Extended Data Fig. 11 |. The suppressed T cell activation induced by Siglec-7/-9 can be reversed by Siglec degradation.

a,b,c, Assessment of activation maker (CD69 (a), CD25 (b) and PD-1(c)) expression on donor CD8⁺ T cells under anti-CD3 (OKT3) stimulation when cocultured with donor-matched hMDMs in the absence or presence of 30 nM Sig7/9de. d,e, Analysis of cell-surface Siglec-7 (d) and -9 (e) depletion in Siglec-7 and Siglec-9 expressing Jurkat cells upon treatment with 30 nM Sig7/9de for 1 hour. f, Flow cytometry analysis of the Siglec-7 and Siglec-9 ligand expression on MDA-MB-435 cancer cells by staining with Siglec-7Fc and Siglec-9Fc, respectively. g, Flow cytometry analysis of sialic acid removal on MDA-MB-435 cells using anti-HER2 BiTE-sialidase by staining with MAL-II and PNA respectively. h, Evaluation of the cancer cell-associated trans ligand effect on IL2 secretion by Jurkat T cells cocultured with MDA-MB-435 cells (HER2⁺) in the presence of anti-HER2 BiTE or anti-HER2 BiTE-sialidase and anti-CD28. Data are mean ± s.d. Two-tailed unpaired Student’s t-test (a,b,c,h).