The role of individual integrins in human ␤-cell development and function is largely unknown. This study describes the contribution of ␣ v -integrins to human ␤-cell adhesion, spreading, and motility. Developmental differences in ␣ v -integrin utilization are addressed by comparing the responses of adult and fetal ␤-cells, and vitronectin is used as a substrate based on its unique pattern of expression in the developing pancreas. Fetal and adult ␤-cells attached equally to vitronectin and

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... in ␣ v ␤ 5 was found to support the adhesion of both mature and immature ␤-cell populations. Fetal ␤-cells were also observed to spread and migrate on vitronectin, and integrin ␣ v ␤ 1 was found to be essential for these responses. In contrast to their fetal counterparts, adult ␤-cells failed to either spread or migrate and this deficit was associated with a marked down-regulation of ␣ v ␤ 1 expression in adult islet preparations. The integrin ␣ v ␤ 3 was not found to support significant ␤-cell attachment or migration. Based on our findings, we conclude that integrins ␣ v ␤ 5 and ␣ v ␤ 1 are important mediators of human ␤-cell adhesion and motility, respectively. By supporting fetal ␤-cell migration, ␣ v ␤ 1 could play an important role in early motile processes required for islet neogenesis.