Bone marrow-derived dendritic cells incorporate and process hydrophobized polysaccharide/oncoprotein complex as antigen presenting cells

We have previously shown that a novel hydrophobized polysaccharide/oncoprot ein complex vaccine can induce immune responses against the HER2/neu/c-erbB 2 (HER2) expressing tumors. Bone marrow-derived dendritic cells (DCs), as a ntigen presenting cells (APCs), are the first candidates for presentation o f tumor antigens. The aim of this study was to see whether DCs are able to elicit antigen specific host immune responses by stimulating the proliferat ion of T cells after exposure to cholesteryl group bearing pullulan (CHP) a nd HER2 protein complex. Vaccination by CHP-HER2 complex was as effective a s cholesteryl group bearing mannan (CHM) and HER2 complex on which we repor ted previously. Immunization of mice with HER2 expressing CMS17HE tumor cel ls generated both CD4(+) T cells and CD8(+) T cells reactive with CHP-HER2 complex pretreated DCs. In addition, immunization with either CHP-HER2 comp lex or HER2 protein alone could also generate both CD4(+) T cells and CD8() T cells specifically reactive with CHP-HER2 complex pretreated DCs. The c omplete rejection of tumors occurred when immunization with CHP-HER2 comple x pretreated DCs was started 10 days after tumor inoculation. Therefore, bo ne marrow-derived DCs pretreated with hydrophobized polysaccharide/oncoprot ein complex are a powerful tool for enhancing the effectiveness of oncoprot ein for anti-tumor vaccination, opening new options for immune cell therapy .