FMC63 scFv in complex with soluble CD19
Ontology highlight
ABSTRACT:
SUBMITTER: Joel R Meyerson
PROVIDER: EMPIAR-11441 | biostudies-other |
REPOSITORIES: biostudies-other
Publications
CD19 CAR antigen engagement mechanisms and affinity tuning.
He Changhao C Mansilla-Soto Jorge J Khanra Nandish N Hamieh Mohamad M Bustos Victor V Paquette Alice J AJ Garcia Angus Andreina A Shore Derek M DM Rice William J WJ Khelashvili George G Sadelain Michel M Meyerson Joel R JR
Science immunology 20230303 81
Chimeric antigen receptor (CAR) T cell therapy relies on T cells that are guided by synthetic receptors to target and lyse cancer cells. CARs bind to cell surface antigens through an scFv (binder), the affinity of which is central to determining CAR T cell function and therapeutic success. CAR T cells targeting CD19 were the first to achieve marked clinical responses in patients with relapsed/refractory B cell malignancies and to be approved by the U.S. Food and Drug Administration (FDA). We rep ...[more]
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Project description: Not available
| EMPIAR-11442 | biostudies-other
Project description:Second-generation anti-CD19-chimeric antigen receptor T cells (anti-CD19-CAR2 T cells) are effective for treating B-cell malignancies; however, anti-CD19-CAR2 T cells can induce human anti-mouse immune responses because anti-CD19 single-chain variable fragment (scFv) in the CAR molecules is derived from a murine FMC63 (mFMC63) monoclonal antibody. Consequently, the persistence of mFMC63-CAR2 T cells and their therapeutic efficiency in patients are decreased, which results in tumor relapse. In an attempt to remedy this shortcoming, we generated a new anti-CD19-CAR T cells containing fully human anti-CD19 scFv (Hu1E7-CAR4 T cells) to pre-clinically evaluate and compare with mFMC63-CAR4 T cells. The human anti-CD19 scFv (Hu1E7) was isolated from a human scFv phage display library and fused to the hinge region of CD8α, the transmembrane domain of CD28, three intracellular costimulatory domains (CD28, 4-1BB, and CD27), and a CD3ζ signaling domain (28BB27ζ). Compared to mFMC63-CAR2 T cells (BBζ) and mFMC63-CAR3 (BB27ζ), the mFMC63-CAR4 T cells (28BB27ζ) exerted superior anti-tumor activity against Raji (CD19+) target cell. The Hu1E7-CAR4 and mFMC63-CAR4 T cells demonstrated comparable cytotoxicity and proliferation. Interestingly, compared to mFMC63-CAR4 T cells, the Hu1E7-CAR4 T cells secreted lower levels of cytokines (IFN-γ and TNF-α), which may be due to the lower binding affinity of Hu1E7-CAR4 T cells. These findings demonstrated the successfulness in creation of a new CAR T cells containing a novel fully human-derived scFv specific to CD19+ cancer cells. In vivo studies are needed to further compare the anti-tumor efficacy and safety of Hu1E7-CAR4 T cells and mFMC63-CAR4 T cells.
| S-EPMC8804167 | biostudies-literature
Project description:Novel methods are reported for evaluating and utilizing single chain fragment variable (scFv) antibodies derived from yeast-display libraries. Yeast-display was used to select scFv specific to invariant surface glycoproteins (ISG) of Trypanosoma brucei. A limiting step in the isolation of scFv from non-immune libraries is the conversion of highly active yeast-displayed scFv into soluble antibodies that can be used in standard immunoassays. Challenges include limited solubility or activity following secretion and purification of scFv. For this reason, few scFv derived from yeast-display platforms have moved into development and implementation as diagnostic reagents. To address this problem, assays were developed that employ both yeast-displayed and -secreted scFv as analytical reagents. The first is a competitive inhibition flow cytometry (CIFC) assay that detects secreted scFv by virtue of their ability to competitively inhibit the binding of biotinylated antigen to yeast-displayed scFv. The second is an epitope binning assay that uses secreted scFv to identify additional yeast-displayed scFv that bind non-overlapping or non-competing epitopes on an antigen. The epitope binning assay was used not only to identify sandwich assay pairs with yeast-displayed scFv, but also to identify active soluble scFv present in low concentration in a crude expression extract. Finally, a CIFC assay was developed that bypasses entirely the need for soluble scFv expression, by using yeast-displayed scFv to detect unlabeled antigen in samples. These methods will facilitate the continued development and practical implementation of scFv derived from yeast-display libraries.
| S-EPMC2851250 | biostudies-literature
Project description:Formation of inclusion bodies is a considerable obstacle threatening the advantages of E. coli expression system to serve as the most common and easiest system in recombinant protein production. To solve this problem, several strategies have been proposed among which application of molecular chaperones is of remarkable consideration. The aim of this study was to evaluate the effects of molecular chaperones on soluble expression of aggregation-prone humanized single chain antibody.To increase the solubility of a humanized single chain antibody (hscFv), different chaperone plasmids including PG-tf2 (GroES- GroEL- tig), ptf16 (tig) and pGro7 (GroES- GroEL) were co-expressed in BL21 cells containing pET-22b- hscFv construct. The solubility of recombinant hscFv was analyzed by SDS-PAGE. After purification of soluble hscFv by Ni-NTA column, the biological activity and cytotoxicity of the recombinant protein were tested by ELISA and MTT assay, respectively.SDS-PAGE analysis of the hscFv revealed that chaperone utility remarkably increased (up to 50%) the solubility of the protein. ELISA test and MTT assay analyses also confirmed the biological activity of the gained hscFv in reaction with A431 cells (OD value: 2.6) and inhibition of their proliferation, respectively.The results of this study revealed that co-expression of chaperones with hscFv leads to remarkable increase in the solubility of the recombinant hscFv, which could be of great consideration for large scale production of recombinant single chain antibodies.
| S-EPMC4708032 | biostudies-other
Project description:Invariant natural killer T (iNKT) cells comprise a unique lineage of CD1d-restricted lipid-reactive T lymphocytes that potently kill tumor cells and exhibit robust immunostimulatory functions. Optimal tumor-directed iNKT cell responses often require expression of the antigen-presenting molecule CD1d on tumors; however, many tumor cells downregulate CD1d and thus evade iNKT cell recognition. We generated a soluble bispecific fusion protein designed to direct iNKT cells to the site of B-cell cancers in a tumor antigen-specific but CD1d-independent manner. This fusion protein is composed of a human CD1d molecule joined to a single chain antibody FV fragment specific for CD19, an antigen widely expressed on B-cell cancers. The CD1d-CD19 fusion protein binds specifically to CD19-expressing, but not CD19-negative cells. Once loaded with the iNKT cell lipid agonist α-galactosyl ceramide (αGC), the CD1d-CD19 fusion induces robust in vitro activation of and cytokine production by human iNKT cells. iNKT cells stimulated by the αGC-loaded CD1d-CD19 fusion also strongly transactivate T-, B-, and NK-cell responses and promote dendritic cell maturation. Importantly, the αGC-loaded fusion induces robust lysis of CD19+CD1d- Epstein-Barr virus immortalized human B-lymphoblastoid cell lines that are otherwise resistant to iNKT cell killing. Consistent with these findings; administration of the αGC-loaded fusion protein controlled the growth of CD19+CD1d- tumors in vivo, suggesting that it can "link" iNKT cells and CD19+CD1d- targets in a therapeutically beneficial manner. Taken together, these preclinical studies demonstrate that this B cell-directed fusion protein can be used to effectively induce iNKT cell antitumor responses in vitro and in vivo.
| S-EPMC6418505 | biostudies-literature
Project description:The bacterial cultivation conditions for obtaining anti-TNF-α single chain variable fragment (scFv) antibody as the soluble product in E. coli was investigated.To avoid the production of inclusion bodies, the effects of lactose, IPTG, incubation time, temperature, shaking protocol, medium additives (Mg+2, sucrose), pH, osmotic and heat shocks were examined. Samples from bacterial growth conditions with promising results of soluble expression of GST-hD2 scFv were affinity purified and quantified by SDS-PAGE and image processing for further evaluation.The results showed that cultivation in LB medium under induction by low concentrations of lactose and incubation at 10 °C led to partial solubilization of the expressed anti-TNF-α scFv (GST-hD2). Other variables which showed promising increase in soluble expression of GST-hD2 were osmotic shock and addition of magnesium chloride. Furthermore, addition of sucrose to medium suppressed the expression of scFv completely. The other finding was that the addition of sorbitol decreased the growth rate of bacteria.It can be concluded that low cultivation temperature in the presence of low amount of inducer under a long incubation time or addition of magnesium chloride are the most effective environmental factors studied for obtaining the maximum solubilization of GST-hD2 recombinant protein.
| S-EPMC4729350 | biostudies-other
Project description:The soluble membrane attack complex (sMAC, a.k.a., sC5b-9 or TCC) is generated on activation of complement and contains the complement proteins C5b, C6, C7, C8, C9 together with the regulatory proteins clusterin and/or vitronectin. sMAC is a member of the MACPF/cholesterol-dependent-cytolysin superfamily of pore-forming molecules that insert into lipid bilayers and disrupt cellular integrity and function. sMAC is a unique complement activation macromolecule as it is comprised of several different subunits. To date no complement-mediated function has been identified for sMAC. sMAC is present in blood and other body fluids under homeostatic conditions and there is abundant evidence documenting changes in sMAC levels during infection, autoimmune disease and trauma. Despite decades of scientific interest in sMAC, the mechanisms regulating its formation in healthy individuals and its biological functions in both health and disease remain poorly understood. Here, we review the structural differences between sMAC and its membrane counterpart, MAC, and examine sMAC immunobiology with respect to its presence in body fluids in health and disease. Finally, we discuss the diagnostic potential of sMAC for diagnostic and prognostic applications and potential utility as a companion diagnostic.
| S-EPMC7683570 | biostudies-literature
Project description:Antibody deficiencies constitute the largest group of symptomatic primary immunodeficiency diseases. In several patients, mutations in CD19 have been found to underlie disease, demonstrating the critical role for the protein encoded by this gene in antibody responses; CD19 functions in a complex with CD21, CD81, and CD225 to signal with the B cell receptor upon antigen recognition. We report here a patient with severe nephropathy and profound hypogammaglobulinemia. The immunodeficiency was characterized by decreased memory B cell numbers, impaired specific antibody responses, and an absence of CD19 expression on B cells. The patient had normal CD19 alleles but carried a homozygous CD81 mutation resulting in a complete lack of CD81 expression on blood leukocytes. Retroviral transduction and glycosylation experiments on EBV-transformed B cells from the patient revealed that CD19 membrane expression critically depended on CD81. Similar to CD19-deficient patients, CD81-deficient patients had B cells that showed impaired activation upon stimulation via the B cell antigen receptor but no overt T cell subset or function defects. In this study, we present what we believe to be the first antibody deficiency syndrome caused by a mutation in the CD81 gene and consequent disruption of the CD19 complex on B cells. These findings may contribute to unraveling the genetic basis of antibody deficiency syndromes and the nonredundant functions of CD81 in humans.
| S-EPMC2846042 | biostudies-literature
Project description:CD19 is expressed on normal and neoplastic B cells and is a promising target for immunotherapy. However, there is still an unmet need to further develop novel therapeutic drugs for the treatment of the refractory/relapsing human CD19+ tumors. We have developed a diphtheria toxin-based anti-human CD19 immunotoxin for targeting human CD19+ tumors. We have constructed three isoforms of the CD19 immunotoxin: monovalent, bivalent, and foldback diabody. In vitro binding affinity and efficacy analysis demonstrated that the bivalent isoform had the highest binding affinity and in vitro efficacy. The in vivo efficacy of the CD19 immunotoxins was assessed using human CD19+ JeKo-1 tumor-bearing NOD/SCID IL-2 receptor γ-/- (NSG) mouse model. In these animals, CD19 immunotoxins significantly prolonged the median survival from 31 days in controls to 34, 36, and 40 days in animals receiving the monovalent isoform, foldback diabody isoform, and bivalent isoform, respectively. The bivalent CD19 immunotoxin is a promising therapeutic drug candidate for targeting relapsing/refractory human CD19+ tumors.
| S-EPMC5527461 | biostudies-other
Project description:The structure of the scFv fragment FITC-E2, obtained from a naive phage antibody scFv library derived from human donors, was determined at 2.1 A resolution in the free form and at 3.0 A in the complexed form. The wild-type (wt) scFv binds fluorescein with a K(D) of 0.75 nM. The free scFv readily crystallizes by compacting its 18 amino acid-long CDR-H3, partially occluding the binding site and further blocking access by binding to the "bottom" of a neighboring scFv molecule with a cluster of exposed aromatic residues within CDR-H3. Only upon mutating one of the residues involved in this dominant crystal contact, an exposed tryptophan in the middle of CDR-H3, crystals of the complex could be obtained. A series of alanine mutants within the putative antigen binding site, covering a range of binding affinities, were used to relate macroscopic thermodynamic and kinetic binding parameters to single-molecule disruption forces measured by AFM. The effects of the mutations on the binding properties, particularly on the fraction of binding-competent molecules within the population, cannot be fully explained by changes in the strength of local interactions. The significant conformational change of CDR-H3 between the free and the liganded form illustrates the plasticity of the binding site. An accompanying study in this issue by Curcio and colleagues presents the molecular dynamics simulation of the forced unbinding experiments and explores possible effects of the mutations on the unbinding pathway of the hapten.
| S-EPMC2253284 | biostudies-literature