Surface markers on human activated T lymphocytes. IV. Comparison of high-affinity E-rosette receptor expression with the expression of other activation markers (receptor for interleukin 2, MHC class II (antigens).

In order to re-examine the value of high-affinity E rosette receptor (Eh-R) as an activation marker of human T lymphocytes, its existence on resting and activated T cells was compared with the expression of such known activation markers as receptor for interleukin 2 (IL-2R; Tac antigen) and MHC class II antigens (DR/DP and DQ). To this aim expression of the above surface markers on lymphocytes of TEe subset, derived from early E rosettes (Eh-R+) and on lymphocytes of TEl subset, derived from late E rosettes (Eh-R-), was examined immediately after purification of the cells from peripheral blood as well as during cell activation with PHA. The phenotypic studies were done by using monoclonal antibodies and indirect immunofluorescence technique. We confirmed previous observation that in the course of PHA stimulation Eh-R like IL-2R marked currently activated T cells. However, it was also found that in the long-term cultures of lymphocytes activated with PHA, the expression of Eh-R was sustained on the cells which lost their IL-2R and DR/DP antigens. The above findings and the fact that TEe cell subset consisting of Eh-R+ lymphocytes was almost completely depleted from cells bearing IL-2R and MHC class II antigens allowed us to conclude that this subset of peripheral blood T lymphocytes represented not currently activated cells but the cells which had been previously activated in vivo.