Related Experiment Video
Updated: Jul 19, 2026
Generation of Escape Variants of Neutralizing Influenza Virus Monoclonal Antibodies
Published on: August 29, 2017
Interprotomer disulfide-stabilized variants of the human metapneumovirus fusion glycoprotein induce high
Guillaume B E Stewart-Jones1, Jason Gorman1,2, Li Ou1
1Vaccine Research Center, NIH, Bethesda, MD 20892.
Abstract:
Human metapneumovirus (HMPV) is a major cause of respiratory disease worldwide, particularly among children and the elderly. Although there is no licensed HMPV vaccine, promising candidates have been identified for related pneumoviruses based on the structure-based stabilization of the fusion (F) glycoprotein trimer, with prefusion-stabilized F glycoprotein trimers eliciting significantly higher neutralizing responses than their postfusion F counterparts. However, immunization with HMPV F trimers in either prefusion or postfusion conformations has been reported to elicit equivalent neutralization responses. Here we investigate the impact of stabilizing disulfides, especially interprotomer disulfides (IP-DSs) linking protomers of the F trimer, on the elicitation of HMPV-neutralizing responses. We designed F trimer disulfides, screened for their expression, and used electron microscopy (EM) to confirm their formation, including that of an unexpected postfusion variant. In mice, IP-DS-stabilized prefusion and postfusion HMPV F elicited significantly higher neutralizing responses than non-IP-DS-stabilized HMPV Fs. In macaques, the impact of IP-DS stabilization was more measured, although IP-DS-stabilized variants of either prefusion or postfusion HMPV F induced neutralizing responses many times the average titers observed in a healthy human cohort. Serological and absorption-based analyses of macaque responses revealed elicited HMPV-neutralizing responses to be absorbed differently by IP-DS-containing and by non-IP-DS-containing postfusion Fs, suggesting IP-DS stabilization to alter not only the immunogenicity of select epitopes but their antigenicity as well. We speculate the observed increase in immunogenicity by IP-DS trimers to be related to reduced interprotomer flexibility within the HMPV F trimer.
Insights
Stabilizing human metapneumovirus (HMPV) fusion (F) glycoprotein trimers with interprotomer disulfides (IP-DSs) significantly enhances neutralizing antibody responses in animal models, paving the way for improved HMPV vaccine development.
Area of Science:
- Virology
- Immunology
- Structural Biology
Background:
- Human metapneumovirus (HMPV) is a significant global cause of respiratory illness, especially in vulnerable populations.
- Current vaccine development for HMPV is limited, unlike for related pneumoviruses where stabilized fusion (F) glycoprotein trimers show promise.
- Previous studies indicated that HMPV F trimers in prefusion or postfusion states elicited similar neutralization responses, unlike other pneumoviruses.
Purpose of the Study:
- To investigate the impact of stabilizing human metapneumovirus (HMPV) fusion (F) glycoprotein trimers using interprotomer disulfides (IP-DSs) on eliciting neutralizing responses.
- To assess whether IP-DS stabilization can enhance immunogenicity and alter antigenicity of HMPV F trimers.
Main Methods:
- Design and construction of HMPV F trimer variants with stabilizing disulfides, including IP-DSs.
- Expression screening and electron microscopy (EM) to confirm trimer formation and conformation.
- Immunization studies in mice and macaques, followed by serological and absorption-based analyses to measure neutralizing antibody responses.
Main Results:
- IP-DS-stabilized prefusion and postfusion HMPV F trimers elicited significantly higher neutralizing responses in mice compared to non-IP-DS-stabilized versions.
- In macaques, IP-DS stabilization showed a notable, though more moderate, increase in neutralizing responses, exceeding titers found in healthy humans.
- Absorption analyses indicated that IP-DS stabilization alters both the immunogenicity and antigenicity of HMPV F trimers by affecting epitope recognition.
Conclusions:
- Interprotomer disulfide (IP-DS) stabilization of HMPV F trimers enhances immunogenicity and elicits potent neutralizing responses.
- This stabilization strategy may overcome limitations seen with non-stabilized HMPV F trimers, offering a promising avenue for HMPV vaccine development.
- Reduced interprotomer flexibility in IP-DS stabilized trimers is a potential mechanism for the observed increase in immunogenicity.
