Human leukocyte antigen-G in the male reproductive system and in seminal plasma

One of the non-classical human leukocyte antigen (HLA) class Ib proteins, HLA-G, is believed to exert important immunoregulatory functions, especially during pregnancy. The presence of HLA protein in paternal seminal fluid has been suggested to have an influence on the risk of developing pre-eclampsia. We have investigated whether HLA-G protein is present in human seminal plasma and in different tissue samples of the male reproductive system.Western blot technique and a soluble HLA-G (sHLA-G) assay were used to detect sHLA-G in human
seminal plasma samples. Immunohistochemical staining was performed on paraffin-embedded tissue samples. We detected sHLA-G protein in
seminal plasma, and HLA-G expression in normal testis and in epididymal tissue of the male reproductive system but not in the seminal vesicle.
Furthermore, the results indicated a weak expression of HLA–G in hyperplastic prostatic tissue. In summary, several of the findings reported in
this study suggest an immunoregulatory role of HLA-G in the male reproductive system and in seminal plasma.