[VP22 enhances the immunological activity of human cytomegalovirus pp65 DNA vaccine: experimental study with mice].
OBJECTIVE
To construct the human cytomegalovirus (HCMV) pp65 DNA vaccine vector and VP22 and pp65 coexpressing vector. To evaluate and compare immunological effects in mice.


METHODS
Twenty-one BALB/C mice were divided into 3 equal groups: pcDNA3.pp65 group undergoing injection of pcDNA3.pp65 as DNA vaccine, pVP22.pp65 group undergoing injection of pVP22.pp65, and control group undergoing injection of normal saline. HCMV pp65 expression vector pcDNA3.pp65, VP22 and pp65 coexpressing vector pVP22.pp65 were constructed by molecular biology methods. The vectors were immunized into BALB/C mice as DNA vaccines. The T cell proliferation activity and IL-2 biological activity were determined using MTT method. NK activity was detected using LDH release test. The serum IgM and IgG levels of HCMV, the concentrations of IL-2 and IL-4 in serum and supernatant of spleen cells were detected using ELISA method.


RESULTS
The HCMV DNA vaccine expression vectors were successfully constructed. Some indexes of the two vaccine groups (pcDNA3.pp65 and pVP22.pp65), that is, T cell proliferation activity (5.11 and 5.55 for SI at 8th week respectively), NK activity (8.74% and 12.08% at 12th week respectively), IgM level (1.20 and 1.58 for A value at 6th week respectively) and IgG level (1.09 and 1.78 for A value at 6th week respectively) were higher than those of negative control, and pVP22.pp65 group was higher than pcDNA3.pp65 group (P < 0.05). The concentrations of IL-2 and IL-4 and the IL-2 biological activity were very low in sera of three groups which showed no significant difference between them (P > 0.05), but higher in the spleen supernatant and the pVP22.pp65 group was highest (411.11 pg/ml, 76.10 pg/ml for the concentrations of IL-2 and IL-4 and 0.22 for IL-2 biological activity).


CONCLUSIONS
The HCMV pp65 could induce certain immunological activity, and VP22 could significantly enhance pp65 in vivo immunological activity.
Ma
Dao-xin
DX
Qilu Hospital of Shandong University, Jinan 250012, China.
Yu
Xiu-ping
XP
Zhang
Xiao-mei
XM
Zhou
Ya-bin
YB
Li
Yong
Y
Jia
Ji-hui
JH
Zhao
Wei-ming
WM
D000818:Animals; D003587:Cytomegalovirus / Q000276:immunology*; D003586:Cytomegalovirus Infections / Q000517:prevention & control; D005260:Female; D005822:Genetic Vectors; D007376:Interleukin-2 / Q000097:blood; D007694:Killer Cells, Natural / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D010750:Phosphoproteins / Q000235:genetics*; D013601:T-Lymphocytes / Q000276:immunology; D019444:Vaccines, DNA / Q000276:immunology*; D014763:Viral Matrix Proteins / Q000235:genetics*; D015678:Viral Structural Proteins / Q000235:genetics*; D014765:Viral Vaccines / Q000276:immunology*
D007376:Interleukin-2; D010750:Phosphoproteins; D019444:Vaccines, DNA; D014763:Viral Matrix Proteins; D015678:Viral Structural Proteins; D014765:Viral Vaccines; C065418:cytomegalovirus matrix protein 65kDa; C073413:herpes simplex virus type 1 protein VP22