CD147 antibodies block aggregation induced via CD98.

(A) Aggregation was measured under standard conditions in the presence of CD98-AHN-18 (1.5 μg/mL, left panel), MEM 101A (CD29, 0.3 μg/mL, middle panel), or 161-46 (CD43, 0.3 μg/mL, right panel). Blocking antibodies to CD147 were added to U937 cultures 1 hour prior to the aggregating antibodies. Results are expressed as the percentage of aggregation relative to the aggregation in the absence of blocking antibody (column labeled 0 in each panel). Means that differ significantly from control (absence of inhibitory antibody,P < .05) are shown with an asterisk. Antibodies were tested at a series of dilutions, starting with the most dilute and increasing in 2-fold steps along the x-axis. To obtain the actual concentration of antibody at each point (in μg/mL), the x-axis value should be multiplied by 1.2 for MEM M6/1 (CD147, □) and 1.1 for H84AF (CD147, ■). (B) U937 cells were incubated in medium alone (i), CD98-AHN-18 (1.5 μg/mL) (ii), or CD98-J3 and MEM M6/1 (CD147, 1.2 μg/mL) (iii) for 6 hours, as described in “Materials and methods.” Images of cells in culture at this time point were obtained by means of an inverted phase contrast microscope, attached to a video camera, and captured with NIH image software.