# How to Build Smaller, Synthetic Antibody-Like Molecules for Medicine > This patent describes a way to create small, single-chain proteins that mimic the binding power of full-sized antibodies to deliver medicine more effectively. - **Patent:** US 5455030 - **Original title:** Immunotheraphy using single chain polypeptide binding molecules - **Owner:** Enzon Labs Inc - **Granted:** 1995 - **Status:** Public domain (expired) - **Times cited:** 440 - **Field:** biotech, pharmaceutical ## What it does The patent details a method for creating a single-chain polypeptide that acts like an antibody but is much smaller. It achieves this by taking the two key binding parts of a natural antibody—the light chain variable region and the heavy chain variable region—and connecting them with a flexible peptide linker. This creates one continuous protein chain rather than the complex, multi-part structure of a natural antibody. In practice, this molecule can be conjugated to a therapeutic agent, such as a drug or toxin, to target specific cells, like cancer cells, while ignoring healthy ones. ## What it does NOT cover - Does not cover full-sized, naturally occurring antibodies with two heavy and two light chains. - Does not cover binding molecules that lack a peptide linker to connect the variable regions. - Does not cover non-protein-based targeting molecules. - Does not cover the specific therapeutic agents themselves, only the method of using the single-chain molecule as a delivery vehicle. ## The clever bit The innovation lies in realizing that you can physically tether the two separate binding domains of an antibody into a single chain without losing their ability to lock onto a target, effectively creating a 'mini-antibody' that is easier to produce in bacteria or yeast. ## Real-world examples 1. Single-chain variable fragments (scFv) 2. Antibody-drug conjugates (ADCs) 3. Bispecific T-cell engagers (BiTEs) ## Why it matters This technology was a foundational step toward modern antibody-based therapies. By shrinking the binding molecule, researchers could improve tissue penetration and simplify the manufacturing process using recombinant DNA technology. It paved the way for the development of bispecific antibodies and various antibody-drug conjugates used in oncology today. ## Frequently asked questions ### What does How to Build Smaller, Synthetic Antibody-Like Molecules for Medicine cover? This patent describes a way to create small, single-chain proteins that mimic the binding power of full-sized antibodies to deliver medicine more effectively. ### Who owns patent US 5455030? Enzon Labs Inc owns this patent, granted in 1995. ### When does this patent expire? This patent has expired and is now in the public domain — anyone can use the invention freely. ### What is patent US 5455030 cited by? This patent has been cited by 440 later patents that build on its ideas. ### What problem does this patent solve? This technology was a foundational step toward modern antibody-based therapies. By shrinking the binding molecule, researchers could improve tissue penetration and simplify the manufacturing process using recombinant DNA technology. It paved the way for the development of bispecific antibodies and various antibody-drug conjugates used in oncology today. ### What does this patent NOT cover? Does not cover full-sized, naturally occurring antibodies with two heavy and two light chains. **Full plain-English explainer:** https://patentbrief.org/patent/us/5455030/immunotheraphy-using-single-chain-polypeptide-binding-molecules **Original patent:** https://patents.google.com/patent/US5455030 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [Making Hybrid Antibodies from Different Animals](https://patentbrief.org/patent/us/4816567/recombinant-antibody-production-in-cho-cells) — This patent describes how to create new, engineered antibodies by combining parts of antibodies from two different animal species, then growing them in a lab. - [Making Cancer-Fighting Antibody Drugs Safer with Precise Attachment](https://patentbrief.org/patent/us/12121527/anthracycline-based-antibody-drug-conjugates-having-high-in-vivo-tolerability) — This patent describes a specific way to build antibody-drug conjugates (ADCs) for cancer treatment by precisely attaching chemotherapy drugs to antibodies to make them safer inside the body. - [How to Create Lab-Made Proteins That Stop Immune System Overreaction](https://patentbrief.org/patent/us/6458360/hpv-vaccine-gardasil) — A method for creating custom proteins that act as 'brakes' for the body's immune system to prevent damage from excessive inflammation. - [How Scientists Create Human-Friendly Antibodies for Medicine](https://patentbrief.org/patent/us/5585089/remicade-infliximab) — This patent describes a method for modifying mouse antibodies so human immune systems accept them as their own, allowing them to be used as powerful, long-lasting medical treatments. - [How Genentech's Antibody Targets Cancerous B Cells](https://patentbrief.org/patent/us/9845355/tecentriq-atezolizumab) — This patent describes a specific humanized antibody designed to bind to a protein called CD79b, which is found on the surface of certain cancer cells.