V-chain preference of gamma/delta T-cell receptors in peripheral blood during term labor

Problem An altered function of the maternal immune system creates a favorable environment for the developing fetus during pregnancy. At term, new regulatory mechanisms are activated, to initiate labor. Earlier we showed that in peripheral blood of pregnant women gamma/delta T cells of cytotoxic phenotype are replaced by those of a non-cytotoxic phenotype. Here we studied the Vgamma and Vdelta chain usage of peripheral gamma/delta T cells from women in labor. Method of study Vgamma and Vdelta chain expression on peripheral blood lymphocytes obtained at the 3rd trimester of pregnancy and during parturition were examined by immuncytochemistry and flow cytometry. Results Increased % of Vgamma9/Vdelta2 and decreased % of Vgamma4/Vdelta1 T cells were found in peripheral blood during labor, together with unaltered percentages of single Vgamma+ or Vdelta+ cells. The initially high Vgamma4/Vdelta1 to Vgamma9/Vdelta2 ratio decreased during labor. Conclusion The initiation of labor is characterized by an altered V-chain usage of gamma/delta T cells.