GSE122894
Pregnancy enables expansion of autoreactive regulatory T cells in an animal model of multiple sclerosis
Disease activity of autoimmune disorders such as multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) is temporarily suppressed by pregnancy. However, whether disease amelioration is due to non-specific immunomodulation or mediated by antigen-specific regulation of disease-causing conventional T cells (Tcon) and immuno- suppressive regulatory T cells (Treg), remains elusive. In the present study, we systematically analyzed changes of the T cell receptor (TCR) ß repertoire driven by EAE and pregnancy using TCR sequencing. We demonstrate that EAE, but not pregnancy, robustly increased TCR repertoire clonality in both peripheral Tcon and Treg. Notably, pregnancy was required for the expansion of Treg harboring the dominant EAE-associated TRBV chain 13.2 and increased the frequency of EAE-associated clonotypes within the Treg compartment. Our findings indicate that pregnancy supports the expansion of Treg clonotypes that are equipped to recognize EAE- associated antigens. These Treg are thereby particularly suited to control corresponding encephalitogenic Tcon responses and likely contribute to pregnancy-associated protection in autoimmunity. Overall design: T cell receptor (TCR) sequencing of CD4+Foxp3+ regulatory T cells and CD4+Foxp3- conventional T cells from pregnant and non-pregnant, EAE and naive mice.