Application Notes
ELISA, Inhib
Each laboratory should determine an optimum working titer for use in its particular application.
Other applications have not been tested but use in such assays should not necessarily be excluded.
General Notes
This clone is able to bind to G-CSF and inhibit G-CSF biological activity and/or downstream pathway(s) mediated by G-CSF signaling. It encompasses antibodies that block, antagonize, suppress or reduce (including significantly) G-CSF biological activity, including downstream pathways mediated by G-CSF signaling.
1B11 specifically binds to and neutralizes the biological activity of human granulocyte colony-stimulating factor (G-CSF). In vitro, 1B11 significantly neutralizes the proliferative effect of both low (0.125 ng/mL) and high (0.625 ng/mL) concentrations of human G-CSF on NFS-60 cells, in a dose-dependent manner. The antibody demonstrates greater neutralization activity against human G-CSF compared to mouse G-CSF, indicating low species cross-reactivity. Additionally, 1B11 is effective against both non-glycosylated (E. coli-derived) and glycosylated (CHO-derived) human G-CSF, suggesting that glycosylation status does not affect its activity. At the signaling level, 1B11 effectively blocks G-CSF-induced STAT3 phosphorylation (pSTAT3) in primary human neutrophils. In vivo, using a MC38 colon carcinoma mouse model engineered to express human G-CSF, treatment with 1B11 (200 μg, three times per week) significantly reduced the frequency of CD11b⁺Ly6G⁺ myeloid-derived suppressor cells (MDSCs) in the spleen and impaired their ability to suppress T cell proliferation. The binding affinity (KD) of 1B11 for G-CSF was determined to be 6.4 × 10⁻¹¹ M by surface plasmon resonance (SPR) at 37°C. A total of 15 humanized variants of 1B11 were generated; all retained the ability to block G-CSF-dependent STAT3 signaling in vitro, with variants 7 and 12 demonstrating dose-dependent neutralization in NFS-60 cell assays. Variant 12 was further shown to reduce G-CSF-induced neutrophilia and block neutrophil pSTAT3 signaling in C57Bl/6 mice in vivo.
COA
Publication 
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