Journal: The Journal of Biological Chemistry

Article Title: Engineering the fragment crystallizable (Fc) region of human IgG1 multimers and monomers to fine-tune interactions with sialic acid-dependent receptors

doi: 10.1074/jbc.M117.795047

Figure Lengend Snippet: Binding of IgG1-Fc variants to glycan receptors. A , mutants lacking the Asn-297 glycan are severely restricted in their capacity to bind DC-SIGN by ELISA. The addition of an N -linked sugar at position 221 results in proteins with a reduced capacity to bind DC-SIGN compared with their equivalent variants in which Asn-221 is absent. B , the hypersialylated D221N mutants bind Siglec-1. No binding was observed with the N297A/N563A glycan-deficient mutant ( error bars represent standard deviations around the mean value, n = 2 independent experiments).

Article Snippet: The same ELISA protocol used to detect DC-SIGN binding was used for human Siglec-1, Siglec-4, and Siglec-3 (Sino Biologicals).

Techniques: Binding Assay, Enzyme-linked Immunosorbent Assay, Mutagenesis

Journal: The Journal of Biological Chemistry

Article Title: Engineering the fragment crystallizable (Fc) region of human IgG1 multimers and monomers to fine-tune interactions with sialic acid-dependent receptors

doi: 10.1074/jbc.M117.795047

Figure Lengend Snippet: Model showing the contribution of different N -linked glycan and cysteine residues on Fc stoichiometry. The presence of Cys-575 allows optimal disulfide bonding between tail pieces of monomeric-Fcs. The tail piece glycan Asn-563 controls the number of monomeric tails that fit into the central corona (five to six in the case of hexa-Fc) while still allowing Cys-309 interdisulfide bridge formation. Cys-575 allows disulfide bonding between tail pieces of different monomers, but the absence of the Asn-563 glycan (the N563A mutant) allows many more tail pieces (up to twelve in the case of dodecamers) to fit into the central corona while still allowing disulfide bond formation through Cys-309 and/or Cys-575. The absence of Cys-575 prevents disulfide bonding between tail pieces, thereby generating sialylated monomers at Asn-563. The additional Asn-563 tail piece glycan in these monomers must explain the increased binding seen to Siglec-1 ( , A and B , and inset in this figure). The bulkier Asn-563 glycan with its predicted overall negative charge may lead to repulsion between two monomers, thus preventing disulfide bond formation between two Cys-309 residues in each monomeric Fc. The loss of both Asn-563 and Cys-575 (the N563A/C575A mutant) means that the observed laddered multimers must arise through Cys-309–mediated disulfide bonding in the Cγ2 domain. The presence of monomers, dimers, trimers, tetramers, pentamers, hexamers, and other intermediates in this mutant ( C ) suggests that these structures arise through a different mechanism, most likely via the sequential addition of 25-kDa half-mer Fc units at Cys-309. The lack of observable ladders with the L448STOP mutant implies that other amino acids in the tail piece are involved in bringing about monomer interactions that then facilitate disulfide bonding through either Cys-309 and/or Cys-575. Monomers with glycans located at both the N- and C-terminal ends of the Fc (Asn-221 and Asn-563) may allow for binding to receptors in cis as shown ( inset ).

Article Snippet: The same ELISA protocol used to detect DC-SIGN binding was used for human Siglec-1, Siglec-4, and Siglec-3 (Sino Biologicals).

Techniques: Mutagenesis, Binding Assay

Journal: The Journal of Biological Chemistry

Article Title: Engineering the fragment crystallizable (Fc) region of human IgG1 multimers and monomers to fine-tune interactions with sialic acid-dependent receptors

doi: 10.1074/jbc.M117.795047

Figure Lengend Snippet: Binding of monomeric IgG1-Fc glycan variants to sialic acid-binding immunoglobulin-type lectins (Siglecs) with specificity for α2,3-linked sialic acid. A , the C575A monomer binds Siglec-1. B , the D221N/C575A monomer binds Siglec-1 and Siglec-4. ELISA as described under “Experimental procedures” with receptors coated down at 2 μg/ml and Fc-fragments at 20 μg/ml in TMS buffer ( error bars represent standard deviations around the mean value, n = 2 independent experiments).

Article Snippet: The same ELISA protocol used to detect DC-SIGN binding was used for human Siglec-1, Siglec-4, and Siglec-3 (Sino Biologicals).

Techniques: Binding Assay, Enzyme-linked Immunosorbent Assay

Journal: Journal of translational medicine

Article Title: Unraveling resistance mechanisms in anti-CD19 chimeric antigen receptor-T therapy for B-ALL: a novel in vitro model and insights into target antigen dynamics.

doi: 10.1186/s12967-024-05254-z

Figure Lengend Snippet: Fig. 5 Observation of CD19-BBζ-CAR expression in relapsed Nalm-6 cells and salvage treatment. A Detection of FMC63 and CD247 transcripts and 4-1BB gene of CAR in CD19+ Nalm-6 (red) and relapsed CD19− Nalm-6 cells (blue) by qRT-PCR. Data of left bar graph represent the relative quantification using ACTB as the internal reference. Error bars represent s.d. The data are the representative of three independent experiments. B Expression of CD19 and CAR on CD19+ Nalm-6 cells and relapsed CD19− Nalm-6 cells analyzed by flow cytometry (representative of 3 experiments). Merge Graphs, the blue dots represent CD19− Nalm-6 cells and the red dots represent Nalm-6 cells. C Confocal imaging of Nalm-6 cells and relapsed CD19− Nalm-6 cells using Alexa Flour 488-conjugated anti-CD19 antibody (green), Alexa Flour 647-conjugated anti-CAR19 antibody (red), and DAPI (blue). D Lentiviral integration sites of CAR transduced Nalm-6 cells were analyzed by linear-amplification mediated PCR (LAM-PCR) and visualized with Circos plots. The integration sites across the genome and genomic features were shown from outer to inner circle: (1) cytogenetic bands; (2) genes that harbor these integration sites along with a bar chart showing the reads of integration sites; (3) the distribution of integration sites, with colored circles representing different gene functional regions of the host sequence: purple for promoter region, green for intron region, and red for distal intergenic region. E Phenotype changes of Nalm-6 cells transduced with small amount of CD19 CAR lentiviruses detected by flow cytometry over time. Gating was based on the same cells stained with isotype-matched antibody. F Dynamics of CD19− B phenotype in relapsed cells after co-culture with different ratios (5×, 20×) of Nalm-6 cells. Gating was based on the same cells stained with isotype-matched antibody. G Relapsed CD19− Nalm-6 cells were tested by qPCR specific for VSV-G sequence. H Comparison of in vitro efficacy of CD19-, CD22-, CD19/CD22- and CD22×CD19- CAR T cells. Cocultures with the relapsed cells were performed at 1:5, 1:1, and 5:1 E: T ratios, and lysis efficacies were detected by the LDH release assay Declarations

Article Snippet: The cells were then washed twice and stained with phycoerythrin (PE) streptavidin (BD bioscience, USA) for 15 min. CART-22 cells and CART-22/19 cells were washed once and incubated with CD22 Fc Alexa Fluor® 647 Protein (R&D Systems, USA) for 15 min. To detect in vitro cytotoxicity of CART-19 cells, transduced and untransduced T cells were co-cultured with Nalm-6 cells (total 1 × 106 cells) at E: T ratios (0.2:1, 0.5:1, 1:1, 5:1) for 6, 24 and 72 h. Cells were pipetted to incubate with antibodies for 30 min at room temperature in the dark and washed twice with PBS.

Techniques: Expressing, Quantitative RT-PCR, Quantitative Proteomics, Flow Cytometry, Imaging, Amplification, Functional Assay, Sequencing, Transduction, Staining, Co-Culture Assay, Comparison, In Vitro, Lysis, Lactate Dehydrogenase Assay

Journal: Molecular Cancer

Article Title: A review of the clinical efficacy of FDA-approved antibody‒drug conjugates in human cancers

doi: 10.1186/s12943-024-01963-7

Figure Lengend Snippet: Overview of FDA-approved ADC drugs

Article Snippet: Developed by AstraZeneca and granted FDA approval in 2018, MP is a recombinant immunotoxin comprising moxetumomab targeting CD22, a 38 kDa fragment of pseudomonas exotoxin A, and the linker mc–VC–PABC.

Techniques:

Journal: bioRxiv

Article Title: Efficient and robust NK-Cell transduction with Baboon Envelope pseudotyped lentivector: a major tool for immunotherapy

doi: 10.1101/625285

Figure Lengend Snippet: (A) Schematic representation of the different LVs used for NK-cell transduction using BaEV-LV (relative scale according to size in base pairs). (B) Percentage of transduced NKAES cells using BaEV-LVs coding for an anti-CD22 CAR (n=9). (C) Flow cytometry plot representative of CAR-CD22 expression after NK-cell transduction with BaEV-LVs. (D) Cytotoxic assays against either parental (n=7) or CD19/22 KO -RS4;11 cells (B-ALL; n=2) using CAR-CD22-NK-cells (p<0.0001; 2-way ANOVA test with Bonferroni correction). (E) Cytotoxic assays against parental (n=7) or CD19/CD22 KO RS4;11 B-ALL cells (n=2) using NK-cells transduced with a dual CAR (3 rd construct illustrated in A) (p<0.0001; 2-way ANOVA test with Bonferroni correction). Data are presented as the mean ± SEM. *p<0.05; **p<0.001, ***p<0.0001

Article Snippet: To detect CAR-expression, cells were incubated with 2 µl Siglec2(CD22)-Fc chimera (50 mg/ml, R&D) for 30 minutes at 4°C, washed and stained with anti-Fc-PE (Jackson Immune), anti-CD56-APC and anti-CD3-FITC (Biolegend).

Techniques: Transduction, Flow Cytometry, Expressing, Construct