The derivation of a human pancreatic beta cell line has been a heroic but elusive quest. Such a line would be a valuable tool to study normal beta cell function, model cell replacement therapy for diabetes and use in drug screening. Now, Philippe Ravassard and his colleagues (J. Clin. Invest. 121, 3589–3597) finally describe the derivation of functional beta cells.

The authors used a sequential method, transducing human fetal pancreases with an immortalizing factor to prevent senescence and then grafting them into severe combined immunodeficiency (SCID) mice, which allowed proliferation and differentiation into beta cells. A second round of transduction with a different immortalizing factor and passaging through SCID mice enabled the authors to amplify the beta cells and subsequently culture them.

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Ravassard et al. analyzed one of their cell lines and found it expressed characteristic beta cell markers and did not show significant expression of markers associated with other types of pancreatic cells. Moreover, the beta cells could secrete insulin in response to glucose stimulation and ameliorated chemically induced diabetes in a mouse model, demonstrating functionality. Thus, the derivation of this new beta cell line represents an important technical step forward.