Human gamma/delta T cell Recognition of lipid A is predominately presented by CD1b or CD1c on dendritic cells
The gamma/delta T cells serve as early immune defense against certain encountered microbes. Only a few gamma/delta T cell-recognized ligands from microbial antigens have been identified so far and the mechanisms by which gamma/delta T cells recognize these ligands remain unknown.
Here we explored the mechanism of interaction of human gamma/delta T cells in peripheral blood with Lipid A (LA).
Results: First, resting gamma/delta T cells (mainly V delta2 T cells) displayed a strong proliferative response to LA-pulsed monocyte-derived dendritic cells (moDC) and LA-pulsed paraformaldehyde-fixed moDC, but not to free LA in a TCR gamma/delta-dependent manner. Second, anti-CD1b or anti-CD1c antibodies could block proliferative response of resting gamma/delta T cells to LA-loaded moDC.
Besides, only LA-loaded CD1b/CD1c-transfected C1R lymphoblastoma cells (CD1b-/CD1c-C1R) were able to stimulate the proliferation of human gamma/delta T cells. Third, the expressions of both Toll-like receptor (TLR)2 and TLR4 on surface of LA-activated gamma/delta T cells were upregulated, whereas only anti-TLR4 antibody could partially block their response to LA; Finally LA-loaded moDCs induce gamma/delta T cells to produce Th1 cytokines, such as IFN-gamma.
Conclusions: Taken together, we found a novel mechanism that human gamma/delta T cells recognize LA in a CD1b- or CD1c-restricted manner in first response against Gram- bacteria, while the interaction between TLR4 on gamma/delta T cells and LA might strengthen the subsequent response of gamma/delta T cells.Reviewers: This article was reviewed by Dr.Youwen He (nominated by Dr.Laurence C Eisenlohr),Dr.Hao Shen,Dr.Michael Lenardo and Dr.
Pushpa Pandiyan.
Author: Yongchun CuiLei KangLianxian CuiWei He
Credits/Source: Biology Direct 2009, 4:47
Published on: 2009-12-01
Copyright by the authors listed above - made available via BioMedCentral (Open Access). Please
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