RESUMO
The SARS-CoV-2 spike (S) glycoprotein contains an immunodominant receptor-binding domain (RBD) targeted by most neutralizing antibodies (Abs) in COVID-19 patient plasma. Little is known about neutralizing Abs binding to epitopes outside the RBD and their contribution to protection. Here, we describe 41 human monoclonal Abs (mAbs) derived from memory B cells, which recognize the SARS-CoV-2 S N-terminal domain (NTD) and show that a subset of them neutralize SARS-CoV-2 ultrapotently. We define an antigenic map of the SARS-CoV-2 NTD and identify a supersite (designated site i) recognized by all known NTD-specific neutralizing mAbs. These mAbs inhibit cell-to-cell fusion, activate effector functions, and protect Syrian hamsters from SARS-CoV-2 challenge, albeit selecting escape mutants in some animals. Indeed, several SARS-CoV-2 variants, including the B.1.1.7, B.1.351, and P.1 lineages, harbor frequent mutations within the NTD supersite, suggesting ongoing selective pressure and the importance of NTD-specific neutralizing mAbs for protective immunity and vaccine design.
Assuntos
Antígenos Virais/imunologia , SARS-CoV-2/imunologia , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , COVID-19/virologia , Cricetinae , Mapeamento de Epitopos , Variação Genética , Modelos Moleculares , Mutação/genética , Testes de Neutralização , Domínios Proteicos , RNA Viral/genética , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/ultraestruturaRESUMO
SARS-CoV-2 infection-which involves both cell attachment and membrane fusion-relies on the angiotensin-converting enzyme 2 (ACE2) receptor, which is paradoxically found at low levels in the respiratory tract1-3, suggesting that there may be additional mechanisms facilitating infection. Here we show that C-type lectin receptors, DC-SIGN, L-SIGN and the sialic acid-binding immunoglobulin-like lectin 1 (SIGLEC1) function as attachment receptors by enhancing ACE2-mediated infection and modulating the neutralizing activity of different classes of spike-specific antibodies. Antibodies to the amino-terminal domain or to the conserved site at the base of the receptor-binding domain, while poorly neutralizing infection of ACE2-overexpressing cells, effectively block lectin-facilitated infection. Conversely, antibodies to the receptor binding motif, while potently neutralizing infection of ACE2-overexpressing cells, poorly neutralize infection of cells expressing DC-SIGN or L-SIGN and trigger fusogenic rearrangement of the spike, promoting cell-to-cell fusion. Collectively, these findings identify a lectin-dependent pathway that enhances ACE2-dependent infection by SARS-CoV-2 and reveal distinct mechanisms of neutralization by different classes of spike-specific antibodies.
Assuntos
Anticorpos Neutralizantes/imunologia , Lectinas/metabolismo , SARS-CoV-2/metabolismo , SARS-CoV-2/patogenicidade , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Moléculas de Adesão Celular/metabolismo , Fusão Celular , Linhagem Celular , Cricetinae , Feminino , Humanos , Lectinas/imunologia , Lectinas Tipo C/metabolismo , Fusão de Membrana , Receptores de Superfície Celular/metabolismo , SARS-CoV-2/imunologia , Lectina 1 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismo , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismoRESUMO
The recent emergence of SARS-CoV-2 variants of concern1-10 and the recurrent spillovers of coronaviruses11,12 into the human population highlight the need for broadly neutralizing antibodies that are not affected by the ongoing antigenic drift and that can prevent or treat future zoonotic infections. Here we describe a human monoclonal antibody designated S2X259, which recognizes a highly conserved cryptic epitope of the receptor-binding domain and cross-reacts with spikes from all clades of sarbecovirus. S2X259 broadly neutralizes spike-mediated cell entry of SARS-CoV-2, including variants of concern (B.1.1.7, B.1.351, P.1, and B.1.427/B.1.429), as well as a wide spectrum of human and potentially zoonotic sarbecoviruses through inhibition of angiotensin-converting enzyme 2 (ACE2) binding to the receptor-binding domain. Furthermore, deep-mutational scanning and in vitro escape selection experiments demonstrate that S2X259 possesses an escape profile that is limited to a single substitution, G504D. We show that prophylactic and therapeutic administration of S2X259 protects Syrian hamsters (Mesocricetus auratus) against challenge with the prototypic SARS-CoV-2 and the B.1.351 variant of concern, which suggests that this monoclonal antibody is a promising candidate for the prevention and treatment of emergent variants and zoonotic infections. Our data reveal a key antigenic site that is targeted by broadly neutralizing antibodies and will guide the design of vaccines that are effective against all sarbecoviruses.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Antivirais/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , Anticorpos Amplamente Neutralizantes/uso terapêutico , COVID-19/prevenção & controle , SARS-CoV-2/classificação , SARS-CoV-2/imunologia , Animais , Anticorpos Monoclonais/química , Anticorpos Antivirais/química , Anticorpos Antivirais/uso terapêutico , Anticorpos Amplamente Neutralizantes/química , COVID-19/imunologia , COVID-19/virologia , Reações Cruzadas/imunologia , Modelos Animais de Doenças , Feminino , Humanos , Evasão da Resposta Imune/genética , Evasão da Resposta Imune/imunologia , Mesocricetus/imunologia , Mesocricetus/virologia , Mutação , Testes de Neutralização , SARS-CoV-2/química , SARS-CoV-2/genética , Zoonoses Virais/imunologia , Zoonoses Virais/prevenção & controle , Zoonoses Virais/virologiaRESUMO
An ideal therapeutic anti-SARS-CoV-2 antibody would resist viral escape1-3, have activity against diverse sarbecoviruses4-7, and be highly protective through viral neutralization8-11 and effector functions12,13. Understanding how these properties relate to each other and vary across epitopes would aid the development of therapeutic antibodies and guide vaccine design. Here we comprehensively characterize escape, breadth and potency across a panel of SARS-CoV-2 antibodies targeting the receptor-binding domain (RBD). Despite a trade-off between in vitro neutralization potency and breadth of sarbecovirus binding, we identify neutralizing antibodies with exceptional sarbecovirus breadth and a corresponding resistance to SARS-CoV-2 escape. One of these antibodies, S2H97, binds with high affinity across all sarbecovirus clades to a cryptic epitope and prophylactically protects hamsters from viral challenge. Antibodies that target the angiotensin-converting enzyme 2 (ACE2) receptor-binding motif (RBM) typically have poor breadth and are readily escaped by mutations despite high neutralization potency. Nevertheless, we also characterize a potent RBM antibody (S2E128) with breadth across sarbecoviruses related to SARS-CoV-2 and a high barrier to viral escape. These data highlight principles underlying variation in escape, breadth and potency among antibodies that target the RBD, and identify epitopes and features to prioritize for therapeutic development against the current and potential future pandemics.
Assuntos
Anticorpos Amplamente Neutralizantes/imunologia , COVID-19/virologia , Reações Cruzadas/imunologia , Evasão da Resposta Imune , SARS-CoV-2/classificação , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto , Idoso , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Afinidade de Anticorpos , Anticorpos Amplamente Neutralizantes/química , COVID-19/imunologia , Vacinas contra COVID-19/química , Vacinas contra COVID-19/imunologia , Linhagem Celular , Cricetinae , Epitopos de Linfócito B/química , Epitopos de Linfócito B/genética , Epitopos de Linfócito B/imunologia , Feminino , Humanos , Evasão da Resposta Imune/genética , Evasão da Resposta Imune/imunologia , Masculino , Mesocricetus , Pessoa de Meia-Idade , Modelos Moleculares , SARS-CoV-2/química , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/genética , Vacinologia , Tratamento Farmacológico da COVID-19RESUMO
BACKGROUND & AIMS: Chronic hepatitis B is a global public health problem, and coinfection with hepatitis delta virus (HDV) worsens disease outcome. Here, we describe a hepatitis B virus (HBV) surface antigen (HBsAg)-targeting monoclonal antibody (mAb) with the potential to treat chronic hepatitis B and chronic hepatitis D. METHODS: HBsAg-specific mAbs were isolated from memory B cells of HBV vaccinated individuals. In vitro neutralization was determined against HBV and HDV enveloped with HBsAg representing eight HBV genotypes. Human liver-chimeric mice were treated twice weekly with a candidate mAb starting 3 weeks post HBV inoculation (spreading phase) or during stable HBV or HBV/HDV coinfection (chronic phase). RESULTS: From a panel of human anti-HBs mAbs, VIR-3434 was selected and engineered for pre-clinical development. VIR-3434 targets a conserved, conformational epitope within the antigenic loop of HBsAg and neutralized HBV and HDV infection with higher potency than hepatitis B immunoglobulins in vitro. Neutralization was pan-genotypic against strains representative of HBV genotypes A-H. In the spreading phase of HBV infection in human liver-chimeric mice, a parental mAb of VIR-3434 (HBC34) prevented HBV dissemination and the increase in intrahepatic HBV RNA and covalently closed circular DNA. In the chronic phase of HBV infection or co-infection with HDV, HBC34 treatment decreased circulating HBsAg by >1 log and HDV RNA by >2 logs. CONCLUSIONS: The potently neutralizing anti-HBs mAb VIR-3434 reduces circulating HBsAg and HBV/HDV viremia in human liver-chimeric mice. VIR-3434 is currently in clinical development for treatment of patients with chronic hepatitis B or D. IMPACT AND IMPLICATIONS: Chronic infection with hepatitis B virus and co-infection with hepatitis D virus place approximately 290 million individuals worldwide at risk of severe liver disease and cancer. Available treatments result in low rates of functional cure or require lifelong therapy that does not eliminate the risk of liver disease. We isolated and characterized a potent human antibody that neutralizes hepatitis B and D viruses and reduces infection in a mouse model. This antibody could provide a new treatment for patients with chronic hepatitis B and D.
RESUMO
Secretory IgA (SIgA) is the most abundant antibody type in intestinal secretions where it contributes to safeguarding the epithelium from invasive pathogens like the Gram-negative bacterium, Salmonella enterica serovar Typhimurium (STm). For example, we recently reported that passive oral administration of the recombinant monoclonal SIgA antibody, Sal4, to mice promotes STm agglutination in the intestinal lumen and restricts bacterial invasion of Peyer's patch tissues. In this report, we sought to recapitulate Sal4-mediated protection against STm in human Enteroids and human intestinal organoids (HIOs) as models to decipher the molecular mechanisms by which antibodies function in mucosal immunity in the human gastrointestinal tract. We confirm that Enteroids and HIO-derived monolayers are permissive to STm infection, dependent on HilD, the master transcriptional regulator of the SPI-I type three secretion system (T3SS). Stimulation of M-like cells in both Enteroids and HIOs by the addition of RANKL further enhanced STm invasion. The apical addition of Sal4 mouse IgA, as well as recombinant human Sal4 dimeric IgA (dIgA) and SIgA resulted a dose-dependent reduction in bacterial invasion. Moreover, basolateral application of Sal4 dIgA to Enteroid and HIO monolayers gave rise to SIgA in the apical compartment via a pathway dependent on expression of the polymeric immunoglobulin receptor (pIgR). The resulting Sal4 SIgA was sufficient to reduce STm invasion of Enteroid and HIO epithelial cell monolayers by ~20-fold. Recombinant Sal4 IgG was also transported in the Enteroid and HIOs, but to a lesser degree and via a pathway dependent on the neonatal Fc receptor (FCGRT). The models described lay the foundation for future studies into detailed mechanisms of IgA and IgG protection against STm and other pathogens.
Assuntos
Imunoglobulina A , Organoides , Animais , Humanos , Imunoglobulina A/metabolismo , Imunoglobulina A Secretora , Imunoglobulina G/metabolismo , Mucosa Intestinal/metabolismo , Camundongos , Organoides/metabolismo , Salmonella typhimurium , TranscitoseRESUMO
BACKGROUND: A significant proportion of patients undergoing radical nephrectomy (RN) for clear-cell renal cell carcinoma (RCC) develop chronic kidney disease (CKD) within a few years following surgery. Chronic kidney disease has important health, social and economic impact and no predictive biomarkers are currently available. MicroRNAs (miRs) are small non-coding RNAs implicated in several pathological processes. METHODS: Primary objective of our study was to define miRs whose deregulation is predictive of CKD in patients treated with RN. Ribonucleic acid from formalin-fixed paraffin embedded renal parenchyma (cortex and medulla isolated separately) situated >3 cm from the matching RCC was tested for miR expression using nCounter NanoString technology in 71 consecutive patients treated with RN for RCC. Validation was performed by RT-PCR and in situ hybridisation. End point was post-RN CKD measured 12 months post-operatively. Multivariable logistic regression and decision curve analysis were used to test the statistical and clinical impact of predictors of CKD. RESULTS: The overexpression of miR-193b-3p was associated with high risk of developing CKD in patients undergoing RN for RCC and emerged as an independent predictor of CKD. The addition of miR-193b-3p to a predictive model based on clinical variables (including sex and estimated glomerular filtration rate) increased the sensitivity of the predictive model from 81 to 88%. In situ hybridisation showed that miR-193b-3p overexpression was associated with tubule-interstitial inflammation and fibrosis in patients with no clinical or biochemical evidence of pre-RN nephropathy. CONCLUSIONS: miR-193b-3p might represent a useful biomarker to tailor and implement surveillance strategies for patients at high risk of developing CKD following RN.
Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma de Células Renais/metabolismo , Neoplasias Renais/metabolismo , MicroRNAs/metabolismo , Nefrectomia/métodos , Carcinoma de Células Renais/fisiopatologia , Carcinoma de Células Renais/cirurgia , Taxa de Filtração Glomerular , Humanos , Neoplasias Renais/fisiopatologia , Neoplasias Renais/cirurgiaRESUMO
The transient receptor potential melastin 8 ion channel (TRPM8) is implicated in bladder sensing but limited information on TRPM8 antagonists in bladder overactivity is available. This study characterizes a new TRPM8-selective antagonist (DFL23448 [5-(2-ethyl-2H-tetrazol-5-yl)-2-(3-fluorophenyl)-1,3-thiazol-4-ol]) and evaluates it in cold-induced behavioral tests and tests on bladder function and experimental bladder overactivity in vivo in rats. DFL23448 displayed IC50 values of 10 and 21 nM in hTRPM8 human embryonic kidney 293 cells activated by Cooling Agent 10 or cold, but it had limited activity (IC50 > 10 µM) at transient receptor potential vanilloids TRPV1, TRPA1, or TRPV4 or at various G protein-coupled receptors. In rats, DFL23448 administered intravenously or orally had a half-life of 37 minutes or 4.9 hours, respectively. DLF23448 (10 mg/kg i.v.) reduced icilin-induced "wet dog-like" shakes in rats. Intravesical DFL23448 (10 mg/l), but not vehicle, increased micturition intervals, micturition volume, and bladder capacity. During bladder overactivity by intravesical prostaglandin E2 (PGE2), vehicle controls exhibited reductions in micturition intervals, micturition volumes, and bladder capacity by 37%-39%, whereas the same parameters only decreased by 12%-15% (P < 0.05-0.01 versus vehicle) in DFL23448-treated rats. In vehicle-treated rats, but not in DFL23448-treated rats, intravesical PGE2 increased bladder pressures. Intravenous DFL23448 at 10 mg/kg, but not 1 mg/kg DFL23448 or vehicle, increased micturition intervals, micturition volumes, and bladder capacity. During bladder overactivity by intravesical PGE2, micturition intervals, micturition volumes, and bladder capacity decreased in vehicle- and 1 mg/kg DFL23448-treated rats, but not in 10 mg/kg DFL23448-treated rats. Bladder pressures increased less in rats treated with DFL23448 10 mg/kg than in vehicle- or 1 mg/kg DFL23448-treated rats. DFL23448 (10 mg/kg i.v.), but not vehicle, prevented cold stress-induced bladder overactivity. Our results support a role for bladder TRPM8-mediated signals in experimental bladder overactivity.
Assuntos
Canais de Cátion TRPM/antagonistas & inibidores , Tetrazóis/farmacologia , Tiazóis/farmacologia , Bexiga Urinária Hiperativa/tratamento farmacológico , Bexiga Urinária/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Temperatura Baixa , Dinoprostona/metabolismo , Feminino , Células HEK293 , Meia-Vida , Humanos , Masculino , Ratos , Ratos Sprague-Dawley , Receptores Acoplados a Proteínas G/efeitos dos fármacos , Tetrazóis/farmacocinética , Tetrazóis/uso terapêutico , Tiazóis/farmacocinética , Tiazóis/uso terapêutico , Micção/efeitos dos fármacos , Urodinâmica/efeitos dos fármacosRESUMO
Warm renal ischemia performed during partial nephrectomy has been found to be associated with kidney disease. Since endogenous ouabain (EO) is a neuro-endocrine hormone involved in renal damage, we evaluated the role of EO in renal ischemia-reperfusion injury (IRI). We measured plasma and renal EO variations and markers of glomerular and tubular damage (nephrin, KIM-1, Kidney-Injury-Molecule-1, α1 Na-K ATPase) and the protective effect of the ouabain inhibitor, rostafuroxin. We studied five groups of rats: (1) normal; (2) infused for eight weeks with ouabain (30 µg/kg/day, OHR) or (3) saline; (4) ouabain; or (5) saline-infused rats orally treated with 100 µg/kg/day rostafuroxin for four weeks. In group 1, 2-3 h after IRI, EO increased in ischemic kidneys while decreased in plasma. Nephrin progressively decreased and KIM-1 mRNA increased starting from 24 h. Ouabain infusion (group 2) increased blood pressure (from 111.7 to 153.4 mmHg) and ouabain levels in plasma and kidneys. In OHR ischemic kidneys at 120 h from IRI, nephrin, and KIM-1 changes were greater than those detected in the controls infused with saline (group 3). All these changes were blunted by rostafuroxin treatment (groups 4 and 5). These findings support the role of EO in IRI and suggest that rostafuroxin pre-treatment of patients before partial nephrectomy with warm ischemia may reduce IRI, particularly in those with high EO.
Assuntos
Androstanóis/uso terapêutico , Nefropatias/tratamento farmacológico , Nefropatias/metabolismo , Rim/efeitos dos fármacos , Ouabaína/metabolismo , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/metabolismo , Animais , Rim/metabolismo , Rim/patologia , Nefropatias/sangue , Nefropatias/patologia , Nefrectomia , Ouabaína/sangue , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/patologiaRESUMO
AIMS: To study micturition and bladder overactivity in female rats after chronic treatment with the fatty acid amide hydrolase (FAAH) inhibitor oleoyl ethyl amide (OEtA). METHODS: Sprague-Dawley rats received daily subcutaneous injections of OEtA (0.3 mg/kg), or vehicle for 2 weeks. Cystometries, organ bath studies, Western blot, and immunofluorescence were then used. Expressions of FAAH, cannabinoid 1 and 2 receptors (CB1 and CB2), mitogen-activated protein kinase (MAPK), vesicular acetyl choline-transporter protein (VAChT), and calcitonin gene-related peptide (CGRP) were evaluated. RESULTS: At baseline, OEtA-treated rats had higher values (P < 0.05) of micturition intervals (MI) and volumes (MV), bladder capacity (BC), threshold pressure, and flow pressure than vehicle controls. Intravesical PGE2 reduced MI, MV, and BC, and increased basal pressure and the area under the curve in all rats. However, these urodynamic parameters were altered less by intravesical PGE2 in OEtA-treated rats (P < 0.05 vs. vehicle controls). Compared to vehicle controls, detrusor from OEtA-treated rats had larger contractions to carbachol at 10-0.1 µM, but no difference in Emax was recorded. FAAH, CB1, CB2, VAChT, or CGRP was similarly expressed in bladders from all rats. In separate experiments, intravesical OEtA increased mucosal expression of phosphorylated MAPK. CONCLUSIONS: Chronic FAAH inhibition altered sensory urodynamic parameters and reduced bladder overactivity. Even if it cannot be excluded that OEtA may act on central nervous sensory pathways to contribute to these effects, the presence of FAAH and CB receptors in the bladder and activation of intracellular signals for CB receptors by intravesical OEtA suggest a local role for FAAH in micturition control.
Assuntos
Amidoidrolases/antagonistas & inibidores , Ácidos Oleicos/farmacologia , Ácidos Oleicos/uso terapêutico , Bexiga Urinária Hiperativa/tratamento farmacológico , Animais , Feminino , Ratos , Ratos Sprague-DawleyRESUMO
Porcine deltacoronavirus (PDCoV) spillovers were recently detected in children with acute undifferentiated febrile illness, underscoring recurrent zoonoses of divergent coronaviruses. To date, no vaccines or specific therapeutics are approved for use in humans against PDCoV. To prepare for possible future PDCoV epidemics, we isolated human spike (S)-directed monoclonal antibodies from transgenic mice and found that two of them, designated PD33 and PD41, broadly neutralized a panel of PDCoV variants. Cryo-electron microscopy structures of PD33 and PD41 in complex with the PDCoV receptor-binding domain and S ectodomain trimer provide a blueprint of the epitopes recognized by these mAbs, rationalizing their broad inhibitory activity. We show that both mAbs inhibit PDCoV by competitively interfering with host APN binding to the PDCoV receptor-binding loops, explaining the mechanism of viral neutralization. PD33 and PD41 are candidates for clinical advancement, which could be stockpiled to prepare for possible future PDCoV outbreaks.
RESUMO
PURPOSE: We assessed whether spinal inhibition of the cannabinoid degrading enzyme FAAH would have urodynamic effects in normal rats and rats with bladder overactivity induced by partial urethral obstruction or prostaglandin E2. We also determined the expression of FAAH, and the cannabinoid receptors CB1 and CB2 in the sacral spinal cord. MATERIALS AND METHODS: We used 44 rats for functional (cystometry) and Western blot experiments. The FAAH inhibitor oleoyl ethyl amide (3 to 300 nmol) was administered intrathecally (subarachnoidally) or intravenously. The expression of FAAH and CB1/CB2 receptors was determined by Western blot. RESULTS: Oleoyl ethyl amide given intrathecally affected micturition in normal rats and rats with bladder overactivity but effects were more pronounced in the latter. In normal rats oleoyl ethyl amide only decreased micturition frequency, while it decreased frequency and bladder pressures in rats with bladder overactivity. Intravenous oleoyl ethyl amide (3 to 300 nmol) had no urodynamic effect. FAAH and CB1/CB2 receptors were expressed in the rat sacral spinal cord. The expression of CB1/CB2 receptors but not FAAH was higher in obstructed than in normal rats. CONCLUSIONS: FAAH inhibition in the sacral spinal cord by oleoyl ethyl amide resulted in urodynamic effects in normal rats and rats with bladder overactivity. The spinal endocannabinoid system may be involved in normal micturition control and it appears altered when there is bladder overactivity.
Assuntos
Amidoidrolases/metabolismo , Ácidos Oleicos/farmacologia , Medula Espinal/efeitos dos fármacos , Bexiga Urinária Hiperativa/tratamento farmacológico , Amidoidrolases/antagonistas & inibidores , Amidoidrolases/genética , Análise de Variância , Animais , Western Blotting , Dinoprostona/farmacologia , Modelos Animais de Doenças , Feminino , Injeções Intravenosas , Injeções Espinhais , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Receptor CB2 de Canabinoide/metabolismo , Valores de Referência , Medula Espinal/metabolismo , Obstrução Uretral/tratamento farmacológico , Micção/efeitos dos fármacos , Urodinâmica/efeitos dos fármacosRESUMO
UNLABELLED: It has previously been shown that elocalcitol might protect bladder contractile function in experimental models and that elocalcitol has beneficial effects in patients with LUTS. In humans, elocalcitol was demonstrated with a very good safety profile but only exhibited limited efficacy on LUTS in patients with BPH and overactive bladder (OAB). Recent reports show that therapies with antimuscarinics, when combined with other drugs in clinical use, might perform better than a monotherapy in managing LUTS. It is not known how a combination of elocalcitol and an antimuscarinic performs on bladder dysfunction. The present study suggests that concomitant use of secosteroids and antimuscarinics has additive beneficial effects on obstruction-related functional changes in an experimental model. If confirmed also in a clinical setting, this could allow for individual dose adjustments to improve efficacy in obstruction-related LUTS, and possibly reduce unwanted adverse activities by antimuscarinic therapy. OBJECTIVE: To evaluate the effects of tolterodine on urodynamics in elocalcitol- or vehicle-treated rats with partial urethral obstruction (PUO). MATERIALS AND METHODS: After ethical approval, 20 female Sprague-Dawley rats were subjected to PUO and treated (gavage) for 14 days (once daily) with elocalcitol (75 µg/kg) or vehicle. Cystometries were performed on day 15 in awake rats before and after i.v. administration of tolterodine (1, 10 and 100 µg/kg). RESULTS: No differences in bladder weights or body/bladder weight ratios were noted between groups. Tolterodine dose-dependently increased micturition intervals and volumes and bladder capacity in both elocalcitol- (n = 11) and vehicle-treated rats (n = 9). In elocalcitol-treated rats, flow pressure (FP) was dose-dependently reduced (12-20%) by tolterodine, whereas no effect on FP was noted in vehicle-treated animals (P < 0.05). Flow compliance (FC) was increased by tolterodine by 21-54% in vehicle-treated rats, and by 47-131% (P < 0.05 vs vehicle) in elocalcitol-treated animals. Maximal tension vs bladder weight was improved in elocalcitol-treated rats in comparison to vehicle (P < 0.05). The area under the curve (AUC) was reduced by tolterodine with 11-16% in vehicle-treated rats and 26-30% in elocalcitol -treated rats (P < 0.05). CONCLUSIONS: Elocalcitol-treatment improved the effects of tolterodine on bladder compliance at the start of flow. The effects of tolterodine on AUC suggest that elocalcitol exerts additional beneficial actions on PUO-induced functional changes during the filling phase of micturition. The reduction of FP and increase in FC by elocalcitol and tolterodine could have translational value and, if valid in humans, support combined therapy in benign prostatic obstruction (BPO)-related lower urinary tract symptoms (LUTS).
Assuntos
Compostos Benzidrílicos/farmacologia , Calcitriol/análogos & derivados , Cresóis/farmacologia , Antagonistas Muscarínicos/farmacologia , Fenilpropanolamina/farmacologia , Obstrução do Colo da Bexiga Urinária/tratamento farmacológico , Bexiga Urinária/efeitos dos fármacos , Vitaminas/farmacologia , Animais , Área Sob a Curva , Compostos Benzidrílicos/administração & dosagem , Calcitriol/administração & dosagem , Calcitriol/farmacologia , Cresóis/administração & dosagem , Quimioterapia Combinada/métodos , Feminino , Infusões Intravenosas , Antagonistas Muscarínicos/administração & dosagem , Fenilpropanolamina/administração & dosagem , Pressão , Ratos , Ratos Sprague-Dawley , Tartarato de Tolterodina , Obstrução do Colo da Bexiga Urinária/fisiopatologia , Urodinâmica/efeitos dos fármacos , Vitaminas/administração & dosagemRESUMO
Understanding broadly neutralizing sarbecovirus antibody responses is key to developing countermeasures against SARS-CoV-2 variants and future zoonotic sarbecoviruses. We describe the isolation and characterization of a human monoclonal antibody, designated S2K146, that broadly neutralizes viruses belonging to SARS-CoV- and SARS-CoV-2-related sarbecovirus clades which use ACE2 as an entry receptor. Structural and functional studies show that most of the virus residues that directly bind S2K146 are also involved in binding to ACE2. This allows the antibody to potently inhibit receptor attachment. S2K146 protects against SARS-CoV-2 Beta challenge in hamsters and viral passaging experiments reveal a high barrier for emergence of escape mutants, making it a good candidate for clinical development. The conserved ACE2-binding residues present a site of vulnerability that might be leveraged for developing vaccines eliciting broad sarbecovirus immunity.
Assuntos
Enzima de Conversão de Angiotensina 2/metabolismo , Anticorpos Antivirais/imunologia , Betacoronavirus/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , COVID-19/terapia , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Enzima de Conversão de Angiotensina 2/química , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Anticorpos Monoclonais/uso terapêutico , Anticorpos Antivirais/química , Anticorpos Antivirais/metabolismo , Afinidade de Anticorpos , Anticorpos Amplamente Neutralizantes/química , Anticorpos Amplamente Neutralizantes/metabolismo , Anticorpos Amplamente Neutralizantes/uso terapêutico , COVID-19/imunologia , Reações Cruzadas , Microscopia Crioeletrônica , Epitopos , Humanos , Evasão da Resposta Imune , Mesocricetus , Modelos Moleculares , Mimetismo Molecular , Mutação , Conformação Proteica , Domínios Proteicos , Receptores de Coronavírus/química , Receptores de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismoRESUMO
The coronavirus spike glycoprotein attaches to host receptors and mediates viral fusion. Using a broad screening approach, we isolated seven monoclonal antibodies (mAbs) that bind to all human-infecting coronavirus spike proteins from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immune donors. These mAbs recognize the fusion peptide and acquire affinity and breadth through somatic mutations. Despite targeting a conserved motif, only some mAbs show broad neutralizing activity in vitro against alpha- and betacoronaviruses, including animal coronaviruses WIV-1 and PDF-2180. Two selected mAbs also neutralize Omicron BA.1 and BA.2 authentic viruses and reduce viral burden and pathology in vivo. Structural and functional analyses showed that the fusion peptide-specific mAbs bound with different modalities to a cryptic epitope hidden in prefusion stabilized spike, which became exposed upon binding of angiotensin-converting enzyme 2 (ACE2) or ACE2-mimicking mAbs.
Assuntos
Enzima de Conversão de Angiotensina 2 , Anticorpos Monoclonais , Anticorpos Antivirais , Anticorpos Amplamente Neutralizantes , COVID-19 , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Enzima de Conversão de Angiotensina 2/química , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/isolamento & purificação , Anticorpos Amplamente Neutralizantes/imunologia , COVID-19/imunologia , Humanos , Peptídeos/imunologia , Ligação Proteica , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologiaRESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron sublineages carry distinct spike mutations resulting in escape from antibodies induced by previous infection or vaccination. We show that hybrid immunity or vaccine boosters elicit plasma-neutralizing antibodies against Omicron BA.1, BA.2, BA.2.12.1, and BA.4/5, and that breakthrough infections, but not vaccination alone, induce neutralizing antibodies in the nasal mucosa. Consistent with immunological imprinting, most antibodies derived from memory B cells or plasma cells of Omicron breakthrough cases cross-react with the Wuhan-Hu-1, BA.1, BA.2, and BA.4/5 receptor-binding domains, whereas Omicron primary infections elicit B cells of narrow specificity up to 6 months after infection. Although most clinical antibodies have reduced neutralization of Omicron, we identified an ultrapotent pan-variant-neutralizing antibody that is a strong candidate for clinical development.
Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , Formação de Anticorpos , COVID-19 , Evasão da Resposta Imune , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Humanos , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , COVID-19/imunologia , Testes de Neutralização , SARS-CoV-2/genética , SARS-CoV-2/imunologia , Memória Imunológica , Células B de Memória/imunologiaRESUMO
SARS-CoV-2 Omicron sublineages carry distinct spike mutations and represent an antigenic shift resulting in escape from antibodies induced by previous infection or vaccination. We show that hybrid immunity or vaccine boosters result in potent plasma neutralizing activity against Omicron BA.1 and BA.2 and that breakthrough infections, but not vaccination-only, induce neutralizing activity in the nasal mucosa. Consistent with immunological imprinting, most antibodies derived from memory B cells or plasma cells of Omicron breakthrough cases cross-react with the Wuhan-Hu-1, BA.1 and BA.2 receptor-binding domains whereas Omicron primary infections elicit B cells of narrow specificity. While most clinical antibodies have reduced neutralization of Omicron, we identified an ultrapotent pan-variant antibody, that is unaffected by any Omicron lineage spike mutations and is a strong candidate for clinical development.
RESUMO
As the predominant antibody type in mucosal secretions, human colostrum, and breast milk, secretory IgA (SIgA) plays a central role in safeguarding the intestinal epithelium of newborns from invasive enteric pathogens like the Gram-negative bacterium Salmonella enterica serovar Typhimurium (STm). SIgA is a complex molecule, consisting of an assemblage of two or more IgA monomers, joining (J)-chain, and secretory component (SC), whose exact functions in neutralizing pathogens are only beginning to be elucidated. In this study, we produced and characterized a recombinant human SIgA variant of Sal4, a well-characterized monoclonal antibody (mAb) specific for the O5-antigen of STm lipopolysaccharide (LPS). We demonstrate by flow cytometry, light microscopy, and fluorescence microscopy that Sal4 SIgA promotes the formation of large, densely packed bacterial aggregates in vitro. In a mouse model, passive oral administration of Sal4 SIgA was sufficient to entrap STm within the intestinal lumen and reduce bacterial invasion into gut-associated lymphoid tissues by several orders of magnitude. Bacterial aggregates induced by Sal4 SIgA treatment in the intestinal lumen were recalcitrant to immunohistochemical staining, suggesting the bacteria were encased in a protective capsule. Indeed, a crystal violet staining assay demonstrated that STm secretes an extracellular matrix enriched in cellulose following even short exposures to Sal4 SIgA. Collectively, these results demonstrate that recombinant human SIgA recapitulates key biological activities associated with mucosal immunity and raises the prospect of oral passive immunization to combat enteric diseases.
Assuntos
Imunoglobulina A Secretora , Salmonella typhimurium , Aglutinação , Humanos , Imunidade nas Mucosas , Imunoglobulina A , Recém-Nascido , Mucosa Intestinal , Tecido LinfoideRESUMO
Understanding broadly neutralizing sarbecovirus antibody responses is key to developing countermeasures effective against SARS-CoV-2 variants and future spillovers of other sarbecoviruses. Here we describe the isolation and characterization of a human monoclonal antibody, designated S2K146, broadly neutralizing viruses belonging to all three sarbecovirus clades known to utilize ACE2 as entry receptor and protecting therapeutically against SARS-CoV-2 beta challenge in hamsters. Structural and functional studies show that most of the S2K146 epitope residues are shared with the ACE2 binding site and that the antibody inhibits receptor attachment competitively. Viral passaging experiments underscore an unusually high barrier for emergence of escape mutants making it an ideal candidate for clinical development. These findings unveil a key site of vulnerability for the development of a next generation of vaccines eliciting broad sarbecovirus immunity.
RESUMO
SARS-CoV-2 entry into host cells is orchestrated by the spike (S) glycoprotein that contains an immunodominant receptor-binding domain (RBD) targeted by the largest fraction of neutralizing antibodies (Abs) in COVID-19 patient plasma. Little is known about neutralizing Abs binding to epitopes outside the RBD and their contribution to protection. Here, we describe 41 human monoclonal Abs (mAbs) derived from memory B cells, which recognize the SARS-CoV-2 S N-terminal domain (NTD) and show that a subset of them neutralize SARS-CoV-2 ultrapotently. We define an antigenic map of the SARS-CoV-2 NTD and identify a supersite recognized by all known NTD-specific neutralizing mAbs. These mAbs inhibit cell-to-cell fusion, activate effector functions, and protect Syrian hamsters from SARS-CoV-2 challenge. SARS-CoV-2 variants, including the 501Y.V2 and B.1.1.7 lineages, harbor frequent mutations localized in the NTD supersite suggesting ongoing selective pressure and the importance of NTD-specific neutralizing mAbs to protective immunity.