scholarly journals Structural Basis for Potent Cross-Neutralizing Human Monoclonal Antibody Protection against Lethal Human and Zoonotic Severe Acute Respiratory Syndrome Coronavirus Challenge

2008 ◽  
Vol 82 (7) ◽  
pp. 3220-3235 ◽  
Author(s):  
Barry Rockx ◽  
Davide Corti ◽  
Eric Donaldson ◽  
Timothy Sheahan ◽  
Konrad Stadler ◽  
...  
Keyword(s):  
Weight Loss ◽  
Severe Acute Respiratory Syndrome ◽  
Human Monoclonal Antibody ◽  
Clinical Signs ◽  
Structural Basis ◽  
Lethal Challenge ◽  
Neutralizing Activity ◽  
Escape Mutants ◽  
Passive Vaccination

ABSTRACT Severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2002, and detailed phylogenetic and epidemiological analyses have suggested that it originated from animals. The spike (S) glycoprotein has been identified as a major component of protective immunity, and 23 different amino acid changes were noted during the expanding epidemic. Using a panel of SARS-CoV recombinants bearing the S glycoproteins from isolates representing the zoonotic and human early, middle, and late phases of the epidemic, we identified 23 monoclonal antibodies (MAbs) with neutralizing activity against one or multiple SARS-CoV spike variants and determined the presence of at least six distinct neutralizing profiles in the SARS-CoV S glycoprotein. Four of these MAbs showed cross-neutralizing activity against all human and zoonotic S variants in vitro, and at least three of these were mapped in distinct epitopes using escape mutants, structure analyses, and competition assays. These three MAbs (S109.8, S227.14, and S230.15) were tested for use in passive vaccination studies using lethal SARS-CoV challenge models for young and senescent mice with four different homologous and heterologous SARS-CoV S variants. Both S227.14 and S230.15 completely protected young and old mice from weight loss and virus replication in the lungs for all viruses tested, while S109.8 completely protected mice from weight loss and clinical signs in the presence of viral titers. We conclude that a single human MAb can confer broad protection against lethal challenge with multiple zoonotic and human SARS-CoV isolates, and we identify a robust cocktail formulation that targets distinct epitopes and minimizes the likely generation of escape mutants.

scholarly journals Miltefosine Administration in Cats with Refractory Sporotrichosis

2018 ◽  
Vol 46 (1) ◽  
pp. 7
Author(s):  
Francina Dos Santos Silva ◽  
Simone Carvalho dos Santos Cunha ◽  
Andrea Regina de Souza Baptista ◽  
Vivian Dos Santos Baptista ◽  
Kássia Valéria Gomes Coelho da Silva ◽  
...  
Keyword(s):  
Weight Loss ◽  
Sporothrix Schenckii ◽  
Clinical Signs ◽  
Public Health Problem ◽  
Parasite Load ◽  
Small Population ◽  
Fungal Culture ◽  
Cutaneous Lesions

Background: Sporotrichosis is a zoonosis caused by fungi of the Sporothrix schenckii complex. Cats have important zoonotic potential due to the high parasite load found in the cutaneous lesions. Refractory cases to antifungal therapy are increasing, becoming a public health problem. Miltefosine is a drug with high in vitro activity against Sporothrix brasiliensis. However, this efficacy has not been confirmed in vivo yet and administration has not been studied in the feline species. This study aimed to evaluate the effectiveness and safety of miltefosine administration in cats with resistant sporotrichosis.Materials, Methods & Results: Ten cats with refractory sporotrichosis were included in this study. Inclusion criteria were previous diagnosis for sporotrichosis associated with therapy with oral antifungals (itraconazole and/or potassium iodide) for more than one year, followed by one of these conditions: incomplete clinical remission, worsening of disease during treatment or recurrence after conventional treatment. Cats underwent clinical and dermatological examinations. Data on lifestyle and previous treatments were provided by the owners. Fungal culture and histochemical techniques were performed in all cats before miltefosine treatment. Blood samples were collected before and during the study for laboratory tests, such as blood count, blood urea nitrogen (BUN), serum creatinine, alanine aminotransferase (ALT) and alkaline phosphatase, as well as serology for Feline Immunodeficiency (FIV) and Feline Leukemia (FeLV). Miltefosine was prescribed at a dosage of 2 mg/kg orally every 24 h. The animals were monitored by phone during the whole process and reassessed on days 0, 15, 30 and 45 of the treatment. Out of 10 cats, lesions were present on the nose in nine, ears in four, periocular areas in one and limbs in four. One cat received treatment for 45 days, six for 30 days, one for 21 days, one for 15 days and one for 3 days. One cat showed no response to the treatment and nine showed disease progression. Hyporexia and weight loss were the most frequent clinical signs related to miltefosine treatment, followed by sialorrhea, vomiting and diarrhea. Few adverse effects on hematology and biochemistry (mainly renal and hepatic parameters) were observed during the study. Hematocrit decrease was observed in four animals. However, only one cat had hematocrit decrease below normal values (anemia), which was already present before miltefosine administration. Other cats had a decrease of five points. Three cats showed elevation in leucometria and four in plasma protein. In relation to renal and hepatic biochemistry, one animal showed a BUN increase and another one showed a transient increase in ALT. Two animals started the treatment with increased ALT but had no problems during the study and values decreased even during the miltefosine administration.Discussion: Although two cats showed sialorrhea, most owners did not report difficulty in administering the drug orally, representing an advantage of this medication. Weight loss, secondary to gastrointestinal changes, was the most clinically relevant alteration. The most frequent hematological alteration was hematocrit decrease and only the animal that started the study with 20% hematocrit ended the study with anemia. Renal and hepatic parameters were not significant in the cats of this study. Miltefosine did not lead to sporotrichosis remission in this small population of cats, which reveals that, despite its in vitro efficacy against Sporothrix spp., the drug is not effective in vivo in the feline species. Further studies are needed to investigate the efficacy of this drug in a larger number of cats, and possible reasons for its in vivo ineffectiveness.

scholarly journals Escape from Human Monoclonal Antibody Neutralization Affects In Vitro and In Vivo Fitness of Severe Acute Respiratory Syndrome Coronavirus

2010 ◽  
Vol 201 (6) ◽  
pp. 946-955 ◽  
Author(s):  
Barry Rockx ◽  
Eric Donaldson ◽  
Matthew Frieman ◽  
Timothy Sheahan ◽  
Davide Corti ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Severe Acute Respiratory Syndrome ◽  
Human Monoclonal Antibody ◽  
Antibody Neutralization

scholarly journals Antibodies with potent and broad neutralizing activity against antigenically diverse and highly transmissible SARS-CoV-2 variants

2021 ◽  
Author(s):  
Lingshu Wang ◽  
Tongqing Zhou ◽  
Yi Zhang ◽  
Eun Sung Yang ◽  
Chaim A. Schramm ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Therapeutic Antibodies ◽  
Resistance Development ◽  
Neutralizing Activity ◽  
Escape Mutants

AbstractThe emergence of highly transmissible SARS-CoV-2 variants of concern (VOC) that are resistant to therapeutic antibodies highlights the need for continuing discovery of broadly reactive antibodies. We identify four receptor-binding domain targeting antibodies from three early-outbreak convalescent donors with potent neutralizing activity against 12 variants including the B.1.1.7 and B.1.351 VOCs. Two of them are ultrapotent, with sub-nanomolar neutralization titers (IC50 <0.0006 to 0.0102 μg/mL; IC80 < 0.0006 to 0.0251 μg/mL). We define the structural and functional determinants of binding for all four VOC-targeting antibodies, and show that combinations of two antibodies decrease the in vitro generation of escape mutants, suggesting potential means to mitigate resistance development. These results define the basis of therapeutic cocktails against VOCs and suggest that targeted boosting of existing immunity may increase vaccine breadth against VOCs.One Sentence SummaryUltrapotent antibodies from convalescent donors neutralize and mitigate resistance of SARS-CoV-2 variants of concern.

scholarly journals Deletion of the Gene for the Type I Interferon Inhibitor I329L from the Attenuated African Swine Fever Virus OURT88/3 Strain Reduces Protection Induced in Pigs

Vaccines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 262 ◽  
Author(s):  
Ana Luisa Reis ◽  
Lynnette C. Goatley ◽  
Tamara Jabbar ◽  
Elisabeth Lopez ◽  
Anusyah Rathakrishnan ◽  
...  
Keyword(s):  
Type I Interferon ◽  
African Swine Fever Virus ◽  
Clinical Signs ◽  
African Swine Fever ◽  
Type I ◽  
Lethal Challenge ◽  
Host Innate Immune Response ◽  
Antibody Levels

Live attenuated vaccines are considered to be the fastest route to the development of a safe and efficacious African swine fever (ASF) vaccine. Infection with the naturally attenuated OURT88/3 strain induces protection against challenge with virulent isolates from the same or closely related genotypes. However, adverse clinical signs following immunisation have been observed. Here, we attempted to increase the OURT88/3 safety profile by deleting I329L, a gene previously shown to inhibit the host innate immune response. The resulting virus, OURT88/3ΔI329L, was tested in vitro to evaluate the replication and expression of type I interferon (IFN) and in vivo by immunisation and lethal challenge experiments in pigs. No differences were observed regarding replication; however, increased amounts of both IFN-β and IFN-α were observed in macrophages infected with the deletion mutant virus. Unexpectedly, the deletion of I329L markedly reduced protection against challenge with the virulent OURT88/1 isolate. This was associated with a decrease in both antibody levels against VP72 and the number of IFN-γ-producing cells in the blood of non-protected animals. Furthermore, a significant increase in IL-10 levels in serum was observed in pigs immunised with OURT88/3ΔI329L following challenge. Interestingly, the deletion of the I329L gene failed to attenuate the virulent Georgia/2007 isolate.

scholarly journals Antibody Pressure by a Human Monoclonal Antibody Targeting the 2009 Pandemic H1N1 Virus Hemagglutinin Drives the Emergence of a Virus with Increased Virulence in Mice

mBio ◽  
2012 ◽  
Vol 3 (3) ◽  
Author(s):  
Christopher D. O’Donnell ◽  
Leatrice Vogel ◽  
Amber Wright ◽  
Suman R. Das ◽  
Jens Wrammert ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Receptor Binding ◽  
H1n1 Virus ◽  
Human Monoclonal Antibody ◽  
Antigenic Drift ◽  
Pandemic H1n1 ◽  
Binding Properties ◽  
Immune Pressure ◽  
Escape Mutants

ABSTRACTIn 2009, a novel H1N1 influenza A virus (2009 pH1N1) emerged and caused a pandemic. A human monoclonal antibody (hMAb; EM4C04), highly specific for the 2009 pH1N1 virus hemagglutinin (HA), was isolated from a severely ill 2009 pH1N1 virus-infected patient. We postulated that under immune pressure with EM4C04, the 2009 pH1N1 virus would undergo antigenic drift and mutate at sites that would identify the antibody binding site. To do so, we infected MDCK cells in the presence of EM4C04 and generated 11 escape mutants, displaying 7 distinct amino acid substitutions in the HA. Six substitutions greatly reduced MAb binding (K123N, D131E, K133T, G134S, K157N, and G158E). Residues 131, 133, and 134 are contiguous with residues 157 and 158 in the globular domain structure and contribute to a novel pH1N1 antibody epitope. One mutation near the receptor binding site, S186P, increased the binding affinity of the HA to the receptor. 186P and 131E are present in the highly virulent 1918 virus HA and were recently identified as virulence determinants in a mouse-passaged pH1N1 virus. We found that pH1N1 escape variants expressing these substitutions enhanced replication and lethality in mice compared to wild-type 2009 pH1N1 virus. The increased virulence of these viruses was associated with an increased affinity for α2,3 sialic acid receptors. Our study demonstrates that antibody pressure by an hMAb targeting a novel epitope in the Sa region of 2009 pH1N1 HA is able to inadvertently drive the development of a more virulent virus with altered receptor binding properties. This broadens our understanding of antigenic drift.IMPORTANCEInfluenza viruses accumulate amino acid substitutions to evade the antibody response in a process known as antigenic drift, making it necessary to vaccinate against influenza annually. Mapping human monoclonal antibody (hMAb) epitopes is a necessary step towards understanding antigenic drift in humans. We defined the specificity of an hMAb that specifically targeted the 2009 pH1N1 virus and describe a novel epitope. In addition, we identified a previously unappreciated potential for antibody escape to enhance the pathogenicity of a virus. The escape mutation that we identified within vitroimmune pressure was independently reported by other investigators usingin vivoselection in nonimmune mice. Althoughin vitrogeneration of escape mutants is unlikely to recapitulate antigenic drift in its entirety, the data demonstrate that pressure by a human monoclonal antibody targeting a novel epitope in the hemagglutinin of the 2009 pandemic H1N1 virus can inadvertently drive the development of escape mutants, of which a subset have increased virulence and altered receptor binding properties.

scholarly journals Ménétrier-like disease in a Pointer with concurrent granulomatous gastritis, helicobacteriosis and leishmaniosis: a case report

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
E. Lagerstedt ◽  
T. Spillmann ◽  
N. Airas ◽  
L. Solano-Gallego ◽  
S. Kilpinen
Keyword(s):  
Weight Loss ◽  
Palliative Treatment ◽  
Human Monoclonal Antibody ◽  
Mucous Cell ◽  
Clinical Signs ◽  
Surgical Removal ◽  
Full Thickness ◽  
Granulomatous Gastritis ◽  
Gastric Biopsies ◽  
Mucosal Folds

Abstract Background Ménétrier-like disease is a rare hypertrophic canine gastropathy, reported in only seven dogs. Clinical signs are vomiting, anorexia and weight loss. Macroscopically, giant cerebriform gastric mucosal folds are typically seen in the corpus and fundus of the stomach. Histopathologically, fundic mucous cell hyperplasia and loss of parietal and chief cells are typical. Case presentation A nine-year-old spayed female Pointer had a history of intermittent vomiting, marked weight loss and hypoalbuminaemia. A gastroduodenoscopy was performed three times within three months with macroscopic changes remaining the same. The gastric mucosa of the corpus, fundus and proximal antrum was markedly irregular, with cerebriform mucosal folds. In the first gastric biopsies, histopathology revealed a moderate granulomatous gastritis, with a severe manifestation of Helicobacter-like organisms. Treatment for Helicobacter spp. decreased the vomiting slightly. The dog was diagnosed with concurrent leishmaniosis; the conventional anti-Leishmania treatment decreased the vomiting moderately, the hypoalbuminaemia resolved and the dog gained weight back to a normal body condition. Granulomatous gastritis was not present in the gastric biopsies after these treatments. The dog increased vomiting when palliative treatment (maropitant citrate, ondansetron and esomeprazole) was discontinued, and thus, full-thickness biopsies of the stomach were taken and Ménétrier-like disease was diagnosed. The affected area was too large to be surgically removed; thus, palliative treatment was reinstated. The dog remained clinically well 39 months after the first clinical presentation. Conclusions This is the first report of Ménétrier-like disease in a dog with a simultaneous manifestation of granulomatous gastritis, helicobacteriosis and leishmaniosis. The clinical signs decreased after treatment of helicobacteriosis and leishmaniosis, but vomiting remained probably as a sign of Ménétrier-like disease. Treatment options for dogs are surgical removal of the abnormal area or palliative treatment. In humans, promising results for a cure have been shown with cetuximab treatment, a human monoclonal antibody, but no canine antibody is commercially available yet. The dog here was doing well 39 months after first presentation, which is the longest reported survival time for Ménétrier-like disease with only palliative treatment in dogs. Full-thickness biopsies are preferred in macroscopic hypertrophic lesions of the stomach for better assessment of Ménétrier-like disease.

scholarly journals Evaluation of Human Monoclonal Antibody 80R for Immunoprophylaxis of Severe Acute Respiratory Syndrome by an Animal Study, Epitope Mapping, and Analysis of Spike Variants

2005 ◽  
Vol 79 (10) ◽  
pp. 5900-5906 ◽  
Author(s):  
Jianhua Sui ◽  
Wenhui Li ◽  
Anjeanette Roberts ◽  
Leslie J. Matthews ◽  
Akikazu Murakami ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Amino Acid ◽  
Severe Acute Respiratory Syndrome ◽  
Human Monoclonal Antibody ◽  
Neutralizing Antibody ◽  
Index Patient ◽  
Binding Domain ◽  
S Protein

ABSTRACT In this report, the antiviral activity of 80R immunoglobulin G1 (IgG1), a human monoclonal antibody against severe acute respiratory syndrome coronavirus (SARS-CoV) spike (S) protein that acts as a viral entry inhibitor in vitro, was investigated in vivo in a mouse model. When 80R IgG1 was given prophylactically to mice at doses therapeutically achievable in humans, viral replication was reduced by more than 4 orders of magnitude to below assay limits. The essential core region of S protein required for 80R binding was identified as a conformationally sensitive fragment (residues 324 to 503) that overlaps the receptor ACE2-binding domain. Amino acids critical for 80R binding were identified. In addition, the effects of various 80R-binding domain amino acid substitutions which occur in SARS-like-CoV from civet cats, and which evolved during the 2002/2003 outbreak and in a 2003/2004 Guangdong index patient, were analyzed. The results demonstrated that the vast majority of SARS-CoVs are sensitive to 80R. We propose that by establishing the susceptibility and resistance profiles of newly emerging SARS-CoVs through early S1 genotyping of the core 180-amino-acid neutralizing epitope of 80R, an effective immunoprophylaxis strategy with 80R should be possible in an outbreak setting. Our study also cautions that for any prophylaxis strategy based on neutralizing antibody responses, whether by passive or active immunization, a genotyping monitor will be necessary for effective use.

scholarly journals Recombinant Pseudorabies Virus with TK/gE Gene Deletion and Flt3L Co-Expression Enhances the Innate and Adaptive Immune Response via Activating Dendritic Cells

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 691
Author(s):  
Lun Yao ◽  
Qiao Hu ◽  
Siqi Chen ◽  
Tong Zhou ◽  
Xuexiang Yu ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Neutralizing Antibodies ◽  
Pseudorabies Virus ◽  
Gene Deletion ◽  
Viral Evolution ◽  
Clinical Signs ◽  
Adaptive Immune Response ◽  
Lethal Challenge ◽  
Recombinant Pseudorabies Virus

Owing to viral evolution and recombination, emerging pseudorabies virus (PRV) strains have caused unprecedented outbreaks in swine farms even when the pigs were previously vaccinated, which might indicate that traditional vaccines were unable to provide effective protection. The development of safe and efficacious vaccines presents prospects to minimize the clinical signs and eventually eradicate the infection. In this study, we used an emerging PRV strain, HNX, as the parental strain to construct a recombinant PRV with TK/gE gene deletion and Fms-related tyrosine kinase 3 ligand (Flt3L) expression, named HNX-TK−/gE−-Flt3L. HNX-TK−/gE−-Flt3L enhanced the maturation of bone marrow derived dendritic cells (DCs) in vitro. Significantly more activated DCs were detected in HNX-TK−/gE−-Flt3L-immunized mice compared with those immunized with HNX-TK−/gE−. Subsequently, a remarkable increase of neutralizing antibodies, gB-specific IgG antibodies, and interferon-gamma (IFN-γ) was observed in mice vaccinated with HNX-TK−/gE−-Flt3L. In addition, a lower mortality and less histopathological damage were observed in HNX-TK−/gE−-Flt3L vaccinated mice with upon PRV lethal challenge infection. Taken together, our results revealed the potential of Flt3L as an ideal adjuvant that can activate DCs and enhance protective immune responses and support the further evaluation of HNX-TK−/gE−-Flt3L as a promising PRV vaccine candidate.

scholarly journals Increased in vitro neutralizing activity of SARS-CoV-2 IgA1 dimers compared to monomers and IgG

2021 ◽  
Vol 118 (44) ◽  
pp. e2107148118
Author(s):  
Lin Sun ◽  
Somanath Kallolimath ◽  
Roman Palt ◽  
Karin Stiasny ◽  
Patrick Mayrhofer ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Severe Acute Respiratory Syndrome ◽  
Nicotiana Benthamiana ◽  
Structural Features ◽  
Antigen Binding ◽  
Glycosylation Profile ◽  
Neutralizing Activity ◽  
Human Proteins

Here, we expressed two neutralizing monoclonal antibodies (Abs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; H4 and B38) in three formats: IgG1, IgA1 monomers (m), and IgA1 dimers (d) in glycoengineered Nicotiana benthamiana plants. All six Ab variants assembled properly and exhibited a largely homogeneous glycosylation profile. Despite modest variation in antigen binding between Ab formats, SARS-CoV-2 neutralization (NT) potency significantly increased in the following manner: IgG1 < IgA1-m < IgA1-d, with an up to 240-fold NT increase of dimers compared to corresponding monomers. Our results underscore that both IgA’s structural features and multivalency positively impact NT potency. In addition, they emphasize the versatile use of plants for the rapid expression of complex human proteins.

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