Sanne Hoeks

Chapter 4 52 always showed a higher percentage of FOXP3 + cells than did T cells from 3- to 12-month-old donors. So, the propensity of CB naive T cells to become Treg cells was dependent on the interaction between T cells and APCs. We conclude that neonatal T cells develop the capacity to differentiate into T H 17 cells before the age of 3 months and retain a propensity to become Treg cells until the age of at least 12 months. So, immunity against pathogens is being raised while at the same time the immune system remains to have a regulatory profile. This latter fact might be important in the maintenance of tolerance toward allergens and food antigens encountered for the first time. We thank all of the infants and their parents who took part in this study, Dr L. Pistorius and Dr G. T. R. Manten for their help with the inclusion of the participants, and Mariska van Dijk for performing the Luminex assay.