Gabriela Alvarado

Project Abstract

The overall goal of this project is to provide a detailed understanding of the human humoral response to Norovirus (NoV) infection and to define the molecular and structural basis for inhibition of NoV by human antibodies. NoV is the leading cause of sporadic and epidemic gastroenteritis in humans. There are currently no vaccines, therapeutics, or prophylactics available to prevent or treat NoV infection. Vaccine design also has been difficult due to the antigenic variation within and between NoV genogroups. To design a vaccine that elicits broad protective immunity, we must have a solid understanding of the NoV-mediated human antibody response to infection and antigenic sites recognized by these antibodies, so a critical area of HuNoV research has become the identification of type specific and cross-genotype and genogroup epitopes. The general hypothesis of this study is that inter- and intragenogroup I and II cross-reactive broadly blocking human antibodies exist and that the blocking function of such antibodies is principally mediated by IgA isotype molecules. The approach to this project will include high-efficiency isolation of human mAbs from patients previously infected with GI and GII strains of human NoV. I then will use this panel of human antibodies to determine if antibody isotype influences binding to NoV virus-like particles (VLPs) and blocking of binding of VLPs to host attachment factors. Finally, using site-directed mutagenesis and three-dimensional structural analysis, I will map immunoreactive epitopes on current circulating strains of NoV and determine whether cross-reactive broadly blocking epitopes exist.

Project Update

As was done below for Norwalk virus, we intend to characterize three-dimensionally where broadly binding and blocking human monoclonal antibodies bind to current circulating strains of norovirus.

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Shanker S, Czakó R, Sapparapu G, Alvarado G, Viskovska M, Sankaran B, Atmar RL, Crowe JE Jr, Estes MK, Prasad BV. Structural basis for norovirus neutralization by an HBGA blocking human IgA antibody. Proc Natl Acad Sci U S A. 2016 Oct 4;113(40):E5830-E5837. PMID: 27647885

Mentors

Primary: James E. Crowe, Jr.

Secondary: Ivelin Georgiev

Type of Trainee

Graduate student