The study, published in Trends in Pharmacological Sciences, found that nanobodies—miniature proteins from camels, llamas, and alpacas—can effectively reach brain cells in mice and produce therapeutic effects with minimal side effects. Scientists also explained how they can safely move on to human trials.
Nanobodies were first discovered in the early 1990s by Belgian scientists studying the immune system of camelids. They noticed that in addition to conventional antibodies consisting of two heavy and two light chains, camelids produced simpler variants consisting of only heavy chains. The active part of these antibodies, called nanobodies, is about one-tenth the size of a regular antibody. Such molecules are unique to camelids and some cartilaginous fishes and are not found in other mammals.
Antibodies are widely used in medicine to treat cancer and autoimmune diseases, but their effectiveness in brain diseases remains limited. Even those rare antibody-containing drugs that demonstrate a positive effect, for example in Alzheimer’s disease, are often accompanied by unwanted side effects.
According to scientists, the compact structure of nanobodies gives them a clear advantage. Their small size allows them to cross the blood-brain barrier and more effectively act on target molecules, which can improve therapeutic effect and reduce the risk of adverse reactions. Previous studies have shown that nanobodies are able to restore normal behavior in mouse models of schizophrenia and other neurological disorders. In addition to their unique biological properties, nanobodies are easier to produce and purify compared to traditional antibodies. They can also be precisely designed and tailored to target specific brain molecules.
There are several important steps ahead before nanobody-based drugs can undergo clinical trials in humans. The researchers emphasize the need for toxicological testing and long-term safety assessment. It will also be important to study the effects of chronic use and determine how long nanobodies remain active in the brain—key to developing precise dosing regimens.