Immunotoxins: monoclonal antibody-toxin conjugates--a new approach to cancer therapy.
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Animals↗
Biomedical subjects
R A Spooner
Publications and source records attributed to R A Spooner.
Activation of the xylDLEGF promoter of the TOL toluene-xylene degradation pathway by overproduction of the xylS regulatory gene product.
The xylS regulatory gene of the Pseudomonas putida TOL plasmid (pWWO) has been cloned under the transcriptional control of the Escherichia coli tac promoter in a broad-host-range controlled-expression vector. Induction with isopropylthiogalactoside allowed overproduction and characterization of the xylS product by specific interaction with the TOL meta-cleavage pathway operator-promoter region (OP2) in vivo in E. coli. Examination of plasmid-specified polypeptides in E. coli maxicells led to identification of the xylS product as a 36-kilodalton polypeptide. The operator sequences required for xylS interactions lay upstream of the OP2 transcriptional start, and the xylS gene product recognized this region even in the absence of known coinducers.
Bacterial Proteins↗
Genetic, functional and sequence analysis of the xylR and xylS regulatory genes of the TOL plasmid pWW0.
Mutant derivatives of a plasmid, pCF20, which carries the XhoI-D fragment of the TOL plasmid pWW0 have been isolated using Tn5 transposon mutagenesis. Insertion mutations of the xylR and xylS regulatory genes of the catabolic pathway have been isolated and characterized and their ability to induce catechol 2,3-oxygenase activity determined. Analysis of the insertion mutants and also segments of the XhoI-D fragment cloned into plasmid pUC8 in maxicells has identified a 68 kDa polypeptide product encoded by the xylR gene. No clear candidate for the xylS polypeptide was observed. The nucleotide sequence of the xylS region, the intergenic region and part of the xylR region has been determined and open reading frames (ORFs) assigned for both genes. The ORF designated xylS appears capable of encoding a polypeptide of approximately 37 kDa.
Autoradiography↗
A recombinant single-chain antibody interleukin-2 fusion protein.
Recombinant interleukin-2 (rIL-2) therapy has been shown to be of value in the treatment of some cases of melanoma and renal cell carcinoma. However, its use can be limited by severe systemic toxicity. Targeting rIL-2 to the tumor should improve the antitumor immune response and decrease the systemic toxicity. With this aim, we have employed recombinant DNA techniques to construct a single-chain antibody interleukin-2 fusion protein (SCA-IL-2). The protein used in this model system consists of the variable domains of the antilysozyme antibody D1.3 fused to human IL-2 and is expressed in E. coli. It retains antigen-binding specificity and has the full biological activity of rIL-2. This approach can be taken to generate SCA-IL-2 proteins that bind to appropriate cellular antigens. In vivo administration of tumor-binding SCA-IL-2 should result in a localized high concentration of rIL-2 in the tumor tissues, maximizing the anti-tumor response while keeping systemic side effects to a minimum.
Amino Acid Sequence↗
A universal antibody-derived targeting agent.
We report bacterial expression of a single-chain antibody (ScFv) reactive against the haptens 4-hydroxy-3 nitrophenylacetic acid (NP) and 4-hydroxy-3-iodo-5-nitrophenylacetic acid (NIP) that is suitable for targeting to mammalian cells in vitro in a novel two-step targeting strategy. Hapten-derivatized primary antibodies of known specificity, bound to target cells, can capture the ScFv. Specificity resides in the interaction of the primary targeting antibody with the target and the interaction of the ScFv for NP/NIP, since the ScFv does not bind cells and nonderivatized antibodies bound at cells cannot capture the ScFv. The ScFv described here can therefore be considered as a universal agent for delivery of drugs, toxins, or radionuclides to any cell type for which a previously characterized antibody exists.
Amino Acid Sequence↗