Impact of Fut1 KO splenocytes and THBS1 on T cell proliferation
and differentiation
Next, to investigate the effects of Fut1 KO splenocytes and their
reduced levels of THBS1 on the proliferation and differentiation of CD4
T cells, we cocultured CD4+ cells isolated from WT
mice with either Fut1 KO splenocytes or WT splenocytes
(Fig. 2A ). The CFSE dilution assay revealed that the
proliferation of CD4+ cells cocultured withFut1 KO splenocytes was significantly higher than those
cocultured with WT splenocytes (Fig. 2B ). Remarkably, the
addition of THBS1 to the coculture reversed the effects of Fut1KO splenocytes on CD4+ cell proliferation (Fig. 2A ).
Similar findings were observed with CD4 T cell differentiation. The
coculture of CD4+ cells with Fut1 KO
splenocytes significantly induced the differentiation of
CD4+ cells into
IFN-γ+CD4+ Th1 cells and
IL-17+CD4+ Th17 cells, compared to
the coculture with WT splenocytes (Fig. 2C ). The replenishment
of THBS1 in CD4+ cell-Fut1 KO splenocyte
cocultures effectively suppressed the differentiation of
CD4+ cells into Th1 and Th17 subsets (Fig.
2C ). However, neither Fut1 KO splenocytes nor THBS1 affected the
differentiation of CD4+ cells into
Foxp3+ regulatory T cells (Tregs) (Fig. 2D ).
Furthermore, we examined the levels of inflammatory cytokines in the
coculture supernatants. The secretion of IL-2, IFN-γ and IL-17 were
significantly increased, while IL-10 was reduced, in
CD4+ cells cocultured with Fut1 KO splenocytes
compared to those cocultured with WT splenocytes (Fig. 2E ).
THBS1 was also effective in reducing the levels of IL-2, IFN-γ and
IL-17, as well as enhancing IL-10, in the coculture of
CD4+ cells and Fut1 KO splenocytes
(Fig. 2E ).
These results suggest that Fut1 KO splenocytes promote CD4 T cell
proliferation and the differentiation towards Th1 and Th17 cells through
reduced levels of THBS1 at least in part.