Reference proteome of highly purified human Th1 cells reveals strong effects on metabolism and protein ubiquitination upon differentiation

The differentiation of human CD4+ T cells into different subtypes of T helper cells and regulatory T cells is crucial for an appropriate immunological response. Among all subtypes Th1 cells are the most prominent specific cell type, representing about 50% of all lymphocytes. So far most global proteomic studies have used either only partially purified T helper cell subpopulations and/or have employed artificial protocols for inducing specific T helper cell subtypes and/or applied gel based approaches. These studies have shed light on molecular details of certain aspects of the proteome. Nevertheless a more global analysis of highly pure primary naïve and Th1 cells by LC-MS/MS is needed in order to contribute to the proteome based T cell subtype characterization. We were able to identify 1757 proteins in total, out of which 49 were significantly regulated. The utilization of highly purified Th1 cells for a global proteome assessment and the bioinformatical comparison to naïve cells reveals the relevance of changes in the metabolism and the ubiquitination pathways upon T cell differentiation.