Kai Hu

An ocular mucosal administration of nanoparticles containing DNA vaccine pRSC-gD-IL-21 confers protection against mucosal challenge with herpes simplex virus type 1 in mice

Herpes stromal keratitis (HSK) is a chronic inflammatory process caused by the infection of herpes simplex virus type 1 (HSV-1). Development of a HSV-1 vaccine is a priority because these infections are common and cannot be well prevented. It appears that the potential of nanocarriers in DNA vaccination will be required to augment the immune response to DNA vaccines. Therefore, in the study, nanoparticles Fe(3)O(4) coated with glutamic acid, DNA vaccine pRSC-gD-IL-21 and polyethylenimine were prepared and immunized in the mice by ocular mucosal administration. The immune responses and protection efficiency against HSV-1 challenge were also tested. The results showed that the nanoparticles containing DNA vaccine pRSC-gD-IL-21 induced mice to generate higher levels of specific neutralizing antibody, sIgA in tears, and IFN-γ, IL-4 in serum, and to enhance the cytotoxicities of NK cells and splenocytes as well as splenocyte proliferative response to glycoprotein D compared with those of the control mice. More importantly, the mice immunized with the experimental vaccine showed less HSK degree than that of the control mice after HSV-1 challenge of the murine ocular mucosa. In conclusion, an ocular mucosal administration of nanoparticles containing DNA vaccine confers strong specific immune responses and effective inhibition of HSK in a HSV-1 infected murine model.

Enhancing therapy of B16F10 melanoma efficacy through tumor vaccine expressing GPI-anchored IL-21 and secreting GM-CSF in mouse model

In the present study, we developed the tumor vaccine expressing IL-21 in the GPI-anchored form together with secreting GM-CSFs and investigated its antitumor efficacy in C57BL/6 mouse model. The fusion genes containing IL-21 and the GPI anchor signal sequence were acquired by overlaping PCR, inserted into the downstream of two multi-clone sites in recombinant plasmid pRSC/GM-CSFs to form pRSC/IL-21-gpi-GM-CSFs that was transfected into the B16F10 cells. The tumor cell vaccine B16F10/IL-21-gpi-GM-CSFs was identified by reverse transcription PCR, IFA and FCM, respectively. The results showed that the pRSC/IL-21-gpi-GM-CSFs had no cell cycle and proliferative state impact on the B16F10 cells after transfected, and that the tumor vaccine B16F10/IL-21-gpi-GM-CSFs increased the cytotoxicities of NK cells and CD8(+)CTL, enhanced the level of serum IFN-gamma, augmented therapy of tumor effect and prolonged survival time in the tumor-bearing mice immunized with the tumor vaccine B16F10/IL-21-gpi-GM-CSFs. The data that we presented here provided a rationale and practical platform for clinical testing of enhancing cell therapy of B16F10 melanoma efficacy by modified tumor vaccine expressing GPI-anchored IL-21 and secreting GM-CSF.

Identifying tumor stem-like cells in mouse melanoma cell lines by analyzing the characteristics of side population cells

Increasingly more evidence shows that TSCs possess the characteristics of stem‐like cells. However, a link between stem cells and TSCs remains to be shown. We have sorted SP cells and non‐SP cells from the B16F10 cell lines by FACS, and then studied their cellular biological characteristics by using a SFCM culture method, proliferative assay in vitro, clone formation assays in soft agar and normal media, tumorigenic assays in C57BL/6 mice, and resistance to chemotherapy assay in vitro, the quantitative detecting expression of ABCG2 and their CD phenotype analysis by a FCM. We detected 0.96% SP cells in the B16F10 cells and found that they had obvious differences in characteristics from non‐SP cells. They possessed a marked capacity for self‐renewal in soft agar and culture medium, strong tumorigenic potential in C57BL/6 mice, apparent resistance to vinblastin in vitro, upregulated ABCG2 expression, and a high expression of CD44+CD133+CD24+ phenotypes. We conclude that there were a few of SP cells that had the characteristics of tumor stem‐like cells which may provide a useful tool and a readily accessible source for further study when specific TSCs markers are unknown.

Antitumor efficacy induced by human ovarian cancer cells secreting IL-21 alone or combination with GM-CSF cytokines in nude mice model.

The ovarian cancer cells (SKOV3) secreting IL-21 alone or combination with GM-CSF cytokines was developed and its antitumor effect was evaluated in the nude mice. The gene of IL-21 was amplified from plasmid pRSC-IL-21 by PCR, cloned into the plasmid pRSC-GM-CSF, and the plasmid pRSC-GM-CSF-IL21 was constructed. The plasmids of pRSC-GM-CSF, pRSC-IL21, pRSC-GM-CSF-IL21 and pRSC were respectively transfected into the SKOV3 cells and antitumor efficacy induced by the SKOV3 cells secreting IL-21 or combination with GM-CSF was evaluated by surveying the tumor growth and the nude mices survival. The results indicated that the secreted IL-21 and GM-CSF were functional because the culture supernatant of SKOV3 cells transfected with the plasmid pRSC-GM-CSF-IL21 enhanced NK cytotoxicity in vitro. The expressions of MIC A/B, NKG2D and ICAM-1 molecules on the SKOV3 cells were up-regulated. The level of IFN-gamma and TNF-alpha, the NK cytotoxicity and the antitumor efficacy were significantly increased in the null mice inoculated with the SKOV3 cells secreting both IL-21 and GM-CSF in comparison with the nude mice inoculated with the other different SKOV3 cells. We concluded that the SKOV3 cells genetically engineered to secrete biologically active IL-21 and GM-CSF elicited antitumor immunity effectively through enhancing NK cytotoxicity, promoting the expressions of MIC A/B , ICAM-1 and NKG2D molecules as well as elevating level of IFN-gamma and TNF-alpha in the nude mice model.

Protection against Mycobacterium tuberculosis challenge in mice by DNA vaccine Ag85A-ESAT-6-IL-21 priming and BCG boosting

Tuberculosis (TB) is one of most important chronic infectious diseases caused by Mycobacterium tuberculosis and remains a major global health problem. In the study, we developed the DNA vaccine encoding fusion protein of antigen 85 A and 6 kDa early secretory antigen target of M. tuberculosis as well as the cytokine IL‐21 to investigate its immune protective efficacy against M. tuberculosis challenge in mice after the DNA vaccine priming and Bacille Calmette‐Guérin (BCG) boosting. Compared with the different control groups, the intranasal DNA vaccine priming twice and BCG boosting once markedly increased the cytotoxicities of natural killer cells and splenocytes and enhanced the interferon‐γ level in the splenocyte supernatant as well as sIgA level in bronchoalveolar lavage in the vaccinated mice. Importantly, this heterologous prime–boost strategy significantly decreased the bacterial load in the mouse lungs in contrast to that of intranasal or subcutaneous BCG immunization alone. These findings provide further approaches for mucosal‐targeted prime–boost vaccination to fight against TB.

Augmenting therapy of ovarian cancer efficacy by secreting IL-21 human umbilical cord blood stem cells in nude mice.

In the present study, CD34+ human umbilical cord blood stem cells (UCBSCs) were engineered to express interleukin-21 (IL-21) and then were transplanted into A2780 ovarian cancer xenograft-bearing Balb/c nude mice. The therapeutic efficacy of this procedure on ovarian cancer was evaluated. The findings from the study indicated that UCBSCs did not form gross or histological teratomas until up to 70 days postinjection. The CD34+ UCBSC-IL-21 therapy showed a consistent effect in the ovarian cancer of the treated mice, delaying the tumor appearance, reducing the tumor sizes, and extending life expectancy. The efficacy was attributable to keeping CD34+ UCBSC-IL-21 in the neoplastic tissues for more than 21 days. The secreted IL-21 not only increased the quantity of CD11a+ and CD56+ NK cells but also increased NK cell cytotoxicities to YAC-1 cells and A2780 cells, respectively. The efficacy was also associated with enhancing the levels of IFN-γ, IL-4, and TNF-α in the mice as well as the high expressions of the NKG2D and MIC A/B molecules in the tumor tissues. This study suggested that transferring CD34+ UCBSC-IL-21 into the nude mice was safe and feasible in ovarian cancer therapy, and that the method would be a promising new strategy for clinical treatment of ovarian cancer.

Investigation of immunogenic effect of the BCG priming and Ag85A- GM-CSF boosting in Balb/c mice model.

Mycobacterium tuberculosis (M. tuberculosis) has once again become a major public health threat owing to the combined effects of a worldwide anti-tuberculosis drug resistance and the emergence of the human immunodeficiency virus pandemic. The Bacille Calmette-Guérin (BCG)-based vaccine has displayed inconsistent efficacy in different trials although it continues to be used to prevent tuberculosis in many countries. In current work, we have developed DNA vaccines expressing M. tuberculosis antigen 85A (Ag85A) and cytokine granulocyte macrophage colony stimulating factor (GM-CSF) and aimed to investigate the immune effect in mice based on BCG priming and DNA vaccine boosting and immune protection against M. tuberculosis challenge. Our results showed that the activity of cytotoxic T lymphocyte and spleen cell proliferative responses to Ag85A and IFN-gamma level as well as the specific antibody titer against Ag85A were significantly increased in mice immunized with prime-boost strategy in comparison with the mice immunized with BCG or DNA vaccine expressing Ag85A and GM-CSF alone. Meanwhile, the immune strategy of BCG-prime and DNA vaccine boost induced mice to generate efficient immune protection against M. tuberculosis challenge. Our data demonstrate that BCG-prime and DNA vaccine expressing Ag85A and GM-CSF boost provides a rational strategy for further development of DNA vaccine against M. tuberculosis infection.

Nanoparticle-based adjuvant for enhanced protective efficacy of DNA vaccine Ag85A-ESAT-6-IL-21 against Mycobacterium tuberculosis infection.

UNLABELLED The goal of this study was to evaluate the protective efficacy of a cationic nanoparticle-based DNA vaccine expressing antigen 85A (Ag85A) and 6-kDa early secretory antigen target (ESAT-6) of Mycobacterium tuberculosis as well as cytokine interleukin-21 (IL-21) against M. tuberculosis infection. The results of this indicated that the anti-M. tuberculosis immune responses were induced in mice that had received the different DNA vaccines. More importantly, compared with using DNA vaccine Ag85A-ESAT-6-IL-21 alone, the nanoparticle-based DNA vaccine Ag85A-ESAT-6-IL-21 showed a statistically significant increase in the protective efficacy against M. tuberculosis infection in the immunized mice. We concluded that the nanoparticle-based DNA vaccine induced a strong immune response and markedly inhibited the growth of the M. tuberculosis in the mice. These findings highlighted the potential utility of Fe3O4-Glu-polyethyleneimine nanoparticles encapsulated with the DNA vaccine as a prophylactic vaccine in the M. tuberculosis-infected mouse model. FROM THE CLINICAL EDITOR This study emphasizes the potential utility of Fe3O4-Glu-polyethyleneimine nanoparticles encapsulated with DNA vaccine against TB as a prophylactic vaccine. The authors demonstrated a strong immune response and marked growth inhibition of mycobacterium tuberculosis in the mice.

Investigation on the anti-tumor efficacy by expression of GPI-anchored mIL-21 on the surface of B16F10 cells in C57BL/6 mice

GPI-anchored membrane cytokines have been shown to play an important role in host immune response against tumor cells. In the present study, we constructed the tumor vaccine expressing mIL-21 in the GPI-anchored form and investigated its anti-tumor effect in C57BL/6 mice model. The fusion genes containing mIL-21 and the GPI anchor signal sequence was acquired by overlaping PCR, inserted into plasmid pcDNA3.1 to form the pcDNA3.1 mIL-21-GPI recombinant, which was transfected into the B16F10 cells, and the tumor vaccine based on B16F10 cells expressing the GPI-anchored membrane mIL-21 was generated. Through transfection, it was found that GPI-anchored membrane mIL-21 has no proliferate impact on B16F10 cells, but it was functional and reflected in inducing CD3-activated murine splenocytes proliferation response to B16F10 cells, improving the cytotoxicities of CTL and NK cells, increasing the numbers of splenocytes-producing IFN-gamma in mice, augmenting therapeutic effect of tumor and prolonging longevity effects in tumor-bearing mice injected with the inactivated GPI-anchored mIL-21 tumor vaccine. We concluded the expression of mIL-21 on the B16F10 cells surface in the GPI-anchored form was proved to be effective in activating immune responses against tumor cells, and our results provided a good foundation for further investigating the immunotherapy of tumor by GPI-mIL-21.

Immunization with DNA Vaccine Expressing Herpes Simplex Virus Type 1 gD and IL-21 Protects against Mouse Herpes Keratitis

The development of novel vaccines to eradicate herpes simplex virus (HSV) is a global public health priority. In this study, we developed a DNA vaccine expressing HSV-1 glycoprotein D (gD) and mouse interleukin-21(IL-21) and intramuscularly inoculated mice 3 times at 2-week intervals with a total of 300 μg/mouse. Two weeks after the last immunization the specific antibody, splenocyte proliferative response to gD, IFN-γ and IL-4 as well as the cytotoxic activities of splenocytes and natural killer (NK) cells were assayed. Immune protection against herpes keratitis was concurrently evaluated in the immunized mice after HSV-1 challenge of the mouse cornea. The results showed that the DNA vaccine pRSC-gD-IL-21 generated higher levels of antibody, IFN-γ and IL-4, and enhanced the splenocyte proliferative response to gD as well as the cytotoxic activity of splenocytes and NK cells to target cells compared with the response in either the pRSC-gD or mock plasmid pRSC immunized mice. Importantly, the pRSC-gD-IL-21 ameliorated herpes keratitis severity and time course after corneal infection with HSV-1. The findings suggest that the DNA vaccine pRSC-gD-IL-21 may induce an immune response that can limit HSV-1 infection and development of herpes keratitis in the immunized mice.