One-dose intradermal rabies booster enhances rabies antibody production and avidity maturation.

The incidence of rabies in Thailand reached its peak in 2018 with 18 human deaths. Preexposure prophylaxis (PrEP) vaccination is thus recommended for high-risk populations. WHO has recently recommended that patients who are exposed to a suspected rabid animal and have already been immunized against rabies should receive a 1-site intradermal (ID) injection of 0.1 mL on days 0 and 3 as postexposure prophylaxis (PEP). In Thailand, village health and livestock volunteers tasked with annual dog vaccination typically receive only a single lifetime PrEP dose and subsequent boosters solely upon confirmed animal bites. However, the adequacy of a single PrEP dose for priming and maintaining immunity in this high-risk group has not been evaluated. Therefore, our study was designed to address two key questions: (1) sufficiency of single-dose PrEP-to determine whether a single ID PrEP dose provides adequate long-term immune protection for high-risk individuals exposed to numerous dogs during their vaccination duties. (2) Booster efficacy for immune maturation-to investigate whether one or two additional ID booster doses effectively stimulate a mature and sustained antibody response in this population. The level and persistence of the rabies antibody were determined by comparing the immunogenicity and booster efficacy among the vaccination groups. Our study demonstrated that rabies antibodies persisted for more than 180 days after cost-effective ID PrEP or the 1st or the 2nd single ID booster dose, and adequate antibody levels were detected in more than 95% of participants by CEE-cELISA and 100% by indirect ELISA. Moreover, the avidity maturation of rabies-specific antibodies occurred after the 1st single ID booster dose. This smaller ID booster regimen was sufficient for producing a sufficient immune response and enhancing the maturation of anti-rabies antibodies. This safe and effective PrEP regimen and a single visit involving a one-dose ID booster are recommended, and at least one one-dose ID booster regimen could be equitably implemented in at-risk people in Thailand and other developing countries. However, an adequate antibody level should be monitored before the booster is administered.

Synthetic phage-based approach for sensitive and specific detection of Escherichia coli O157.

Escherichia coli O157 can cause foodborne outbreaks, with infection leading to severe disease such as hemolytic-uremic syndrome. Although phage-based detection methods for E. coli O157 are being explored, research on their specificity with clinical isolates is lacking. Here, we describe an in vitro assembly-based synthesis of vB_Eco4M-7, an O157 antigen-specific phage with a 68-kb genome, and its use as a proof of concept for E. coli O157 detection. Linking the detection tag to the C-terminus of the tail fiber protein, gp27 produces the greatest detection sensitivity of the 20 insertions sites tested. The constructed phage detects all 53 diverse clinical isolates of E. coli O157, clearly distinguishing them from 35 clinical isolates of non-O157 Shiga toxin-producing E. coli. Our efficient phage synthesis methods can be applied to other pathogenic bacteria for a variety of applications, including phage-based detection and phage therapy.

[The Applications of qNMR in Drug Quality Control].

NMR is well known as one of the most important methods for elucidating the structure of organic compounds. Furthermore, it has recently been recognized as a powerful tool for quantitative analysis. The quantitative NMR (qNMR) has become an official analytical method described in detail in the Japanese Pharmacopoeia. And today, it is widely applied in drug development. The qNMR method offers many new advantages over traditional and conventional quantitative analysis methods. For example, this method requires only a few milligrams of the analyte and allows absolute quantitation of the analyte without using a qualified reference standard as a control sample. Then, it can be easily applied to most chemicals without expending significant time and resources on method development. In addition, residual solvent can be determined using qNMR methods. The peak area of an NMR spectrum is directly proportional to the number of protons contributing to the resonance. Based on this principle, the residual solvent can be determined by counting the signal corresponding to the residual solvent in the sample solution. We have applied qNMR as an alternative to GC. Thus, qNMR is an innovative and promising analytical technique that is expected to make significant progress in the future. Recently, the analytical research and quality control departments have been working together to expand this technology to a wide range of areas in the pharmaceutical industry.

Harnessing a T1 Phage-Derived Spanin for Developing Phage-Based Antimicrobial Development.

The global increase in the prevalence of drug-resistant bacteria has necessitated the development of alternative treatments that do not rely on conventional antimicrobial agents. Using bacteriophage-derived lytic enzymes in antibacterial therapy shows promise; however, a thorough comparison and evaluation of their bactericidal efficacy are lacking. This study aimed to compare and investigate the bactericidal activity and spectrum of such lytic enzymes, with the goal of harnessing them for antibacterial therapy. First, we examined the bactericidal activity of spanins, endolysins, and holins derived from 2 Escherichia coli model phages, T1 and T7. Among these, T1-spanin exhibited the highest bactericidal activity against E. coli. Subsequently, we expressed T1-spanin within bacterial cells and assessed its bactericidal activity. T1-spanin showed potent bactericidal activity against all clinical isolates tested, including bacterial strains of 111 E. coli, 2 Acinetobacter spp., 3 Klebsiella spp., and 3 Pseudomonas aeruginosa. In contrast, T1 phage-derived endolysin showed bactericidal activity against E. coli and P. aeruginosa, yet its efficacy against other bacteria was inferior to that of T1-spanin. Finally, we developed a phage-based technology to introduce the T1-spanin gene into target bacteria. The synthesized non-proliferative phage exhibited strong antibacterial activity against the targeted bacteria. The potent bactericidal activity exhibited by spanins, combined with the novel phage synthetic technology, holds promise for the development of innovative antimicrobial agents.

Overcoming antibody-resistant SARS-CoV-2 variants with bispecific antibodies constructed using non-neutralizing antibodies.

A current challenge is the emergence of SARS-CoV-2 variants, such as BQ.1.1 and XBB.1.5, that can evade immune defenses, thereby limiting antibody drug effectiveness. Emergency-use antibody drugs, including the widely effective bebtelovimab, are losing their benefits. One potential approach to address this issue are bispecific antibodies which combine the targeting abilities of two antibodies with distinct epitopes. We engineered neutralizing bispecific antibodies in the IgG-scFv format from two initially non-neutralizing antibodies, CvMab-6 (which binds to the receptor-binding domain [RBD]) and CvMab-62 (targeting a spike protein S2 subunit epitope adjacent to the known anti-S2 antibody epitope). Furthermore, we created a bispecific antibody by incorporating the scFv of bebtelovimab with our anti-S2 antibody, demonstrating significant restoration of effectiveness against bebtelovimab-resistant BQ.1.1 variants. This study highlights the potential of neutralizing bispecific antibodies, which combine existing less effective anti-RBD antibodies with anti-S2 antibodies, to revive the effectiveness of antibody therapeutics compromised by immune-evading variants.

Mpox Neutralizing Antibody Response to LC16m8 Vaccine in Healthy Adults.

BACKGROUND: Vaccination against mpox (formerly known as monkeypox), an infectious disease caused by the monkeypox virus (MPXV), is needed to prevent outbreaks and consequent public health concerns. The LC16m8 vaccine, a dried cell-cultured proliferative live attenuated vaccinia virus­based vaccine, was approved in Japan against smallpox and mpox. However, its immunogenicity and efficacy against MPXV have not been fully assessed. We assessed the safety and immunogenicity of LC16m8 against MPXV in healthy adults. METHODS: We conducted a single-arm study that included 50 participants who were followed up for 168 days postvaccination. The primary end point was the neutralizing antibody seroconversion rate against MPXVs, including the Zr599 and Liberia strains, on day 28. The secondary end points included the vaccine "take" (major cutaneous reaction) rate, neutralizing titer kinetics against MPXV and vaccinia virus (LC16m8) strains, and safety outcomes. RESULTS: Seroconversion rates on day 28 were 72% (36 of 50), 70% (35 of 50), and 88% (44 of 50) against the Zr599 strain, the Liberia strain, and LC16m8, respectively. On day 168, seroconversion rates decreased to 30% (15 of 50) against the Zr599 and Liberia strains and to 76% (38 of 50) against LC16m8. The vaccine "take" (broad definition) rate on day 14 was 94% (46 of 49). Adverse events (AEs), including common solicited cutaneous reactions, occurred in 98% (45 of 48) of participants; grade 3 severity AEs occurred in 16% (8 of 50). No deaths, serious AEs, or mpox onset incidences were observed up to day 168. CONCLUSIONS: The LC16m8 vaccine generated neutralizing antibody responses against MPXV in healthy adults. No serious safety concerns occurred with LC16m8 use. (Funded by the Ministry of Health, Labour and Welfare of Japan; Japan Registry of Clinical Trials number, jRCTs031220171.)

Abaloparatide promotes bone repair of vertebral defects in ovariectomized rats by increasing bone formation.

Osteoporotic vertebral fracture (OVF) is the most common type of osteoporotic fracture and is associated with immobility and mortality. Bone anabolic agents, such as abaloparatide (ABL), are usually administered to patients with OVF to prevent subsequent fractures. Although several studies have shown that bone anabolic agents promote healing of long bone fractures, there is little evidence of their healing effect on vertebral bone fractures. In the present study, we investigated the effect of ABL on vertebral bone defects using ovariectomized (OVX) rats with vertebral body drill-hole defects, an animal model of OVF. Eight-week-old female Sprague-Dawley rats were subjected to OVX, followed by the 32-36 days of bone depletion period, once-daily subcutaneous ABL was administered to OVX rats at a dose of 30 µg/kg for a maximum of 6 weeks from the day of the vertebral defect surgery. We found that ABL significantly increased bone mineral content and improved trabecular structural parameters at the vertebral defect site. Moreover, ABL significantly increased bone strength of the defected vertebrae. Bone histochemical analysis revealed formation of thick trabecular bone networks at the defect site after ABL administration, consistent with an improvement in trabecular structural parameters by ABL. ABL increased ALPase- and PHOSPHO1-positive osteoblastic cells and ALPase/PCNA double-positive cells, indicating enhanced preosteoblast proliferation as well as bone formation at the defect site. On the other hand, ABL did not affect the number of cathepsin K-positive osteoclasts per bone surface, suggesting that ABL did not promote excessive bone resorption. Our findings suggest that ABL is useful not only for preventing secondary vertebral fractures but also for promoting bone healing in OVF.

Structural basis for cross-group recognition of an influenza virus hemagglutinin antibody that targets postfusion stabilized epitope.

Plasticity of influenza virus hemagglutinin (HA) conformation increases an opportunity to generate conserved non-native epitopes with unknown functionality. Here, we have performed an in-depth analysis of human monoclonal antibodies against a stem-helix region that is occluded in native prefusion yet exposed in postfusion HA. A stem-helix antibody, LAH31, provided IgG Fc-dependent cross-group protection by targeting a stem-helix kinked loop epitope, with a unique structure emerging in the postfusion state. The structural analysis and molecular modeling revealed key contact sites responsible for the epitope specificity and cross-group breadth that relies on somatically mutated light chain. LAH31 was inaccessible to the native prefusion HA expressed on cell surface; however, it bound to the HA structure present on infected cells with functional linkage to the Fc-mediated clearance. Our study uncovers a novel non-native epitope that emerges in the postfusion HA state, highlighting the utility of this epitope for a broadly protective antigen design.

Structural delineation and computational design of SARS-CoV-2-neutralizing antibodies against Omicron subvariants.

SARS-CoV-2 Omicron subvariants have evolved to evade receptor-binding site (RBS) antibodies that exist in diverse individuals as public antibody clones. We rationally selected RBS antibodies resilient to mutations in emerging Omicron subvariants. Y489 was identified as a site of virus vulnerability and a common footprint of broadly neutralizing antibodies against the subvariants. Multiple Y489-binding antibodies were encoded by public clonotypes and additionally recognized F486, potentially accounting for the emergence of Omicron subvariants harboring the F486V mutation. However, a subclass of antibodies broadly neutralized BA.4/BA.5 variants via hydrophobic binding sites of rare clonotypes along with high mutation-resilience under escape mutation screening. A computationally designed antibody based on one of the Y489-binding antibodies, NIV-10/FD03, was able to bind XBB with any 486 mutation and neutralized XBB.1.5. The structural basis for the mutation-resilience of this Y489-binding antibody group may provide important insights into the design of therapeutics resistant to viral escape.

Identification of IMP Dehydrogenase as a Potential Target for Anti-Mpox Virus Agents.

Mpox virus (formerly monkeypox virus [MPXV]) is a neglected zoonotic pathogen that caused a worldwide outbreak in May 2022. Given the lack of an established therapy, the development of an anti-MPXV strategy is of vital importance. To identify drug targets for the development of anti-MPXV agents, we screened a chemical library using an MPXV infection cell assay and found that gemcitabine, trifluridine, and mycophenolic acid (MPA) inhibited MPXV propagation. These compounds showed broad-spectrum anti-orthopoxvirus activities and presented lower 90% inhibitory concentrations (0.026 to 0.89 µM) than brincidofovir, an approved anti-smallpox agent. These three compounds have been suggested to target the postentry step to reduce the intracellular production of virions. Knockdown of IMP dehydrogenase (IMPDH), the rate-limiting enzyme of guanosine biosynthesis and a target of MPA, dramatically reduced MPXV DNA production. Moreover, supplementation with guanosine recovered the anti-MPXV effect of MPA, suggesting that IMPDH and its guanosine biosynthetic pathway regulate MPXV replication. By targeting IMPDH, we identified a series of compounds with stronger anti-MPXV activity than MPA. This evidence shows that IMPDH is a potential target for the development of anti-MPXV agents. IMPORTANCE Mpox is a zoonotic disease caused by infection with the mpox virus, and a worldwide outbreak occurred in May 2022. The smallpox vaccine has recently been approved for clinical use against mpox in the United States. Although brincidofovir and tecovirimat are drugs approved for the treatment of smallpox by the U.S. Food and Drug Administration, their efficacy against mpox has not been established. Moreover, these drugs may present negative side effects. Therefore, new anti-mpox virus agents are needed. This study revealed that gemcitabine, trifluridine, and mycophenolic acid inhibited mpox virus propagation and exhibited broad-spectrum anti-orthopoxvirus activities. We also suggested IMP dehydrogenase as a potential target for the development of anti-mpox virus agents. By targeting this molecule, we identified a series of compounds with stronger anti-mpox virus activity than mycophenolic acid.

High-throughput isolation of SARS-CoV-2 nucleocapsid antibodies for improved antigen detection.

SARS-CoV-2 nucleocapsid protein (NP) is the main target for COVID-19-diagnostic PCR and antigen rapid diagnostic tests (Ag-RDTs). Ag-RDTs are more convenient than PCR tests for point-of-care testing or self-testing to identify the SARS-CoV-2 antigen. The sensitivity and specificity of this method depends mainly on the affinity and specificity of NP-binding antibodies; therefore, antigen-antibody binding is key elements for the Ag-RDTs. Here, we applied the high-throughput antibody isolation platform that has been utilized to isolate therapeutic antibodies against rare epitopes. Two NP antibodies were identified to recognize non-overlapping epitopes with high affinity. One antibody specifically binds to SARS-CoV-2 NP, and the other rapidly and tightly binds to SARS-CoV-2 NP with cross-reactivity to SARS-CoV NP. Furthermore, these antibodies were compatible with a sandwich enzyme-linked immunosorbent assay that exhibited enhanced sensitivity for NP detection compared to the previously isolated NP antibodies. Thus, the NP antibody pair is applicable to more sensitive and specific Ag-RDTs, highlighting the utility of a high-throughput antibody isolation platform for diagnostics development.

Post-fusion influenza vaccine adjuvanted with SA-2 confers heterologous protection via Th1-polarized, non-neutralizing antibody responses.

Development of a universal influenza vaccine that can provide robust and long-lasting protection against heterologous infections is a global public health priority. A variety of vaccine antigens are designed to increase the antigenicity of conserved epitopes to elicit cross-protective antibodies that often lack virus-neutralizing activity. Given the contribution of antibody effector functions to cross-protection, adjuvants need to be added to modulate antibody effector functions as well as to enhance antibody quantity. We previously showed that post-fusion influenza vaccine antigens elicit non-neutralizing but cross-protective antibodies against conserved epitopes. Here, using a murine model, we comparably assessed the adjuvanticity of the newly developed SA-2 adjuvant containing a synthetic TLR7 agonist DSP-0546 and squalene-based MF59 analog as representative Th1- or Th2-type adjuvants, respectively. Both types of adjuvants in the post-fusion vaccine comparably enhanced cross-reactive IgG titers against heterologous strains. However, only SA-2 skewed the IgG subclass into the IgG2c subclass in association to its Th1-polarizing nature. SA-2-enhanced IgG2c responses exhibited antibody-dependent cellular cytotoxicity against heterologous virus strains, without cross-neutralizing activity. Eventually, the SA-2-adjuvanted vaccination provided protection against lethal infection by heterologous H3N2 and H1N1 viruses. Together, we conclude that the combination with a SA-2 is advantageous for enhancing the cross-protective capability of post-fusion HA vaccines that elicit non-neutralizing IgG antibodies.

Potent neutralizing broad-spectrum antibody against SARS-CoV-2 generated from dual-antigen-specific B cells from convalescents.

Several antibody therapeutics have been developed against SARS-CoV-2; however, they have attenuated neutralizing ability against variants. In this study, we generated multiple broadly neutralizing antibodies from B cells of convalescents, by using two types of receptor-binding domains, Wuhan strain and the Gamma variant as bait. From 172 antibodies generated, six antibodies neutralized all strains prior to the Omicron variant, and the five antibodies were able to neutralize some of the Omicron sub-strains. Structural analysis showed that these antibodies have a variety of characteristic binding modes, such as ACE2 mimicry. We subjected a representative antibody to the hamster infection model after introduction of the N297A modification, and observed a dose-dependent reduction of the lung viral titer, even at a dose of 2 mg/kg. These results demonstrated that our antibodies have certain antiviral activity as therapeutics, and highlighted the importance of initial cell-screening strategy for the efficient development of therapeutic antibodies.

CD62L expression marks SARS-CoV-2 memory B cell subset with preference for neutralizing epitopes.

Severe acute respiratory syndrome coronavirus 2-neutralizing antibodies primarily target the spike receptor binding domain (RBD). However, B cell antigen receptors (BCRs) on RBD-binding memory B (Bmem) cells have variation in the neutralizing activities. Here, by combining single Bmem cell profiling with antibody functional assessment, we dissected the phenotype of Bmem cell harboring the potently neutralizing antibodies in coronavirus disease 2019 (COVID-19)-convalescent individuals. The neutralizing subset was marked by an elevated CD62L expression and characterized by distinct epitope preference and usage of convergent VH (variable region of immunoglobulin heavy chain) genes, accounting for the neutralizing activities. Concordantly, the correlation was observed between neutralizing antibody titers in blood and CD62L+ subset, despite the equivalent RBD binding of CD62L+ and CD62L- subset. Furthermore, the kinetics of CD62L+ subset differed between the patients who recovered from different COVID-19 severities. Our Bmem cell profiling reveals the unique phenotype of Bmem cell subset that harbors potently neutralizing BCRs, advancing our understanding of humoral protection.

Saturation time of exposure interval for cross-neutralization response to SARS-CoV-2: Implications for vaccine dose interval.

Evaluating the serum cross-neutralization responses after breakthrough infection with various SARS-CoV-2 variants provides valuable insight for developing variant-proof COVID-19 booster vaccines. However, fairly comparing the impact of breakthrough infections with distinct epidemic timing on cross-neutralization responses, influenced by the exposure interval between vaccination and infection, is challenging. To compare the impact of pre-Omicron to Omicron breakthrough infection, we estimated the effects on cross-neutralizing responses by the exposure interval using Bayesian hierarchical modeling. The saturation time required to generate saturated cross-neutralization responses differed by variant, with variants more antigenically distant from the ancestral strain requiring longer intervals of 2-4 months. The breadths of saturated cross-neutralization responses to Omicron lineages were comparable in pre-Omicron and Omicron breakthrough infections. Our results highlight the importance of vaccine dosage intervals of 4 months or longer, regardless of the antigenicity of the exposed antigen, to maximize the breadth of serum cross-neutralization covering SARS-CoV-2 Omicron lineages.

Specific COVID-19 risk behaviors and the preventive effect of personal protective equipment among healthcare workers in Japan.

As coronavirus disease 2019 (COVID-19) outbreaks in healthcare facilities are a serious public health concern, we performed a case-control study to investigate the risk of COVID-19 infection in healthcare workers. We collected data on participants' sociodemographic characteristics, contact behaviors, installation status of personal protective equipment, and polymerase chain reaction testing results. We also collected whole blood and assessed seropositivity using the electrochemiluminescence immunoassay and microneutralization assay. In total, 161 (8.5%) of 1,899 participants were seropositive between August 3 and November 13, 2020. Physical contact (adjusted odds ratio 2.4, 95% confidence interval 1.1-5.6) and aerosol-generating procedures (1.9, 1.1-3.2) were associated with seropositivity. Using goggles (0.2, 0.1-0.5) and N95 masks (0.3, 0.1-0.8) had a preventive effect. Seroprevalence was higher in the outbreak ward (18.6%) than in the COVID-19 dedicated ward (1.4%). Results showed certain specific risk behaviors of COVID-19; proper infection prevention practices reduced these risks.

Systemically inoculated adjuvants stimulate pDC-dependent IgA response in local site.

The stimulation of local immunity by vaccination is desirable for controlling virus replication in the respiratory tract. However, the local immune stimulatory effects of adjuvanted vaccines administered through the non-mucosal route are poorly understood. Here, we clarify the mechanisms by which non-mucosal inoculation of adjuvants stimulates the plasmacytoid dendritic cell (pDC)-dependent immunoglobulin (Ig)A response in the lungs. After systemic inoculation with type 1 interferon (IFN)-inducing adjuvants, type 1 IFN promotes CXCL9/10/11 release from alveolar endothelial and epithelial cells and recruits CXCR3-expressing pDCs into the lungs. Because adjuvant-activated pulmonary pDCs highly express major histocompatibility complex II, cluster of differentiation 80, and cluster of differentiation 86, transplantation of such cells into the lungs successfully enhances antigen-specific IgA production by the intranasally sensitized vaccine. In contrast, pDC accumulation in the lungs and subsequent IgA production are impaired in pDC-depleted mice and Ifnar1-/- mice. Notably, the combination of systemic inoculation with type 1 IFN-inducing adjuvants and intranasal antigen sensitization protects mice against influenza virus infection due to the pDC-dependent IgA response and type I IFN response. Our results provide insights into the novel mucosal vaccine strategies using non-mucosal inoculated adjuvants.

Heterologous SARS-CoV-2 spike protein booster elicits durable and broad antibody responses against the receptor-binding domain.

The immunogenicity of mRNA vaccines has not been well studied when compared to different vaccine modalities in the context of additional boosters. Here we show that longitudinal analysis reveals more sustained SARS-CoV-2 spike receptor-binding domain (RBD)-binding IgG titers with the breadth to antigenically distinct variants by the S-268019-b spike protein booster compared to the BNT162b2 mRNA homologous booster. The durability and breadth of RBD-angiotensin-converting enzyme 2 (ACE2) binding inhibitory antibodies are pronounced in the group without systemic adverse events (AEs) after the S-268019-b booster, leading to the elevated neutralizing activities against Omicron BA.1 and BA.5 variants in the stratified group. In contrast, BNT162b2 homologous booster elicited antibodies to spike N-terminal domain in proportion to the AE scores. High-dimensional immune profiling identifies early CD16+ natural killer cell dynamics with CCR3 upregulation, as one of the correlates for the distinct anti-RBD antibody responses by the S-268019-b booster. Our results illustrate the combinational effects of heterologous booster on the immune dynamics and the durability and breadth of recalled anti-RBD antibody responses against emerging virus variants.

Potential Anti-Mpox Virus Activity of Atovaquone, Mefloquine, and Molnupiravir, and Their Potential Use as Treatments.

BACKGROUND: Mpox virus (MPXV) is a zoonotic orthopoxvirus and caused an outbreak in 2022. Although tecovirimat and brincidofovir are approved as anti-smallpox drugs, their effects in mpox patients have not been well documented. In this study, by a drug repurposing approach, we identified potential drug candidates for treating mpox and predicted their clinical impacts by mathematical modeling. METHODS: We screened 132 approved drugs using an MPXV infection cell system. We quantified antiviral activities of potential drug candidates by measuring intracellular viral DNA and analyzed the modes of action by time-of-addition assay and electron microscopic analysis. We further predicted the efficacy of drugs under clinical concentrations by mathematical simulation and examined combination treatment. RESULTS: Atovaquone, mefloquine, and molnupiravir exhibited anti-MPXV activity, with 50% inhibitory concentrations of 0.51-5.2 µM, which was more potent than cidofovir. Whereas mefloquine was suggested to inhibit viral entry, atovaquone and molnupiravir targeted postentry processes. Atovaquone was suggested to exert its activity through inhibiting dihydroorotate dehydrogenase. Combining atovaquone with tecovirimat enhanced the anti-MPXV effect of tecovirimat. Quantitative mathematical simulations predicted that atovaquone can promote viral clearance in patients by 7 days at clinically relevant drug concentrations. CONCLUSIONS: These data suggest that atovaquone would be a potential candidate for treating mpox.

Multimodal single-cell analyses of peripheral blood mononuclear cells of COVID-19 patients in Japan.

SARS-CoV-2 continues to spread worldwide. Patients with COVID-19 show distinct clinical symptoms. Although many studies have reported various causes for the diversity of symptoms, the underlying mechanisms are not fully understood. Peripheral blood mononuclear cells from COVID-19 patients were collected longitudinally, and single-cell transcriptome and T cell receptor repertoire analysis was performed. Comparison of molecular features and patients' clinical information revealed that the proportions of cells present, and gene expression profiles differed significantly between mild and severe cases; although even among severe cases, substantial differences were observed among the patients. In one severely-infected elderly patient, an effective antibody response seemed to have failed, which may have caused prolonged viral clearance. Naïve T cell depletion, low T cell receptor repertoire diversity, and aberrant hyperactivation of most immune cell subsets were observed during the acute phase in this patient. Through this study, we provided a better understanding of the diversity of immune landscapes and responses. The information obtained from this study can help medical professionals develop personalized optimal clinical treatment strategies for COVID-19.