title: The role of surface charge density in cationic liposome-promoted dendritic cell maturation and vaccine-induced immune responses.
abstract: Cationic liposomes have emerged as a novel adjuvant and antigen delivery system to enhance vaccine efficacy. However, the role of surface charge density in cationic liposome-regulated immune responses has not yet been elucidated. In the present study, we prepared a series of DOTAP/DOPC cationic liposomes with different surface densities by incorporating varying amounts of DOPC (a neutral lipid) into DOTAP (a cationic lipid). The results showed that DOTAP/DOPC cationic liposome-regulated immune responses relied on the surface charge density, and might occur through ROS signaling. The liposomes with a relatively high charge density, such as DOTAP/DOPC 5:0 and 4:1 liposomes, potently enhanced dendritic cell maturation, ROS generaion, antigen uptake, as well as the production of OVA-specific IgG2a and IFN-γ. In contrast, low-charge liposomes, such as DOTAP/DOPC 1:4 liposome, failed to promote immune responses even at high concentrations, confirming that the immunoregulatory effect of cationic liposomes is mostly attributable to their surface charge density. Moreover, the DOTAP/DOPC 1:4 liposome suppressed anti-OVA antibody responses in vivo. Overall, maintaining an appropriate surface charge is crucial for optimizing the adjuvant effect of cationic liposomes and enhancing the efficacy of liposome-based vaccines.
authors.affiliation: Key Lab of Health Informatics of Chinese Academy of Sciences, Institute of Biomedical and Health Engineering, Chinese Academy of Sciences, Shenzhen, PR China 518055. yf.ma@siat.ac.cn
authors.forename: Yifan
authors.initials: Y
authors.lastname: Ma
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhuang
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Xie
authors.forename: Ce
authors.initials: C
authors.lastname: Wang
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.forename: Dongmei
authors.initials: D
authors.lastname: Zhou
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Zeng
authors.forename: Lintao
authors.initials: L
authors.lastname: Cai
mesh_terms: D002412:Cations; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000187:drug effects* / Q000276:immunology*; D006801:Humans; D008081:Liposomes / Q000737:chemistry*; D053769:Nanocapsules / Q000737:chemistry*; D055672:Static Electricity; D014612:Vaccines / Q000008:administration & dosage*
chemical_list: D002412:Cations; D008081:Liposomes; D053769:Nanocapsules; D014612:Vaccines