Anti‑CD206 antibody‑conjugated Fe3O4‑based PLGA nanoparticles selectively promote tumor‑associated macrophages to polarize to the pro‑inflammatory subtype

Abstract

M2 macrophages serve roles in inhibiting inflam‑ mation and promoting tumor development. Reversing tumor‑associated macrophages (TAMs) from M2‑ to M1‑type polarization may provide an important strategy for tumor immunotherapy. The present study aimed to enhance antitumor immunity by targeting the concentration of iron in macrophages. Fe3O4‑based poly(lactic‑co‑glycolic) acid (PLGA) nanoparticles surface‑modified with an anti‑CD206 monoclonal antibody were prepared using the oil in water single‑emulsion technique. Particle size was measured using a particle size analyzer, the ζ potential was determined using a ζ potential analyzer and the carrier rate of Fe3O4 was measured using an iron assay kit. The conjuga‑ tion of anti‑CD206, and the ability to target M2 macrophages were studied via immunofluorescence. Polarization indexes of the macrophages were detected using both western blot‑ ting and reverse transcription‑quantitative PCR (RT‑qPCR), and a mouse model with subcutaneous tumors was estab‑ lished to verify the antitumor effects of the nanoparticles in vivo. Nanoparticles had a mean diameter in the range of 260‑295 nm, and the ζ potential values were between ‑19 and ‑33 mV. The Fe3O4 association efficiency ranged from 65‑75%, whereas the anti‑CD206 conjunction efficiency ranged from 65‑70%. The immunofluorescence experiments were able to demonstrate the successful targeting of the M2 macrophages. The western blotting and RT‑qPCR experi‑ ments identified that CD206‑Fe3O4‑PLGA and Fe3O4‑PLGA.