作者: Boyd, Lisa F. ; Honda, Mitsuo ; Komine‐Aizawa, Shihoko ; Matsuo, Kazuhiro ; Hayakawa, Satoshi ; Jiang, Jiansheng ; Margulies, David H. ; Mizuno, Satoru

AbstractDespite efforts to develop effective treatments and vaccines, Mycobacterium tuberculosis (Mtb), particularly pulmonary Mtb, continues to provide major health challenges worldwide. To improve immunization against the persistent health challenge of Mtb infection, we have studied the CD8+ T cell response to Bacillus Calmette‐Guérin (BCG) and recombinant BCG (rBCG) in mice. Here, we generated CD8+ T cells with an rBCG‐based vaccine encoding the Ag85B protein of M. kansasii, termed rBCG‐Mkan85B, followed by boosting with plasmid DNA expressing the Ag85B gene (DNA‐Mkan85B). We identified two MHC‐I (H2‐Kd)‐restricted epitopes that induce cross‐reactive responses to Mtb and other related mycobacteria in both BALB/c (H2d) and CB6F1 (H2b/d) mice. The H2‐Kd‐restricted peptide epitopes elicited polyfunctional CD8+ T cell responses that were also highly cross‐reactive with those of other proteins of the Ag85 complex. Tetramer staining indicated that the two H2‐Kd‐restricted epitopes elicit distinct CD8+ T cell populations, a result explained by the X‐ray structure of the two peptide/H2‐Kd complexes. These results suggest that rBCG‐Mkan85B vector‐based immunization and DNA‐Mkan85B boost may enhance CD8+ T cell response to Mtb, and might help to overcome the limited effectiveness of the current BCG in eliciting tuberculosis immunity.

2017-05-01·Experimental and Therapeutic Medicine4区 · 医学

Recombinant Bacille Calmette-Guérin coexpressing Ag85B-IFN-γ enhances the cell-mediated immunity in C57BL/6 mice

4区 · 医学

Article

作者: Wang, Honghai ; Yan, Jingran ; Shen, Hongbo ; Xu, Ying ; Liu, Wei ; Yang, Enzhuo

The only available vaccine against pulmonary tuberculosis is Bacille Calmette-Guérin (BCG). As the efficacy reported of the vaccine is not up to the mark, there is an urgent need to develop improved anti-tuberculosis vaccines. Antigen 85B (Ag85B) is a very promising vaccine candidate molecule of Mycobacterium tuberculosis and interferon (IFN)-γ and has been considered the most attractive correlate of protective immunity. The aim of this study was to construct a novel recombinant BCG (rBCG) to secrete Ag85B and mouse IFN-γ under control of the Mycobacterial heat shock protein 60 (hsp60) promoter and the antigen signal sequence. Second aim of the present study is to evaluate the immune response in C57BL/6 elicted by the new rBCG. Expression of the fusion protein was readily detectable by western blotting and IFN-γ bioactivity was detected indirectly by enzyme-linked immunosorbent assay (ELISA). Compared with BCG, rBCG::Ag85B-IFN-γ was substantially more active in inducing the production of IFN-γ and tumor necrosis factor (TNF)-α from mouse splenocytes. ELISA analysis for IgG, IgG1 and IgG2c showed that rBCG::Ag85B-IFN-γ induced higher titer of Ag85B and facilitated Th1 type immune response. rBCG::Ag85B-IFN-γ also improved nitric oxide production levels and enhanced antigen-specific splenocyte proliferation. Moreover, rBCG::Ag85B-IFN-γ induced human monocytes such as THP-1 cells to enhance expression of CD80, CD86, CD40 and HLA-DR. Flow cytometry analysis confirmed that rBCG::Ag85B-IFN-γ significantly activated CD4⁺ T cells. Assessing combinations of IFN-γ, TNF-α and interleukin-2 at the single-cell level by multiparameter flow cytometry, we found that rBCG::Ag85B-IFN-γ improved the multifunctional T cells level in comparison to BCG. In conclusion, the present study indicates that rBCG::Ag85B-IFN-γ increases cell mediated immune response and is a potential candidate vaccine for immunotherapeutic protocols against pulmonary tuberculosis.

2016-11-01·Innate Immunity4区 · 生物学

IL-21 inhibits IL-17A-producing γδ T-cell response after infection with Bacillus Calmette-Guérin via induction of apoptosis

4区 · 生物学

Article

作者: Ohara, Naoya ; Matsumura, Yumiko ; Huang, Yinxia ; Noguchi, Naoto ; Murakami, Tesshin ; Sun, Xun ; Hatano, Shinya ; Yoshikai, Yasunobu ; Iwakura, Yoichiro

Innate γδ T cells expressing Vγ6 produce IL-17A at an early stage following infection with Mycobacterium bovis Bacillus Calmette-Guérin (BCG). In this study, we used IL-21 receptor knockout (IL-21R KO) mice and IL-21-producing recombinant BCG mice (rBCG-Ag85B-IL-21) to examine the role of IL-21 in the regulation of IL-17A-producing innate γδ T-cell response following BCG infection. IL-17A-producing Vγ6+ γδ T cells increased in the peritoneal cavity of IL-21R KO mice more than in wild type mice after BCG infection. In contrast, the number of IL-17A-producing Vγ6+ γδ T cells was significantly lower after inoculation with rBCG-Ag85B-IL-21 compared with control rBCG-Ag85B. Notably, exogenous IL-21 selectively induced apoptosis of IL-17A-producing Vγ6+ γδ T cells via Bim. Thus, these results suggest that IL-21 acts as a potent inhibitor of a IL-17A-producing γδ T-cell subset during BCG infection.

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