Authors: Y-W Yang and C-A Wu
Affilation: National Taiwan University, Taiwan
Pages: 140 - 143
Keywords: vaccine, adjuvant, delivery
The nano-structured vaccine delivery systems, containing tomatine, n-octyl-b-D-glucopyranoside (OGP), phosphatidylethanolamine (PE), cholesterol, and ovalbumin, were examined in the present study by transmission electron microscopy. This adjuvant has been shown to elicit cytoxic T-lymphocyte (CTL) effect when co-immunized with the antigens. Transmission electron microscopy was carried out to examine the nano-structures of this complex vaccine delivery system and its interaction with the dendritic cells, the most powerful antigen-presenting cells in vitro. To examine the nano-structures, tomatine adjuvant was separated by isopycnic ultracentrifugation. Examination by transmission electron microscopy revealed the heterogeneity characteristics of the adjuvant, containing several micro- and nano- structures with the major fraction consisting of cylindrical-shaped nano-crystals, approximately 80-160 nm in width and 2-4 mm in length (Fig. 1). Tomatine alone in 0.9% NaCl, on the other hand, was shown to be cylindrical crystals of hundreds of nanometers up to a few microns in length, along which n-octyl-b-glucopyranoside was speculated to serve as a seeding nano- templates for complexation with the antigens. Several other forms of micro- and nano-structures were observed, showing multiple dispersion features with the nano-gel characteristics. The presence of the nano-gel structures was speculated to correlate with the sustained immunopotentiation effect of tomatine adjuvant.