Mechanism of CD138 expression in CD3+ T cells of MRL/lpr mice
Current research on CD138+ T cells remains limited, and little is known
about the mechanism underlying the CD138 expression in CD3+ T cells. A
recent study revealed that CD138+ T cells accumulated in MRL/lpr mice,
but not in non-lupus prone mice 14. Furthermore, CD3+
T cells in MRL/lpr mice have been shown to exhibit significantly
defective activation and proliferation, compared with the cells in
MRL/MPJ mice (unpublished data by Tianhong Xie et al.). Importantly,
previous research has demonstrated CD138+ T cells exhibit significantly
lower proliferation and activation in MRL/lpr mice, compared with
CD3+CD138- T cells 14. The activation levels of CD3+ T
and CD138+ T cells have also been shown to be inversely correlated with
the frequency of CD138+ T cells in splenocytes (unpublished data by
Tianhong Xie et al.). It has also been suggested that the mechanistic
target of rapamycin controls the expression of CD138 in T cells.
Furthermore, rapamycin has been reported to significantly reduce the
expression of CD138 and the frequency of CD138+ T cells14. However, an in vitro effort to decrease the
frequency of CD138+ cells in CD3+ T cells with rapamycin treatment was
unsuccessful. On the contrary, phorbol 12-myristate 13-acetate and
Ionomycin treatments were found to significantly decrease the frequency
of CD138+ cells in CD3+ T cells and induce the specific apoptosis of
CD138+ T cells (unpublished data by Tianhong Xie et al.). This suggests
that the defective activation of CD3+ T cells in MRL/lpr mice probably
leads to the expression of CD138 in CD3+ T cells.