Mechanistic and Structural Studies on Human Astrovirus Serotype 8
Physical and Biological Sciences
STEM Diversity Programs
The human astrovirus is a primary cause of acute non-bacterial gastroenteritis in immunocompromised individuals, such as the elderly and infants. By the age of nine, an estimated 90% of children will have developed antibodies against the most common strain. Causing symptoms like vomiting, fever, diarrhea, and, more recently, meningitis, it is a relevant but poorly understood virus. The capsid of the virus contains globular proteins called spikes that are thought to be primarily responsible for attachment to the unknown host cell receptor. Although there are no vaccines or antiviral therapeutics to treat infection, current efforts in regards to viral treatment include identifying the unknown host cell receptor binding site and understanding the mechanism by which the spike infects human cells through identification and production of neutralizing monoclonal antibodies and studying their interaction with spike. Structural studies of HAstv spike and antibody binding are essential for identification of functional epitopes that are involved in receptor host cell attachment as well as possible therapeutic targets. The Human Astrovirus serotype 8 (HAstV8) spike was expressed and purified in order to perform mechanistic and structural studies with monoclonal antibody 2D9, which binds to a novel epitope not previously studied. Additionally, two engineered forms of the neutralizing antibody 2D9 were produced -- a humanized monoclonal antibody and a single chain variable fragment -- in order to increase the chance of crystallization. In conjunction to a solved structure of this complex, mechanistic studies done by a collaborator will allow for functional classification of epitopes and insights to viral biology. Future efforts will include binding studies of 2D9 with other strains in order to test for cross-reactivity for the purpose of vaccine design, and X-ray crystallography determination of the structure of 2D9-bound HAstV8 spike to understand binding epitopes and their functional role in neutralizing the virus. The goal of this project is to advance knowledge on the infective mechanism of a prevalent strain of the virus, HAstV8.
