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Published on: May 2, 2011
A novel bispecific nanobody protects mice against RSV infection via intranasal administration
Min Zhang1, Liuxing Qin1, Raoqing Guo2,3
1State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, Guangdong, China.
Insights
A novel nanobody, 4-H1, effectively neutralizes respiratory syncytial virus (RSV). Engineered into a bispecific nanobody (4-H1-anti-HSA-4-H1), it provides potent, long-lasting protection against RSV infection when delivered intranasally.
Area of Science:
- Virology
- Immunology
- Nanotechnology
Background:
- Respiratory syncytial virus (RSV) is a major cause of hospitalization in young children.
- Developing effective interventions against RSV is a critical public health need.
- Nanobodies targeting the RSV prefusion F protein offer a promising therapeutic strategy.
Purpose of the Study:
- To identify and characterize a novel nanobody targeting the RSV prefusion F protein.
- To engineer a bispecific nanobody with enhanced efficacy and stability for prophylactic use.
- To evaluate the in vivo protective potential of the engineered nanobody against RSV challenge.
Main Methods:
- Identification and characterization of a novel anti-RSV F nanobody (4-H1).
- Epitope mapping using binning assays, molecular docking, and mutational analyses.
- Engineering of a heterotrimeric bispecific nanobody (4-H1-anti-HSA-4-H1) with anti-RSV F and anti-human serum albumin domains.
- In vitro neutralization assays and in vivo challenge studies in BALB/c mice following intranasal administration.
Main Results:
- The novel nanobody 4-H1 demonstrated potent neutralization against both RSV A and B subtypes.
- The engineered bispecific nanobody 4-H1-anti-HSA-4-H1 exhibited sub-nanogram per milliliter neutralization potency.
- The bispecific nanobody showed a prolonged in vivo half-life and conferred robust protection against RSV challenge upon intranasal administration.
- Epitope characterization revealed 4-H1 binds a unique region of the RSV pre-F protein.
Conclusions:
- The novel nanobody 4-H1 is a potent neutralizer of RSV.
- The engineered bispecific nanobody 4-H1-anti-HSA-4-H1 demonstrates enhanced potency, stability, and prolonged efficacy.
- Intranasal administration of 4-H1-anti-HSA-4-H1 offers a promising prophylactic strategy against RSV, particularly for infants and young children.
Abstract:
Respiratory syncytial virus (RSV) is the leading cause of respiratory infection-related hospitalizations in children younger than 5 years. Neutralizing nanobody-based interventions represent a promising strategy against RSV. Here, we identify a novel nanobody (4-H1) targeting the RSV prefusion F (pre-F) protein, which demonstrates potent neutralization against both RSV A and B subtypes. Epitope characterization via binning assays, molecular docking, and mutational analyses revealed that 4-H1 interacts with a unique region within antigenic site Ø by engaging critical residues L207, K209, and the K65-N67-C69 cluster. To improve the in vivo efficacy and stability of the 4-H1 nanobody, we engineered a heterotrimeric bispecific nanobody (4-H1-anti-HSA-4-H1). This single-chain molecule contains two anti-RSV F nanobody domains and one anti-human serum albumin (HSA) domain, resulting in a trivalent molecule with dual specificity. This construct demonstrated sub-nanogram per milliliter (sub-ng/mL) neutralization potency against both RSV A and B subtypes, with prolonged in vivo half-life. Notably, intranasal administration of this construct before exposure conferred robust protection against RSV challenge in BALB/c mice. These results underscore the potential of 4-H1-anti-HSA-4-H1 as a respiratory-delivered prophylactic against RSV.IMPORTANCERSV is the leading cause of infant respiratory hospitalizations, highlighting the urgent need for effective prophylaxis. Here, we engineered a potent bispecific nanobody (4-H1-anti-HSA-4-H1) that exhibits exceptional neutralization against both RSV A and B subtypes with prolonged serum persistence. Prophylactic intranasal delivery of this construct conferred robust protection against RSV challenge in mice, indicating its potential as a respiratory-delivered prophylactic candidate against RSV.
