# Role of immune modulating butyrophilins in gamma delta T cell activation

> **NIH NIH R01** · UNIVERSITY OF CONNECTICUT STORRS · 2021 · $419,931

## Abstract

Abstract
Immune cells protect us from disease by detecting and responding to foreign molecules. Understanding the
molecular basis of this response is critical if we are to generate new therapies for treatment or prevention of
diseases involving immune cells. The objective of our research is to characterize a newly discovered antigen
detecting protein (butyrophilin 3, BTN3) which influences the immune response mediated by gamma delta T
cells. Gamma delta T cells are cytotoxic T cells that respond quickly to foreign threats and serve a variety of
roles, including direct lysis of infected or malignant cells, and as such, their activation holds great promise for
therapeutic manipulation. In contrast to T cells that express the more prevalent alpha beta T cell receptor and
respond to peptide antigens, T cells that express the Vgamma9Vdelta2 T cell receptor respond to small
phosphorous-containing compounds known as phosphoantigens. Butyrophilin 3A1 (BTN3A1) is the receptor for
phosphoantigens and mediates their activation of T cells through unclear mechanisms. We developed a library
of novel synthetic phosphoantigens, as well as a library of butyrophilin constructs and point mutations, both of
which are valuable tools for understanding the underlying biology of butyrophilins. Here, we propose aims that
test the underlying hypothesis that ligand binding to the intracellular domain of BTN3A1 produces conformational
and organizational changes that are required for interaction with counter receptors on T cells. Understanding
how BTN3A1 and the related 3A2, 3A3, and 2A1 isoforms function at the molecular level is important because it
1) will help optimize past and present clinical trials that have examined phosphoantigens and phosphoantigen-
expanded cells as immunotherapies, and 2) will identify new molecular targets or strategies within this complex
for therapeutic manipulation. Our studies in Aim 1 will show a structural basis for how phosphoantigens affect
the full length endogenous BTN3A1 using multiple biophysical and molecular biological approaches. In Aim 2,
we will investigate the function of BTN3A1 in phosphoantigen-induced Vgamma9Vdelta2 T cell lysis of
phosphoantigen containing cells and associated cytokine production. Together, this will allow us to build a
structure-function model of BTN3 with regards to how its domain organization, oligomerization status, protein-
protein interactions, and relationship to BTN2A1 influence its function. This will largely be done in the context of
biological membranes through use of a novel in vitro membrane nanodisc/cryo-EM model system. Our ultimate
goal is to present a clear structural model that demonstrates how phosphoantigen-induced conformational and/or
compositional changes in the BTN3 complex promote effector functions of T cells. This will enable clinical
development of therapies that modulate butyrophilin function to overcome immune checkpoints. These findings
will come at a point when the biological...

## Key facts

- **NIH application ID:** 10271491
- **Project number:** 5R01AI150869-02
- **Recipient organization:** UNIVERSITY OF CONNECTICUT STORRS
- **Principal Investigator:** OLGA VINOGRADOVA
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $419,931
- **Award type:** 5
- **Project period:** 2020-09-27 → 2025-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10271491

## Citation

> US National Institutes of Health, RePORTER application 10271491, Role of immune modulating butyrophilins in gamma delta T cell activation (5R01AI150869-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10271491. Licensed CC0.

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