# ECM/Integrin Tfh positioning cues for support of the germinal center response

> **NIH NIH R01** · UNIVERSITY OF ROCHESTER · 2020 · $482,772

## Abstract

Project Summary/Abstract
 The generation of a robust high-affinity antibody response is the goal of most vaccination strategies
against infection. T follicular helper cells play a critical role in provision of help to B cells for the selection of
high-affinity B cells in germinal centers (GC). While there is a growing understanding of the signals required to
generate Tfh, the signals that position or retain Tfh within the GC are not well understood. Elegant
photoactivation studies have revealed that the majority of Tfh cells entering a particular GC stay in that GC
long-term. How Tfh persist for many days in the GC is unclear. Identifying signals that regulate Tfh dwell time
in individual GCs could be important targets to regulate or boost the positioning of Tfh cells to GCs to facilitate
the generation of a robust protective antibody response or limit Tfh in Ab mediated autoimmunity.
 We have identified an ECM/integrin axis that appears to modulate the association of Tfh with the GC
and has a major impact on GC formation and antibody production. The RGD-motif ECM (extracellular matrix)
components are highly restricted to the GC upon immune challenge and co-localize with follicular dendritic
cells (FDC). Correspondingly, T cells express the matrix-binding integrin αVβ3 that binds to the RDG-motif in
ECM components. Integrin αV deficiency in T cells led to a striking defect in GC development, attenuated GC B
cells and reduced antigen-specific IgG to protein immunization and Influenza A infection. Moreover, in the
absence of integrin αV, LLPCs were lost but Bmem remained. The altered B cell response was not associated
with a failure of αV cKO T cells to differentiate into Tfh, but rather, the failure of αV cKO Tfh to accumulate
within the GC. Based on these novel observations, we hypothesize that integrin αV expression by Tfh cells
provides a positioning cue for location to, or retention/survival within, the GC via interaction with FDC-
associated ECM. The overall goal is to use this model to define immune mechanisms that influence Tfh
positioning or dwell time within the GC and to determine the consequence of Tfh miss-positioning on the
developing B cell repertoire.
Specific Aim 1. Integrin αV regulation of Tfh cell dynamics in germinal genters.
Specific Aim 2. The role of αV in Tfh fate and function?
Specific Aim 3. The consequence of integrin αV Tfh positioning on the B cell effector fate and
repertoire.
 Knowledge gained on the role of this ECM/integrin axis in Tfh GC support should provide novel targets
for the development of vaccines that optimize Tfh help and enhance high affinity antibody production.

## Key facts

- **NIH application ID:** 9815422
- **Project number:** 5R01AI136536-02
- **Recipient organization:** UNIVERSITY OF ROCHESTER
- **Principal Investigator:** Deborah J Fowell
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $482,772
- **Award type:** 5
- **Project period:** 2018-11-01 → 2023-10-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9815422

## Citation

> US National Institutes of Health, RePORTER application 9815422, ECM/Integrin Tfh positioning cues for support of the germinal center response (5R01AI136536-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9815422. Licensed CC0.

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