Activation of integrin β1 does not recapitulate the effects of laminin. (A) Cells were dissociated from human neurospheres and plated at 500 cells per well in the presence of medium supplemented with either an isotype control antibody or a β1 integrin stimulatory antibody (TS2/16; both at 10 μg/ml). Note that no alteration to the number of primary neurospheres which formed was observed. (B) Primary neurospheres were dissociated and re-plated in medium alone. Again, TS2/16 had no effect on secondary neurosphere formation. (C) As for (A), except that the cells were grown in 2 ng/ml EGF and FGF-2, rather than 20 ng/ml. (D) Secondary neurosphere formation from the primary neurospheres in (C). Statistics were determined by a one-way ANOVA with Tukey post-test. (A) n = 5; (B) n = 4; (C, D) n = 2.