Distinct Epitopes on CD13 Mediate Opposite Consequences for Cell Adhesion

Figure 5

Inhibition of homotypic aggregation by mAbs C and E requires crosslinking of CD13. U-937 cells in 96-well plates were incubated with the indicated doses of Fab fragments of inhibitory mAbs C (a) or E (b). Cells were washed, resuspended, and divided into two, a half was incubated with fragments of goat anti-mouse Ig (GαM) and the other half in medium alone. After incubation for 1 h at 37°C, HA-inducing anti-CD13 mAb 452 was added and cells were incubated for 2 additional hours. Percentage of aggregation was determined under light microscopy as described in Materials and Methods. The graphs represent the arithmetic mean ± SD of three independent experiments. , .

(a)

(b)