J. Vet. Sci. 2016; 17(4): 505-513  https://doi.org/10.4142/jvs.2016.17.4.505
Mycobacterium vaccae induces a strong Th1 response that subsequently declines in C57BL/6 mice
Lijiao Zhang1,2, Yanlong Jiang1, Ziyin Cui1, Wentao Yang1, Limin Yue1, Yingcong Ma1, Shaohua Shi1, Chunfang Wang1, Chunfeng Wang1,*, Aidong Qian1,*
1College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China
2College of Biological Science, Changchun Teacher University, Changchun 130032, China
Correspondence to: Chunfeng Wang, Aidong Qian
Tel/Fax: +86-43184533425;
E-mails: wangchunfeng@jlau.edu.cn (C Wang), qianaidong0115@163.com (A Qian)
Received: October 5, 2015; Revised: December 24, 2015; Accepted: March 4, 2016; Published online: December 30, 2016.
Abstract
Mycobacterium (M.) vaccae is a fast-growing species of saprophytic bacteria that is widely distributed. To understand the host immune responses induced by M. vaccae isolated from bovine submaxillary lymph nodes, C57BL/6 mice were infected with reference strain M. bovis Bacillus Calmette-Gu?rin (BCG) and isolated M. vaccae using intraperitoneal injections. Comparison of the bacterial replication and organ pathology between M. vaccae and M. bovis BCG revealed that M. vaccae was more malignant than M. bovis in mice. We also demonstrated that serum from the M. vaccae-infected mice contained a higher expression level of gamma-interferon (IFN-γ), tumor necrosis factor alpha, monocyte chemoattractant protein-1, interleukin (IL)-4, IL-12, IL-10 and transforming growth factor beta than did the other groups, especially after week 4. Furthermore, when the numbers of CD3+CD4+IFN-γ+ and CD3+CD4+IL4+ cells in the infected mice were observed by flow cytometry, we found that a powerful T helper 1 (Th1) response was induced by M. vaccae infection, which was associated with the emergence of CD3+CD4+IFN-γ+ cells. However, the Th1 response declined over time, which was associated with appearance of the CD4+CD25+FoxP3+ and CD4+CD25+CD152+Treg cell reaction. In addition, a strong Th2 response was found. Finally, we found that M. vaccae infection increased the production of type I IFNs, which was associated with a reduced Th1 response.
Keywords: Mycobacterium bovis Bacillus Calmette-Gu?rin, Mycobacterium vaccae, Th1 cells response, regulatory T cell


© 2016 The Korean Society of Veterinary Science.