Functional T-cell subset defined by cluster formation with EB virus transformed B-cells.

This study compares functional properties of T-cells capable of forming clusters with EB virus transformed B lymphoblastoid cells (B-LCL) as accessory cells (A-cells). T-cell functional properties examined include T-cell activation, interleukin 2 (IL-2) production and cell proliferation. In addition, functional properties were compared with the presence or absence of surface markers. T-cells were divided into those that formed clusters with the B-LCL (clustered T-cells) and those that failed to form clusters (nonclustered T-cells). Each subpopulation of T-cells was also incubated with B-LCL and Concanavalin A (Con A) to test for changes in proliferative capabilities. Functional studies indicated that IL-2 activity was higher in the culture supernatant fluids from clustered T-cells than nonclustered T-cells. Spontaneous proliferation of clustered T-cells was equivalent to proliferation of clustered T-cells stimulated with Con A or human IL-2. However, weak spontaneous proliferation by non clustered T cells was enhanced after culturing with Con A or human IL-2. The nonclustered T-cells also produced less IL-2 in cultures containing both B-LCL or Con A. Quantification of T-cell surface markers showed that the expression of Tac antigen was greater on the clustered T-cells than on the nonclustered T-cells. These data suggest that functionally different T-cell subsets can be identified and isolated by their capacity to form clusters with B-LCL A-cells.