In the Islets of Langerhan ( human anatomy), which cell secretes insulin?

Type 1 diabetes is an autoimmune condition. Islet cell transplantation is unlikely to become a so-called ‘cure’, because the body’s immune system will continue to destroy the transplanted cells unless the immune system is suppressed to a dangerous degree.

My wife had the islet cell transplant surgery...hopefully it kickstarts her pancreas to start producing insulin.

I suppose anyone in the medical field would be able to answer this question..