TY - JOUR
T1 - Mycobacterium tuberculosis RpfB drives Th1-type T cell immunity via a TLR4-dependent activation of dendritic cells
AU - Kim, Jong Seok
AU - Kim, Woo Sik
AU - Choi, Han Gyu
AU - Jang, Byungki
AU - Lee, Keehoon
AU - Park, Jong Hwan
AU - Kim, Hwa Jung
AU - Cho, Sang Nae
AU - Shin, Sung Jae
PY - 2013/10
Y1 - 2013/10
N2 - The failure of Mycobacterium bovis BCG as a TB vaccine against TB reactivation suggests that latency-associated proteins should be included in alternative TB vaccine development. Further, antigens known to generate protective immunity against the strong Th1 stimulatory response to reactivated TB should be included in novel vaccine design. Recent studies have emphasized the importance of Rpfs from Mycobacterium tuberculosis in the reactivation process and cellular immunity. However, little is known about how RpfB mediates protective immunity against M. tuberculosis. Here, we investigated the functional roles and signaling mechanisms of RpfB in DCs and its implications in the development of T cell immunity. DCs treated with RpfB displayed features of mature and functional status, with elevated expression of cell surface molecules (CD80, CD86, and MHC class I and II) and proinflammatory cytokine production (TNF-α, IL-1β, IL-6, and IL-12p70). Activation of DCs was mediated by direct binding of RpfB to TLR4, followed by MyD88/TRIF-dependent signaling to MAPKs and NF-κB signaling pathways. Specifically, we found that the RpfB G5 domain is the most important part in RpfB binding to TLR4. RpfB-treated DCs effectively polarized naïve CD4+ and CD8+ T cells to secrete IFN-γ and IL-2. Importantly, RpfB induced the expansion of memory CD4+/CD8+CD44highCD62Llow T cells in the spleen of M. tuberculosis-infected mice. Our data suggest that RpfB regulates innate immunity and activates adaptive immunity through TLR4, a finding that may help in the design of more effective vaccines.
AB - The failure of Mycobacterium bovis BCG as a TB vaccine against TB reactivation suggests that latency-associated proteins should be included in alternative TB vaccine development. Further, antigens known to generate protective immunity against the strong Th1 stimulatory response to reactivated TB should be included in novel vaccine design. Recent studies have emphasized the importance of Rpfs from Mycobacterium tuberculosis in the reactivation process and cellular immunity. However, little is known about how RpfB mediates protective immunity against M. tuberculosis. Here, we investigated the functional roles and signaling mechanisms of RpfB in DCs and its implications in the development of T cell immunity. DCs treated with RpfB displayed features of mature and functional status, with elevated expression of cell surface molecules (CD80, CD86, and MHC class I and II) and proinflammatory cytokine production (TNF-α, IL-1β, IL-6, and IL-12p70). Activation of DCs was mediated by direct binding of RpfB to TLR4, followed by MyD88/TRIF-dependent signaling to MAPKs and NF-κB signaling pathways. Specifically, we found that the RpfB G5 domain is the most important part in RpfB binding to TLR4. RpfB-treated DCs effectively polarized naïve CD4+ and CD8+ T cells to secrete IFN-γ and IL-2. Importantly, RpfB induced the expansion of memory CD4+/CD8+CD44highCD62Llow T cells in the spleen of M. tuberculosis-infected mice. Our data suggest that RpfB regulates innate immunity and activates adaptive immunity through TLR4, a finding that may help in the design of more effective vaccines.
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U2 - 10.1189/jlb.0912435
DO - 10.1189/jlb.0912435
M3 - Article
C2 - 23825389
AN - SCOPUS:84884860727
VL - 94
SP - 733
EP - 749
JO - Journal of Leukocyte Biology
JF - Journal of Leukocyte Biology
SN - 0741-5400
IS - 4
ER -