Kinetic analysis of the response to anti-CD3 in conventional and regulatory CD4+ T cells, in mice and in vitro.

Several clinical trials have shown anti-CD3 treatment to be a promising therapy for autoimmune diabetes, but its mechanism of action remains unclear. Foxp3+ regulatory T (Treg) cells are likely to be involved, and we have shown a strong effect of anti-CD3 on homeostatic control of CD4+ FoxP3+ regulatory T (Treg) cells. To analyze the early consequences of anti-CD3 treatment, we sorted and profiled Treg and conventional CD4+ T (Tconv) cells in the first hours and days after anti-CD3 treatment of NOD mice. In practice, NOD mice carrying the Foxp3-GFP reporter were treated with anti-CD3 mAb KT3 (50 ug iv) and CD4+ T cells were sorted from pooled spleen and lymph nodes after 2, 8, 24 and 72 hrs, separating Treg and Tconv cells on the basis of GFP expression. Anti-CD3 treatment led to a transient transcriptional response, terminating faster than most antigen-induced responses. Most transcripts were similarly induced in Treg and Tconv cells, but several were differential, in particular those encoding the IL7 receptor (IL7R) and transcription factors Id2/3 and Gfi1, upregulated in Treg but repressed in Tconv cells. In parallel experiments, we tested the effect of soluble anti-CD3 added to cultures of fresh splenocytes, sorting Treg and Tconv cells at the same time points. Many of the anti-CD3 elicited changes, and of the differential response observed in vivo, were also observed in vitro. Two independent replicate series; Treg and Tconv samples abbreviated TR and TC, respectively. Keywords: Transcriptional activation, TCR

42

Li L, Nishio J, van Maurik A, Mathis D, Benoist C