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.