Langerhans cells week 10

Langerhans cell granules are detectable by electron microscopy.

The characteristic Birbeck or racquet-shaped granule first appears in the 10th week of gestation. The T-cell differentiation antigen CD1a begins to appear on Langerhans cells, indicating functional maturation of these cells. The Langerhans cell becomes much larger, and more dendritic, presenting a 5-fold increase in surface area to encompass a wider area of immunologic surveillance.