Human seminal plasma fosters CD4(+) regulatory T-cell phenotype and transforming growth factor-β1 expression.
OBJECTIVE
Semen mediates expansion of CD4(+)  regulatory T cells (Treg) in the murine female reproductive tract. The impact of semen on Treg in humans, however, remains unclear.


METHODS
Using seminal plasma (SP) from 20 healthy donors, we investigated the impact of human semen on CD4(+)  T-cell expression of CD127 and CD49d as well as CD4(+)  CD127(low)  CD49d(low)  Treg proliferation, apoptosis, and intracellular expression of FoxP3, TGF-β1, and IL-10.


RESULTS
SP reduced CD4(+)  T-cell expression of CD127 and CD49d and increased the proportion of CD127(low)  CD49d(low)  Treg. This increase was non-proliferative, mediated in part via the conversion of CD4(+)  helper T cells into FoxP3(-)  but not FoxP3(+)  Treg. Additionally, SP induced an increase in intracellular expression of the immunosuppressive cytokine TGF-β1 by the FoxP3(-)  but not FoxP3(+)  Treg. SP had no impact on Treg intracellular expression of IL-10.


CONCLUSIONS
Human seminal plasma fosters the non-proliferative increase in the proportion and immunoregulatory activity of FoxP3(-)  Treg.
Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA. Emmanuel.Balandya@Dartmouth.edu
Emmanuel
E
Balandya
Wendy
W
Wieland-Alter
Katherine
K
Sanders
Timothy
T
Lahey
D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D016207:Cytokines / Q000276:immunology; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007108:Immune Tolerance; D016130:Immunophenotyping; D008297:Male; D012661:Semen / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
D016207:Cytokines; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D053773:Transforming Growth Factor beta1