Expression of TAP1 by human trophoblast.
Successful placentation in the human is dependent on the trophoblast evading recognition and destruction by the maternal immune system. However, invasive cytotrophoblast express HLA-G which may be able to present peptide to T cells. Transporter proteins are essential for peptide presentation and major histocompatibility complex (MHC) class I assembly. We have determined their expression by trophoblast in relation to HLA-G, using immunohistochemistry. Anti-transporter protein antibody (TAP1) labeling closely paralleled that of MHC class I, but the intensity of its expression was much greater on the HLA-G+ extravillous cytotrophoblast than any other fetal or maternal tissue in the first trimester and at term. This suggests that the extravillous cytotrophoblast are very actively assembling MHC class I antigens with peptides. However, expression of MHC class I by the cytotrophoblast was not correspondingly elevated. This pattern could result from HLA-G being shed from the surface of the trophoblast, a process which may play a central role in protecting the fetus from maternal immune attack.
Clover
L M
LM
Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital.
Sargent
I L
IL
Townsend
A
A
Tampé
R
R
Redman
C W
CW
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters / Q000032:analysis*; D000818:Animals; D005260:Female; D006680:HLA Antigens / Q000032:analysis* / Q000235:genetics; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000032:analysis* / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012333:RNA, Messenger / Q000032:analysis; D014327:Trophoblasts / Q000737:chemistry*
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters; D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I; D012333:RNA, Messenger; C073119:TAP1 protein, human; C486171:Tap1 protein, mouse