Enhanced DNA vaccine potency by mannosylated lipoplex after intraperitoneal administration.
BACKGROUND
Here we describe a novel DNA vaccine formulation that can enhance cytotoxic T lymphocyte (CTL) activity through efficient gene delivery to dendritic cells (DCs) by mannose receptor-mediated endocytosis.


METHODS
Ovalbumin (OVA) was selected as a model antigen for vaccination; accordingly, OVA-encoding pDNA (pCMV-OVA) was constructed to evaluate DNA vaccination. Mannosylated cationic liposomes (Man-liposomes) were prepared using cholesten-5-yloxy-N-{4-[(1-imino-2-D-thiomannosylethyl)amino]butyl}formamide (Man-C4-Chol) with cationic lipid. The potency of the mannosylated liposome/pCMV-OVA complex (Man-lipoplex) was evaluated by measuring OVA mRNA in CD11c+ cells, CTL activity, and the OVA-specific anti-tumor effect after in vivo administration.


RESULTS
An in vitro study using DC2.4 cells demonstrated that Man-liposomes could transfect pCMV-OVA more efficiently than cationic liposomes via mannose receptor-mediated endocytosis. In vivo studies revealed that the Man-lipoplex exhibited higher OVA mRNA expression in CD11c+ cells in the spleen and peritoneal cavity and provided a stronger OVA-specific CTL response than intraperitoneal (i.p.) administration of the conventional lipoplex and intramuscular (i.m.) administration of naked pCMV-OVA, the standard protocol for DNA vaccination. Pre-immunization with the Man-lipoplex provided much better OVA-specific anti-tumor effect than naked pCMV-OVA via the i.m. route.


CONCLUSIONS
These results suggested that in vivo active targeting of DNA vaccine to DCs with Man-lipoplex might prove useful for the rational design of DNA vaccine.
Hattori
Yoshiyuki
Y
Department of Drug Delivery Research, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Kawakami
Shigeru
S
Lu
Yan
Y
Nakamura
Kazumi
K
Yamashita
Fumiyoshi
F
Hashida
Mitsuru
M
D000818:Animals; D000941:Antigens / Q000235:genetics; D001483:Base Sequence; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000235:genetics; D002460:Cell Line; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D015870:Gene Expression; D007274:Injections, Intraperitoneal; D008081:Liposomes; D008358:Mannose; D008564:Membrane Potentials; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000276:immunology / Q000517:prevention & control; D010047:Ovalbumin / Q000235:genetics / Q000276:immunology; D010316:Particle Size; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014162:Transfection; D019444:Vaccines, DNA / Q000008:administration & dosage* / Q000235:genetics
D000941:Antigens; D019496:Cancer Vaccines; D008081:Liposomes; D012333:RNA, Messenger; D019444:Vaccines, DNA; D010047:Ovalbumin; D008358:Mannose