IgG and IgA3.0 (hereafter called IgA) antibodies targeting GD2 (ch14.18, dinutuximab) were produced by WuXi Biologics in CHO-K1 cells. To block CD47, we either used an engineered human SIRPα D1 domain with high affinity for both mouse and human CD47 fused to IgG1 L234A/L235A/P329G (LALAPG) as described in Chernyavska et al33 (link) or an IgG1 LALAPG anti-CD47 (Clone 2.3D11) produced and purified in-house. Antibodies were produced and purified as described previously.20 34 (link) In short, antibodies were produced through transient transfection of Expi-CHO-S cells (Thermo Fisher Scientific). Subsequently, supernatant containing the antibody was affinity purified using a HiTrap Protein A column (Cytiva) for IgG antibodies or a HiTrap KappaSelect column (Cytiva) for IgA antibodies, coupled to a ÄKTA liquid chromatography system (Cytiva). The captured IgG was eluted and subsequently dialyzed against PBS, while IgA was additionally purified by size exclusion chromatography. The eluate was filtered using a 0.22 µm filter and the antibody concentration was measured by UV absorbance at 280 nm using the corresponding extinction coefficient (ε280).