3d rendering of nanomedicine inside of liposome lipid bilayer with cholesterol molecules
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Antibody drugs have transformed the treatment of cancer, autoimmune disorders, and infectious diseases. Yet they share one major limitation: they can only reach targets outside cells. A new delivery system overcomes that barrier by transporting full-length antibodies directly into the cell interior, where many of the proteins responsible for cancer, inflammation, and neurodegenerative disease reside.
Many of the most important disease-causing proteins have remained inside the cell. For decades, those proteins have remained beyond the reach of antibody medicines. Transcription factors that drive cancer growth, inflammatory proteins that worsen tissue damage, and α-synuclein, the protein linked to Parkinson’s disease, all remain hidden behind the cell membrane. Although antibodies are highly selective, they are too large to cross that membrane on their own, leaving many of these disease targets inaccessible.
Bringing Antibodies into Cells
The new platform packages antibodies inside lipid nanoparticles, tiny fat-based particles already used in several approved medicines. The nanoparticles carry the antibodies into cells and release them into the cytoplasm, where they can bind intracellular proteins. Before encapsulation, the antibody surface is temporarily modified with negatively charged molecules that allow it to bind efficiently to the nanoparticles. Once inside the cell, the modification is removed, restoring the antibody’s normal structure and function. Because lipid nanoparticles are already used to deliver medicines in patients, the platform builds on a delivery technology that has already been validated in the clinic.
Many antibody drugs have already been developed for cancer, autoimmune disease, and other conditions but cannot reach proteins inside cells. Because the platform delivers intact antibodies, it could be paired with existing antibody drugs rather than requiring entirely new molecules to be designed from scratch. Swapping one antibody for another may allow the same delivery system to target entirely different diseases.
Blocking Disease from Within
The researchers tested the platform against several intracellular proteins linked to human disease. In cancer cells, delivered antibodies selectively blocked transcription factors that regulate genes involved in cancer and inflammation. These proteins help control which genes cells turn on and off and have long been difficult to target with antibody therapies. The same platform successfully delivered multiple therapeutic antibodies without requiring a new delivery system for each target.
The approach also worked in animals. In a mouse model of acute lung injury, antibodies targeting an inflammatory protein reduced signs of inflammation after systemic treatment. In a separate study, antibodies against α-synuclein were successfully delivered into the brains of mice, where they reached cells involved in Parkinson’s disease.
The two disease models required antibodies to reach very different organs. One application delivered antibodies to the lungs, while another carried them into the brain, demonstrating that the platform can be adapted for organs with very different biological barriers.
Beyond Individual Diseases
The platform could be applied far beyond the diseases tested in this study. Thousands of therapeutic antibodies have already been developed, but most can only target proteins found outside cells. Many of the proteins that drive cancer, chronic inflammation, and neurodegenerative disease remain inaccessible because they never leave the cell.
Delivering antibodies into cells could dramatically expand the range of diseases they can treat. Rather than designing entirely new therapies, researchers may be able to pair existing antibodies with this delivery platform to reach proteins that have long remained inaccessible. Because the platform can deliver different antibodies without changing the underlying technology, simply swapping one antibody for another could adapt it for a wide variety of diseases. Rather than creating new antibodies for every disease, the next generation of therapies may simply deliver existing ones to targets they have never been able to reach before.