Expression Profile of in vitro Expanded Human Tregs

Understanding human Regulatory T cell (Treg) heterogeneity may identify markers of disease pathogenesis and facilitate the development of optimized cellular therapeutics. Previous analysis revealed that the co-inhibitory receptor T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) was highly expressed on tTreg. The negative regulator TIGIT and the co-stimulatory factor CD226 bind the common ligand CD155. Human regulatory T cells (CD4+CD25+CD127-/lo) from adult peripheral blood were sub-fractionated based on the markers CD226 and TIGIT and were subsequently expanded in vitro according to clinical expansion protocols. The transcriptional profile of the final cell products uncovered considerable heterogeneity in terms of in vitro expansion and suppressive capacity. Most notably, the CD226+TIGIT- fraction adopted a transcriptional profile most similar to that of conventional T cells, including the capacity for effector cytokine production. Tregs and corresponding Tconv were expanded from peripheral blood of three normal healthy control male subjects.