ovalbumin and 1-2-dielaidoylphosphatidylethanolamine

In an attempt to enhance the immunological efficacy of genetic immunization, we investigated a new biological means for delivering antigen gene directly to the cytoplasm via membrane fusion. In this context, we investigated fusogenic liposome (FL) encapsulating DNA as a possible genetic immunization vehicle. RT-PCR analysis indicated that a FL could introduce and express encapsulating OVA gene efficiently and rapidly in vitro. Consistent with this observation, an in vitro assay showed that FL-mediated antigen-gene delivery can induce potent presentation of antigen via the MHC class I-dependent pathway. Accordingly, immunization with FL containing the OVA-gene induced potent OVA-specific Th1 and Th2 cytokine production. Additionally, OVA-specific CTL responses and antibody production were also observed in systemic compartments including the spleen, upon immunization with the OVA-gene encapsulating FL. These findings suggest that FL is an effective genetic immunization carrier system for the stimulation of antigen-specific immune responses against its encoding antigen.

Topics: Animals; Antigen Presentation; Antigens; Cell Line, Tumor; DNA; Genetic Vectors; Histocompatibility Antigens Class I; Immunoglobulin G; Interferon-gamma; Interleukin-4; Liposomes; Male; Membrane Fusion; Mice; Mice, Inbred C57BL; Ovalbumin; Phosphatidylethanolamines; Spleen; T-Lymphocytes, Cytotoxic; Vaccines, DNA

We previously reported that exogenous antigens complexed with the cationic liposome lipofectin (LF) were efficiently presented via major histocompatibility complex (MHC) class I molecules on pulsed dendritic cells (DCs) in vitro. In the present study, we demonstrated that MHC class I-restricted antigen presentation on DC2.4 cells, a murine immature DC line, treated with LF-antigen complexes was remarkably suppressed through the inhibition of endocytosis, proteasome catalysis, and Golgi transport. We also found that LF did not influence expression of interleukin-12 p40 mRNA, MHC molecules, or co-stimulatory molecules in DC2.4 cells. These findings suggest that an antigen-loading procedure using LF could enhance delivery of exogenous antigens to the classical MHC class I pathway in DCs, but it does not initiate DC maturation.

Topics: Acetylcysteine; Animals; Antigen Presentation; Antigens; Brefeldin A; Cell Line; Cell Survival; Chloroquine; Cytochalasin B; Dendritic Cells; Histocompatibility Antigens Class I; Major Histocompatibility Complex; Mice; Ovalbumin; Phosphatidylethanolamines; Time Factors

Topics: Administration, Intranasal; Animals; Antibody Formation; Biocompatible Materials; Cloning, Molecular; Drug Carriers; Immunoglobulin G; Injections, Intramuscular; Latex; Mice; Mice, Inbred BALB C; Microspheres; Nasal Mucosa; Ovalbumin; Phosphatidylethanolamines; Plasmids; Polyesters; Recombinant Proteins; Vaccines, DNA