Researchers in China recently published a study in Science Translational Medicine describing a new antibody cocktail for protection against two common viruses. The proposed preventative treatment consists of antibodies identified in pediatricians who have been repeatedly exposed to viruses throughout their careers, causing them to build up an immune system capable of defending against an array of pathogens.
Protection against RSV and hMPV
The respiratory syncytial virus (RSV) causes mild cold-like symptoms in healthy adults, but is the leading cause of lower respiratory tract infections in children, accounting for 30–50% of hospitalizations. The human metapneumovirus (hMPV) is the second most common cause of lower respiratory tract infections in children, accounting for 6–15% of hospitalizations. Both are also major causes of severe respiratory infections in older adults and immunocompromised people.
While RSV vaccines exist, they are currently only approved for older adults, as pediatric vaccines have faced safety challenges associated with enhanced respiratory disease risks. Vaccination before immune-ablative therapies in immunocompromised individuals has also been shown to be ineffective. Meanwhile, there are currently no approved therapies or prophylactics for hMPV.
Monoclonal antibodies (mAbs), which have an ability to neutralize viruses, may offer a better alternative for preventative treatments against RSV and hMPV. In prior studies, mAbs targeting a particular RSV protein have shown promise, but lost efficacy due to mutations that caused viral escape—a mechanism in which viruses mutate and evade the immune system, causing infection. Now, researchers are on the lookout for more escape-resistant antibody therapies.
Leveraging immunity acquired by pediatricians
Doctors, and especially pediatricians, come into contact with various viruses more often than most people, allowing many of them to build up a stronger immune system containing many antibodies. The research team involved in the new study decided to take advantage of this diverse source of antibodies.
To do this, they established a cohort consisting of 10 pediatric health care workers who have worked at a children’s hospital for more than 10 years and isolated immune cells from them. In comparison with 14 healthy adults, the team found that RSV-specific neutralizing antibody titers in the pediatricians were more than threefold higher than those in those without occupational exposure to RSV/hMPV. The team then selected three pediatricians with high neutralizing titers for their study.
Upon further analysis, the team identified three mAbs, referred to as CNR2056, CNR2053 and CNR2047. CNR2056 and CNR2053 were found to neutralize RSV A and B strains, while CNR2047 neutralized both RSV and hMPV. All exhibited surprisingly potent neutralizing activity when characterized for binding and neutralization.
“Collectively, these findings highlight that a subset of anti-F antibodies isolated from healthy pediatricians exhibits high potency and neutralizing breadth, positioning these antibodies as promising candidates for the development of next-generation immunoprophylactic agents against RSV and hMPV,” the study authors write.
Strong protection at low doses
To further validate their findings and test for efficacy, the team conducted animal studies on cotton rats and mice. Their results showed that CNR2056 and CNR2053 provided prophylactic protection against RSV in cotton rats. When testing against a benchmark, they found that the antibodies demonstrated dose dependent protection. While the benchmark achieved reduced viral titers or complete viral clearance at a maximum dose of 2 mg/kg, CNR2053 and CNR2056 enabled viral clearance at lower doses of 1 and 0.5 mg/kg, respectively.
When the team tested the efficacy of CNR2047 in cotton rats, they found a more than 100-fold reduced viral replication in two RSV strains. This was comparable in protective capacity to their benchmark, but slightly weaker compared with CNR2053 and CNR2056. However, hMPV studies with CNR2047 resulted in complete protection from hMPV infection in the lungs of mice and a dose-dependent reduction in pulmonary inflammation.
Furthermore, combing the mAbs into cocktails expanded coverage and reduced risk of escape variants, improving upon past mAb studies. The team’s findings mark a major step toward protecting vulnerable populations from two major respiratory viruses, but there is still work to be done. The researchers hope to expand on their work, and eventually, human trials will need to occur before these preventive therapies will be available.
The study authors write, “In conclusion, by leveraging natural immunity in repeatedly exposed individuals, we identified mAbs with high potency against RSV and hMPV. Their structural and functional characterization not only advance our mechanistic understanding but also pave the way for broad-spectrum immunoprophylaxis against pneumoviruses.”
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Publication details
Hui Zhai et al, Antibody cocktails based on the occupationally acquired immunity of pediatricians neutralize and confer protection against RSV and hMPV, Science Translational Medicine (2026). DOI: 10.1126/scitranslmed.adz4170
Journal information:
Science Translational Medicine
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