Detection of soluble HLA-G molecules in plasma and amniotic fluid

• Published in: Tissue antigens 1999-01, Vol.53 (1), p.14-22
• Main Authors: Rebmann, V., Pfeiffer, K., Päßler, M., Ferrone, S., Maier, S., Weiss, E., Grosse-Wilde, H.
• Format: Article
• Language: English
• Subjects: Adult; alternative splicing products of HLA-G; Amniotic Fluid - immunology; Animals; Antibodies, Monoclonal - immunology; beta 2-Microglobulin - immunology; Blood Protein Electrophoresis; Cell Line; Choriocarcinoma - pathology; Cross Reactions; Culture Media, Serum-Free; Drosophila melanogaster - cytology; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Female; Fetal Blood - immunology; Histocompatibility Antigens Class I - analysis; Histocompatibility Antigens Class I - blood; Histocompatibility Antigens Class I - genetics; Histocompatibility Antigens Class I - immunology; HLA Antigens - analysis; HLA Antigens - blood; HLA Antigens - genetics; HLA Antigens - immunology; HLA-E Antigens; HLA-G Antigens; Humans; Immunomagnetic Separation; Infant, Newborn; isoforms of sHLA-G; K562 Cells; Male; Molecular Weight; native soluble HLA-G; Plasma - immunology; Pregnancy; RNA Splicing; Sensitivity and Specificity; Sex Characteristics; Solubility; soluble HLA class I; Transfection; Tumor Cells, Cultured; Uterine Neoplasms - pathology
• ISSN: 0001-2815; 1399-0039
• DOI: 10.1034/j.1399-0039.1999.530102.x

: Although the cDNA sequence of HLA‐G antigens is compatible with their expression as soluble molecules (sHLA‐G), the determination of native sHLA‐G levels in body fluids has not yet been described. The lack of this information is likely to reflect the difficulties in developing an assay suitable to measure sHLA‐G antigens in the presence of soluble HLA‐A, ‐B and ‐C (sHLA‐I) antigens, since most of the available anti‐HLA‐G mAb do not detect soluble β2‐m associated HLA‐G antigens or crossreact with sHLA‐I antigens. Therefore, we have developed a two‐step assay which eliminates the interference of classical HLA class I antigens. In the first step, the sample is depleted of sHLA‐I antigens and of HLA‐E antigens with mAb TP25.99. Then, HLA‐G antigens are captured with mAb W6/32 and detected with anti‐β2‐m mAb in ELISA. Utilizing this assay, sHLA‐G antigen levels were measured in EDTA plasma from 92 controls with known HLA types, 28 women at delivery and the corresponding cord bloods and in 50 amniotic fluids. Mean sHLA‐G plasma levels did not differ between males (24.9±3.0 SEM ng/ml; n=42) and females (20.1±2.1 SEM ng/ml; n=50). However, sHLA‐G levels in HLA‐A11 positive probands (mean: 13.0±4.4 SEM ng/ml; n=12) were significantly (P