Figure 7.

Fyn is required for the formation of stable APC-T cell conjugates induced by both agonist and antagonist peptides. CH27 APCs labeled with green fluorescent membrane dye were pulsed with antagonist (T102G) or agonist (PCC 88–104) peptide for 2 h at 37°C, washed, and added to AD10 (open bars) or Fyn-deficient AD10 (hatched bars). T cells were labeled with red fluorescent membrane dye. After 30-min incubation at 37°C, conjugate formation was measured by two-color flow cytometry. The percentage of APCs that formed conjugates with T cells, as indicated by double fluorescent positive cell couplets, was quantitated. The background of the percentage of nonspecific conjugates formed in the absence of any added peptide (1.4%) was subtracted from the plotted date.