Hybridoma cells producing antibodies against A-chain of mistletoe lectin I are resistant to this toxin.
Immunol Lett
; 46(1-2): 5-8, 1995 May.
Article
en En
| MEDLINE
| ID: mdl-7590928
The cytotoxic effect of mistletoe lectin I (MLI) on TA5 hybridoma cells which produce monoclonal antibodies (mAb) to MLI A-chain (MLA) was investigated. In vitro cytotoxic tests with colorimetric assay were carried out for LD50 determination. TA5 hybridoma cells were 100 times more resistant to MLI and 30 times to chimeric toxin consisting of MLA and ricin B-chain (MLA/RTB) than control cells. The TA5 mAb (IgG1) recognized MLI A-chain in Western blotting and bound 125I-labeled MLI with Ka of 0.43 x 10(8) M-1. The TA5 and control hybridomas had the same number of 125I-labeled MLI binding sites. Therefore cell-surface TA5 antibodies did not influence MLI binding with the cell. The cytotoxic effect and binding of MLI were completely blocked in the presence of 20 mM lactose. Thus, MLI cytotoxicity was mediated only by cell-surface galactosyl residues; intracellular mAb molecules block MLI toxicity. Our data suggest that MLA molecules mediating cytotoxicity pass through an anti-MLA antibody-containing vesicular compartment and that mAbs inhibit the translocation activity of MLI A-chain from intracellular vesicles into the cytosol.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas de Plantas
/
Plantas Medicinales
/
Toxinas Biológicas
/
Muérdago
/
Preparaciones de Plantas
/
Hibridomas
/
Lectinas
/
Anticuerpos Monoclonales
Límite:
Animals
Idioma:
En
Revista:
Immunol Lett
Año:
1995
Tipo del documento:
Article
Pais de publicación:
Países Bajos