Regulation of three-dimensional growth of EIII8-HUVEC co-cultures by galectin-3. Control cultures were untreated (control) or 24 hours after seeding treated with 0.5 or 1.0 μg of HL-31 or TIB166, or 1 μg of corresponding rat or rabbit nonimmune IgG. a: Phase-contrast morphology of heterotypic three-dimensional EIII8-HUVEC co-cultures. A and B: Co-cultures that were untreated or treated with 1.0 μg of normal rabbit IgG, respectively. C and D: Co-cultures that were treated with 1.0 μg of TIB166 or HL-31 galectin-3 antibody, respectively. Arrows indicate ductal alveolar outgrowths that co-localize with endothelial enriched regions. b: Cultures were treated with dispase to solubilize Matrigel- and trypan blue-excluded cells were counted by hemocytometer. Results obtained from three independent experiments performed in triplicate are expressed as mean ± SE. *, P < 0.001 and **, P < 0.005 are amounts of antibody that inhibited cell number significantly over corresponding control. Scale bar, 40 μm (a).