Antibody recognition of paramyxovirus surface proteins

While vaccines are available for SARS-CoV-2, influenza virus, and RSV, and our laboratory has advanced mAbs and vaccines for hMPV, there has been a lack of research on parainfluenza virus (PIV) disease prevention and treatment, despite being the second highest cause of acute lower respiratory infection (ALRI) in young children. Globally, PIVs cause 18 million ALRI cases, 700,000 hospital admissions, and 34,000 deaths in children younger than five years of age each year. As a comparison, RSV causes nearly 60,000 deaths in children under 5 years of age each year, while hMPV causes approximately 12,000 deaths in the same age range. Among adults, severe disease can occur in those with immuncompromising conditions, especially those with hematopoietic stem cell and solid organ transplants, as well as those with hematologic malignancy, with high resulting mortality rates. PIVs are members of the Paramyxoviridae family, which consists of both endemic viruses as well as zoonotic viruses with pandemic potential. This R01 proposal seeks to advance the development of monoclonal antibodies (mAbs) for the treatment of infectious diseases, which is a major priority of NIAID and our research laboratory. Our major objective is to define the structural and mechanistic determinants mediating the neutralization and protection against paramyxoviruses. For this proposal, we will specifically focus on the PIV fusion (F) and hemagglutinin-neuraminidase (HN) surface proteins. In Aim 1, we will define the human B cell repertoire to PIV HN and F in adults and children. We will leverage recent advances in single B cell sequencing for the generation of human mAbs, which will then be assessed for neutralization potency, epitope specificity, and interfering with the viral life cycle. In Aim 2, we will determine the optimal therapeutic strategy for anti-PIV mAbs. We will utilize two rodent models, including Syrian golden hamsters for mAb screening, followed by cotton rats for verification of therapeutic value. In Aim 3, we will determine the structural epitopes mediating antibody functionality and protective efficacy. We will define these protective mAb epitopes at the molecular level using cryo-electron microscopy, which will be essential to advancing the mAb candidates and future vaccine candidates by identifying the optimal epitopes for mAb efficacy. With the recent approval of the first RSV vaccine, and the critical use of antibody guided structure-based vaccine design to stabilize the RSV F protein in the pre- fusion conformation, this proposal is conceptually innovative as we will incorporate recently described PIV pre- fusion F proteins in our strategies, conduct the first in-depth B cell repertoire studies for PIV infection, and by the exciting collaborations. Furthermore, this proposal is technically innovative as we will leverage state of the art tools, including high-throughput single B cell sequencing and cryo-electron microscopy for determination of protective and non-protective epitopes on the PIV surface proteins. Our research will advance the field by developing new human mAb therapeutics for the treatment of PIV infection, and by defining protective epitopes important for vaccine development for PIVs, which will translate to additional paramyxoviruses.