Linkage of modified human papillomavirus type 16 E7 to CD40 ligand enhances specific CD8+ T-lymphocyte induction and anti-tumour activity of DNA vaccine / 中国医学科学院学报

<p><b>OBJECTIVE</b>To develop human papillomavirus (HPV) 16 DNA vaccine for the treatment of HPV16 infection and its related tumors.</p><p><b>METHODS</b>HPV16 oncogene E7 was modified by combined approaches including insertion and replication of specific region of E7 gene, murine codon optimization, and point-mutation at transforming regions of the E7 protein. The resulting artificial gene, named as mE7, was obtained by gene synthesis. The mE7 gene was then genetically fused to murine CD40 ligand (CD40L) by overlapping PCR to form the mE7/CD40L fusion gene. The mE7/CD40L gene was inserted into pVR1012 plasmid and then immunized C57/BL6 mice intramuscularly. The E7-specific IFN-gamma-secreting CD8+ T cells were analyzed with EIISPOT, and E7-specific antibody was measured by indirect ELISA. FACS assays were performed to analyze the activation of E7-specific Th cells. Mice were vaccinated, followed by tumor challenged or challenged before immunization. Tumor growth was observed.</p><p><b>RESULTS</b>The mE7 DNA vaccine elicited an increased E7-specific antibody level (P < 0.01), E7-specific IFN-gamma-secreting CD8+ T (P < 0.01), and CD4+ T cells number (P < 0.05), compared with those of mice immunized with wE7 gene. Furthermore, the mE7/CD40L DNA vaccine elicited an increased number of E7-specific IFN-gamma secreting CD8+ T cell compared with that of mice immunized with mE7 gene (P < 0.01); however, no significant differences were found between mice immunized with the mE7 gene and mE7/CD40L fusion gene in the E7-specific antibody production and Th cell activation. In the preventive experiment, all mice received the mE7 or mE7/CD40L remained tumor-free 7 weeks after challenges with TC-1 tumor cells, while the wE7 group exhibited tumor growth within 2 weeks. In the therapeutic experiment, all the mice in the wE7 group exhibited tumor growth within 8 days, while among mice receiving the mE7 and mE7/CD40L, 30% and 45% of mice remained tumor-free after TC-1 challenge, respectively. HE staining of tumor tissues showed copious lymphocytes infiltration around tumor cells in mE7 and mE7/CD40L mice with regression of tumor growth.</p><p><b>CONCLUSIONS</b>The mE7 DNA vaccine increases the E7-specific humoral and cellular immune responses, and the fusion of CD40L to mE7 gene enhances the specific immune responses and anti-tumor effects against HPV16 E7-expressing murine tumors. mE7/CD40L may therefore be a suitable and promising target for HPV16 therapeutic vaccine.</p>

Encapsidating artificial human papillomavirus-16 mE7 protein in human papillomavirus-6b L1/L2 virus like particles / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Human papillomaviruses (HPVs) can infect squamous or mucosal epithelia and cause cervical cancer or genital warts. Coinfection with multiple HPV types is a common finding of many epidemiological studies. Therefore, it is necessary to develop a vaccine, which can eradicate established HPV infections and prevent other HPV infections. In this study, we generated chimeric virus like particles (cVLPs) composed of HPV-6b L1, HPV-6b L2 and one artificial HPV-16 mE7 proteins.</p><p><b>METHODS</b>The artificial HPV-16 mE7 gene was designed by codon modification, point mutation and gene shuffling then chemically synthesized and subcloned behind HPV-6b L2. HPV-6b L1 and L2-mE7 were expressed in insect cells by using Bac-to-Bac system. The generated cVLPs were purified by CsCl gradient ultracentrifuge and analyzed by immunoblot, electron microscope and haemagglutination assay.</p><p><b>RESULTS</b>The HPV-6b L1 and L2-mE7 proteins were well expressed in insect cells and could selfassemble into cVLPs, whose diameter was about 55 nm and similar to that of HPV-6b L1/L2 VLPs. Intact cVLPs could be recognized by H6.M48 neutralizing monoclonal antibody and HPV-6b L2 polyclonal antibody, while the denatured cVLPs, but not the intact cVLPs, were reactive to HPV-16 E7 polyclonal antibody. HPV-6b L1/L2-mE7 cVLPs haemagglutinated mouse erythrocytes as efficiently as HPV-6b L1/L2 VLPs did.</p><p><b>CONCLUSIONS</b>The insertion of the 158 amino acid HPV-16 mE7 protein behind L2 did not disrupt the correct assembling of cVLPs. The morphological characteristics and haemagglutinating activity of cVLPs were similar to those of HPV-6b L1/L2 VLPs. The cVLPs retained conformational B cell epitopes of HPV-6 VLPs and HPV-16 mE7 protein had an internal location in the cVLPs. Therefore, large modified E7 protein with higher immunogenicity could be incorporated into cVLPs by fusing to the C-terminus of L2, which would help to improve the therapeutic effects of L1/L2-E7 cVLPs.</p>

Enhancement of herpes simplex virus-1 glycoprotein-D DNA vaccine induced specific immune responses by coimmunization with interleukin-2 genetic adjuvant / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the immune responses and protection from virus challenge, induced by the coinjection of IL-2cDNA with herpes simplex virus type 1 (HSV-1) glycoprotein-D (gD) DNA vaccine.</p><p><b>METHODS</b>Two DNA vaccines (pgD and pIL-2) were constructed by inserting the gD gene and IL-2 cDNA into the eukaryotic expression vector pcDNA3.1, respectively. The BALB/c mice were inoculated intramuscularly three times at 2-week intervals. Two weeks after the final immunization, mice were bled for antibody assay and spleen cells were separated for Th cell proliferation and cytokine assays. Delayed type hypersensitivity (DTH) response was detected by the pinna-swelling test. Corneal protection under HSV-1 virus challenge was continuously observed with slit-lamp microscope.</p><p><b>RESULTS</b>IL-2 cDNA coinjection remarkably enhanced the specific IgG2a level when compared with gD plasmid vaccination alone. Th cell proliferation and secretion of cytokines (IL-2 and IFN-gamma) were significantly increased by IL-2 cDNA coinjection. However, the production of IL-10 was inhibited. The DTH response was also enhanced by IL-2 coinjection. When the mice were challenged with HSV-1, the cornea epithelial lesions were significantly alleviated by IL-2 coinjection as compared with gD vaccination alone.</p><p><b>CONCLUSION</b>IL-2 cDNA can enhance both the humoral and cellular immune responses, and thus increase the vaccine potency.</p>