Systems analysis of immune responses to Norovirus infection in a human challenge model.

PROJECT SUMMARY/ABSTRACT Noroviruses are a group of highly infectious viruses responsible for over 600 million cases of gastroenteritis worldwide annually. Despite their widespread prevalence, currently there is no licensed vaccine against norovirus infection and disease. Very little is known about the nature of innate immune responses to norovirus infection in humans. In recent decades, advances in high-throughput “omics” technologies, along with the computational algorithms developed to analyze and interpret such data, have created the ability to profile immune responses at unprecedented depth and to better understand the complex interactions between the numerous components of the immune system. Here we propose to delineate the transcriptomic responses in human peripheral blood and stool collected from volunteers early after controlled infection with varying doses of two different strains of Norovirus and to use them as early innate transcriptional predictors of the effective adaptive anti-norovirus humoral and cellular immunity that develops later. We will perform transcriptomic, cytokine, and innate (NK and CD14+) cell profiling of peripheral blood and transcriptomic profiling of stool collected as part of two parallel DMID trials of healthy adults challenged with different strains and doses of Norovirus (clinicaltrials.gov ID NCT02473224, GII.2 strain, n=38, and NCT04174560 GII.4 strain, n=45). Samples will be collected pre challenge and on days 1, 3, 5, and 14 post-challenge, enabling profiling of the response kinetics during the acute phase of infection. Integration of transcriptomic data with our recently published atlas of human transcriptional responses across 13 vaccines, including many live attenuated vaccines, will enable a comparative analysis that will provide deep insight into how immune responses to gastrointestinal viruses, like Norovirus, may differ from those against respiratory or other types of viruses. Additionally, we will utilize norovirus-specific antibody titer (IgA, IgG, and blocking antibodies) and antibody-secreting cell and memory B cell frequency data, together with measurements of activated and cytokine (IFN-g, TNF-a, IL-2, IL-13 etc.) secreting Norovirus-specific T cells and combined single cell RNA and immune repertoire sequencing to comprehensively evaluate the humoral and cellular immune responses to Norovirus infection. We will incorporate the transcriptomic response data with machine learning approaches to identify transcriptional signatures of innate immune activity that predict each parameter of anti-norovirus humoral and cellular immunity, leveraging the independent trials as discovery/validation datasets to identify robust predictors. Together, these analyses will provide deeper insight into the immune responses to wild-type norovirus infection in humans and help understand mechanisms leading to the induction of effective anti-norovirus immunity. This information will lay important groundwork and provide a unique reference to compare immune responses to potential Norovirus vaccine candidates.