Laminin increases human primary neurosphere formation. (A) Cells dissociated from human neurospheres and plated in medium alone or medium containing 10 μg/ml laminin (Medium+Laminin). After 21 days, significantly more primary neurospheres had formed in the presence of laminin. (B) The neurospheres from (A) were dissociated and re-plated in medium alone. Note that no laminin was added to the culture medium in (B). No difference in secondary neurosphere numbers was observed. *p < 0.05, as determined by Student's t-test; n = 2. (C) Dissociated neurosphere cells were grown for 24 h in the absence (medium) or presence (Ln) of laminin, in addition to either an isotype control (Iso. Cont.) or integrin β1-blocking antibody (β1 block), before being analysed for annexin-V expression by flow cytometry. The number of annexin-V+ cells, relative to medium alone, is shown. Annexin V-binding was significantly reduced in the presence of laminin compared to medium alone, indicating an increase in cell survival. The addition of an integrin β1-blocking antibody returned the number of annexin V+ cells to control levels, indicating that laminin acts through integrin β1. Statistics were determined by a one-way ANOVA with Tukey post-test. n = 5 for medium and laminin, n = 3 for all other conditions. **p < 0.01, *p < 0.05.