(A) TLC analysis of Gb3 expression in
various cells. Neutral glycolipids were extracted from 1 ×
107 monocytes, 2 × 107 macrophages,
2 × 107 imDCs, and 1 × 106 HeLa
cells, separated by TLC, and Gb3 was detected and
quantified (Table 1) by overlay with STxB. (B) FACS analysis of STxB
binding to and internalization into monocyte-derived cells.
Fluorescein-labeled STxB (0.1 μM; 5 μg/ml) was incubated on ice
(gray profiles) or for 30 min at 37°C (black lines) with the
indicated cells that were then analyzed by FACS. Background signal of
nonlabeled cells is also shown (dotted lines). Note the weak but
detectable binding after incubation on ice and strong signal after
incubation at 37°C.