scholarly journals In vitro evaluation of therapeutic antibodies against a SARS-CoV-2 Omicron B.1.1.529 isolate

2022 ◽  
Author(s):  
Franck Touret ◽  
Cecile Baronti ◽  
Hawa Sophia Bouzidi ◽  
Xavier de Lamballerie
Keyword(s):  
Monoclonal Antibodies ◽  
Significant Loss ◽  
The Other ◽  
Clinical Strain ◽  
Significant Activity ◽  
Therapeutic Antibodies ◽  
Combination Therapies ◽  
Fold Reduction ◽  
Rapid Spread

The emergence and rapid spread of the Omicron variant of SARS-CoV-2, which has more than 30 substitutions in the spike glycoprotein, compromises the efficacy of currently available vaccines and therapeutic antibodies. Using a clinical strain of the Omicron variant, we analyzed the neutralizing power of eight currently used monoclonal antibodies compared to the ancestral B.1 BavPat1 D614G strain. We observed that six of these antibodies have lost their ability to neutralize the Omicron variant. Of the antibodies still having neutralizing activity, Sotrovimab/Vir-7831 shows the smallest reduction in activity, with a factor change of 3.1. Cilgavimab/AZD1061 alone shows a reduction in efficacy of 15.8, resulting in a significant loss of activity for the Evusheld cocktail (42.6 fold reduction) in which the other antibody, Tixagevimab, does not retain significant activity against Omicron. Our results suggest that the clinical efficacy of the initially proposed doses should be rapidly evaluated and the possible need to modify doses or propose combination therapies should be considered.

scholarly journals Possible Future Monoclonal Antibody (mAb)-Based Therapy against Arbovirus Infections

2013 ◽  
Vol 2013 ◽  
pp. 1-21 ◽  
Author(s):  
Giuseppe Sautto ◽  
Nicasio Mancini ◽  
Giacomo Gorini ◽  
Massimo Clementi ◽  
Roberto Burioni
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Side Effects ◽  
Antiviral Activity ◽  
The Other ◽  
Viral Escape ◽  
Passive Immunotherapy ◽  
Medical Need

More than 150 arboviruses belonging to different families are known to infect humans, causing endemic infections as well as epidemic outbreaks. Effective vaccines to limit the occurrence of some of these infections have been licensed, while for the others several new immunogens are under development mostly for their improvements concerning safety and effectiveness profiles. On the other hand, specific and effective antiviral drugs are not yet available, posing an urgent medical need in particular for emergency cases. Neutralizing monoclonal antibodies (mAbs) have been demonstrated to be effective in the treatment of several infectious diseases as well as in preliminaryin vitroandin vivomodels of arbovirus-related infections. Given their specific antiviral activity as well-tolerated molecules with limited side effects, mAbs could represent a new therapeutic approach for the development of an effective treatment, as well as useful tools in the study of the host-virus interplay and in the development of more effective immunogens. However, before their use as candidate therapeutics, possible hurdles (e.g., Ab-dependent enhancement of infection, occurrence of viral escape variants) must be carefully evaluated. In this review are described the main arboviruses infecting humans and candidate mAbs to be possibly used in a future passive immunotherapy.

Efficacy of a ciprofloxacin/amikacin combination against planktonic and biofilm cultures of susceptible and low-level resistant Pseudomonas aeruginosa

2019 ◽  
Vol 74 (11) ◽  
pp. 3252-3259 ◽  
Author(s):  
Anaïs Soares ◽  
Kévin Alexandre ◽  
Fabien Lamoureux ◽  
Ludovic Lemée ◽  
François Caron ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Biofilm ◽  
The Other ◽  
Clinical Strain ◽  
Bacterial Reduction ◽  
Low Level ◽  
Mechanical Dispersion ◽  
Resistant Mutants ◽  
High Level

Abstract Background Eradicating bacterial biofilm without mechanical dispersion remains a challenge. Combination therapy has been suggested as a suitable strategy to eradicate biofilm. Objectives To evaluate the efficacy of a ciprofloxacin/amikacin combination in a model of in vitro Pseudomonas aeruginosa biofilm. Methods The antibacterial activity of ciprofloxacin and amikacin (alone, in combination and successively) was evaluated by planktonic and biofilm time–kill assays against five P. aeruginosa strains: PAO1, a WT clinical strain and three clinical strains overexpressing the efflux pumps MexAB-OprM (AB), MexXY-OprM (XY) and MexCD-OprJ (CD), respectively. Amikacin MIC was 16 mg/L for XY and ciprofloxacin MIC was 0.5 mg/L for CD. The other strains were fully susceptible to ciprofloxacin and amikacin. The numbers of total and resistant cells were determined. Results In planktonic cultures, regrowth of high-level resistant mutants was observed when CD was exposed to ciprofloxacin alone and XY to amikacin alone. Eradication was obtained with ciprofloxacin or amikacin in the other strains, or with the combination in XY and CD strains. In biofilm, bactericidal reduction after 8 h followed by a mean 4 log10 cfu/mL plateau in all strains and for all regimens was noticed. No regrowth of resistant mutants was observed whatever the antibiotic regimen. The bacterial reduction obtained with a second antibiotic used simultaneously or consecutively was not significant. Conclusions The ciprofloxacin/amikacin combination prevented the emergence of resistant mutants in low-level resistant strains in planktonic cultures. Biofilm persister cells were not eradicated, either with monotherapy or with the combination.

TSH receptor structure

1987 ◽  
Vol 116 (1_Suppl) ◽  
pp. S166-S172 ◽  
Author(s):  
John Chan ◽  
Pilar Santisteban ◽  
Michele De Luca ◽  
Osamu Isozaki ◽  
Evelyn Grollman ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Low Ph ◽  
The Other ◽  
Tsh Receptor ◽  
Cross Linking ◽  
Thyroid Cells ◽  
Autoimmune Thyroid ◽  
Receptor Structure ◽  
Rat Thyroid

Abstract. When solubilized, radiolabelled membrane preparations from FRTL-5 rat thyroid cells are applied to TSH affinity columns, two separate peaks of protein can be eluted by high salts/high pH and low pH buffers, respectively. Immunoprecipitation with monoclonal antibodies to the TSH receptor shows that both peaks contain proteins related to the TSH receptor. If extracts were from cells grown without TSH, one peak has a ~ 300 K and the other a ~ 70 K protein the 70 K protein can be derived from the purified 300 K protein in vitro. A 50 and 20 K protein can be derived from the 70 K protein. If extracts are from cells grown with TSH, the peaks contain a multiplicity of additional immunoprecipitable bands of ~ 200, 175, 130, 90, 50, 20 K etc. These bands are shown to result from the ability of TSH to increase the synthesis (3–4-fold) and degradation (2–3-fold) of the 300 and 70 K proteins. The 300/70 K protein fractions are reactive with monoclonal autoimmune thyroid stimulating antibodies and contain a specific disialo ganglioside. The ganglioside migrates near GM2, i.e., like a lower order ganglioside, and contains fucose. In translation experiments, the monoclonal antibodies to the TSH receptor identify a single mRNA component which produces a protein of ~ 220 K. This protein is not present in thyroid cells which have no functional TSH receptor and which cannot be surface labelled with monoclonal antibodies to the TSH receptor. The data thus indicate that the multiplicity of TSH binding proteins demonstrated in many labs may be breakdown products of a receptor which is synthesized by a single message but has both 330 and 70 K forms and is tightly complexed with a specific thyroid ganglioside. The 70 K form is composed of ~ 50 and ~ 20 K fragments seen in TSH cross-linking studies.

In vitro affinity maturation of HuCAL antibodies: complementarity determining region exchange and RapMAT technology

Immunotherapy ◽  
2009 ◽  
Vol 1 (4) ◽  
pp. 571-583
Author(s):  
Josef Prassler ◽  
Stefan Steidl ◽  
Stefanie Urlinger
Keyword(s):  
Monoclonal Antibodies ◽  
Affinity Maturation ◽  
Optimization Techniques ◽  
Human Diseases ◽  
Therapeutic Antibodies ◽  
Naturally Occurring ◽  
Human Immunoglobulins ◽  
Antibody Libraries ◽  
Complementarity Determining Region

Monoclonal antibodies gain ever-increasing importance in the treatment of human diseases across a broad range of indications. Diverse technologies currently exist, which are used to generate recombinant therapeutic antibodies that are basically indistinguishable from naturally occurring human immunoglobulins. We describe how human combinatorial antibody libraries are used together with unique optimization techniques to produce such therapeutically relevant proteins, for instance in the areas of oncology and inflammation.

Monoclonal Antibodies to Human Fibrin: Interaction with other Animal Fibrins

1996 ◽  
Vol 75 (04) ◽  
pp. 595-599 ◽  
Author(s):  
Tracey Edgell ◽  
F McEvoy ◽  
P Webbon ◽  
P J Gaffney
Keyword(s):  
Monoclonal Antibodies ◽  
Dissociation Constant ◽  
Dissociation Constants ◽  
The Other ◽  
Limited Data ◽  
Thrombolytic Agents ◽  
Thrombus Imaging ◽  
Fibrin Clots

SummaryFour monoclonal antibodies have previously been raised in our laboratory for possible use in thrombus imaging and the targeting of thrombolytic agents. These antibodies were raised to various human fibrin-related immunogens and each antibody had been selected for its specificity towards fibrin and not fibrinogen. To study further these antibodies in animal circulation models both in vivo and in vitro, their selectivity towards human fibrin as opposed to other animal fibrins was examined. In this study dissociation constants for each antibody with each of six species fibrins (human, baboon, pig, dog, sheep, and rabbit) were estimated using both fibrin clots and monolayers. Some limited data were also obtained with Sepharose-fibrin. Of the antibodies two (denoted 12B3B10 and 12B3A11) are seen to bind almost exclusively to human fibrin with dissociation constants of about 8 × 10−10 M using fibrin clots and monolayers. These same two mabs bound to baboon fibrin with a dissociation constant of 2 × 10−9 M, while neither displayed significant levels of binding to the fibrins from dog, pig, sheep and rabbit. The other two antibodies investigated (1H10 and 5F3) were found to bind well to fibrins of human, baboon, pig and dog, with dissociation constants in the range of 1.4-4.2 × 10−9 M. However neither 1H10 nor 5F3 displayed significant recognition of sheep and rabbit fibrins. Both 1H10 and 5F3 were also found by means of competitive ELISA’s to retain their selectivity to baboon, dog and pig fibrins in the presence of their respective fibrinogens.

scholarly journals Impact of the N501Y substitution of SARS-CoV-2 Spike on neutralizing monoclonal antibodies targeting diverse epitopes

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Lin Cheng ◽  
Shuo Song ◽  
Bing Zhou ◽  
Xiangyang Ge ◽  
Jiazhen Yu ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Binding Affinity ◽  
Neutralizing Antibodies ◽  
Therapeutic Antibodies ◽  
Wild Type ◽  
Neutralization Activity ◽  
Neutralizing Activity ◽  
Rapid Spread ◽  
Global Concern

AbstractThe emergence and rapid spread of the B.1.1.7 lineage (VOC-202012/01) SARS-CoV-2 variant has aroused global concern. The N501Y substitution is the only mutation in the interface between the RBD of B.1.1.7 and ACE2, raising concerns that its recognition by neutralizing antibodies may be affected. Here, we assessed the neutralizing activity and binding affinity of a panel of 12 monoclonal antibodies against the wild type and N501Y mutant SARS-CoV-2 pseudovirus and RBD protein, respectively. We found that the neutralization activity and binding affinity of most detected antibodies (10 out of 12) were unaffected, although the N501Y substitution decreased the neutralizing and binding activities of CB6 and increased that of BD-23. These findings could be of value in the development of therapeutic antibodies.

scholarly journals In-vitro screening of antihelmintic and antibacterial activity of malvastrum coromandelianum leaves

2021 ◽  
pp. 4-7
Author(s):  
Tirupathi Rao Annavarapu ◽  
Pragna Malavika B ◽  
Aravinda Swami P
Keyword(s):  
Antibacterial Activity ◽  
Anthelmintic Activity ◽  
Ethanolic Extract ◽  
The Other ◽  
Gram Negative Bacteria ◽  
Significant Activity ◽  
Zone Of Inhibition ◽  
Gram Negative ◽  
Malvastrum Coromandelianum

The main objective of the work is to investigate the antithelmintic and antibacterial activity of the Malvastrumcoromandelianum leaves. The extract was tested for antithelmintic activity against adult Indian earthworm and also tested for antibacterial activity against the gram positive bacteriaS.aureus,B.subtilis and gram negative bacteria against E.Coli, P.aerugenosa, P.putida.The anthelmintic activity was observed at 100mg/ml with reference to standardAlbendazole(10mg/ml).The maximum antibacterial activity was observed in S.aureus at 500mg/ml with of zone of inhibition17 mm and next is S.aureus, the best antibacterial activity was observed against P.aerugenosa and P.putidawith 15 mm of zone of inhibition. The zone of inhibition of extract was compared with standard Gentamycin 25 µg/ml. The extract shows significant activity against the other bacterial pathogens. From the results, it was concluded that the ethanolic extract of Malvastrumcoromandelianum leaves have anthelmintic and antibacterial activity.

scholarly journals Monoclonal Antibodies to Distinct Sites on Herpes Simplex Virus (HSV) Glycoprotein D Block HSV Binding to HVEM

1998 ◽  
Vol 72 (5) ◽  
pp. 3595-3601 ◽  
Author(s):  
Anthony V. Nicola ◽  
Manuel Ponce de Leon ◽  
Ruliang Xu ◽  
Wangfang Hou ◽  
J. Charles Whitbeck ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Cho Cells ◽  
Chinese Hamster ◽  
The Other ◽  
Cell Group ◽  
Glycoprotein D ◽  
Simplex Virus

HVEM (for herpesvirus entry mediator) is a member of the tumor necrosis factor receptor superfamily and mediates entry of many strains of herpes simplex virus (HSV) into normally nonpermissive Chinese hamster ovary (CHO) cells. We used sucrose density centrifugation to demonstrate that purified HSV-1 KOS virions bind directly to a soluble, truncated form of HVEM (HVEMt) in the absence of any other cell-associated components. Therefore, HVEM mediates HSV entry by serving as a receptor for the virus. We previously showed that soluble, truncated forms of HSV glycoprotein D (gDt) bind to HVEMt in vitro. Here we show that antibodies specific for gD, but not the other entry glycoproteins gB, gC, or the gH/gL complex, completely block HSV binding to HVEM. Thus, virion gD is the principal mediator of HSV binding to HVEM. To map sites on virion gD which are necessary for its interaction with HVEM, we preincubated virions with gD-specific monoclonal antibodies (MAbs). MAbs that recognize antigenic sites Ib and VII of gD were the only MAbs which blocked the HSV-HVEM interaction. MAbs from these two groups failed to coprecipitate HVEMt in the presence of soluble gDt, whereas the other anti-gD MAbs coprecipitated HVEMt and gDt. Previous mapping data indicated that site VII includes amino acids 11 to 19 and site Ib includes 222 to 252. The current experiments indicate that these sites contain residues important for HSV binding to HVEM. Group Ib and VII MAbs also blocked HSV entry into HVEM-expressing CHO cells. These results suggest that the mechanism of neutralization by these MAbs is via interference with the interaction between gD in the virus and HVEM on the cell. Group Ia and II MAbs failed to block HSV binding to HVEM yet still neutralized HVEM-mediated entry, suggesting that these MAbs block entry at a step other than HVEM binding.

scholarly journals Fine Specificity Epitope Analysis by HX-MS Identifies Contact Points on Ricin Toxin Recognized by Protective Monoclonal Antibodies

2018 ◽  
Author(s):  
Greta Van Slyke ◽  
Siva Krishna Angalakurthi ◽  
Ronald T. Toth ◽  
David J Vance ◽  
Yinghui Rong ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Hydrogen Exchange ◽  
The Other ◽  
Back Side ◽  
Exchange Mass Spectrometry ◽  
Contact Points ◽  
Protein Toxin ◽  
Control And Prevention

AbstractRicin is a fast-acting protein toxin classified by the Centers for Disease Control and Prevention as a biothreat agent. In this report we describe five new mouse monoclonal antibodies (mAbs) directed against an immunodominant region, so-called epitope cluster II, on the surface of ricin’s ribosome-inactivating enzymatic subunit, RTA. The five mAbs were tested alongside four previously described cluster II-specific mAbs for their capacity to passively protect mice against 10 × LD50 ricin challenge by injection. Only three of the mAbs (LE4, PH12 and TB12) afforded protection over the seven-day study period. Neither binding affinity nor in vitro toxin-neutralizing activity could fully account for LE4, PH12 and TB12’s potent in vivo activity relative to the other six mAbs. However, epitope mapping studies by hydrogen exchange-mass spectrometry (HX-MS) revealed that LE4, PH12 and TB12 shared common contact points (i.e., “strong” protection by HX-MS) on RTA that encompassed residues 154-164 and 62-69, which correspond to RTA α-helices D-E and β-strands d-e, respectively, located on the back side of RTA relative to the active site. The other six mAbs recognized overlapping epitopes on RTA but none shared the same HX-MS profile as LE4, PH12 and TB12. A high-density competition ELISA with a panel of ricin-specific single domain camelid antibodies (VHHs) indicated that even though LE4, PH12 and TB12 make contact with similar secondary motifs, they ultimately approach RTA different from angles. These results underscore how subtle differences in epitope specificity have significant impacts on the antibody functionality in vivo and have important implications in the design of immune-based countermeasures against ricin.

scholarly journals The influence of purified recombinant human heavy-subunit and light- subunit ferritins on colony formation in vitro by granulocyte- macrophage and erythroid progenitor cells

Blood ◽  
1986 ◽  
Vol 68 (6) ◽  
pp. 1257-1263 ◽  
Author(s):  
HE Broxmeyer ◽  
L Lu ◽  
DC Bicknell ◽  
DE Williams ◽  
S Cooper ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Progenitor Cells ◽  
Inhibitory Activity ◽  
Colony Formation ◽  
Mouse Bone Marrow ◽  
Significant Activity ◽  
Erythroid Progenitor ◽  
Erythroid Progenitor Cells ◽  
Normal Human

Abstract Purified recombinant human heavy subunit (rHF, acidic) and recombinant human light subunit (rLF, basic) ferritins were assessed for their effects in vitro on colony formation by normal human granulocyte- macrophage (CFU-GM) and erythroid (BFU-E) progenitor cells. The purity of the samples was confirmed by electrophoresis in both nondenaturing and denaturing conditions and silver staining. Concentrations of 10(-8) to 10(-10) mol/L rHF caused an approximately 40% significant decrease in colony formation. Some significant activity was detected at 10(-11) mol/L, and activity was lost at 10(-12) mol/L. In contrast, rLF had no significant activity at 10(-8) to 10(-16) mol/L. rHF was significantly active against mouse bone marrow CFU-GM to concentrations as low as 10(- 8) to 10(-9) mol/L. The inhibitory activity of rHF was inactivated with three different monoclonal antibodies recognizing the heavy subunit of ferritin, but not with two monoclonal antibodies recognizing the light subunit of ferritin. The inhibitory activity of rHF was similar in the absence or presence of serum, monocytes, and T lymphocytes. We and others have shown an association of a glycosylated natural acidic isoferritin (AIF) with inhibitory activity, but since the rHF was expressed in Escherichia coli and did not bind to concanavalin A, glycosylation of AIF is not an absolute prerequisite for this activity. These results demonstrate that rHF has suppressive activity in vitro and substantiate our original observations using purified natural acidic isoferritins.

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