Characterization of CD127− CD25++ Treg from human colostrum

Problem Breastfeeding's influence on the tolerance to environmental antigens is essential for short‐ and long‐term homeostasis for children. Colostrum is rich in leucocytes, but it is unknown whether regulatory T cells (Treg) account for part of this cell population. Method of study Frequencies of CD127− CD25++ Treg and levels of immunoregulatory‐associated cell markers were determined in colostrum and were compared with autologous blood cells. In addition, we evaluated whether the birth conditions can affect these features. Results Higher frequencies of CD127 −CD25++ Treg cells expressing Foxp3 and CD45RO were observed in the colostrum. The cells’ CD25, CD152, CD279, and TGF‐β expression levels were greater than those in autologous blood cells. In addition, the CD279 and TGF‐β expressions of colostrum CD127− CD25++ Treg cells were influenced by gestational age and delivery mode. Conclusion The higher proportion of these cells with a function‐associated phenotype may reflect certain tolerogenic effects of breastmilk on newborns and infants, contributing to immune system homeostasis. Helper T cells with CD127− CD25++ phenotype (Treg) were identified in colostrum by flow cytometry (a). Colostrum Treg cells express the transcription factor Foxp3 (b), and their frequencies are higher than those in autologous blood(c).