Expression of CD138 prevents T cell apoptosis and contributes to
accumulation of DN T cells
DN T cells are a subset of T cells that are CD3 and B220 positive and
are negative for both CD4 and CD8. DN T cells have been found to
accumulate in the peripheral blood of SLE patients and in an SLE murine
model 9-11. They were found to account for
<7% in the T cells of healthy mice6,
and resulted in profound lymphadenopathy in an SLE murine model10, 31. DN T cells have been shown to express
activation-associated antigens, such as CD44,
Ly-6C,
CD138, and CD69 13, 26, 32-34. Interestingly, it has
recently been shown that a majority of DN T cells express high levels of
CD138 12-14. Moreover, the expression of CD138 in T
cells has been demonstrated to significantly prevent the apoptosis of T
cells 14. Thus, it appears that the expression of
CD138 contributes to the accumulation of DN T cells in lupus mice by
decreasing the number of apoptotic DN T cells (Figure 2). However, the
underlying mechanism for the expression of CD138 in CD3+ T cells remains
undeciphered.