Distinct Epitopes on CD13 Mediate Opposite Consequences for Cell Adhesion

Figure 7

Effect of anti-CD13 mAbs on CD13 phosphorylation. (a) Time course of CD13 phosphorylation in U-937 cells stimulated with mAb 452 (1 microgram/ml). After stimulation for 5, 30, and 60 min, cells were lysed and immunoprecipitated with mAb C-protein G agarose. Tyrosine phosphorylation was determined as described in Materials and Methods. (b, c) CD13 phosphorylation induced by anti-CD13 mAbs 452 and C. U-937 cells were stimulated with mAb 452 or mAb C for 5 or 30 min, or with mAb C for 30 min followed by mAb 452 for 30 additional min (last lane). Phosphotyrosine (b) and CD13 (c) were detected as described in Materials and Methods.

(a)

(b)

(c)