Truncated TERT mRNA transfected dendritic cells evoke TERT specific antitumor response in vivo

To evaluate the antitumor immune response induced by truncated TERT (TERTt) mRNA transfected dendritic cells (DCs) in

Truncated mouse TERT sequence (according to mice telomerase reverse transcriptase mRNA 1776bp-2942bp) was cloned from B16 mice melanoma cells and inserted into pBluescript II KS(+) plasmid downstreaming of T7 promoter. The in vitro transcription was performed to prepare TERTt mRNA. The bone marrow-derived DCs isolated from BALB/c or C57B/L mice were electroporated with TERTt mRNA and recruited to immunize syngeneic naive mice respectively. The quantity and cytotoxic activity of tumor specific cytotoxic T lymphocytes (CTLs) in mice spleen were evaluated by using IFN-gamma enzyme-linked immunospot (ELIspot) and LDH release assay. The immunoprophylactic effects induced by TERTt mRNA transfected DC were evaluated in immunized-challenged mouse model.

TERTt was cloned and transcripted into TERTt mRNA in vitro. TERTt mRNA transfected bone marrow-derived DCs were prepared. As shown by transfecting with EGFP mRNA, the DC transfected efficiency is 35.1% and there was a subtle increase of costimulator and MHC-II molecule expression after electroporation. Immunization with TERTt mRNA transfected DCs can induce TERTt and TERT-specific IFN-gamma secreting CTLs in the spleen of immunized mice. The splenocytes isolated from mice immunized with TERTt mRNA transfected DCs showed specific cytotoxic activity against TERTt and TERT-positive target cells. Using a syngeneic cancer mouse model, it was shown that TERTt mRNA transfected DCs vaccination can suppress the growth of TERT-positive tumor inoculation.

TERTt mRNA transfected bone marrow-derived DCs can evoke antitumor immune response in vivo effectively and TERTt can serve as a universal tumor associated antigen to produce DC-based tumor vaccine.