Initial characterization of the apoptosis-inducing receptor for natural human anti-neuroblastoma IgM.
Med Pediatr Oncol
; 36(1): 251-7, 2001 Jan.
Article
em En
| MEDLINE
| ID: mdl-11464898
ABSTRACT
BACKGROUND:
Human neuroblastoma (NB) cells contain a 260 kDa surface antigen (NB-p260), which serves as receptor for natural human IgM antibodies (anti-NB IgM). Upon binding to NB-p260, these antibodies induce apoptosis in human NB cells. PROCEDURE ANDRESULTS:
In this study, we purified NB-p260 to homogeneity from human LA-N-1 NB cells by sequential ion exchange chromatography followed by preparative SDS gel electrophoresis. Purified NB-p260 exhibited rapid autodegradation despite the presence of various protease inhibitors. The autodegradation process precluded extensive N-terminal sequencing. However, from repeat N-terminal sequence analysis, a consensus sequence of seven amino acid residues emerged that exhibited significant homology to the subunit c of the human mitochondrial ATP synthase, a hydrophobic membrane protein of 7.6 kDa. Western blot analyses demonstrated that purified NB-p260 was recognized by polyclonal antibodies raised against both subunit c-containing storage bodies and a synthetic peptide consisting of amino acid residues 32-45 of subunit c. In addition to peptide sequences related to subunit c, NB-p260 also contained epitopes related to the human heat shock protein HSP90. In Western blots, a monoclonal anti-HSP90 antibody reacted with purified NB-p260 as well as with a predominant protein fragment of approximately 90 kDa that appeared during the process of NB-p260 autodegradation. The anti-HSP90 antibody was also capable of binding to the surface of LA-N-1 cells and inhibiting the binding of human anti-NB IgM in a dose-dependent manner.CONCLUSIONS:
Collectively, our data suggest that NB-p260, the apoptosis-mediating receptor for natural human anti-NB IgM, represents a novel surface protein of human NB cells containing polypeptide sequences related to the subunit c of the mitochondrial ATP synthase and the heat shock protein HSP90.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Imunoglobulina M
/
Apoptose
/
Anticorpos Antineoplásicos
/
Antígenos de Neoplasias
/
Neuroblastoma
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Med Pediatr Oncol
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Alemanha