Fig. 4.

Detection of CD4⁺ T cell antigen-specific responses. (a) Representative fluorescence activated cell sorter (FACS) plots of carboxyfluorescein succinimidyl ester (CFSE) dilution obtained in subject 2. T cells were labelled with CFSE and incubated with alpha-casein or no antigen (medium). In response to alpha-casein, most of the proliferating CD4⁺CFSE^dim T cells (Q1; upper panel) also up-regulated the activation marker CD25 and memory marker CD45RO (Q2; lower panel) underlining the specificity of the T cell response. (b) The percentage of CD4 T cells which were CFSE^dim and CD25⁺CD45RO⁺ after 7-day culture with alpha-casein (5 µg/ml), beta-casein (5 µg/ml), bovine serum albumin (BSA) (5 µg/ml), proinsulin (10 µg/ml), tetanus toxoid (TT, 1 µl/ml) or medium only in subjects 2 and 5 and patients T1D_·1 and T1D_·2 from Fig. 1.