New research insights: understanding how the immune system responds to cytomegalovirus in kidney transplant patients

23 March 2026

In new results published in npj Vaccines, with funding from Kidney Research UK, Professor Matthew Reeves and the team from University College London (UCL) showed how one of the most successful cytomegalovirus (CMV) vaccines in development that has been tested, could inform the design of more effective vaccines for kidney transplant patients.

Transplant patients are more vulnerable to cytomegalovirus infection

Cytomegalovirus (CMV) is part of the herpes group of viruses, closely related to the viruses that cause cold sores, chickenpox and glandular fever. CMV is a common virus and over half of the world's population are currently infected with CMV for life.

Transplant patients are more vulnerable to CMV infection because the drugs that protect their new kidney (called immunosuppressants) weaken their immune system. For these individuals, CMV can cause serious illness and increase the risk of kidney rejection.

Developing CMV vaccines is important, especially to protect transplant recipients and newborns.

Matt and his team have been studying the immune responses of vaccinated transplant patients to pinpoint exactly which parts of the virus are most important to develop a safe and effective vaccine.

Understanding how the immune system responds to a CMV vaccine

The team studied the gB/MF59 vaccine which works by producing an immune response against a protein called glycoprotein B (gB) that sits on the surface of CMV and helps it invade and spread between cells. Early studies show that this vaccine triggers a novel antibody response that targets a specific section of this protein, called AD-6.

What are antibodies?

Antibodies are proteins made by the immune system to protect the body from potentially harmful invaders. They recognise specific parts of these invaders, block them from infecting cells, and help the body get rid of them. Vaccines work by teaching your body to make the right antibodies.

Vaccine antibodies show promise against CMV for kidney transplant patients

The team studied immune responses in people who received the gB/MF59 vaccine, focusing on the AD-6 antibody. They found that AD-6 can block the virus from spreading between cells and prevent it from reactivating; this is a key step in controlling infections.

Using computer-based and laboratory techniques, they mapped where AD-6 was on glycoprotein B and compared its structure to similar proteins in other herpesviruses. They discovered that AD-6 has key chemical and structural features which are likely important for the function of gB making it a good target to produce effective antibodies against.

“We also found that AD-6 antibodies target a part of glycoprotein B that changes shape during infection, suggesting they may stop the virus by interfering with these shape changes. Interestingly, because AD-6 antibodies recognise similar regions in other herpesviruses, this hints at this being a target with broader protective potential beyond CMV.” Dr Matthew Reeves.

What does this mean for kidney transplant patients?

This study shows that AD-6 is an important target of the vaccine response and shows that the vaccine worked not just by blocking the virus outside cells, but by stopping it from spreading between them.

Dr Matthew Reeves added: “This work shows that AD-6 targets a critical part of glycoprotein B, explaining why the gB/MF59 vaccine antibody response can block CMV spread and reactivation. These findings could help to guide the design of future vaccines that protect kidney transplant patients who are most at risk from CMV and we are grateful to Kidney Research UK and all patient volunteers in the original gB/MF59 phase II vaccine trial for supporting this work.”