Intracerebral infusion of the bispecific targeted toxin DTATEGF in a mouse xenograft model of a human metastatic non-small cell lung cancer.

The aim of this study is to investigate the anti-cancer effect of the bispecific diphtheria toxin (DT) based immunotoxin DTATEGF, which targets both the epidermal growth factor (EGF) receptor (EGFR) and the urokinase-type plasminogen activator (uPA) receptor (uPAR) in vitro and in vivo when delivered by convection-enhanced delivery (CED) via an osmotic minipump in a human metastatic non-small cell lung cancer (NSCLC) brain tumor mouse xenograft model. The effects of the bispecific immunotoxin DTATEGF, and monospecific DTAT, DTEGF and control DT at various concentrations were tested for their ability to inhibit the proliferation of human metastatic NSCLC PC9-BrM3 cells in vitro by MTT assay. A xenograft model of human metastatic NSCLC intracranial model was established in nude mice using the human NSCLC PC9-BrM3 cell line genetically marked with a firefly luciferase reporter gene.

Genetic alteration of a bispecific ligand-directed toxin targeting human CD19 and CD22 receptors resulting in improved efficacy against systemic B cell malignancy.

A bispecific ligand-directed toxin (BLT) called DT2219ARL consisting of two scFv ligands recognizing CD19 and CD22 and catalytic DT390 was genetically enhanced for superior in vivo anti-leukemia activity. Genetic alterations included reverse orienting VH-VL domains and adding aggregation reducing/stabilizing linkers. In vivo, these improvements resulted in previously unseen long-term tumor-free survivors measured in a bioluminescent xenograft imaging model in which the progression of human Raji Burkitt's lymphoma could be tracked in real time and in a Daudi model as well.

Radiotherapy of CD45-expressing Daudi tumors in nude mice with yttrium-90-labeled, PEGylated anti-CD45 antibody.

Studies were performed to determine the suitability of using the polyethylene glycol (PEG)-labeled AHN-12 anti-CD45 monoclonal antibody to deliver the high-energy beta-particle-emitting isotope 90Y to a CD45+ B-cell Daudi lymphoma grown as flank tumors in athymic nude mice. The PEGylated radiolabeled antibody displayed a significantly better antitumor effect in the mouse tumor flank model (p<0.03) and significantly better blood pharmacokinetics in normal rats (p<0.

A bispecific recombinant immunotoxin, DT2219, targeting human CD19 and CD22 receptors in a mouse xenograft model of B-cell leukemia/lymphoma.

A novel bispecific single-chain fusion protein, DT2219, was assembled consisting of the catalytic and translocation domains of diphtheria toxin (DT(390)) fused to two repeating sFv subunits recognizing CD19 and CD22 and expressed in Escherichia coli. Problems with yield, purity, and aggregation in the refolding step were solved by incorporating a segment of human muscle aldolase and by using a sodium N-lauroyl-sarcosine detergent-based refolding procedure. Problems with reduced efficacy were addressed by combining the anti-CD19 and anti-CD22 on the same single-chain molecule.

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.