Acetylation ; Animals ; Humans ; Phosphorylation ; Tumor Suppressor Protein p53 ; chemistry ; genetics ; metabolism ; physiology

Objective To construct the human interleukin-18(hIL-18) DNA plasmids vaccine and to express the eukaryotic plasmids vaccine in mammalian cell lines Cos-7 and D5.Methods Gene recombinant technique was used to construct hIL-18 eukaryotic expression vectors.Calcium phosphate method was performed to transect recombinant hIL-18 eukaryotic expression vectors into Cos-7 and D5 cells.In situ hybridization and Western Blot were implemented to verify the transient expression of recombinant hIL-18 in Cos-7 and D5.Results The eukaryotic expression plasmid pVAX1-IL 18 was constructed successfully.hIL-18 was transiently expressed in Cos-7 and D5.Conclusion The eukaryotic expression plasmid pVAX1-IL 18 was constructed.In situ hybridization and Western Blot results proved the successful transient expression of pVAX1-IL 18 in Cos-7 and D5.Therefore,the work has settled the foundation for further biological research on hIL-18,including immunogene therapy through hIL-18.

Objective To prepare the monoclonal antibody against human perforin(HP). Methods Recombinant eukaryotic expression plasmid pCDM8-HP was extracted and purified, and the BALB/C mice were immunized with the plasmid. The hybridomas producing anti-HP McAbs were established by using hybridoma technique, then the specificity of the McAbs was identified by using immunocytochemical technique and Western blot. Results Three hybridoma cell lines secreting McAbs against human perforin were established, and the three McAbs showed positive only with LAK cells containing human perforin protein, and showed negative with inactive human peripheral blood lymphocytes (PBLs). The subclasses of the three McAbs were determined as lgG2bK. Western blot results showed that the three McAbs recognized a specific band of LAK cell lysateds with molecular weight of 70.0Kd. Conclusion The three hybridoma cell lines secreting McAbs against human perforin were established and the secreted McAbs were specific.

Objective To construct eukaryotic expression vector of HPV18 L1- E6, E7 chimeric gene and examine the humoral and cellular immune responses induced by this DNA vaccines in mice. Methods The C-terminal of major capsid protein L1 gene and mutant zinc finger domains of early E6/7 oncogenes in HPV18 were integrated and inserted into eukaryotic expression vector pVAX1 to generate vaccines pVAX1-L1E6Mxx, E7Mxx. CHO cells were transiently transfected with the individual construct. Target protein expressions in the lysate of the transfected cells were measured by ELISA and immunocytochemistry. After BALB/c mice were vaccinated with various recombinant plasmids(pVAX1-L1-E6M3 or pVAX1-L1-E7M3) and immunie adjuvants (pLXHDmB7-2 or LTB) through different administration routes (intramuscular or intranasal) , the great cellular immune responses were produced as revealed by delayed-type hypersensitivity (DTH) and lymphocyte proliferation, and the expression of IL-4 and IFN- γ cells in CD4+ and CD8+subpopulations. Results The highly efficient expression of pVAX1-L1E6Mxx, E7Mxx vector in host eukaryotic cells were demonstrated both by ELISA and immunocytochemistry. The level of specific serum IgG against HPV in experiment groups mice was much higher than that of control group, and intranuscular immunization group had the highest antibody level. Intramuscular immunization groups were superior to intranasal immunization groups in DTH response, splenocyte proliferation and CD8+ IFN-γ + cells number, but CD4+ IL4+ cell number was higher in intranasal immunization groups. The immunization groups using pLXHDmB7-2 as adjuvant were superior to other groups in immunoresponse. Conclusion These DNA vaccines produce remarkable cellular and humoral immuneresponses in the mouse and may provide as prophylatic and therapeutic candidates for HPV induced cancer treatment.

Objective Attenuated strains of Shigella are attractive live vaccine candidates for eliciting mucosal immune responses which is a suitable carrier for the prophylactic human papillomaviruses (HPV) vaccine development, To examine the potential of a live Shigella based prophylactic HPV vaccine, HPV16L1should be expressed in attenuated shigella strain. Methods A Shigella large invasive plasmid (icsA/virG) based prokaryotic expression plasmid pHS3199 was constructed. HPV16L1 gene was inserted into plasmid pHS3199 to form pHS3199-HPV16 L1 construct, and pHS3199-hpv16L1 was electroporated into a live attenuated shigella strain sh42. The expression of HPV16L1 protein was demonstrated by Western blotting with monoclonal antibody to HPV16L1, The genetic stability of recombinant strain sh42-HPV16 L1 was monitored by consecutive passage culture. Invasive ability of sh42-HPV16L1 was evaluated by Hela cell infection assay. Results HPV16 L1 protein can be expressed in recombinant strain sh42-HPV16 L1, and the protein stably expressed over 140 generations. The invasive ability of sh42-HPV16L1 was diminished dramatically compared to its parent strain, but not abolished completely. Conclusion HPV16L1 protein was constitutively expressed in the attenuated strain of shigella flexneri sh42, and maintained partial invasive ability. Our strategy may represent a promising vaccine candidate against genital HPV16 infection.

Objective To express human B7.2 extracellular domain with prokaryote expression system and to evaluate its biological activity in vitro. Methods PCR was used to amplify the extracellular region of human B7. 2which contained both the IgV and IgC domains. The recombinant PGEX-4T-3/hB7. 2 (IgV+C) was obtained by cloning the PCR product into a prokaryote expression plasmid PGEX-4T-3 and was transformed into the host strain of DH5-α. The fusion protein consisted of GST and hB7.2(IgV+C) was identified by SDS-PAGE and Western blotting.T cell activation was observed by exposing purified T lymphocytes to the fusion protein and [3H]-TdR incorporation with the presence of the first signal imitated by anti-CD3 antibody. Results The fusion protein GST-hB7.2 (IgV+C) was produced and detected in inclusive body form from engineered bacterial cells. With the first signal existed,T lymphocytes proliferated when it was co-stimulated by the fusion protein. Conclusion These results indicated that the functional human B7.2(IgV+C) fusion protein can be produced in bacterial cells and the fusion protein displays the co-stimulatory activity in T lymphocytes activation.

Objective　To elucidate the mechanism of interferon-gamma (IFN-γ) to inhibit the restenosis after successful percutaneous transluminal angioplasty (PTA). Methods　A rabbit vascular restenotic model was constructed and the proliferation of intimal smooth muscle cells (SMCs) were observed by monitoring their expression of proliferating cell nuclear antigen (PCNA) and platelet-derived growth factor β chain mRNA (PDGF-β mRNA) at the indicated time points. Results　IFN-γ could significantly inhibit the expression of PCNA by intimal SMCs one week after denudation, when counting 200 intimal cells for PCNA-positive reactions with an inhibitory rate of 88.50% (P<0.001). IFN-γ could downregulate in situ expression of PDGF-β mRNA by these cells as we calculated the average number of PDGF-β mRNA positive cells per square millimetre area at ×400 magnification with reduced rates of 86.85% in 1 week group (P<0.001), of 93.66% in 2 week group (P<0.001) and of 52.92% in 4 week group (0.02

OBJECTIVETo investigate the specific cell-mediated immune efficacy of the an HPV16 prophylactic vaccine.

METHODSC57BL/6 mice were randomly divided into 3 groups: experimental group I (treated with pcDNA L1), control group II (treated with pcDNA3.1) and control group III (treated with PBS buffer). The mice were immunized three times during a three-week interval. Ten to fourteen days after the third inoculation, a footpad swelling test was used to detect delayed-type hypersensitivity (DTH) responses. Antigen-specific splenocyte proliferation assay and quantitation of IFN-gamma cells in splenocytes were performed by FACS assay.

RESULTSIn the experimental group, splenocytes actively proliferated after stimulation with HPV16 VLP, and had developed a markedly larger amount of CD8(+) IFN-gamma(+) cells, which is an index for special CTL. Also, the footpad was significantly thickened upon inoculation with HPV16 VLP.

CONCLUSIONNaked DNA vaccine of HPV16 L1 can induce specific cell-mediated immune responses in mice, which should be considered for evaluation of HPV16 DNA vaccine feasibility.

Animals ; Hypersensitivity, Delayed ; etiology ; Immunization ; Interferon-gamma ; biosynthesis ; Lymphocyte Activation ; Mice ; Mice, Inbred C57BL ; Papillomaviridae ; immunology ; Spleen ; cytology ; Vaccines, DNA ; immunology ; Viral Vaccines ; immunology

Objective It has been well accepted that human papillomavirus type 16 (HPV16) is associated with human cervical cancer and HPV16 L1 protein could induce both humoral and cellular immune responses. The objective of this study is to map epitopes on HPV16 L1 protein and to provide information to the design of HPV16 prophylactic peptide vaccine.Methods The epitopes on L1 protein were screened by polyclonal and 2 monoclonal antibodies (B8 and F4G3) against HPV16 L1 protein from a 6-mer phage display epitope library with the method of immuno-affinity screening (Bio-panning). After 3 rounds of Bio-panning, the positive phages were detected by L1 antibodies again with ELISA. The positive phages reacted strongly with L1 antibodies were then identified by DNA sequencing.Results Three mimotopes have been screened by polyclonal and two monoclonal antibodies. The mimotope (LSLFSC) which reacted with monoclonal antibody B8 showed 50% homology with the sequence 270～275a.a (DSLFFY) of prototype HPV16 L1. Another mimotope (LTSSYS) which reacted with polyclonal antibodies had 66% homology with the L1 sequence 516～521a.a (TTSSTS), also a mimotope (DRWDRF) was found to have the homologic RF with the known L1 sequense 441～446a.a. The mimotopes LSLFSC and DRWDRF were adjacent to the epitopes at 267～269a.a and 422～441a.a reported by other researchers previously.Conclusions Our results suggested that there might be a batch of epitopes on HPV16 L1 protein, and the predominant epitopes of HPV16 L1 protein were located in the above two domains. These results would be heplful for the design of HPV16 prophylactic peptide vaccines and HPV polyvalent vaccines.

OBJECTIVETo investigate which of the two immunoglobulin (Ig)-like domains, the immunoglobulin variable region homologous domain IgV (hB7.2 IgV) and the immunoglobulin constant region homologous domain IgC (hB7.2 IgC) on the human B7.2 molecule contains receptor binding sites, and to evaluate whether the B7.2 protein expressed in bacteria has biological activity in vitro.

METHODSThree fragments of hB7.2 IgV,hB7.2 IgC and the complete extracellular region of human B7.2 containing both the IgV and IgC domains,hB7.2 Ig (V+C), were amplified by PCR and subcloned into pGEM-Teasy. Three recombinants,pGEX-4T-3-hB7.2 IgV,pGEX-4T-3-hB7.2 IgC and pGEX-4T-3-hB7.2 Ig (V+C), were generated by cloning the fragments into a prokaryote expression plasmid (pGEX-4T-3) and transformed into the host strain E. coli DH5alpha. The relevant target fusion proteins consisting of GST and hB7.2 IgV,hB7.2 IgC and hB7.2 Ig (V+C), were identified by SDS-PAGE and Western blotting. With the presence of the first signal imitated by anti-CD3 antibody, T cell activation was observed by exposing purified T lymphocytes to each soluble form of the three bacterially-produced human B7.2 fusion proteins by [(3)H]-TdR incorporation.

RESULTSThree recombinant fusion proteins of human B7.2, GST-hB7.2 IgV, GST-hB7.2 IgC and GST-hB7.2 Ig (V+C) were produced and detected in inclusion body form from engineered bacteria. With the first signal present,T lymphocytes proliferated when co-stimulated by bacterially-produced either GST-hB7.2 Ig (V+C) or GST-hB7.2 IgV fusion proteins, but not by GST-hB7.2 IgC.

CONCLUSIONSFunctional human B7.2 fusion protein can be produced in bacteria. The IgV-like domain of human B7.2 is sufficient for B7.2 to interact with its counter-receptors and co-stimulate T lymphocytes.

Antigens, CD ; pharmacology ; B7-2 Antigen ; Escherichia coli ; genetics ; Humans ; Immunoglobulin Constant Regions ; pharmacology ; Immunoglobulin Variable Region ; pharmacology ; Lymphocyte Activation ; Membrane Glycoproteins ; pharmacology ; Plasmids ; Recombinant Fusion Proteins ; pharmacology ; T-Lymphocytes ; immunology