Xenogenization by tetanus toxoid loading into lymphoblastoid cell lines and primary human tumor cells mediated by polycations and liposomes

We explored the potential of the xenogenization concept as an adjuvant procedure in anti-tumor immunity. To mediate effective loading we used polyarginine (pArg) molecules of various degrees of polymerization, cationic liposomes, or chimeric molecules of transferrin (Tf) and the polycation polyethyleneimine (PEI). Tetanus toxoid (TT) was loaded onto primary human leukemia cells, culture adapted primary human neuroblastoma cells, and human lymphoblastoid cell lines (LCLs) with high efficiency by all procedures. Trypsin treatment of loaded cells provided evidence that only liposomes and Tf–PEI mediated internalization of TT. Lymphocytes primed with xenogenized LCLs and challenged with unmodified LCLs showed increased IFNγ secretion compared with lymphocytes primed with non-xenogenized LCLs.