Role of aluminum-containing adjuvants in antigen internalization by dendritic cells in vitro

Garry L. Morefield, Anna Sokolovska, Dongping Jiang, Harm Hogenesch, J. Paul Robinson, Stanley L. Hem

Research output: Contribution to journalArticle

200 Scopus citations

Abstract

An important step in the induction of an immune response to vaccines is the internalization of antigens by antigen presenting cells, such as dendritic cells (DCs). Many current vaccines are formulated with antigens adsorbed to an aluminum-containing adjuvant. Following injection of the vaccine the antigens may either elute or stay adsorbed to the adjuvant surface. Antigens, which elute from the adjuvant surface, are internalized by dendritic cells through macropinocytosis while those that remain adsorbed are internalized with the adjuvant particle by phagocytosis. The relative efficiency of these two routes of internalization was studied. Alpha casein (AC) labeled with a green fluorescent dye was selected as the model antigen. In order to model vaccine antigens that elute from aluminum-containing adjuvants following administration, dendritic cells were incubated with a solution of fluorochrome-labeled alpha casein. To model vaccine antigens that do not elute from aluminum-containing adjuvants following administration, dendritic cells were exposed to fluorochrome-labeled alpha casein adsorbed to aluminum hydroxide adjuvant (AH). Alpha casein has eight phosphate groups and adsorbs to aluminum hydroxide adjuvant through ligand exchange. Alpha casein does not elute from aluminum hydroxide adjuvant upon exposure to cell culture media. The uptake of antigen by dendritic cells was determined at 0.5, 1, 2 and 3 h by confocal microscopy and flow cytometry. Dendritic cells internalized both alpha casein in solution and alpha casein adsorbed to aluminum hydroxide adjuvant. However, the mean fluorescence intensity of dendritic cells incubated with adsorbed alpha casein was four times greater than dendritic cells incubated with alpha casein in solution. In addition, the internalization of alpha casein was enhanced when the mean aggregate diameter of the adjuvant in the cell culture media was reduced from 17 μm to 3 μm. It was concluded that antigen internalization by dendritic cells was enhanced when the antigen remained adsorbed to the aluminum-containing adjuvant following administration and the aggregate size of the adjuvant was smaller than dendritic cells which are approximately 10 μm in diameter.

Original languageEnglish (US)
Pages (from-to)1588-1595
Number of pages8
JournalVaccine
Volume23
Issue number13
DOIs
StatePublished - Feb 18 2005
Externally publishedYes

Keywords

  • Aluminum-containing adjuvants
  • Antigen internalization
  • Dendritic cells
  • Macropinocytosis
  • Phagocytosis

ASJC Scopus subject areas

  • Molecular Medicine
  • Immunology and Microbiology(all)
  • veterinary(all)
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases

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  • Cite this

    Morefield, G. L., Sokolovska, A., Jiang, D., Hogenesch, H., Robinson, J. P., & Hem, S. L. (2005). Role of aluminum-containing adjuvants in antigen internalization by dendritic cells in vitro. Vaccine, 23(13), 1588-1595. https://doi.org/10.1016/j.vaccine.2004.07.050