ABSTRACT
Objective Cytotoxic T lymphocytes are the main effector cells of anti-tumor immunity. Active targeting of nanoparticles to T cells and activation of T cells can be achieved by conjugation with specific antibodies. We prepared the biotin-grafted pullulan acetate nanoparticles conjugated with CD3 (Bio-PA-CD3 NPs), and explored their effects on the proliferation, cytokine secretion and uptake of CD8+T cells.Methods We prepared Bio-PA NPs by the dialysis method, conjugated CD3 antibodies to the surface of NPs to make Bio-PA-CD3 NPs, and measured the diameter and Zeta potential of the NPs. We evaluated the effects of the NPs on the proliferation of CD8+T cells and the secretion of cytokines by CCK-8 assay and ELISA, respectively, and quantitatively analyzed the cellular uptakes of the Bio-PA-CD3 NPs by the flow cytometry.Results The Bio-PA-CD3 NPs exhibited regular spherical shapes of even size and with no adhesion. The content of CD3 antibodies on the surface of the NPs decreased with the increased degree of biotin substitution. The CD3 contents of the Bio-PA-CD3 NPs with biotin substitution degrees of 1.6%, 5.4% and 6.3% were (36.1±4.4), (21.4±4.3) and (10.3±4.7) μg/mg, respectively. Compared with Bio-PA NPs, Bio-PA-CD3 NPs at a certain concentration significantly enhanced the proliferation of CD8+T cells in vitro and promoted the secretion of IFN-γ, TNF-β and IL-2 cytokines. The Bio-PA-CD3 NPs manifested a higher cellular uptake with the increased content of CD3 antibodies.Conclusion The Bio-PA-CD3 NPs we prepared could be a promising agent to enhance the immune effect of T cells.