A unique type of antibody-like molecule, naturally found only in camelids such as alpacas, llamas, and dromedaries, may offer new hope for treating human neurological conditions, including Alzheimer’s disease, according to recent research.
The study focused on so-called nanobodies—tiny proteins derived from camelid antibodies—which, due to their small size, enabled researchers to address neurological disorders in mice more effectively and with reduced side effects.
Published in Trends in Pharmacological Sciences, the study also outlines the steps needed to develop nanobody-based therapies that are safe for human use.
“Camelid nanobodies mark a transformative moment in the development of biologic treatments for brain disorders, changing the way we think about therapeutics,” said Dr. Philippe Rondard of France’s Centre National de la Recherche Scientifique (CNRS).
He added, “We envision them as a new category of drugs that bridges the gap between traditional antibodies and small-molecule medications.”
First identified in the early 1990s by Belgian researchers examining camelid immune systems, nanobodies originate from a special type of antibody that contains only heavy chains, unlike conventional antibodies, which have both heavy and light chains. The binding regions of these antibodies are now known as nanobodies. Measuring just a tenth the size of typical antibodies, nanobodies have yet to be found in other mammals, though some recent evidence suggests they may exist in certain cartilaginous fish.
While conventional antibody-based therapies are already used for cancer and autoimmune diseases, their application in neurological conditions—including a few Alzheimer’s treatments—often comes with significant side effects. Nanobodies, however, could provide more precise treatment with fewer adverse effects due to their compact size. Previous studies have shown that these molecules can reverse behavioral abnormalities in mouse models of schizophrenia and other brain disorders.
“These small, highly soluble proteins can cross the blood-brain barrier on their own,” explained co-author Dr. Pierre-André Lafon, also of CNRS. “In contrast, small-molecule drugs need to be hydrophobic to penetrate the brain, which reduces their availability, increases off-target effects, and can lead to side effects.”
Nanobodies are not only more versatile than traditional antibodies but are also easier to produce, purify, and engineer for specific targets, researchers say.
However, several hurdles remain before human clinical trials can begin. Long-term safety, toxicology assessments, and the effects of chronic administration all need careful evaluation.
“To move forward, we must develop clinical-grade nanobodies and stable formulations that retain activity over extended storage and transport periods,” Dr. Rondard emphasized.
Dr. Lafon noted that his team has already begun investigating these factors for several brain-penetrant nanobodies, demonstrating that the molecules can potentially be used safely in long-term treatments.