# The role of Entamoeba histolytica trogocytosis (trogo-: nibble) in the pathogenesis of amoebiasis

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2022 · $176,726

## Abstract

Abstract
 Entamoeba histolytica is a protozoan pathogen and the causative agent of amoebiasis in humans. The
species name (histo-: tissue; lytic-: dissolving) derives from the ability to destroy host tissues. E. histolytica
trophozoites (“amoebae”) invade the large intestine, causing ulceration and can spread to other tissues (e.g.,
liver, lungs, brain), causing fatal abscesses. Amoebae possess contact-dependent cell-killing activity that is likely
to drive tissue damage, but the mechanism was unclear. We established a new paradigm by discovering that
amoebae kill by biting off and ingesting human cell fragments, which we named “amoebic trogocytosis” (trogo-:
nibble) (Ralston, et al., Nature, 2014). Building on this discovery, here we propose to delineate the
unexpected contribution of trogocytosis to immune evasion. We will apply imaging flow cytometry, host and
amoeba mutants, and a variety of host cell types to dissect the contribution of trogocytosis to immune avoidance
in vitro, and we will use the mouse model of amoebiasis to extend these findings to pathogenesis in vivo. Beyond
E. histolytica, trogocytosis has far-reaching applications to eukaryotic biology. Several microbial eukaryotes
appear to use trogocytosis for cell-killing. In multicellular eukaryotes, trogocytosis is used for cell-killing, cell-cell
communication and cell-cell remodeling. Trogocytosis plays roles in the immune system, in the central nervous
system, and during development. Therefore, an improved understanding of the mechanism and biology of E.
histolytica trogocytosis will apply both directly to the pathogenesis of amoebiasis and broadly to eukaryotic
trogocytosis in general. This work is significant and high-impact as it will define a novel strategy for
immune evasion and an important aspect of amoebiasis pathogenesis. Moreover, these studies apply
broadly to trogocytosis as a conserved mode of eukaryotic cell-cell interaction.
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## Key facts

- **NIH application ID:** 10404102
- **Project number:** 5R01AI146914-04
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** Katherine S Ralston
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $176,726
- **Award type:** 5
- **Project period:** 2019-06-01 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10404102

## Citation

> US National Institutes of Health, RePORTER application 10404102, The role of Entamoeba histolytica trogocytosis (trogo-: nibble) in the pathogenesis of amoebiasis (5R01AI146914-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10404102. Licensed CC0.

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