PRONOUNCED PHENOTYPE IN ACTIVATED TREG CELLS DURING A CHRONIC HELMINTH INFECTION

Although several markers have been associated with the characterization of regulatory T cells (Treg) and their function, no studies have investigated the dynamics of their phenotype during infection. Since the necessity of Treg to control immunopathology has been demonstrated, we used the chronic helminth infection model S. mansoni to address the impact on the Treg gene repertoire. Before gene expression profiling we first chose to study the localization and antigen-specific suppressive nature of classically defined Treg during infection. Presence of Foxp3+ cells were found especially in the periphery of granulomas and isolated CD4+CD25hiFoxp3+ Treg from infected mice blocked IFN-gamma and IL-10 cytokine secretion from infected CD4+CD25- effector T cells (Teff). Furthermore the gene expression patterns of Treg and Teff showed that in total 474 genes were significantly regulated during chronic schistosomiasis. Upon k-means clustering we identified genes exclusively regulated in all four populations including Foxp3, CD103, GITR, OX40 and CTLA-4: classical Treg markers. During infection however, several non-classical genes were up-regulated solely within the Treg population such as Slpi, Gzmb, Mt1, Fabp5, Nfil3, Socs2, Gpr177 and Klrg1. Using RT-PCR we confirmed aspects of the microarray data and in addition showed that the expression profile of Treg from S. mansoni-infected mice is simultaneously unique and comparative with Treg derived from other infections

10

Layland LE, Mages J, Loddenkemper C, Hoerauf A, Wagner H, Lang R, da Costa CU