Antibodies to α6 and α3inhibit CG outgrowth on laminin-1, but not on merosin.Dissociated E7.5 CG neurons were plated on laminin-1 (Ln) or merosin (Mn) and cultured for 4–5 hr (Mn) or 9–10 hr (Ln) in the presence of no antibody (0), normal rabbit IgG Fab (NRIgG Fab, 500 μg/ml), anti-α8Ex Fab (500 μg/ml), anti-α6Ex Fab (500 μg/ml), anti-α3Ex1 Fab (500 μg/ml), Fab combinations, anti-β1 mAb (W1B10, 25 μg/ml), or control mAb (anti-P75NGFR, 20 μg/ml). Values were normalized to the percentage of neurons with neurites in the absence of antibody (mean ± SD or range). The number of cultures examined per condition is indicated above each bar. Dunnett’s test for multiple comparisons against a single control was used to determine significance (Glanz, 1992). *p < 0.01 compared to no antibody (0) control.