Properties of murine CD8+CD27- T cells

In humans, loss of CD27 expression is associated with the stable acquisition of effector functions by CD8(+) T cells. We found that murine CD8(+)CD27(-) T cells were confined to the primed CD62L(dull/-)CD44(bright)CCR7(-) T cell population. CD8(+)CD27(-) T cells were absent from lymph nodes but could be found in blood, spleen and in non-lymphoid organs such as lung and liver. Late after primary influenza virus infection, low percentages of antigen-specific CD27(-) cells emerged in the lung and spleen. After recovery from secondary influenza virus infection, high percentages of influenza-specific CD27(-) T cells were found in the lung and the loss of CD27 on lung CD8(+) T cells coincided with high granzyme B expression. After murine cytomegalovirus infection, loss of CD27 expression on virus-specific CD8(+) T cell populations was sustained and especially marked in liver and lung. We suggest that in mice, CD27 is lost from CD8(+) T cells only after repetitive antigenic stimulation. Moreover, the high expression of both granzyme B and perforin in the CD27(-) T cells suggests that the lack of CD27 on murine CD8(+) T cells can be used to identify memory T cells with expression of cytotoxic effector molecules.