Asunto(s)
Anticuerpos Monoclonales/biosíntesis , Hibridomas/efectos de los fármacos , Lectinas/farmacología , Preparaciones de Plantas , Proteínas de Plantas , Toxinas Biológicas/farmacología , Animales , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Hibridomas/citología , Hibridomas/inmunología , Lectinas/química , Ratones , Ratones Endogámicos BALB C , Ensayo de Unión Radioligante , Proteínas Inactivadoras de Ribosomas Tipo 2 , Toxinas Biológicas/químicaRESUMEN
Chimeric toxin protein was prepared from the mistletoe lectin I A-chain and ricin B-chain by using the disulfide exchange reaction. Ricin and chimeric protein were indistinguishable in binding to immobilized asialofetuin in ELISA. Chimeric protein was more toxic to Jurkat cells than native mistletoe lectin I, but not so effective as native ricin. In the presence of NH4Cl, which enhances the toxicity of some toxins and immunotoxins, but does not influence ricin toxicity, both ricin and chimeric toxin had equal cytotoxic activity. The possibility is discussed that the ricin B-chain protects the ricin A-chain (RTA) from degradation during delivering RTA from the cell surface to the place where RTA is translocated into the cytosol.
Asunto(s)
Lectinas/toxicidad , Muérdago/química , Preparaciones de Plantas , Proteínas de Plantas , Plantas Medicinales , Ricina/toxicidad , Toxinas Biológicas/toxicidad , Línea Celular , Supervivencia Celular/efectos de los fármacos , Humanos , Lectinas/química , Lectinas de Plantas , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/toxicidad , Proteínas Inactivadoras de Ribosomas Tipo 2 , Ricina/química , Toxinas Biológicas/químicaRESUMEN
Monoclonal anti-CD5 antibody was coupled to the enzymatically active subunit of plant toxin [either mistletoe lectin I (ML) or ricin]. The obtained conjugates proved to be selectively toxic to CD5-bearing target cells. The immunotoxin prepared from ML A-chain (MLA) was as toxic as native ML and approximately 80-fold more active than the corresponding conjugate with ricin A-chain (RTA). The comparative studies of the structural properties of isolated MLA and RTA were carried out using intrinsic fluorescence spectroscopy. The results showed similar properties for both proteins. No antigenic cross-reactivity against both toxins was detected when using polyclonal antibodies. The results suggest that MLA-antibody conjugates may be potential candidates for therapeutical use.