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Identification and Purification of Cytolytic Antibodies directed against O-Acetylated Sialic Acid in Childhood acute Lymphoblastic Leukemia

IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata

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Title Identification and Purification of Cytolytic Antibodies directed against O-Acetylated Sialic Acid in Childhood acute Lymphoblastic Leukemia
 
Creator Pal, Santanu
Chatterjee, Mitali
Bhattacharya, Dilip K
Bandyopadhyay, Santu
Mandal, Chitra
 
Subject Infectious Diseases and Immunology
 
Description Sialic acids typically present as terminal sugars of oligo­saccharides are reported to be modified by O-acetylation at the C-9 position on lymphoblasts of childhood acute lymphoblastic leukemia (ALL) patients (Sinha et al., 1999a, Leukaemia, 13, 119–125). We now report high titers of IgG antibodies directed against O-acetylated derivatives of sialic acids (O-AcSA) in serum of ALL patients. These antibodies were purified using bovine submaxillary mucin (BSM) and the IgG distribution was confined to IgG1 and IgG2 subclasses; their binding was totally abolished with de-O-acetylation confirming their specificity towards O-AcSA determinants. Flow cytometry demonstrated binding of these antibody fractions to peripheral blood mononuclear cells (PBMC) of both T- and B-ALL patients having increased cell surface 9-O-AcSA determinants. Western blotting of membranes derived from PBMC of ALL patients confirmed binding of the antibody to O-acetylated sialoglycoconjugates corresponding to 144, 135, 120, 90, and 36 kDa whereas binding to PBMC from normal individuals corresponded to 144 and 36 kDa. Specificity of the antibody fraction towards 9-O-AcSA was substantiated by hemagglutination and hemagglutination–inhibition assays. The antibody purified from ALL serum selectively mediates complement dependent cytolysis of lymphoblasts expressing O-AcSAs and thereby possibly confers passive protection. The enhanced anti O-AcSA antibody levels allowed for development of a serodiagnostic assay (BSM-ELISA) specific for ALL. Minimal crossreactivity was observed with other hematological disorders like acute myeloid leukemia (n = 16), chronic myeloid leukemia (n = 6), chronic lymphocytic leukemia (n = 7) and non-Hodgkin’s lymphoma (n = 3) as well as normal healthy individuals (n = 28). The BSM-ELISA therefore provides a simple, noninvasive alternative diagnostic approach for ALL and merits clinical consideration.
 
Publisher Oxford University Press
 
Date 2000
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://www.eprints.iicb.res.in/823/1/GLYCOBIOLOGY_10(_6)_539%2D549;2000[39].pdf
Pal, Santanu and Chatterjee, Mitali and Bhattacharya, Dilip K and Bandyopadhyay, Santu and Mandal, Chitra (2000) Identification and Purification of Cytolytic Antibodies directed against O-Acetylated Sialic Acid in Childhood acute Lymphoblastic Leukemia. Glycobiology, 10 (6). pp. 539-549.
 
Relation http://dx.doi.org/
http://www.eprints.iicb.res.in/823/