O-acetyl sialic acid specific IgM in childhood acute lymphoblastic leukaemia.
Initial studies have revealed an enhanced surface expression of O-acetylated sialoglycoconjugates (O-AcSGs) on lymphoblasts concomitant with high titres of IgG in childhood Acute Lymphoblastic Leukaemia (ALL) (Mandal C, Chatterjee M, Sinha D, Br J Haematol 110, 801-12, 2000). In our efforts to identify disease specific markers for ALL, we have affinity-purified IgM directed against O-AcSGs that reacts with three disease specific O-AcSGs present on membrane proteins derived from peripheral blood mononuclear cells (PBMC) of ALL patients. Antibody specificity towards O-AcSGs was confirmed by selective binding to erythrocytes bearing surface O-AcSGs, decreased binding with de-O-acetylated BSM and following pretreatment with O-acetyl esterase. Competitive inhibition ELISA demonstrated a higher avidity of IgM for O-AcSG than IgG. Flow cytometry demonstrated the diagnostic potential of purified O-AcSA IgM as binding was specific with ALL patients and minimal with other haematological disorders and normal individuals. It therefore may be adopted as a non-invasive approach for detection of childhood ALL. Taken together, the data indicates that carbohydrate epitopes having terminal O-AcSA alpha2 --> 6 GalNAc determinants induce disease specific IgG and IgM, potentially useful molecular markers for childhood ALL.
Pal
S
S
Immunobiology Division, Indian Institute of Chemical Biology, Calcutta 700032, India.
Chatterjee
M
M
Bhattacharya
D K
DK
Bandhyopadhyay
S
S
Mandal
C
C
Mandal
C
C
D000920:Antibody-Dependent Cell Cytotoxicity; D015153:Blotting, Western; D002648:Child; D002675:Child, Preschool; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology* / Q000302:isolation & purification; D019158:N-Acetylneuraminic Acid / Q000276:immunology*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000276:immunology*
D007075:Immunoglobulin M; C467440:O-acetyl sialic acid; D019158:N-Acetylneuraminic Acid