Quantitative Assessment of Human Leukocyte Antigen-G Protein in Amniotic Fluid by a Double-Determinant Enzyme-Linked Immunosorbent Assay Using Anti-Human Leukocyte Antigen-G-Specific Antibody ‘87G’


Department of Obstetrics and Gynecology, Faculty of Medicine, University of okyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113–8655 Japan.


PROBLEM: The objective of this study was to establish an enzyme-linked immunosorbent assay (ELISA) system, in an attempt to quantify the amount of human leukocyte antigen (HLA)-G protein in amniotic fluid.

METHOD OF STUDY: We established a double-determinant ELISA system using the anti-HLA-G-specific mouse monoclonal antibody ‘87G’ as a capture antibody and the horseradish-peroxidase-labeled rabbit anti-human β2-microglobulin antibody as a detection antibody. We then measured the concentration of HLA-G protein in amniotic fluid samples from nine normal second-trimester pregnant women and in serum samples from eight normal males.

RESULTS AND CONCLUSION: HLA-G protein was detected in amniotic fluid at a concentration of 275 ng/ml (197–343 ng/ml) (median value and 95% confident range), whereas the concentration of HLA-G protein in male serum was below the minimum detection level.