Intracranial therapy of glioblastoma with the fusion protein DTAT in immunodeficient mice.

A gene splicing technique was used to create a hybrid fusion protein DTAT encoding the 390 amino acid portion of diphtheria toxin (DT(390)), a linker, and the downstream 135-amino terminal fragment portion of human urokinase plasminogen activator. DTAT was assembled to target human glioblastoma cell lines in a murine intracranial model. Previously published in vitro studies demonstrated that DTAT was highly selective and toxic to human glioblastoma cell lines in a flank tumor model.

Molecular modification of a recombinant, bivalent anti-human CD3 immunotoxin (Bic3) results in reduced in vivo toxicity in mice.

A novel bivalent single chain fusion protein, Bic3, was assembled consisting of the catalytic and translocation domains of diphtheria toxin (DT(390)) fused to two repeating sFv molecules recognizing human CD3 epsilon of the human T-cell receptor. Historically, problems with these constructs include low yield, toxicity, and reduced efficacy. Instead of using conventional Gly(4)Ser linkers to connect heavy/light chains, aggregation reducing linkers (ARL) were used which when combined with a new SLS-based refolding method reduced aggregation and enhanced the yield of final product.