[Construction of genetically modified dendritic cell vaccine expressing bcr/abl fusion gene and inducing specific cytotoxic T lymphocytes to kill K562 cells in vitro].
OBJECTIVE
Specific immunological effect mediated by T lymphocytes plays an important role in treating chronic myelocytic leukemia (CML). Dendritic cells (DCs)-based immunotherapy has become popular in treating tumors. This study was to construct DC vaccines by transducing with replication-defective recombinant adenoviruses expressing bcr/abl fusion gene of CML, observe the lethal effects of specific cytotoxic T lymphocytes (CTLs) triggered by genetically modified DC vaccines expressing bcr/abl fusion gene against K562 cells in vitro.


METHODS
DNA fragment of bcr/abl fusion gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR) to construct a recombinant adenovirus vector and produce recombinant adenoviruses. DCs were induced from peripheral blood monocytes in vitro, and transfected with recombinant adenoviruses or pulsed with peptide to induce specific CTLs. The lethal effect of CTLs against leukemic K562 cells in vitro was observed.


RESULTS
We successfully constructed the replication-defective recombinant adenoviral vector expressing bcr/abl fusion gene. The recombinant adenoviruses we produced had a high virus titer of 2.0 x 10(10) pfu/mL. Transfection efficiency of DCs in vitro was 50%-60%. DC vaccines expressing bcr/abl fusion gene were successfully prepared and used to induce specific CTLs. With effector:target cell ratios of 40:1 and 20:1, the killing rates of K562 cells by CTLs were (47.6+/-4.7)% and (47.5+/-1.6)% in genetically modified DCs group, (25.8+/-4.4)% and (24.6+/-6.3)% in peptide-pulsed DCs group, and were (5.7+/-1.3)% and (4.5+/-1.6)% in control DCs group. The differences between every two groups were significant (all P<0.05).


CONCLUSIONS
Genetically modified DC vaccine expressing bcr/abl fusion gene has a stronger contribution than peptide-pulsed DCs in triggering specific CTLs against K562 cells.
Wang
Wen-Wen
WW
Department of Hematology, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510630, P.R. China.
Huang
Ren-Wei
RW
Hu
Yuan
Y
Li
Xu-Dong
XD
Wang
Dong-Ning
DN
He
Yi
Y
Liu
Jia-Jun
JJ
D000256:Adenoviridae / Q000235:genetics; D019496:Cancer Vaccines / Q000276:immunology*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D016044:Fusion Proteins, bcr-abl / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D016313:Genes, abl; D006801:Humans; D020014:K562 Cells; D010957:Plasmids; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology / Q000276:immunology*; D014162:Transfection
D019496:Cancer Vaccines; D016044:Fusion Proteins, bcr-abl