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Fig. 1 | Journal of Hematology & Oncology

Fig. 1

From: Targeting the myeloid checkpoint receptor SIRPα potentiates innate and adaptive immune responses to promote anti-tumor activity

Fig. 1

Pan-allelic and species cross-reactive antibody, hAB21, binds SIRPα with high affinity and blocks CD47–SIRPα interaction. a Binding affinities (pM) of AB21 and humanized hAB21 to human SIRPα v1 and v2 were determined by SPR. b Binding curves of hCD47 on CD14+ monocytes in the presence of titrated AB21 and hAB21. PBMCs were incubated with 500 nM fluorescent hCD47-Fc and increasing concentration of AB21 and hAB21 at 4 °C for 60 min, washed and evaluated by flow cytometry. Data are shown as ratio of CD14+ incubated with hCD47-Fc only. c Flow cytometry analysis of AB21 and hAB21 binding to human, cynomolgus and mouse CD14+ monocytes. Fluorescent-labeled AB21 and hAB21 were incubated in increasing concentration with cells at 4 °C for 60 min, washed and evaluated by flow cytometry. Mean fluorescent intensity is measured. d Crystal structure of hAB21 anti-SIRPα Fab bound to the Ig-V domain of human SIRPα V1 (purple). CD47 domain (pink) was superimposed onto the crystallized complex. The adjacent Venn diagram and surface map depict the epitopes bound by CD47 (green) and hAB21 (red); shared epitopes bound by both CD47 and hAB21 to SIRPα V1 are colored yellow accordingly

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