Binding analysis of HLA-G specific antibodies to hematopoietic cells isolated from leukemia patients.
Expression of HLA-G on the surface of malignant hematopoietic cells isolated from leukemia patients was analyzed by flow cytometry using monoclonal antibodies (mAbs) recognizing both, intact HLA-G complex (87G, 01G and MEM-G9) as well as HLA-G free heavy chain (4H84, MEM-G/1 and MEM-G/2). Prerequisite of HLA-G detection by mAbs specific to free heavy chain was mild acid treatment, which dissociates intact HLA-G complex. All mAbs, with the exception of 4H84 mAb, did not indicate the presence of HLA-G antigen in leukemia cells. Positive staining with 4H84 mAb was detected in acid-treated cells isolated from 16 out of 30 patients. Intensity of staining increased after IFN-g pre-incubation in most cases. Immunoblot analyses and RT-PCR, however, failed to detect HLA-G antigen or HLA-G transcripts in cells that bind 4H84 mAb after acid-treatment. The binding of 4H84 mAb can be explained by the acid-induced cross-reactivity of this HLA-G specific mAb with classical HLA class I molecules [15]. The results described here further demonstrate that the HLA-G molecule is not expressed in freshly isolated human leukemia cells.
Poláková
K
K
Cancer Research Institute; Slovak Academy of Sciences, 833 91 Bratislava, Slovak Republic.
Bandzuchová
E
E
Hofmeister
V
V
Weiss
E H
EH
Hutter
H
H
Russ
G
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D001854:Bone Marrow Cells / Q000276:immunology / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006680:HLA Antigens / Q000276:immunology*; D059951:HLA-G Antigens; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D007938:Leukemia / Q000097:blood / Q000145:classification / Q000276:immunology* / Q000473:pathology; D008223:Lymphoma / Q000097:blood / Q000145:classification / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged
D000911:Antibodies, Monoclonal; D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I