# Rotavirus: Studies of the Effectors and Mechanisms of Heterotypic Humoral Immunity in Human Intestinal Epithelial Cells

> **NIH VA I01** · VETERANS ADMIN PALO ALTO HEALTH CARE SYS · 2021 · —

## Abstract

Rotaviruses (RVs) are the most important cause of severe diarrhea in young children worldwide.
These viruses also cause diarrheal disease in healthy adults, the elderly, and the immune
compromised. RV replicates primarily in the mature villous tip cells of the small intestine. RVs infect most
mammals in a host-specific fashion; in general, RV strains that cause infection in one mammal do not
cause disease in another species. Natural RV infection and live attenuated vaccination effectively
induces heterotypic (as well as homotypic) protection from symptomatic re-infection despite the existence
of great serotype diversity among circulating RV strains. B cells and RV-specific antibodies mediate this
immunity to symptomatic re-infection. Neither the RV target of humoral heterotypic immunity nor the
mechanism that results in broadly cross-reactive immunity in people are currently well understood. To
address these two unknowns, we propose to study a library of human intestine origin RV monoclonal
antibodies (mAbs) with the following Specific Aims: Aim 1) Identify the targets of heterotypic and
homotypic neutralizing human antibodies on the rotavirus virion at the protein, epitope, and
structural levels. We will expand and extend our initial studies of the binding and traditional serologic
neutralization phenotypes of human intestine-derived anti RV mAbs. Phenotyping will include novel
neutralization assays employing primary human intestinal epithelial cell (IECs) small bowel enteroids. We
will further extend these studies to identify, at the atomic level, the structural interaction between these
functionally important mAbs and the three target RV surfaces proteins.
Aim 2) Determine the mechanisms by which human mAbs to RV proteins VP8*, VP5*, and VP7
neutralize RV infection in a novel human small intestinal enteroid culture system. We will identify the
mechanism by which these mAbs suppress (neutralize) RV replication using a variety of traditional and novel
technical approaches to assess the ability of the mAbs to inhibit RV binding to human IECs, to inhibit cell
entry, and to inhibit viral decapsidation.
Aim 3) Use the human mAbs that most efficiently inhibit the binding of human rotaviruses to human
intestinal epithelial cells to characterize the RV cell surface receptor on human intestinal cells. We
will exploit the novel observation that many human mAbs targeting RV VP8* efficiently neutralize human RVs
in human enteroid cultures and in HT-29 cells but not in MA104 cells. This finding suggests different RV
receptor usage in human IECs vs. MA104 monkey kidney cells. We will use several genetic and biochemical
characteristics of the putative RV receptor to better characterize/ identify the receptor that human RVs utilize
to initially bind to human IECs.
Aim 4). Use a selection of RV-specific neutralizing mAbs to VP8*, VP5*, and/or VP7 to design a
competition-based serologic assay to better predict the level and effectiveness of humoral immunity
to R...

## Key facts

- **NIH application ID:** 10084207
- **Project number:** 5I01BX000158-11
- **Recipient organization:** VETERANS ADMIN PALO ALTO HEALTH CARE SYS
- **Principal Investigator:** Harry Bernard Greenberg
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2021
- **Award amount:** —
- **Award type:** 5
- **Project period:** 2010-07-01 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10084207

## Citation

> US National Institutes of Health, RePORTER application 10084207, Rotavirus: Studies of the Effectors and Mechanisms of Heterotypic Humoral Immunity in Human Intestinal Epithelial Cells (5I01BX000158-11). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10084207. Licensed CC0.

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