Llama ‘nanobodies’ could outwit HCMV VU scientists found

September 14, 2021

A small fragment of a llama antibody, also called ‘nanobody’, is capable of reducing human cytomegalovirus (HCMV) in patients, scientists at the Vrije Universiteit and University of Cambridge found in a study. This could lower CMV-associated diseases and mortality during life-saving solid organ and stem cell transplantation and could be a potential lifesaving drug.

HCMV infections are common. Almost half of the adults in the Netherlands have had HCMV infections. Healthy people with a HCMV infection usually do not experience symptoms. However, every year 170 babies in the Netherlands with HCMV do experience serious consequences, such as hearing loss. For people with a weakened immune system, such as transplant recipients who need to take immunosuppressant drugs to prevent organ rejection, reactivation of HCMV can also be harmful and even life-threatening. Currently, there is no effective vaccine against HCMV and drugs are often ineffective or have serious side effects.

As HCMV hides in blood cells, the scientists searched for an approach to chase away the virus. The Llama nanobody “reactivates the virus just enough to make it visible to the immune system, but not enough for it to do what the virus normally does, replicating and spreading,” explains Dr. Elizabeth Elder from University of Cambridge. As a consequence, the immune cells can find and kill the virus. Dr. Timo De Groof from Vrije Universiteit Amsterdam: “As the name suggests, nanobodies are much smaller than regular antibodies, which make them perfectly suited for particular types of antigens and relatively easy to manufacture and adjust. That’s why they’re being hailed as having the potential to revolutionise antibody therapies.”

Professor Martine Smit of VU concludes “we believe our approach could lead to a much-needed new type of treatment for reducing – and potentially even preventing – CMV infectious in patients eligible for organ and stem cell transplants.”