Recombinant immunotoxins containing the VH or VL domain of monoclonal antibody B3 fused to Pseudomonas exotoxin.

摘要: We prepared recombinant immunotoxins in Escherichia coli which the VH or VL domains of mAb B3 were fused to a truncated form Pseudomonas exotoxin (PE) (PE38KDEL). binds carbohydrate Ag found on surfaces many types cancers and only few normal tissues. PE38KDEL is 38-kDa PE (66 kDa) that missing cell-binding domain has carboxyl end changed from REDLK KDEL. show H chain L V region bind kill carcinoma cells containing Ag. Ag-negative not affected. The cytotoxicity these molecules between 20- 100-fold less than B3(Fv)-immunotoxins, both regions. VL-containing toxin was more active VH-containing toxin, indicating probably contributes Ag-binding chain. Refolding experiments B3(VL)-PE38KDEL aggregates VH-derivative single immunotoxin B3(Fv)-PE38KDEL, contains form. Furthermore, addition monomers, homodimers B3(VH)- obtained renaturation experiments. VL-toxin dimers, might have their binding regions arranged manner similar Bence Jones proteins (L homodimers), almost same as whereas VH-toxin dimers had decreased cytotoxic activity.