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Abstract: The aim of the present study was to evaluate two vesicular carrier systems, ethosomes and elastic liposomes loaded with hepatitis B surface antigen, for in vitro qualitative and quantitative uptake by human dendritic cells (DCs) and ability to stimulate T lymphocytes. Quantitative uptake of antigen-loaded carriers was documented by flow cytometry, and internalization of the systems by the DCs was studied using spectral bioimaging. Ability of antigen-pulsed DCs to stimulate autologous peripheral blood lymphocytes and levels of TH1/TH2 cytokines were also examined using flow cytometry. Both vesicular carrier systems as antigen delivery modules and DCs as antigen-presenting cells were able to generate a protective immune response. However, ethosomes were found to have higher internalizing ability and immunogenicity in comparison with elastic liposomes. These properties of ethosomes coupled with their skin-navigating potential, make it an attractive vehicle for development of a transcutaneous vaccine against hepatitis B in preference to elastic liposomes. From the Clinical Editor: Two carrier systems for more potent vaccine administration - ethosomes and elastic liposomes loaded with hepatitis B surface antigen – are compared. Ethosomes demonstrated higher internalizing ability and immunogenicity. Due to their known skin-navigating potential, ethosomes may represent an attractive vehicle for development of a transcutaneous vaccine against hepatitis B. [Copyright &y& Elsevier]

Abstract: We have evaluated the efficiency of novel modified liposomes (ethosomes) for transcutaneous immunization (TCI) against Hepatitis B. Antigen-loaded ethosomes were prepared and characterized for shape, lamellarity, fluidity, size distribution, and entrapment efficiency. Spectral bio-imaging and flow cytometric studies showed efficient uptake of Hepatitis B surface antigen (HBsAg)-loaded ethosomes by murine dendritic cells (DCs) in vitro, reaching a peak by 180min. Transcutaneous delivery potential of the antigen-loaded system using human cadaver skin demonstrated a much higher skin permeation of the antigen in comparison to conventional liposomes and soluble antigen preparation. Topically applied HBsAg-loaded ethosomes in experimental mice showed a robust systemic and mucosal humoral immune response compared to intramuscularly administered alum-adsorbed HBsAg suspension, topically applied plain HBsAg solution and hydroethanolic (25%) HBsAg solution. The ability of the antigen-pulsed DCs to stimulate autologous peripheral blood lymphocytes was demonstrated by BrdU assay and a predominantly TH1 type of immune response was observed by multiplex cytometric bead array analysis. HBsAg-loaded ethosomes are able to generate a protective immune response and their ability to traverse and target the immunological milieu of the skin may find a potential application in the development of a transcutaneous vaccine against Hepatitis B virus (HBV). [Copyright &y& Elsevier]

Abstract: Hepatitis B surface antigen (HBsAg)-loaded elastic liposomes were studied for qualitative and quantitative uptake in vitro by murine dendritic cells (DCs) generated from bone marrow mononuclear cells. Internalization of the vesicles by the DCs was documented using fluorescence microscopy. Kinetics of uptake of antigen-loaded elastic vesicles by the DCs studied through flow cytometry showed a peak uptake at 6h. The ability of the antigen pulsed DCs to stimulate autologous peripheral blood lymphocytes was demonstrated by BrdU assay. Further evaluation by multiplex cytometric bead array analysis demonstrated a predominantly TH1 type of immune response. Our results suggest that HBsAg-loaded elastic vesicles as antigen delivery module and DCs as antigen presenting cells are able to generate a protective immune response. The property of elastic liposomes to traverse and target the immunological milieu of the skin makes it an attractive vehicle for development of a transcutaneous vaccine against hepatitis B virus. [Copyright &y& Elsevier]