Antibodies to trophoblast antigens HLA-G, placenta growth factor, and neuroD2 do not improve detection of circulating trophoblast cells in maternal blood.
OBJECTIVE
Non-invasive prenatal diagnosis using circulating fetal trophoblast cells has been challenging due to lack of a reproducible trophoblast-specific antibody. We investigated the use of three trophoblast cell-specific antibodies, HLA-G, placenta growth factor, and neuroD2, for the isolation of trophoblast cells from the maternal circulation.


METHODS
Trophoblast cells were isolated by density centrifugation from maternal blood samples (gestational age 10-20 weeks, n = 9). All women were carrying a male fetus. Following immunocytochemical staining with the trophoblast-specific antibodies, fluorescent in situ hybridization was performed, to verify whether any stained cells were indeed fetal.


RESULTS
The HLA-G antibody had a ubiquitous staining pattern, which was not specific for trophoblast cells. Neither the placenta growth factor nor the neuroD2 antibodies were able to identify any trophoblast cells. Following fluorescent in situ hybridization, no male cells were detected on any of the slides.


CONCLUSIONS
The antibodies used in this study were unable to improve detection of trophoblast cells in the maternal circulation.
Tjoa
M L
ML
Division of Genetics, Department of Pediatrics, Tufts-New England Medical Center, Boston, MA 02111, USA.
Delli-Bovi
L
L
Johnson
K L
KL
Bianchi
D W
DW
D000911:Antibodies, Monoclonal; D051792:Basic Helix-Loop-Helix Proteins / Q000097:blood*; D002469:Cell Separation; D002499:Centrifugation, Density Gradient; D005260:Female; D005865:Gestational Age; D006680:HLA Antigens / Q000097:blood*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000097:blood*; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D009479:Neuropeptides / Q000097:blood*; D000072483:Placenta Growth Factor; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000097:blood*; D011296:Prenatal Diagnosis / Q000379:methods; D012732:Sex Determination Analysis; D014327:Trophoblasts / Q000276:immunology*
D000911:Antibodies, Monoclonal; D051792:Basic Helix-Loop-Helix Proteins; D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I; D009479:Neuropeptides; D000072483:Placenta Growth Factor; D011257:Pregnancy Proteins; C490925:NEUROD2 protein, human; C000608036:PGF protein, human