Cross desensitization with three CD66 mAbs to further stimulation of neutrophil adhesion to HUVECs. TNF-stimulated HUVECs were washed and Ca2+ free buffer containing 10 ug/ml final concentration each of IgG (panel A), the CD66ae mAb, CD66b mAb, and CD66c mAb (panel B), the CD66ae mAb, CD66b mAb, and CD66de mAb (panel C), the CD66ae mAb, CD66c mAb, and CD66de mAb (panel D), or the CD66b mAb, CD66c mAb, and CD66de mAb (panel E), were added (see Methods). Neutrophils in Ca2+ free buffer were then added. After 15 sec (solid bars) or 15 min (hatched bars), buffer containing 10 ug/ml final concentration of the indicated next mAb or buffer, and Ca2+ (1.8 mM final concentration) were added. After 30 min the wells were washed. The * > (panel A) indicates the amount of adhesion observed when neutrophils were incubated for 30 min in the presence of buffer containing Ca2+ with or without 10 ug/ml IgG (final concentration). The percent of neutrophils remaining adherent are shown. Selective desensitization at 15 min was statistically significant (p < 0.05).