Antigens in water-in-oil emulsion: a simple antigen extraction method for analysis and proof of equal antigen distribution in vaccination syringe after mixture

Therapeutic vaccination of antigens in oil emulsions is an approach becoming increasingly popular. Water-in-oil emulsions enable the formation of a depot, a slow passive antigen release and a decelerated antigen degradation. Furthermore, particularly advantageous for peptide vaccinations with a low clinical response rate is the increased immunogenicity and activation of CD8+ and CD4+ T-cells. Therefore, the use of personalized peptide vaccination cocktails in oil emulsions are tested in the treatment of cancer patients. An equal peptide distribution in the emulsion is striking for a successful depot effect to ensure the optimal efficacy and additionally, to enable reliable drug release analytics. First, the stability of the generated peptide-Montanide ISA51 emulsion was demonstrated with a cocktail of heterogeneous peptides for 24 h in room temperature. Furthermore, we developed a simple peptide extraction method to investigate the equal peptide distribution in a Montanide ISA51 emulsion in the syringe after mixing. Peptides were successfully extracted from a peptide-Montanide ISA51 vaccination cocktail in sufficient volume for analysis and an equal peptide distribution in the syringe was verified via HPLC.