[Immunostimulatory and antitumor effect of Flt3L and CCL5 on DNA vaccine in DNA prime/protein boost strategy].
OBJECTIVE
To investigate the immune enhancment and antitumor effect of the recombinant plasmids pFlt3L and pCCL5 in DNA prime/protein boost regimens.


METHODS
The mice were coimmunized with HBcAg DNA vaccine and the two cytokines DNA constructs by intramuscular injection for three times at an interval of 2 weeks. Then the mice were boosted with HBc particle proteins or DNA vaccines, respectively. The immune efficacy was evaluated by tumor growth curve. To further investigate the mechanism of inhibiting tumor growth, lymphocytes proliferation response and the number of IFN-gamma-producing cells in splenocytes were measured by MTT or flow cytometry, respectively. The levels of IL-2 and IL-4 in supernatant of spleno-lymphocyte cultures were measured by ELISA. The CTL activity of spleno-lymphocyte was detected with LDH release assay.


RESULTS
Compared with negative control, DDP/Adj group significantly inhibit tumor growth; splenocytes proliferation response and the numbers of IFN-gamma-producing cells in DDD/Adj group and DDP/Adj group were significantly higher (P<0.05 or P<0.01). The levels of IL-2 in supernatant of spleno-lymphocyte cultures in DDD/Adj group and DDP/Adj group were also markedly higher than that of negative control (P<0.05); but the levels of IL-4 were no differences in all groups (P>0.05). The CTL activities in group of DDS/Adj and DDD/Adj were stronger than that of other groups (P<0.01 or P<0.05). While, the CTL killing activity in DDS/Adj group was over that of DDD/Adj (P<0.01 or P<0.05).


CONCLUSIONS
The significant Th1 response and specific CTL against B16-HBc tumor cells are elicited by the combination of Flt3L and CCL5 in the DNA prime/protein boost strategy.
Liu
Chun-Yan
CY
Department of Molecular Biology and Key Lab of Laboratory Animal Science, Hebei Medical University, Shijiazhuang 050017, China.
Zheng
Long
L
You
Hong-Yu
HY
Zhang
Yan
Y
Wang
Jun-Xia
JX
Song
Shu-Xia
SX
D000276:Adjuvants, Immunologic / Q000235:genetics / Q000378:metabolism; D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D018946:Chemokine CCL5 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D007117:Immunization, Secondary / Q000379:methods*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D019444:Vaccines, DNA / Q000276:immunology*
D000276:Adjuvants, Immunologic; D018946:Chemokine CCL5; D008565:Membrane Proteins; D019444:Vaccines, DNA; C084881:flt3 ligand protein