Antibody-conjugated LNP-mRNA preparation

To prepare targeted LNPs, monoclonal anti-CD2 (TS1/8, BioLegend, cat# 309202), anti-CD4 (A161A1, BioLegend, cat# 94222), anti-CD5 (UCHT2, BioLegend, cat# 98889), anti-CD7 (CD7 6B7, BioLegend, cat# 94122), anti-CD8 (SK1, BioLegend, cat# 92401), and anti-CD71 (B3/25, Bio X Cell, cat# BE036) were conjugated to LNP-mRNA using SATA-maleimide chemistry as described previously[27-29]. Briefly, LNP-mRNA was modified with maleimide functional groups (DSPE-PEG-mal) via post-insertion. The antibody was functionalized with SATA (N-succinimidyl S-acetylthioacetate) to introduce sulfhydryl groups for conjugation to maleimide. The sulfhydryl groups on the antibody were then conjugated to maleimide moieties through thioether chemistry. The resulting conjugates were purified using Sepharose CL-4B gel filtration columns (MilliporeSigma).