Boukhvalova, M. S. | Search bioRxiv

bioRxiv2026

Pan-neutralization of parainfluenza viruses by a hemagglutinin-neuraminidase antibody

Human parainfluenza viruses (HPIVs) can cause severe respiratory illnesses, such as croup, bronchiolitis, and pneumonia, particularly in children, the elderly and immunocompromised individuals. No vaccines or specific therapeutics are available for use in humans. Here, we report the discovery of a human monoclonal antibody designated PVA269 that broadly and potently neutralizes all four HPIV subtypes, PIV5, and Sendai virus by targeting the hemagglutinin-neuraminidase (HN) glycoprotein. We show that PVA269 inhibits neuraminidase activity and hemagglutination of erythrocytes through insertion of a long heavy chain complementary-determining region 3 in the enzyme active site. We reveal that the antibody markedly remodels its interactions to accommodate distinct viral features across HPIV subtypes, such as HPIV2 N-linked glycans. These results define the molecular basis for the unique PVA269 pan-neutralizing activity of human and animal viruses spanning two genera. PVA269 provides potent prophylactic activity against HPIV3 replication in the upper and lower airways of the clinically predictive cotton rat model, thus supporting translation of its protective efficacy to humans. These data establish PVA269 as a best-in-class monoclonal antibody and a promising clinical candidate to prevent HPIV infection, transmission, and disease in vulnerable populations.

immunology↗

bioRxiv2024

Systematic computer-aided disulfide design as a general strategy to stabilize prefusion class I fusion proteins

Numerous enveloped viruses, such as coronaviruses, influenza, and respiratory syncytial virus (RSV), utilize class I fusion proteins for cell entry. During this process, the proteins transition from a prefusion to a postfusion state, undergoing substantial and irreversible conformational changes. The prefusion conformation has repeatedly shown significant potential in vaccine development. However, the instability of this state poses challenges for its practical application in vaccines. While non-native disulfides have been effective in maintaining the prefusion structure, identifying stabilizing disulfide bonds remains an intricated task. Here, we present a general computational approach to systematically identify prefusion-stabilizing disulfides. Our method assesses the geometric constraints of disulfide bonds and introduces a ranking system to estimate their potential in stabilizing the prefusion conformation. We found, for the RSV F protein, that disulfides restricting the initial stages of the conformational switch can offer higher stability to the prefusion state than those preventing unfolding at a later stage. The implementation of our algorithm on the RSV F protein led to the discovery of prefusion-stabilizing disulfides, providing evidence that supports our hypothesis. Furthermore, the evaluation of our top design as a vaccine candidate in a cotton rat model demonstrated robust protection against RSV infection, highlighting the potential of our approach for vaccine development. Significance statementClass I fusion proteins, pivotal for cellular entry, constitute primary targets for neutralizing antibodies across a wide range of highly pathogenic viruses. Notably, the prefusion conformation of these proteins has demonstrated to be a robust immunogen, presenting a promising avenue for vaccine development. Despite of this, the inherent structural instability of this conformation poses a substantial hurdle for vaccine formulations. To overcome this limitation and to optimize these proteins as vaccines candidates, we developed an automated computational approach to enhance the structural stability of the prefusion conformation without compromising its immunogenic properties. Given the clinical significance of class I fusion proteins, our computational tool offers a mechanism to accelerate the development of preventive measures against a multitude of viral infections.

bioengineering↗