Comparison of Immune Responses Induced in Mice by Vaccination with DNA Vaccine Constructs Expressing Mycobacterial Antigen 85A and Interleukin-21 and Bacillus Galmette-Guérin

Abstract

In this paper, we addressed the immune adjuvant effects of interleukin(IL)-21 on DNA vaccine constructs expressing mycobacterium tuberculosis (TB) Ag85A and compared immune responses induced in mice inoculated DNA vaccine constructs expressing Ag85A and IL-21 with mice inoculated DNA vaccine constructs expressing Ag85A alone or Bacillus Galmette-Guérin(BCG.). In this experiment, the gene of IL-21 was firstly amplified from plasmid pcDNA3.1-mIL21 by PCR and cloned into the plasmid pRSC, forming recombinant plasmid pRSC-IL21. Then, the gene of Ag85A was amplified from the plasmid pIRES-Ag85A by PCR and cloned into the recombinant pRSC-IL21 again, finally forming co-expression DNA vaccine constructs pRSC-IL21-Ag85A. It was identified by the analysis of endonuclease digestion, DNA sequencing, the IL-21 and Ag85A expression in SP2/0 cells. Mice were i.m. immunized with BCG, DNA vaccine constructs pRSC-Ag85A or pRSC-IL21-Ag85A respectively, and the immune responses induced in mice was compared with other vaccines. The results showed that the DNA vaccine constructs pRSC-IL21-Ag85A was successfully constructed since the Ag85A and IL-21 was correctly expressed in SP2/0 cells respectively, and it elicited stronger immune responses in Balb/c mice than that of mice immunized with pRSC-Ag85A and the efficiency was as BCG did. We concluded that the IL-21 was a promising immune adjunctive modality to enhance immunigenicity of DNA vaccine containing Ag85A and the study provided the possibility of further development of immune accessory effect of IL-21 on DNA vaccine against TB.

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

“…The activity of NK was detected by MTT colorimetry method (Dou et al, 2008;Mosmann, 1983). The harvested splenocytes were washed with phosphatebuffered saline (PBS) and resuspended in complete medium.…”

“…Recombinant plasmid pRSC-GM-CSF-IL21 was developed using the method from the published report (Dou et al, 2008), which was identified by the analysis of an endonuclease digestion, DNA sequence and RT-PCR, respectively.…”

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

“…Clearly, on the basis of these experimental data, our results suggest that the vaccination strategies based on the BCG priming-D-NA vaccine boosting is a good way in eliciting CMI and the humoral immune response to M. tuberculosis. We think that the biological function of GM-CSF is similar to that of IL-21 (Dou et al 2008), being a promising immune adjunctive modality to enhance immunigenicity of the DNA vaccine containing Ag85A in the mouse model. The strategy of BCG priming-DNA vaccine boosting can enhance the helper T lymphocyte type 1 immunity response and production of antigen-specific antibody.…”

“…The reported data showed that the GM-CSF could induce secondary cytokine production, particularly IFN-g. The increased IFN-g can efficiently enhance CTL activity and in turn CTL, macrophage and NK cells can also promote IFN-g production, enhancing the lymphocytes immune response to target cells (Carlo et al 2004;Herrlinger et al 2004;Dou et al 2008). Our results indicated that the increased IFN-g was secreted by the NK cells and the CTL in mice immunized by different vaccines, and that the increased IFN-g can also react on the CTL and the NK cells, enhancing their cytotoxic activities, playing a key biological role in anti-tuberculosis.…”

Immunoprophylaxis of Tuberculosis: An Update of Emerging Trends

“…The other advantage of DNA vaccines is that they can be constructed together with immunostimulatory DNA sequences such as the CpG sequences (Iwasaki et al 1997;Tokunaga et al 1999) and cytokines to enhance their immunogenicity. Interleukins were found to possess promising adjunctive modality and the capability to enhance immunogenicity of many DNA vaccines, such as DNA vaccines encoding antigen 85B with interleukin (IL)-23 (Wozniak et al 2006), antigen 85A with IL-21 (Dou et al 2008), heat-shock protein 65 (HSP65) with IL-12 (Yoshida et al 2006), and HSP65 with IL-2 (Wang et al 2008). Xu et al reported the adjuvant character of Flt3 ligand (FL), a growth factor of dendritic cells (Xu et al 2008).…”