[Comparison of antitumor effects of dendritic cells modified with different forms of hepatocellular cancer antigens]

To explore the antitumor effects of dendritic cells (DCs) modified with different forms of hepatocellular cancer antigens.

DCs were modified with freeze-thawed H22 cell lysate, small molecular H22 peptides and Hsp70-H22 peptide complex, respectively. The cytotoxicity of DCs-activated CTLs to H22 cells was detected by MTT colorimetry. The expression level of IFN-gamma mRNA in splenocytes was detected by RT-PCR. The DCs modified with different antigens were used to immunize mice and then the suppressive effects on the growth of tumor were measured.

The DCs modified with H22 peptides alone could not activate CTLs. The ability to activate CTLs by DCs modified with Hsp70-H22 peptide complex was stronger than that by DCs modified with freeze-thawed H22 lysate, with the killing rates of CTLs being 47.3% and 18.3%, respectively. The expression level of IFN-gamma mRNA in 3 groups of splenocytes was consistent with the killing rate of CTLs.The growth of H22 cells in mice immunized with DCs modified with freeze-thawed H22 lysate or Hsp70-H22 peptide complex was suppressed, but the suppressive effect of the latter was stronger than that of the former. The tumorigenesis rate in the Hsp70-22 peptide complex group was only 40%, whereas the tumorigenesis rates in the other two groups were 100%.

Hsp70-H22 peptide complex is a strong sensitizer for DCs, which participates in immune rejection of tumor through activating CTLs and inducing CD4 (+) T cells to differentiate into Th1 cells.