Activity of SS2 against PHA stimulated T cells.

Splenocytes were stimulated with PHA to induce T-cell proliferation, and then cultured in triplicate with IT. Three days later thymidine incorporation was assayed as a measure of T-cell activation. (A) SS2 added to PHA stimulated T-cells; (B) monomeric IT added to T cells. Background counts were determined by measuring incorporation of splenocytes without PHA stimulation (mean 254 ± SD 58). The counts of PHA-stimulated cells without the addition of any IT were mean 22 416 ± SD 4 229. Data are expressed as activity versus concentration. Activity was calculated by averaging triplicates and subtracting the spontaneous background.