Extrathymic rearrangement of alphabetaT-lymphocyte antigen receptor genes during pregnancy

Effect of Estriol, Chorionic Gonadotropin, and Oncostatin M on the Expression of Recombinase RAG-1 in Regulatory T Lymphocyte Subpopulations

We studied the effect of estriol, chorionic gonadotropin, oncostatin M, and hormone-cytokine combinations on the expression of recombinase RAG-1 in T-regulatory (Treg) and T helper 17 (Th17) lymphocytes. It was found that estriol in a concentration corresponding to the first trimester of pregnancy increased the level of Treg (CD4⁺FoxP3⁺) cells and suppressed the formation of Th17 (CD4⁺RORC⁺) lymphocytes. This effect was nor observed after individual administration of chorionic gonadotropin and oncostatin M, but some combinations of the studied hormones with oncostatin M increased the percentage of CD4⁺FOXP3⁺ cells. In the presence of oncostatin M, the studied hormones enhanced the expression of RAG-1 in CD4⁺FoxP3⁺ cells, but not in CD4⁺RORC⁺ cells, thereby initiating of Treg T-cell receptor (TCR) revision. The mechanisms of hormone cytokine control of induction of the immune tolerance during pregnancy are discussed.

Regulation of Recombinase Rag-1 Expression by Female Sex Steroids in Treg and Th17 Lymphocytes: Role of Oncostatin M

The effect of estradiol (E₂), progesterone (P₄), and oncostatin M (OSM) on the differentiation of CD4⁺ T cells to T regulatory (Treg) lymphocytes and T helpers 17 (Th17) was investigated. The possibility of revision of the T cell receptor in these subpopulations by evaluating the expression of RAG-1 recombinase was also studied. E₂ at concentrations characteristic of pregnancy trimester I, but no P₄ or OSM, increased the Treg level. Combination of sex steroids with OSM increased the percent of CD4⁺FOXP3⁺ cells and enhanced RAG-1 expression in these cells, thus promoting the development of immune tolerance during pregnancy. In the study of Th17, such effect of the hormones and OSM was not detected.