Journal:

Article Title: CTLA-4 regulates allergen response by modulating GATA-3 protein level per cell

doi: 10.1111/j.1365-2567.2007.02537.x

Figure Lengend Snippet: Effects of in vitro CTLA-4 blockade on GATA-3 protein level/cell and frequency of IL-4-producing cells. Naive CD4+ T cells purified from the spleens of normal mice were induced to differentiate with anti-CD3 mAb, a recombinant form of CD80-Fc, IL-4 and anti-IFN-γ mAb for 3 days. Anti-CTLA-4 mAb was added in soluble form at increasing concentrations (0·1–10 μg/ml). (a) Mean fluorescence intensity for GATA-3 staining, (b) percentage of IL-4+ cells.

Article Snippet: 18 CD4 cell culture For in vitro experiments, splenic naive CD4 cells were purified from non-immunized BALB/c mice by immuno-magnetic cell sorting as previously described 19 and cultured in 24-well plates precoated with anti-CD3ε mAb (clone 145-2C11; 10 μg/ml) and/or recombinant mouse B7-1(CD80)/Fc chimeric protein (R & D Systems, cat. 740-B1; 0·33 μg/ml).

Techniques: In Vitro, Purification, Recombinant, Fluorescence, Staining

Journal: bioRxiv

Article Title: Lack of blocking activity in anti-CTLA-4 antibodies reduces toxicity, but not anti-tumor efficacy

doi: 10.1101/2021.07.12.452090

Figure Lengend Snippet: A. The ability of CTLA-4 mAbs to block binding of CD80 or CD86 was measured using a plate-based ELISA method. CTLA-4 was used to coat the plate, then after the antibody samples were incubated, His-tagged CD80 or CD86 was added, and the amount of ligand able to bind to CTLA-4 was measured. Blocking mAbs that prevent CD80 or CD86 from binding to CTLA-4 reduce the absorbance signal due to lack of CD80 or CD86 binding to CTLA-4. Weak-blocking mAbs still allow CD80 or CD86 to bind, preventing the loss of all absorbance signal. B. Plots show the ability of GIGA-564 to block the interaction between CTLA-4 and the B7 ligands CD80 and CD86 compared to ipilimumab and CTLA-4.28, as assessed by ELISA as described in (A). Absorbance values were normalized to an anti-PD-1 control (pembrolizumab) and displayed as the average of two technical replicates. C-D. The key residues mediating CTLA-4 binding were identified for GIGA-564 and ipilimumab by shotgun mutagenesis of CTLA-4, followed by staining and flow cytometry assessment of binding. C. Shown is the crystal structure (Protein Database [PDB] 1I8L) of the complex between CD80 (blue) and CTLA-4 (gray) on which the CTLA-4 epitope residues shared between ipilimumab and GIGA-564 were colored orange and the key differentiating residue R70 was colored red (visualized with Pymol). Additionally, G142 was identified as a secondary residue for the epitope of ipilimumab but not GIGA-564. D. Table showing key amino acids on CTLA-4 of interest for these epitopes; those found by mutational analysis to be important for binding of CTLA-4 to CD80 or CD86 in a cell-based assay are marked in gray to indicate the epitope residues for those proteins .

Article Snippet: Recombinant human His-tagged CD80 (R&D Systems 9050-B1, Minneapolis, MN, USA) or CD86 (R&D Systems 9090-B2, Minneapolis, MN, USA) was then added to the plates at 1 μg/mL.

Techniques: Blocking Assay, Binding Assay, Enzyme-linked Immunosorbent Assay, Incubation, Control, Mutagenesis, Staining, Flow Cytometry, Residue, Cell Based Assay

Journal: bioRxiv

Article Title: Lack of blocking activity in anti-CTLA-4 antibodies reduces toxicity, but not anti-tumor efficacy

doi: 10.1101/2021.07.12.452090

Figure Lengend Snippet: Top panel: Ipilimumab blocks CTLA-4 interaction with CD80/CD86, which allows antigen presenting cells (APCs) to co-stimulate peripheral Tregs enhancing their proliferation. GIGA-564 weakly blocks CTLA-4 interaction with CD80/CD86 and thus induces less Treg proliferation. Bottom panel: Ipilimumab and GIGA-564 bind CTLA-4 on intratumoral Tregs to induce Treg killing via interactions with Fc receptor (FcR) on effector cells. GIGA-564 induces stronger FcR signaling and thus more efficiently depletes intratumoral Tregs than ipilimumab.

Article Snippet: Recombinant human His-tagged CD80 (R&D Systems 9050-B1, Minneapolis, MN, USA) or CD86 (R&D Systems 9090-B2, Minneapolis, MN, USA) was then added to the plates at 1 μg/mL.

Techniques: