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Fig. 6. Truncation of I-Ak prevents DIG-dependent PKC-
translocation to the site of I-Ak engagement. (A) SaI/Ak
and SaI/Ak tr cells were incubated with 10.2.16-coated beads
(Anti-I-Ak) or irrelevant mouse Ig-coated beads (nonstimulated, NS)
for 30 minutes. Cells were cytospun, fixed and stained with anti-PKC-
antibody and revealed with a FITC-labeled secondary antibody. Bright-field
images (a,c,e,g,i,k) indicate the site of interaction between the bead and the
cell and the corresponding fluorescent images reveal the localization of
PKC-
(b,d,f,h,j,l). A single cell-bead conjugate is shown in each
panel. Cells pretreated with MßCD prior to I-Ak stimulation
(Anti-I-Ak + MßCD) are indicated. (B) The percentage of cells
undergoing PKC-
recruitment to the site of I-Ak engagement
was determined. At least 200 cell-bead interactions from each condition were
examined and cells in which PKC-
recruitment had occurred (to at least
the same degree as shown in A, panel d) were counted as positive events. Data
from one of three typical experiments is shown.