Detection and quantitation of interleukin-2 from individual cells

In this report we present the use of cell blotting for the detection of interleukin-2 (IL-2)-producing lymphocytes. This is a rapid and sensitive immunochemical method analogous to Western blotting of proteins. When combined with image analysis one can determine the percentages of IL-2 positive cells as well as quantitate the amount of IL-2 surrounding each cell. When bovine lymph node cells (bLNC) were stimulated with the combination of concanavalin A (ConA) and 12-O-tetradecanoylphorbol-13-acetate (TPA) for 24 h, 46.4 +/- 0.6% stained positive for IL-2 and, on average, each cell produced 0.92 +/- 0.6 pg of IL-2 in 24 h. Phytohemagglutinin (PHA) and TPA-stimulated human peripheral blood mononuclear cells (hPBMC) produced approximately the same amount. 0.86 +/- 0.4 pg of IL-2 per cell in 24 h; 45.6 +/- 3.6% stained positive for IL-2.