Impaired phagocytosis after degradation of VAMP-2
in FcγRIIA-transfected CHO cells. (A and
B) VAMP-2 immunostaining of CHO cells. (A)
Nomarski image. (B) VAMP-2 immunostaining in the cells shown
in A. Arrows indicate specific, vesicular staining.
(C and D) FcγRIIA-expressing CHO cells
were transiently transfected with cDNA-encoding TeTx-LC, along with
cDNA for GFP as a transfection marker, and immunostained with antibody
to VAMP-2. (C) Green (GFP) fluorescence identifying
transfected cells. (D) VAMP-2 immunostaining of cells shown
in C. (E and F)
FcγRIIA-expressing CHO cells were cotransfected with TeTx-LC and GFP
as above and allowed to internalize opsonized SRBCs. (E)
Bright field image. Inset (E′) shows
cells transfected with GFP alone. Arrowhead indicates location of
representative internalized SRBCs. (F and
F′) GFP fluorescence identifying transfected cells in
the field shown in E. The arrowhead demonstrates the
displacement of GFP by internalized SRBCs in cells transfected with GFP
alone. (G) Effect of TeTx-LC expression on phagocytosis and
adherence of SRBCs by FcγRIIA-CHO cells. Means ± SE of five
individual experiments, with more than 200 cells per group per
experiment. Asterisks indicate P < 0.05 vs.
control (Ctl.). Bar, 10 μm.