panel of infectious disease clinicians, pharmacists, and methodologists with varied areas of expertise to regularly review the evidence and make recommendations about the treatment and management of persons with COVID-19. The process used a living guideline approach and followed a rapid recommendation development checklist. The panel prioritized questions and outcomes. A systematic review of the peer-reviewed and grey literature was conducted at regular intervals. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess the certainty of evidence and make recommendations. Based on the most recent search conducted on 31 May 2022, the IDSA guideline panel has made 32 recommendations for the treatment and management of the following groups/populations: pre- and postexposure prophylaxis, ambulatory with mild-to-moderate disease, and hospitalized with mild-to-moderate, severe but not critical, and critical disease. As these are living guidelines, the most recent recommendations can be found online at: https://idsociety.org/COVID19guidelines. At the inception of its work, the panel has expressed the overarching goal that patients be recruited into ongoing trials. Since then, many trials were conducted that provided much-needed evidence for COVID-19 therapies. There still remain many unanswered questions as the pandemic evolved, which we hope future trials can answer.

Nigella sativa, Anthemis hyaline and Citrus sinensis extracts reduce SARS-CoV-2 replication by fluctuating Rho GTPase, PI3K-AKT, and MAPK/ERK pathways in HeLa-CEACAM1a cells

Traditional remedies have long utilized Anthemis hyaline, Nigella sativa, and Citrus sinensis peel extracts as treatments for microbial infections. This study aimed to investigate the influence of Anthemis hyaline, Nigella sativa, and Citrus sinensis extracts on coronavirus replication and apoptosis-related pathways. HeLa-CEACAM1a cells were exposed to mouse hepatitis virus-A59. After viral inoculation, the mRNA levels of 36 genes were quantified using a Fluidigm Dynamic Array nanofluidic chip. IL-8 level and intracellular Ca2+ concentration was measured, and viral titer was assessed by the TCID50/ml assay to detect the extent of infection. Treatment with Nigella sativa extract surged the inflammatory cytokine IL-8 level at both 24 and 48-hour. Changes in gene expression were notable for RHOA, VAV3, ROCK2, CFL1, RASA1, and MPRIP genes following treatment with any of the extracts. The addition of Anthemis hyaline, Nigella sativa, or Citrus sinensis extracts to coronavirus-infected cells reduced viral presence, with Anthemis hyaline extract leading to a virtually undetectable viral load at 6- and 8-hours after infection. While all treatments influenced IL-8 production and viral levels, Anthemis hyaline extract displayed the most pronounced reduction in viral load. Consequently, Anthemis hyaline extract emerges as the most promising agent, harboring potential therapeutic compounds.

Early antiviral CD4 and CD8 T cell responses and antibodies are associated with upper respiratory tract clearance of SARS-CoV-2

T cells are involved in protective immunity against numerous viral infections1. Data regarding functional roles of human T cells in SARS-CoV-2 (SARS2) viral clearance in primary COVID-19 are limited. To address this knowledge gap, samples were assessed for associations between SARS2 upper respiratory tract viral RNA levels and early virus-specific adaptive immune responses, for 95 unvaccinated clinical trial participants with acute primary COVID-19. Functionality and quantity of acute SARS2-specific CD4 and CD8 T cell responses were evaluated, in addition to antibody responses. Most individuals with acute COVID-19 developed SARS2-specific T cell responses within 6 days of symptom onset. Early CD4 T cell and CD8 T cell responses were strongly associated with reduced upper respiratory tract SARS2 viral RNA, independent of neutralizing antibody titers. Overall, these findings indicate a protective role for SARS2-specific T cells during acute COVID-19.

Identification and Analysis of Biomarkers Associated with Lipophagy and Therapeutic Agents for COVID-19

BACKGROUND

Lipids, as a fundamental cell component, play an regulating role in controlling the different cellular biological processes involved in viral infections. A notable feature of coronavirus disease 2019 (COVID-19) is impaired lipid metabolism. The function of lipophagy-related genes in COVID-19 is unknown. The present study aimed to investigate biomarkers and drug targets associated with lipophagy and lipophagy-based therapeutic agents for COVID-19 through bioinformatics analysis.

METHODS

Lipophagy-related biomarkers for COVID-19 were identified using machine learning algorithms such as random forest, Support Vector Machine-Recursive Feature Elimination, Generalized Linear Model, and Extreme Gradient Boosting in three COVID-19-associated GEO datasets: scRNA-seq (GSE145926) and bulk RNA-seq (GSE183533 and GSE190496). The cMAP database was searched for potential COVID-19 medications.

RESULTS

The lipophagy pathway was downregulated, and the lipid droplet formation pathway was upregulated, resulting in impaired lipid metabolism. Seven lipophagy-related genes, including ACADVL, HYOU1, DAP, AUP1, PRXAB2, LSS, and PLIN2, were used as biomarkers and drug targets for COVID-19. Moreover, lipophagy may play a role in COVID-19 pathogenesis. As prospective drugs for treating COVID-19, seven potential downregulators (phenoxybenzamine, helveticoside, lanatoside C, geldanamycin, loperamide, pioglitazone, and trichostatin A) were discovered. These medication candidates showed remarkable binding energies against the seven biomarkers.

CONCLUSIONS

The lipophagy-related genes ACADVL, HYOU1, DAP, AUP1, PRXAB2, LSS, and PLIN2 can be used as biomarkers and drug targets for COVID-19. Seven potential downregulators of these seven biomarkers may have therapeutic effects for treating COVID-19.

Rapid initiation of nasal saline irrigation to reduce severity in high-risk COVID+ outpatients

OBJECTIVE

To determine whether initiating saline nasal irrigation after COVID-19 diagnosis reduces hospitalization and death in high-risk outpatients compared with observational controls, and if irrigant composition impacts severity.

METHODS

Participants 55 and older were enrolled within 24 hours of a + PCR COVID-19 test between September 24 and December 21, 2020. Among 826 screened, 79 participants were enrolled and randomly assigned to add 2.5 mL povidone-iodine 10% or 2.5 mL sodium bicarbonate to 240 mL of isotonic nasal irrigation twice daily for 14 days. The primary outcome was hospitalization or death from COVID-19 within 28 days of enrollment by daily self-report confirmed with phone calls and hospital records, compared to the CDC Surveillance Dataset covering the same time. Secondary outcomes compared symptom resolution by irrigant additive.

RESULTS

Seventy-nine high-risk participants were enrolled (mean [SD] age, 64 [8] years; 36 [46%] women; 71% Non-Hispanic White), with mean BMI 30.3. Analyzed by intention-to-treat, by day 28, COVID-19 symptoms resulted in one ED visit and no hospitalizations in 42 irrigating with alkalinization, one hospitalization of 37 in the povidone-iodine group, (1.27%) and no deaths. Of nearly three million CDC cases, 9.47% were known to be hospitalized, with an additional 1.5% mortality in those without hospitalization data. Age, sex, and percentage with pre-existing conditions did not significantly differ by exact binomial test from the CDC dataset, while reported race and hospitalization rate did. The total risk of hospitalization or death (11%) was 8.57 times that of enrolled nasal irrigation participants (SE = 2.74; P = .006). Sixty-two participants completed daily surveys (78%), averaging 1.8 irrigations/day. Eleven reported irrigation-related complaints and four discontinued use. Symptom resolution was more likely for those reporting twice daily irrigation (X2 = 8.728, P = .0031) regardless of additive.

CONCLUSION

SARS-CoV-2+ participants initiating nasal irrigation were over 8 times less likely to be hospitalized than the national rate.

Screening and optimization of shark nanobodies against SARS-CoV-2 spike RBD

SARS-CoV-2 continues to threaten human health, antibody therapy is one way to control the infection. Because new SARS-CoV-2 mutations are constantly emerging, there is an urgent need to develop broadly neutralizing antibodies to block the viral entry into host cells. VNAR from sharks is the smallest natural antigen binding domain, with the advantages of small size, flexible paratopes, good stability, and low manufacturing cost. Here, we used recombinant SARS-CoV-2 Spike-RBD to immunize sharks and constructed a VNAR phage display library. VNAR R1C2, selected from the library, efficiently binds to the RBD domain and blocks the infection of ACE2-positive cells by pseudovirus. Next, homologous bivalent VNARs were constructed through the tandem fusion of two R1C2 units, which enhanced both the affinity and neutralizing activity of R1C2. R1C2 was predicted to bind to a relatively conserved region within the RBD. By introducing mutations at four key binding sites within the CDR3 and HV2 regions of R1C2, the affinity and neutralizing activity of R1C2 were significantly improved. Furthermore, R1C2 also exhibits an effective capacity of binding to the Omicron variants (BA.2 and XBB.1). Together, these results suggest that R1C2 could serve as a valuable candidate for preventing and treating SARS-CoV-2 infections.

SARS-CoV-2 active infection and antibodies amongst health personnel during the outbreak in Cameroon: Strengthening the health system for response to future public health emergencies

BACKGROUND

Health personnel (HP) are on the frontlines during response to public health emergencies like COVID-19. This risk of exposure suggests the need for safety in responding to any pandemic. Therefore, to ascertain the rate of SARS-CoV-2 infection and immunity, and their determinants amongst HP become relevant.

METHODS

A cross sectional health facility-based study was carried-out amongst HP in the Centre Region of Cameroon from 1st February to 30th June 2021. Characteristics and access to preventive tools were collected using face-to-face administered questionnaire. Nasopharyngeal swabs and whole blood were collected for PCR, IgG and IgM testing respectively. STATA version 17 software was used for data analysis. Determinants of COVID-19 infection were explored by estimating crude and adjusted Odd Ratio.

RESULTS

Out of 510 HP reached, 458 were enrolled with mean age of 35 (±10) years. Thirty-four (7.4%) were PCR-positive to SARS-CoV-2 with 73.5% being clinicians versus 9 (26.4%) non-clinicians (p = 0.05). Sero-positivity to SARS-CoV-2 IgG/IgM was 40.2% (184/458), with 84.2% being clinicians versus 29 (15.8%) non-clinicians (p = 0.733). Amongst the 34 HP with PCR-positivity, 16 (47%) had no antibodies, while, 15 (44%) were IgG only. An estimate of HP (43.7%) had at least an evidence of PCR, IgG or IgM contact to COVID-19. Determinants of PCR-positivity was being clinical staff (AOR = 0.29, P = 0.039); and that of IgG/IgM were being non clinical staff (AOR = 0.41, p = 0.018) and regular use of face masks (AOR = 0.44, p = 0.001). HP trained on IPC (24%) were mainly from peripheral level (74.7%, p = 0.002).

CONCLUSION

Active infections were within the range of pandemic control (<10%). However, around two-fifths of participants have had contact with the virus, indicating that HP remains a population at risk of COVID-19 and other similarly-transmitted epidemic prone diseases, and also an important source of transmission. There is need of vaccine to achieve protectiveness, and optimal response also requires capacity building to improve the health system when challenged by a future pandemic.

Predicting the risk of primary Sjögren's syndrome with key N7-methylguanosine-related genes: A novel XGBoost model

Objectives

N7-methylguanosine (m7G) plays a crucial role in mRNA metabolism and other biological processes. However, its regulators' function in Primary Sjögren's Syndrome (PSS) remains enigmatic.

Methods

We screened five key m7G-related genes across multiple datasets, leveraging statistical and machine learning computations. Based on these genes, we developed a prediction model employing the extreme gradient boosting decision tree (XGBoost) method to assess PSS risk. Immune infiltration in PSS samples was analyzed using the ssGSEA method, revealing the immune landscape of PSS patients.

Results

The XGBoost model exhibited high accuracy, AUC, sensitivity, and specificity in both training, test sets and extra-test set. The decision curve confirmed its clinical utility. Our findings suggest that m7G methylation might contribute to PSS pathogenesis through immune modulation.

Conclusions

m7G regulators play an important role in the development of PSS. Our study of m7G-realted genes may inform future immunotherapy strategies for PSS.

The serological IgG and neutralizing antibody of SARS-CoV-2 omicron variant reinfection in Jiangsu Province, China

Background

It is important to figure out the immunity of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) reinfection to understand the response of humans to viruses. A serological survey for previously infected populations in Jiangsu Province was conducted to compare the antibody level of SARS-CoV-2 in reinfection by Omicron or not.

Methods

Reinfection with SARS-CoV-2 was defined as an individual being infected again after 90 days of the initial infection. Telephone surveys and face-to-face interviews were implemented to collect information. Experimental and control serum samples were collected from age-sex-matched reinfected and non-reinfected cases, respectively. IgG anti-S and neutralizing antibodies (Nab) concentrations were detected by the Magnetism Particulate Immunochemistry Luminescence Method (MCLIA). Antibody titers were log(2)-transformed and analyzed by a two-tailed Mann-Whitney U test. Subgroup analysis was conducted to explore the relationship between the strain type of primary infection, SARS-Cov-2 vaccination status, and antibody levels. Multivariate linear regression models were used to identify associations between reinfection with IgG and Nab levels.

Results

Six hundred thirty-one individuals were enrolled in this study, including 327 reinfected cases and 304 non-reinfected cases. The reinfection group had higher IgG (5.65 AU/mL vs. 5.22 AU/mL) and Nab (8.02 AU/mL vs. 7.25 AU/mL) levels compared to the non-reinfection group (p < 0.001). Particularly, individuals who had received SARS-CoV-2 vaccination or were initially infected with the Wild type and Delta variant showed a significant increase in antibody levels after reinfection. After adjusting demographic variables, vaccination status and the type of primary infection together, IgG and Nab levels in the reinfected group increased by log(2)-transformed 0.71 and 0.64 units, respectively (p < 0.001). This revealed that reinfection is an important factor that affects IgG and Nab levels in the population.

Conclusion

Reinfection with Omicron in individuals previously infected with SARS-CoV-2 enhances IgG and Nab immune responses.

Genomic Context of SARS-CoV-2 Outbreaks in Farmed Mink in Spain during Pandemic: Unveiling Host Adaptation Mechanisms

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects various mammalian species, with farmed minks experiencing the highest number of outbreaks. In Spain, we analyzed 67 whole genome sequences and eight spike sequences from 18 outbreaks, identifying four distinct lineages: B.1, B.1.177, B.1.1.7, and AY.98.1. The potential risk of transmission to humans raises crucial questions about mutation accumulation and its impact on viral fitness. Sequencing revealed numerous not-lineage-defining mutations, suggesting a cumulative mutation process during the outbreaks. We observed that the outbreaks were predominantly associated with different groups of mutations rather than specific lineages. This clustering pattern by the outbreaks could be attributed to the rapid accumulation of mutations, particularly in the ORF1a polyprotein and in the spike protein. Notably, the mutations G37E in NSP9, a potential host marker, and S486L in NSP13 were detected. Spike protein mutations may enhance SARS-CoV-2 adaptability by influencing trimer stability and binding to mink receptors. These findings provide valuable insights into mink coronavirus genetics, highlighting both host markers and viral transmission dynamics within communities.

The relationship between viral clearance rates and disease progression in early symptomatic COVID-19: a systematic review and meta-regression analysis

BACKGROUND

Effective antiviral drugs accelerate viral clearance in acute COVID-19 infections; the relationship between accelerating viral clearance and reducing severe clinical outcomes is unclear.

METHODS

A systematic review was conducted of randomized controlled trials (RCTs) of antiviral therapies in early symptomatic COVID-19, where viral clearance data were available. Treatment benefit was defined clinically as the relative risk of hospitalization/death during follow-up (≥14 days), and virologically as the SARS-CoV-2 viral clearance rate ratio (VCRR). The VCRR is the ratio of viral clearance rates between the intervention and control arms. The relationship between the clinical and virological treatment effects was assessed by mixed-effects meta-regression.

RESULTS

From 57 potentially eligible RCTs, VCRRs were derived for 44 (52 384 participants); 32 had ≥1 clinical endpoint in each arm. Overall, 9.7% (R2) of the variation in clinical benefit was explained by variation in VCRRs with an estimated linear coefficient of -0.92 (95% CI: -1.99 to 0.13; P = 0.08). However, this estimate was highly sensitive to the inclusion of the recent very large PANORAMIC trial. Omitting this outlier, half the variation in clinical benefit (R2 = 50.4%) was explained by variation in VCRRs [slope -1.47 (95% CI -2.43 to -0.51); P = 0.003], i.e. higher VCRRs were associated with an increased clinical benefit.

CONCLUSION

Methods of determining viral clearance in COVID-19 studies and the relationship to clinical outcomes vary greatly. As prohibitively large sample sizes are now required to show clinical treatment benefit in antiviral therapeutic assessments, viral clearance is a reasonable surrogate endpoint.

SARS-CoV-2 Viral Load in the Nasopharynx at Time of First Infection Among Unvaccinated Individuals: A Secondary Cross-Protocol Analysis of 4 Randomized Trials

Importance

SARS-CoV-2 viral load (VL) in the nasopharynx is difficult to quantify and standardize across settings, but it may inform transmission potential and disease severity.

Objective

To characterize VL at COVID-19 diagnosis among previously uninfected and unvaccinated individuals by evaluating the association of demographic and clinical characteristics, viral variant, and trial with VL, as well as the ability of VL to predict severe disease.

Design, Setting, and Participants

This secondary cross-protocol analysis used individual-level data from placebo recipients from 4 harmonized, phase 3 COVID-19 vaccine efficacy trials sponsored by Moderna, AstraZeneca, Janssen, and Novavax. Participants were SARS-CoV-2 negative at baseline and acquired COVID-19 during the blinded phase of the trials. The setting included the US, Brazil, South Africa, Colombia, Argentina, Peru, Chile, and Mexico; start dates were July 27, 2020, to December 27, 2020; data cutoff dates were March 26, 2021, to July 30, 2021. Statistical analysis was performed from November 2022 to June 2023.

Main Outcomes and Measures

Linear regression was used to assess the association of demographic and clinical characteristics, viral variant, and trial with polymerase chain reaction-measured log10 VL in nasal and/or nasopharyngeal swabs taken at the time of COVID-19 diagnosis.

Results

Among 1667 participants studied (886 [53.1%] male; 995 [59.7%] enrolled in the US; mean [SD] age, 46.7 [14.7] years; 204 [12.2%] aged 65 years or older; 196 [11.8%] American Indian or Alaska Native, 150 [9%] Black or African American, 1112 [66.7%] White; 762 [45.7%] Hispanic or Latino), median (IQR) log10 VL at diagnosis was 6.18 (4.66-7.12) log10 copies/mL. Participant characteristics and viral variant explained only 5.9% of the variability in VL. The independent factor with the highest observed differences was trial: Janssen participants had 0.54 log10 copies/mL lower mean VL vs Moderna participants (95% CI, 0.20 to 0.87 log10 copies/mL lower). In the Janssen study, which captured the largest number of COVID-19 events and variants and used the most intensive post-COVID surveillance, neither VL at diagnosis nor averaged over days 1 to 28 post diagnosis was associated with COVID-19 severity.

Conclusions and Relevance

In this study of placebo recipients from 4 randomized phase 3 trials, high variability was observed in SARS-CoV-2 VL at the time of COVID-19 diagnosis, and only a fraction was explained by individual participant characteristics or viral variant. These results suggest challenges for future studies of interventions seeking to influence VL and elevates the importance of standardized methods for specimen collection and viral load quantitation.

Outcomes of a home telemonitoring program for SARS-CoV-2 viral infection at a large academic medical center

INTRODUCTION

Telemedicine serves as a viable option during the COVID-19 pandemic to provide in-home care, maintain home isolation precautions, reduce unnecessary healthcare exposures, and de-burden hospitals.

METHODS

We created a novel telemedicine program to closely monitor patients infected with SARS-CoV-2 (COVID-19) at home. Adult patients with COVID-19 were enrolled in the program at the time of documented infection. Patients were followed by a team of providers via telephone or video visits at frequent intervals until resolution of their acute illness. Additionally, patients were stratified into high-risk and low-risk categories based on demographics and underlying comorbidities. The primary outcome was hospitalization after enrollment in the home monitoring program, including 30 days after discharge from the program.

RESULTS

Over a 3.5-month period, 1128 patients met criteria for enrollment in the home monitoring program. 30.7% were risk stratified as high risk for poor outcomes based on their comorbidities and age. Of the 1128 patients, 6.2% required hospitalization and 1.2% required ICU admission during the outcome period. Hospitalization was more frequent in patients identified as high risk (14.2% vs 2.7%, P < 0.001).

DISCUSSION

Enrollment in a home monitoring program appears to be an effective and sustainable modality for the ambulatory management of COVID-19.

Research progress in Fc-effector functions against SARS-CoV-2

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has caused more than 676 million cases in the global human population with approximately 7 million deaths and vaccination has been proved as the most effective countermeasure in reducing clinical complications and mortality rate of SARS-CoV-2 infection in people. However, the protective elements and correlation of protection induced by vaccination are still not completely understood. Various antibodies with multiple protective mechanisms can be induced simultaneously by vaccination in vivo, thereby complicating the identification and characterization of individual correlate of protection. Recently, an increasing body of observations suggests that antibody-induced Fc-effector functions play a crucial role in combating SARS-CoV-2 infections, including neutralizing antibodies-escaping variants. Here, we review the recent progress in understanding the impact of Fc-effector functions in broadly disarming SARS-CoV-2 infectivity and discuss various efforts in harnessing this conserved antibody function to develop an effective SARS-CoV-2 vaccine that can protect humans against infections by SARS-CoV-2 virus and its variants of concern.

The hinge-engineered IgG1-IgG3 hybrid subclass IgGh47 potently enhances Fc-mediated function of anti-streptococcal and SARS-CoV-2 antibodies

Streptococcus pyogenes can cause invasive disease with high mortality despite adequate antibiotic treatments. To address this unmet need, we have previously generated an opsonic IgG1 monoclonal antibody, Ab25, targeting the bacterial M protein. Here, we engineer the IgG2-4 subclasses of Ab25. Despite having reduced binding, the IgG3 version promotes stronger phagocytosis of bacteria. Using atomic simulations, we show that IgG3's Fc tail has extensive movement in 3D space due to its extended hinge region, possibly facilitating interactions with immune cells. We replaced the hinge of IgG1 with four different IgG3-hinge segment subclasses, IgGhxx. Hinge-engineering does not diminish binding as with IgG3 but enhances opsonic function, where a 47 amino acid hinge is comparable to IgG3 in function. IgGh47 shows improved protection against S. pyogenes in a systemic infection mouse model, suggesting that IgGh47 has promise as a preclinical therapeutic candidate. Importantly, the enhanced opsonic function of IgGh47 is generalizable to diverse S. pyogenes strains from clinical isolates. We generated IgGh47 versions of anti-SARS-CoV-2 mAbs to broaden the biological applicability, and these also exhibit strongly enhanced opsonic function compared to the IgG1 subclass. The improved function of the IgGh47 subclass in two distant biological systems provides new insights into antibody function.

SARS-CoV-2 variant of concern fitness and adaptation in primary human airway epithelia

The severe acute respiratory syndrome coronavirus 2 pandemic is characterized by the emergence of novel variants of concern (VOCs) that replace ancestral strains. Here, we dissect the complex selective pressures by evaluating variant fitness and adaptation in human respiratory tissues. We evaluate viral properties and host responses to reconstruct forces behind D614G through Omicron (BA.1) emergence. We observe differential replication in airway epithelia, differences in cellular tropism, and virus-induced cytotoxicity. D614G accumulates the most mutations after infection, supporting zoonosis and adaptation to the human airway. We perform head-to-head competitions and observe the highest fitness for Gamma and Delta. Under these conditions, RNA recombination favors variants encoding the B.1.617.1 lineage 3' end. Based on viral growth kinetics, Alpha, Gamma, and Delta exhibit increased fitness compared to D614G. In contrast, the global success of Omicron likely derives from increased transmission and antigenic variation. Our data provide molecular evidence to support epidemiological observations of VOC emergence.

SARS-CoV-2 resistance to monoclonal antibodies and small-molecule drugs

Over four years have passed since the beginning of the COVID-19 pandemic. The scientific response has been rapid and effective, with many therapeutic monoclonal antibodies and small molecules developed for clinical use. However, given the ability for viruses to become resistant to antivirals, it is perhaps no surprise that the field has identified resistance to nearly all of these compounds. Here, we provide a comprehensive review of the resistance profile for each of these therapeutics. We hope that this resource provides an atlas for mutations to be aware of for each agent, particularly as a springboard for considerations for the next generation of antivirals. Finally, we discuss the outlook and thoughts for moving forward in how we continue to manage this, and the next, pandemic.

Efficacy and safety of Link Natural Sudarshana, an Ayurvedic herbal preparation in COVID-19 patients: A phase II multicenter double-blind randomized placebo-controlled trial

ETHNOPHARMACOLOGICAL RELEVANCE

In vitro and in vivo studies have shown anti-viral and immunomodulatory actions in components of many traditional medicines. Various constituents of traditional medicines have been found to be effective against coronavirus disease (COVID-19) in several clinical trials and in-silico studies. Sudarshana cúrna, a polyherbal Ayurvedic medicine, has been used over thousands of years for a variety of infectious fevers.

AIMS OF THE STUDY

This study aimed to evaluate the efficacy and safety of Link Natural Sudarshana (LNS) tablets, in patients with COVID 19 disease. LNS is a polyherbal preparation comprising 49 medicinal plants included in the Sudarshana cúrna.

MATERIALS AND METHODS

A randomized parallel-group double-blind placebo-controlled multi-center phase II clinical trial was conducted in patients with mild to moderate COVID-19 disease. They were randomly allocated to intervention and control groups. The intervention group received LNS tablets whereas the control group received placebo tablets for 10 days or until the patient was discharged from the hospital. All patients received standard symptomatic treatment. The primary outcome, a reduction in mean log viral load was assessed at day 5 of treatment. The secondary outcomes, clinical progression and safety, were assessed by, monitoring changes in symptoms daily on a Likert scale ranging from 1 to 4 and laboratory tests respectively.

RESULTS

A total of 171 patients (treatment group 83, control group 88) completed the trial. There were no significant differences between the baseline status of the two groups except that body mass index was significantly higher in the placebo group. The mean log viral load reduction at day 5 was higher in the treatment group (2.20 ± 1.67) compared to the placebo group (1.93 ± 1.80), with a mean difference of -0.278. This difference was not statistically significant at the 5% significant level. Reduction of mean cumulative symptom score, which included 16 symptoms graded according to severity, was higher in the treatment group compared to the placebo group. This difference was not statistically significant. None of the study participants developed hypoxia. Among the 7 lymphopenia patients in the placebo group, 3 continued to have lymphopenia at day 10, whereas 9 lymphopenia patients in the treatment group, reverted to normal counts. C reactive proteins (CRP) showed a greater reduction in the treatment group. None reported adverse effects. No significant changes occurred in hematological and biochemical parameters that assessed safety.

CONCLUSIONS

LNS is safe to use in COVID-19 patients and accelerated the decline in viral load, relieved symptoms, reduced CRP levels and reversed lymphopenia earlier, when compared to the placebo.

Prevention and treatment strategies for kidney transplant recipients in the context of long-term existence of COVID-19

The sudden outbreak of coronavirus disease 2019 (COVID-19) in early 2020 posed a massive threat to human life and caused an economic upheaval worldwide. Kidney transplant recipients (KTRs) became susceptible to infection during the COVID-19 pandemic owing to their use of immunosuppressants, resulting in increased hospitalization and mortality rates. Although the current epidemic situation is alleviated, the long-term existence of COVID-19 still seriously threatens the life and health of KTRs with low immunity. The Omicron variant, a highly infectious but less-pathogenic strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has raised concerns among transplant physicians regarding managing KTRs diagnosed with this variant. However, currently, there are no clear and unified guidelines for caring for KTRs infected with this variant. Therefore, we aimed to summarize the ongoing research on drugs that can treat Omicron variant infections in KTRs and explore the potential of adjusting immunotherapy strategies to enhance their responsiveness to vaccines. Herein, we discuss the situation of KTRs since the emergence of COVID-19 and focus on various prevention and treatment strategies for KTRs since the Omicron variant outbreak. We hope to assist physicians in managing KTRs in the presence of long-term COVID-19 variants.

Modeling the emergence of viral resistance for SARS-CoV-2 during treatment with an anti-spike monoclonal antibody

To mitigate the loss of lives during the COVID-19 pandemic, emergency use authorization was given to several anti-SARS-CoV-2 monoclonal antibody (mAb) therapies for the treatment of mild-to-moderate COVID-19 in patients with a high risk of progressing to severe disease. Monoclonal antibodies used to treat SARS-CoV-2 target the spike protein of the virus and block its ability to enter and infect target cells. Monoclonal antibody therapy can thus accelerate the decline in viral load and lower hospitalization rates among high-risk patients with variants susceptible to mAb therapy. However, viral resistance has been observed, in some cases leading to a transient viral rebound that can be as large as 3-4 orders of magnitude. As mAbs represent a proven treatment choice for SARS-CoV-2 and other viral infections, evaluation of treatment-emergent mAb resistance can help uncover underlying pathobiology of SARS-CoV-2 infection and may also help in the development of the next generation of mAb therapies. Although resistance can be expected, the large rebounds observed are much more difficult to explain. We hypothesize replenishment of target cells is necessary to generate the high transient viral rebound. Thus, we formulated two models with different mechanisms for target cell replenishment (homeostatic proliferation and return from an innate immune response antiviral state) and fit them to data from persons with SARS-CoV-2 treated with a mAb. We showed that both models can explain the emergence of resistant virus associated with high transient viral rebounds. We found that variations in the target cell supply rate and adaptive immunity parameters have a strong impact on the magnitude or observability of the viral rebound associated with the emergence of resistant virus. Both variations in target cell supply rate and adaptive immunity parameters may explain why only some individuals develop observable transient resistant viral rebound. Our study highlights the conditions that can lead to resistance and subsequent viral rebound in mAb treatments during acute infection.

Genomic epidemiology of SARS-CoV-2 δ sublineages of the second wave of 2021 in Antioquia, Colombia

Introduction. During the development of the SARS-CoV-2 pandemic in Antioquia, we experienced epidemiological peaks related to the α, ɣ, β, ƛ, and δ variants. δ had the highest incidence and prevalence. This lineage is of concern due to its clinical manifestations and epidemiological characteristics. A total of 253 δ sublineages have been reported in the PANGOLIN database. The sublineage identification through genomic analysis has made it possible to trace their evolution and propagation. Objective. To characterize the genetic diversity of the different SARS-CoV-2 δ sublineages in Antioquia and to describe its prevalence. Materials and methods. We collected sociodemographic information from 2,675 samples, and obtained 1,115 genomes from the GISAID database between July 12th, 2021, and January 18th, 2022. From the analyzed genomes, 515 were selected because of their high coverage values (>90%) to perform phylogenetic analysis and to infer allele frequencies of mutations of interest. Results. We characterized 24 sublineages. The most prevalent was AY.25. Mutations of interest as L452R, P681R, and P681H were identified in this sublineage, comprising a frequency close to 0.99. Conclusions. This study identified that the AY.25 sublineage has a transmission advantage compared to the other δ sublineages. This attribute may be related to the presence of the L452R and P681R mutations associated in other studies with higher evasion of the immune system and less efficacy of drugs against SARS-CoV-2.

Emerging anti-spike monoclonal antibodies against SARS-CoV-2

INTRODUCTION

Anti-spike monoclonal antibodies (mAbs) were previously authorized for the prevention and treatment of COVID-19 in immunocompromised patients. However, they are no longer authorized in the U.S. due to their lack of neutralizing activity against current circulating SARS-CoV-2 Omicron variants.

AREAS COVERED

We summarized the available data on emergent mAbs in the early stages of clinical development. Consistent with data on prior mAbs, these novel agents have been well tolerated and demonstrated a good safety profile in early clinical trials. Additionally, many of them have been engineered to ensure prolonged half-life and combined with other mAbs to overcome the potential for emerging resistant mutants. Interestingly, one of these agents has been evaluated using an inhaled route of administration, and another agent is being evaluated for treatment of long COVID.

EXPERT OPINION

Although the available data of novel mAbs holds promise, we anticipate that these agents will face similar challenges encountered by prior authorized agents, including the continued evolution of SARS-CoV-2 and emergence of new escape mutations. Strategies to potentially mitigate this are discussed. Based on prior successful experience, immunocompromised patients will certainly benefit from the utilization of mAbs for the prevention and treatment of COVID-19; thus, we need to design potential interventions to ensure the sustained activity of these agents.

Efficacy and safety of bamlanivimab in patients with COVID-19: A systematic review and meta-analysis

BACKGROUND

Monoclonal antibodies (mAbs) have shown clinical benefits against coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Several studies have reported the use of bamlanivimab as a promising treatment option for COVID-19.

AIM

To synthesize the latest evidence for the efficacy and safety of bamlanivimab alone in the treatment of adult patients with COVID-19.

METHODS

A literature search was conducted in PubMed, Cochrane Library, Web of Science, medRxiv, and Google Scholar using "SARS-CoV-2", "COVID-19", "LY-CoV555", and "Bamlanivimab" keywords up to January 25, 2023. The quality of included studies was assessed using the Cochrane bias tools. The Comprehensive Meta-Analysis software version 3.0 was used to analyze the data.

RESULTS

A total of 30 studies involving 47368 patients were included. A significant difference was observed between the bamlanivimab and standard of care/placebo groups in terms of mortality rate [risk ratio (RR) = 50, 95% confidence interval (CI): 0.36-0.70], hospitalization rate (RR = 0.51; 95%CI: 0.39-0.68), and emergency department (ED) visits (RR = 0.69; 95%CI: 0.47-0.99); while the two groups exhibited no significant difference in terms of intensive care unit (ICU) admission (P > 0.05). Compared to other mAbs, bamlanivimab was associated with a higher rate of hospitalization (RR = 1.44; 95%CI: 1.07-1.94). However, no significant difference was detected between the bamlanivimab and other mAbs groups in terms of mortality rate, ICU admission, and ED (P > 0.05). The incidence of any adverse events was similar between the bamlanivimab and control groups (P > 0.05).

CONCLUSION

Although the results suggest the efficacy and safety of bamlanivimab in COVID-19 patients, further research is required to confirm the efficacy of this drug for the current circulating SARS-CoV-2 variants.

A narrative review on adverse drug reactions of COVID-19 treatments on the kidney

Studies showed that the respiratory is not the only system affected by coronavirus 2, while cardiovascular, digestive, and nervous systems, as well as essential organs such as the kidneys, can be affected by this virus. In this review, we have studied the epidemiology, clinical, and laboratory findings on COVID-19 infection renal involvement, mortality, physiopathology, remaining renal sequels after recovery, underlying renal disease, and renal injury due to its treatment. Also, protective measures for kidney injury are explained in three levels. Evidence of viral particles and genome in the urine and renal tubular cells and signs of damage such as microangiopathy, hypercoagulopathy, and fibrosis are found in COVID-19 patients. The result of this study showed, in hospitalized COVID-19 patients, that the rate of acute kidney injury (AKI) was up to 46%, with a mortality ranging from 11 to 96%. A considerable proportion of patients with AKI would remain on renal replacement therapy. Proteinuria and hematuria are observed in 87 and 75% patients, and increased Cr and glomerular filtration rate (GFR) <60 ml/min per 1.73 m2 are observed in 29.6 and 35.3% of the patients, respectively. Remedsivir is considered to have adverse effects on GFR. COVID-19 patients need special attention to prevent AKI. Those with underlying chronic kidney disease or AKI need proper and explicit evaluation and treatment to improve their prognosis and decrease mortality, which should not be limited to the hospitalization period.

Efficacy of the combination of BRII-196/BRII-198 in the treatment of COVID-19 vaccine breakthrough infections

BACKGROUND

BRII-196 and BRII-198 are two recombinant human immunoglobulin (Ig) G1 monoclonal antibodies (mAbs) that non-competitively target distinct epitope regions within the receptor-binding domain (RBD) of the coronavirus spike glycoproteins. These antibodies are derived directly from human B cells of individuals who recovered from COVID-19.

OBJECTIVE

To analyze the efficacy of BRII-196/BRII-198 in the treatment of coronavirus disease 2019 (COVID-19) vaccine breakthrough infections.

METHODS

COVID-19 patients at high risk of progressing to severe and critical illness, with an initial SARS-CoV-2 immunoglobulin (Ig) G antibody level < 1.0 S/CO (detected within 24-48 hours post COVID-19 diagnosis), were treated with BRII-196/BRII-198 within three days of symptom onset. Treatment continued until the antibody level exceeded 1.0 S/CO. Patients whose absolute lymphocyte count (ALC) at first detection (within 24-48 h post-diagnosis) was < 0.8 × 109/L received thymalfasin therapy within three days of symptom onset, continuing until the ALC level surpassed 0.8 × 109/L. We determined the correlation of SARS-CoV-2 IgG antibody level and ALC with the condition of COVID-19 patients. Additionally, we analyzed the effects of BRII-196/BRII-198 on SARS-CoV-2 nucleic acid (NA) negative conversion, lymphocyte count recovery, and the change in SARS-CoV-2 IgG antibody level from the first positive NA test for SARS-CoV-2 to negative conversion in COVID-19 patients.

RESULTS

A total of 61 cases of breakthrough infections were observed, classified as 10 mild cases, 31 ordinary cases, and 20 severe cases. Among these, 20%, 48.4% and 75% of the patients with mild, ordinary, and severe COVID-19, respectively, had initial SARS-CoV-2 IgG antibody level < 1.0 S/CO. Additionally, 0%, 35% and 70% had initial ALC < 0.8 × 109/L, respectively. Fifteen ordinary and 15 severe COVID-19 patients were treated with BRII-196/BRII-198. In severely infected patients, BRII-196/BRII-198 treatment showed statistically significant differences in NA negative conversion time and changes in SARS-CoV-2 IgG antibody levels (P < 0.05). However, in patients classified with ordinary severity, BRII-196/BRII-198 treatment did not lead to notable differences in NA negative conversion time or changes in SARS-CoV-2 IgG antibody level (P > 0.05). BRII-196/BRII-198 therapy was not associated with lymphocyte count recovery time in patients with either ordinary and/or severe COVID-19 (P > 0.05).

CONCLUSIONS

The initial levels of SARS-CoV-2 IgG antibody and lymphocytes in fully vaccinated patients with breakthrough infections are inversely correlated with the severity of the disease. Early treatment with BRII-196/BRII-198 can shorten NA negative conversion time in severe COVID-19 patients and increase in vivo neutralizing antibody levels post-conversion, providing lasting protection. However, BRII-196/BRII-198 does not influence lymphocyte count recovery in patients with either ordinary and/or severe COVID-19.

Filamentous fungus-produced human monoclonal antibody provides protection against SARS-CoV-2 in hamster and non-human primate models

Monoclonal antibodies are an increasingly important tool for prophylaxis and treatment of acute virus infections like SARS-CoV-2 infection. However, their use is often restricted due to the time required for development, variable yields and high production costs, as well as the need for adaptation to newly emerging virus variants. Here we use the genetically modified filamentous fungus expression system Thermothelomyces heterothallica (C1), which has a naturally high biosynthesis capacity for secretory enzymes and other proteins, to produce a human monoclonal IgG1 antibody (HuMab 87G7) that neutralises the SARS-CoV-2 variants of concern (VOCs) Alpha, Beta, Gamma, Delta, and Omicron. Both the mammalian cell and C1 produced HuMab 87G7 broadly neutralise SARS-CoV-2 VOCs in vitro and also provide protection against VOC Omicron in hamsters. The C1 produced HuMab 87G7 is also able to protect against the Delta VOC in non-human primates. In summary, these findings show that the C1 expression system is a promising technology platform for the development of HuMabs in preventive and therapeutic medicine.

Antiviral Protein-Protein Interaction Inhibitors

Continually repeating outbreaks of pathogenic viruses necessitate the construction of effective antiviral strategies. Therefore, the development of new specific antiviral drugs in a well-established and efficient manner is crucial. Taking into account the strong ability of viruses to change, therapies with diversified molecular targets must be sought. In addition to the widely explored viral enzyme inhibitor approach, inhibition of protein-protein interactions is a very valuable strategy. In this Perspective, protein-protein interaction inhibitors targeting HIV, SARS-CoV-2, HCV, Ebola, Dengue, and Chikungunya viruses are reviewed and discussed. Antibodies, peptides/peptidomimetics, and small molecules constitute three classes of compounds that have been explored, and each of them has some advantages and disadvantages for drug development.

Adequacy to immunosuppression management guidelines in kidney transplant recipients with severe COVID-19 pneumonia: a practice survey

Introduction

Coronavirus disease 2019 (COVID-19) poses an important risk of morbidity and of mortality, in patients after solid organ transplantation. Recommendations have been issued by various transplantation societies at the national and European level to manage the immunosuppressive (IS) regimen upon admission to intensive care unit (ICU).

Method

The aim of this study was to evaluate the adequacy of IS regimen minimization strategy in kidney transplant recipients hospitalized in an ICU for severe COVID-19, in relation to the issued recommendations.

Results

The immunosuppressive therapy was minimized in all patients, with respectively 63% and 59% of the patients meeting the local and european recommendations upon admission. During ICU stay, IS was further tapered leading to 85% (local) and 78% (european) adequacy, relative to the guidelines. The most frequent deviation was the lack of complete withdrawal of mycophenolic acid (22%). Nevertheless, the adequacy/inadequacy status was not associated to the ICU- or one-year-mortality.

Discussion

In this single-center cohort, the only variable associated with a reduction in mortality was vaccination, emphasizing that the key issue is immunization prior to infection, not restoration of immunity during ICU stay.

Discordant Antigenic Properties of Soluble and Virion SARS-CoV-2 Spike Proteins

Efforts to develop vaccine and immunotherapeutic countermeasures against the COVID-19 pandemic focus on targeting the trimeric spike (S) proteins of SARS-CoV-2. Vaccines and therapeutic design strategies must impart the characteristics of virion S from historical and emerging variants onto practical constructs such as soluble, stabilized trimers. The virus spike is a heterotrimer of two subunits: S1, which includes the receptor binding domain (RBD) that binds the cell surface receptor ACE2, and S2, which mediates membrane fusion. Previous studies suggest that the antigenic, structural, and functional characteristics of virion S may differ from current soluble surrogates. For example, it was reported that certain anti-glycan, HIV-1 neutralizing monoclonal antibodies bind soluble SARS-CoV-2 S but do not neutralize SARS-CoV-2 virions. In this study, we used single-molecule fluorescence correlation spectroscopy (FCS) under physiologically relevant conditions to examine the reactivity of broadly neutralizing and non-neutralizing anti-S human monoclonal antibodies (mAbs) isolated in 2020. Binding efficiency was assessed by FCS with soluble S trimers, pseudoviruses and inactivated wild-type virions representing variants emerging from 2020 to date. Anti-glycan mAbs were tested and compared. We find that both anti-S specific and anti-glycan mAbs exhibit variable but efficient binding to a range of stabilized, soluble trimers. Across mAbs, the efficiencies of soluble S binding were positively correlated with reactivity against inactivated virions but not pseudoviruses. Binding efficiencies with pseudoviruses were generally lower than with soluble S or inactivated virions. Among neutralizing mAbs, potency did not correlate with binding efficiencies on any target. No neutralizing activity was detected with anti-glycan antibodies. Notably, the virion S released from membranes by detergent treatment gained more efficient reactivity with anti-glycan, HIV-neutralizing antibodies but lost reactivity with all anti-S mAbs. Collectively, the FCS binding data suggest that virion surfaces present appreciable amounts of both functional and nonfunctional trimers, with neutralizing anti-S favoring the former structures and non-neutralizing anti-glycan mAbs binding the latter. S released from solubilized virions represents a nonfunctional structure bound by anti-glycan mAbs, while engineered soluble trimers present a composite structure that is broadly reactive with both mAb types. The detection of disparate antigenicity and immunoreactivity profiles in engineered and virion-associated S highlight the value of single-virus analyses in designing future antiviral strategies against SARS-CoV-2.

Rapid isolation of pan-neutralizing antibodies against Omicron variants from convalescent individuals infected with SARS-CoV-2

Introduction

The emergence of SARS-CoV-2 Omicron subvariants has presented a significant challenge to global health, as these variants show resistance to most antibodies developed early in the pandemic. Therapeutic antibodies with potent efficacy to the Omicron variants are urgently demanded.

Methods

Utilizing the rapid antibody discovery platform, Berkeley Lights Beacon, we isolated two monoclonal neutralizing antibodies, 2173-A6 and 3462-A4. These antibodies were isolated from individuals who recently recovered from Omicron infections.

Results

Both antibodies, 2173-A6 and 3462-A4, demonstrated high affinity for the RBD and effectively neutralized pseudoviruses from various Omicron lineages, including BA.4/5, XBB.1.16, XBB.1.5, and EG.5.1. This neutralization was achieved through binding to identical or overlapping epitopes.

Discussion

The use of the Beacon platform enabled the rapid isolation and identification of effective neutralizing antibodies within less than 10 days. This process significantly accelerates the development of novel therapeutic antibodies, potentially reducing the time required to respond to unknown infectious diseases in the future.

Physics-driven structural docking and protein language models accelerate antibody screening and design for broad-spectrum antiviral therapy

Therapeutic antibodies have become one of the most influential therapeutics in modern medicine to fight against infectious pathogens, cancer, and many other diseases. However, experimental screening for highly efficacious targeting antibodies is labor-intensive and of high cost, which is exacerbated by evolving antigen targets under selective pressure such as fast-mutating viral variants. As a proof-of-concept, we developed a machine learning-assisted antibody generation pipeline that greatly accelerates the screening and re-design of immunoglobulins G (IgGs) against a broad spectrum of SARS-CoV-2 coronavirus variant strains. These viruses infect human host cells via the viral spike protein binding to the host cell receptor angiotensin-converting enzyme 2 (ACE2). Using over 1300 IgG sequences derived from convalescent patient B cells that bind with spike's receptor binding domain (RBD), we first established protein structural docking models in assessing the RBD-IgG-ACE2 interaction interfaces and predicting the virus-neutralizing activity of each IgG with a confidence score. Additionally, employing Gaussian process regression (also known as Kriging) in a latent space of an antibody language model, we predicted the landscape of IgGs' activity profiles against individual coronaviral variants of concern. With functional analyses and experimental validations, we efficiently prioritized IgG candidates for neutralizing a broad spectrum of viral variants (wildtype, Delta, and Omicron) to prevent the infection of host cells in vitro and hACE2 transgenic mice in vivo. Furthermore, the computational analyses enabled rational redesigns of selective IgG clones with single amino acid substitutions at the RBD-binding interface to improve the IgG blockade efficacy for one of the severe, therapy-resistant strains - Delta (B.1.617). Our work expedites applications of artificial intelligence in antibody screening and re-design even in low-data regimes combining protein language models and Kriging for antibody sequence analysis, activity prediction, and efficacy improvement, in synergy with physics-driven protein docking models for antibody-antigen interface structure analyses and functional optimization.

A panel of multivalent nanobodies broadly neutralizing Omicron subvariants and recombinant

The emerging Omicron subvariants have a remarkable ability to spread and escape nearly all current monoclonal antibody (mAb) treatments. Although the virulence of SARS-CoV-2 has now diminished, it remains a significant threat to public health due to its high transmissibility and susceptibility to mutation. Therefore, it is urgent to develop broad-acting and potent therapeutics targeting current and emerging Omicron variants. Here, we identified a panel of Omicron BA.1 spike receptor-binding domain (RBD)-targeted nanobodies (Nbs) from a naive alpaca VHH library. This panel of Nbs exhibited high binding affinity to the spike RBD of wild-type, Alpha B.1.1.7, Beta B.1.351, Delta plus, Omicron BA.1, and BA.2. Through multivalent Nb construction, we obtained a subpanel of ultrapotent neutralizing Nbs against Omicron BA.1, BA.2, BF.7 and even emerging XBB.1.5, and XBB.1.16 pseudoviruses. Protein structure prediction and docking analysis showed that Nb trimer 2F2E5 targets two independent RBD epitopes, thus minimizing viral escape. Taken together, we obtained a panel of broad and ultrapotent neutralizing Nbs against Omicron BA.1, Omicron BA.2, BF.7, XBB.1.5, and XBB.1.16. These multivalent Nbs hold great promise for the treatment against SARS-CoV-2 infection and could possess a superwide neutralizing breadth against novel omicron mutants or recombinants.

CCR5/CXCR3 antagonist TAK-779 prevents diffuse alveolar damage of the lung in the murine model of the acute respiratory distress syndrome

Introduction: The acute respiratory distress syndrome (ARDS), secondary to viral pneumonitis, is one of the main causes of high mortality in patients with COVID-19 (novel coronavirus disease 2019)-ongoing SARS-CoV-2 infection- reached more than 0.7 billion registered cases. Methods: Recently, we elaborated a non-surgical and reproducible method of the unilateral total diffuse alveolar damage (DAD) of the left lung in ICR mice-a publicly available imitation of the ARDS caused by SARS-CoV-2. Our data read that two C-C chemokine receptor 5 (CCR5) ligands, macrophage inflammatory proteins (MIPs) MIP-1α/CCL3 and MIP-1β/CCL4, are upregulated in this DAD model up to three orders of magnitude compared to the background level. Results: Here, we showed that a nonpeptide compound TAK-779, an antagonist of CCR5/CXCR3, readily prevents DAD in the lung with a single injection of 2.5 mg/kg. Histological analysis revealed reduced peribronchial and perivascular mononuclear infiltration in the lung and mononuclear infiltration of the wall and lumen of the alveoli in the TAK-779-treated animals. Administration of TAK-779 decreased the 3-5-fold level of serum cytokines and chemokines in animals with DAD, including CCR5 ligands MIP-1α/β, MCP-1, and CCL5. Computed tomography revealed rapid recovery of the density and volume of the affected lung in TAK-779-treated animals. Discussion: Our pre-clinical data suggest that TAK-779 is more effective than the administration of dexamethasone or the anti-IL6R therapeutic antibody tocilizumab, which brings novel therapeutic modality to TAK-779 and other CCR5 inhibitors for the treatment of virus-induced hyperinflammation syndromes, including COVID-19.

Single-domain antibodies against SARS-CoV-2 RBD from a two-stage phage screening of universal and focused synthetic libraries

BACKGROUND

Coronavirus disease 2019 (COVID-19) is an evolving global pandemic, and nanobodies, as well as other single-domain antibodies (sdAbs), have been recognized as a potential diagnostic and therapeutic tool for infectious diseases. High-throughput screening techniques such as phage display have been developed as an alternative to in vivo immunization for the discovery of antibody-like target-specific binders.

METHODS

We designed and constructed a highly diverse synthetic phage library sdAb-U (single-domain Antibody - Universal library ) based on a human framework. The SARS-CoV-2 receptor-binding domain (RBD) was expressed and purified. The universal library sdAb-U was panned against the RBD protein target for two rounds, followed by monoclonal phage ELISA (enzyme-linked immunosorbent assay) to identify RBD-specific binders (the first stage). High-affinity binders were sequenced and the obtained CDR1 and CDR2 sequences were combined with fully randomized CDR3 to construct a targeted (focused) phage library sdAb-RBD, for subsequent second-stage phage panning (also two rounds) and screening. Then, sequences with high single-to-background ratios in phage ELISA were selected for expression. The binding affinities of sdAbs to RBD were measured by an ELISA-based method. In addition, we conducted competition ELISA (using ACE2 ectodomain S19-D615) and SARS-CoV-2 pseudovirus neutralization assays for the high-affinity RBD-binding sdAb39.

RESULTS

Significant enrichments were observed in both the first-stage (universal library) and the second-stage (focused library) phage panning. Five RBD-specific binders were identified in the first stage with high ELISA signal-to-background ratios. In the second stage, we observed a much higher possibility of finding RBD-specific clones in phage ELISA. Among 45 selected RBD-positive sequences, we found eight sdAbs can be well expressed, and five of them show high-affinity to RBD (EC50 < 100nM). We finally found that sdAb39 (EC50 ~ 4nM) can compete with ACE2 for binding to RBD.

CONCLUSION

Overall, this two-stage strategy of synthetic phage display libraries enables rapid selection of SARS-CoV-2 RBD sdAb with potential therapeutic activity, and this two-stage strategy can potentially be used for rapid discovery of sdAbs against other targets.

Immunoglobulin replacement products protect against SARS-CoV-2 infection in vivo despite poor neutralizing activity

Immunoglobulin (IG) replacement products are used routinely in patients with immune deficiency and other immune dysregulation disorders who have poor responses to vaccination and require passive immunity conferred by commercial antibody products. The binding, neutralizing, and protective activity of intravenously administered IG against SARS-CoV-2 emerging variants remains unknown. Here, we tested 198 different IG products manufactured from December 2019 to August 2022. We show that prepandemic IG had no appreciable cross-reactivity or neutralizing activity against SARS-CoV-2. Anti-spike antibody titers and neutralizing activity against SARS-CoV-2 WA1/2020 D614G increased gradually after the pandemic started and reached levels comparable to vaccinated healthy donors 18 months after the diagnosis of the first COVID-19 case in the United States in January 2020. The average time between production to infusion of IG products was 8 months, which resulted in poor neutralization of the variant strain circulating at the time of infusion. Despite limited neutralizing activity, IG prophylaxis with clinically relevant dosing protected susceptible K18-hACE2-transgenic mice against clinical disease, lung infection, and lung inflammation caused by the XBB.1.5 Omicron variant. Moreover, following IG prophylaxis, levels of XBB.1.5 infection in the lung were higher in FcγR-KO mice than in WT mice. Thus, IG replacement products with poor neutralizing activity against evolving SARS-CoV-2 variants likely confer protection to patients with immune deficiency disorders through Fc effector function mechanisms.

Coronavirus Disease 2019 (COVID-19) in Heart Transplant Recipients and Anti-SARS-CoV-2 Monoclonal Antibodies: Experience, Lessons Learnt, and Future Challenges

Solid organ transplant recipients (SOTRs), including heart transplant (HT) recipients, infected with Coronavirus disease 2019 (COVID-19) are at higher risk of hospitalization, mechanical ventilation, or death when compared with general population. Advances in diagnosis and treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have reduced COVID-19-related mortality rates from ~30% in the early pandemic to <3% in 2022 among HT recipients. We performed a retrospective chart review including adult HT recipients at Westchester Medical Center from January 1, 2020 to December 10, 2022, who received anti-SARS-CoV-2 monoclonal antibodies (mAbs) for treatment of mild-to-moderate COVID-19, and those who received tixagevimab/cilgavimab for preexposure prophylaxis. Additionally, a comprehensive review of the literature involving SOTRs who received mAbs for COVID-19 was conducted. In this largest single-center study in this population, 42 adult HT recipients received casirivimab/imdevimab (36%), sotrovimab (31%), or bebtelovimab (29%) for treatment of mild-to-moderate COVID-19. Among these recipients, no infusion-associated adverse effects, progression of disease, COVID-19-associated hospitalizations, or death were noted. Preexposure prophylaxis with tixagevimab/cilgavimab was given to 63 HT recipients in a dedicated infusion center (40%), inpatient setting (33%), or at time of annual heart biopsy (27%). No immediate adverse events were noted. There were 11 breakthrough infections, all mild. Overall, the data suggests that HT recipients receiving mAbs have reduced rates of hospitalization, need for intensive care unit care, or death. Use of anti-SARS-CoV-2 mAbs in SOTRs is resource intensive and requires a programmatic team approach for optimal administration and to minimize any risk of disparities in their use.

Novel neutralizing SARS-CoV-2-specific mAbs offer detection of RBD linear epitopes

BACKGROUND

To stop the spread of the COVID-19 disease, it is crucial to create molecular tools to investigate and diagnose COVID-19. Current efforts focus on developing specific neutralizing monoclonal antibodies (NmAbs) elicited against the receptor-binding domain (RBD).

METHODS

In the present study, recombinant RBD (rRBD) protein was produced in E. coli, followed by immunizing mice with purified rRBD. ELISA was applied to screen the hybridomas for positive reactivity with rRBD protein. The linear and conformational epitopes of the mAbs were subsequently identified using western blot. Finally, the reactivity, affinity, and neutralization activity of the purified mAbs were evaluated using ELISA.

RESULTS

All mAbs exhibited similar reactivity trends towards both eukaryotic RBD and prokaryotic rRBD in ELISA. Among them, 2E7-D2 and 2B4-G8 mAbs demonstrated higher reactivity than other mAbs. Additionally, in western blot assays, these two mAbs could detect reducing and non-reducing rRBD, indicating recognition of linear epitopes. Notably, five mAbs effectively blocked rRBD- angiotensin-converting enzyme 2 (ACE2) interaction, while two high-affinity mAbs exhibited potent neutralizing activity against eukaryotic RBD.

CONCLUSION

In the current study, we generated and characterized new RBD-specific mAbs using the hybridoma technique that recognized linear and conformational epitopes in RBD with neutralization potency. Our mAbs are novel candidates for diagnosing and treating SARS-CoV-2.