[Recombinant eukaryotic expression plasmid of bcr-abl gene fragment induces specific immune response in mice].
OBJECTIVE
To study the specific immune response induced by a recombinant eukaryotic expression plasmid encoding bcr-abl fusion gene fragment so as to explore new immunotherapy in mouse.


METHODS
A recombinant eukaryotic vector pVbcr-abl expression cDNA fragment of bcr-abl fusion gene was constructed and used to immunize BALB/c mice. Serum level of bcr-abl specific antibody was detected by enzyme-linked immunosorbent assay (ELISA). Twenty days later the immunized mice were subcutaneously inoculated SP2/0/bcr-abl cells. The survival time, tumor growth time and lymphocytic infiltration were observed. T cells infiltration into tumor tissue was analyzed by immunohistochemistry. Changes of T cell subset in the spleen of mice was analyzed by fluorescent-activated cell sorting (FACS) and the cytotoxicity T lymphocyte (CTL) activity in spleen by lactate dehydrogenase (LDH)-release assay.


RESULTS
The eukaryotic expression vector pVbcr-abl was constructed successfully, and highly expressed the cDNA fragment of bcr-abl fusion gene. The BALB/c mice immunized with the vector could generate the specific antibody and CTL, resulting in a specific immunoprotection. There were dramatic differences in the tumor-forming time, tumor ulcer appearing time and tumor-growing speed between the immunized and the control groups. The mice had longer survival time in the immunized group than in the control group. There were a large amount of CD3(+) T cells infiltration in tumor tissue of the immunized mice. The spleen cells from the immunized mice had higher CTL activity with a alteration of T cell subset, the CD4(+)/CD8(+) ratio being 1.54 +/- 0.29, higher than that of control group (1.18 +/- 0.30).


CONCLUSIONS
The recombinant eukaryotic expression plasmid pVbcr-abl can induce in vivo not only the generation of specific antibody, but also high level of specific CTL activity, resulting in killing the SP2/0/bcr-abl tumor cells directly and inhibiting the tumor growth.
Jiang
Yang-wen
YW
Department of Haematology, Affiliated Hospital of Yangzhou University, Yangzhou 225001, China.
Qian
Li
L
Gong
Wei-juan
WJ
Liu
Wei
W
Jiang
Gui-hua
GH
Ji
Ming-chun
MC
D000818:Animals; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D015870:Gene Expression; D005822:Genetic Vectors; D007167:Immunotherapy; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids / Q000235:genetics; D011897:Random Allocation; D014162:Transfection
D016044:Fusion Proteins, bcr-abl