Quantification of a recombinant antigen in an immuno-stimulatory whole yeast cell-based therapeutic vaccine

Therapeutic vaccines represent an emerging class of immune-modulatory treatments for cancer, infections, and chronic diseases. One such vaccine was designed as an immune stimulator of the T cell response against HBV antigens to eliminate HBV infected cells and offer a therapeutic avenue to treat patients suffering from chronic hepatitis B infection. Whole deactivated Saccharomyces cerevisiae cells expressing a recombinant fusion of HBV X, S and Core antigens elicit T cell responses in mice and activate human T cells linked with viral clearance. As the therapeutic efficacy of the yeast-based vaccine relies on the production of the recombinant antigen, analytical methods designed to accurately and precisely quantitate the fusion protein in the midst of all the yeast proteins are necessary. We report the development and characterization of western blot, quantitative ELISA and mass spectrometry based orthogonal methods to support the assessment of manufacturing consistency.