Differential expression of a 70 kDa O-glycoprotein on T cells: a possible marker for naive and early activated murine T cells.

Abstract We purified a 70 kDa O -glycoprotein that binds to the GalNAc specific lectin from Amaranthus leucocarpus (ALLr) and determined its expression pattern on T lymphocytes from different murine lymphoid organs. High level of ALLr expression was demonstrated in 95–98% of both CD4 + 8 + and CD4 − 8 + thymocytes, and in 80–95% of CD8 + T cells from peripheral blood, lymph nodes, and spleen, whereas a minor fraction of CD4 + 8 − thymocytes (46–67%) and peripheral CD4 + T cells (9–40%) showed low ALLr expression. Peripheral CD19 + B cells were ALLr negative and most of the peripheral ALL + T cells showed a CD62L hi CD45RB hi CD44 lo/− phenotype, indicating features of naive cells. Mitogenic activation of peripheral T cells increased 3-fold the number of ALL + CD4 + T cells 24 h after stimulation, as opposed to a >80% decrease in CD8 + T cells 72 h after stimulation. Our results suggest that ALL detects a non-described surface O -glycoprotein selectively expressed by naive CD8 + T cells and by early activated CD4 + T cells.