Polysaccharide from Fruits of Physalis Alkekengi L. Enhances Antitumor Efficacy by a DNA Vaccine

 Physalis. alkekengi fruit has long been used in traditional Chinese medicine for tumor therapy. In the present study, using plasmids that encode ovalbumin (OVA) gene, we investigate the adjuvant activity of a polysaccharide fraction (PPSB) isolated from P.alkekengi fruit. Formulation by simple procedures of mixing of the OVA-encoding pCI-neo-sOVA plasmid with PPSB not only induced specific antibody responses, but also induced antigen-specific cytotoxic T lymphocyte (CTL) responses (Graph abstract). Furthermore, immunization using this vaccine prevented the growth of OVA-expressing B16-OVA tumor cell growth in the immunized mice. Thus, we provide evidence supporting the adjuvant activity of PPSB in DNA vaccine against tumor.