# Immunoregulation by TLR-activated TIM-1+ ProB Cells in Transplantation

> **NIH NIH P01** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2020 · $437,500

## Abstract

Abstract (Project 2)
Rather than use passive transfer of well differentiated adult immunoregulatory cells as a means to create
transplant tolerance, we have discovered that a population CpG activated pro-B cells are extraordinarily potent,
far more potent on a per cell basis than Tregs and far easier to prepare. Transfer of only 40,000, but not
90,000, induces permanent engraftment and probably tolerance in MHC incompatible islet and cardiac allograft
mouse models. We have discovered that CpG induces expression TIM-1 a potential master switch for
expression of an immunoregulatory module in mature Bregs (see Project 1/ Kuchroo). We also learned that
ligation of TIM-1 by anti-TIM-1 mAb induces expression of IL-10, a member of the regulatory model discovered
by Kuchroo. The stepwise contributions of CpG and activation of the TIM-1 pathway are examined through
RNAseq and NanoString based analysis. To more precisely characterize the fate and phenotype, proliferative
and differentiation of CpG activated pro-B cells, lineage-tracking methods are utilized throughout. We know
that CpG activated pro-B cells proliferate and differentiate after transfer when introduced in optimal, not
excessive, cell number. Depending upon environmental cues CpG activated pro-B cells can differentiate into a
variety Bregs but CpG activated pro-B cells from RAG KO mice do not generate Bregs. In this project we will
analyze the cellular basis of tolerance believing that CpG activated B regs and their progeny create an
environment conducive to activation, expansion and retention of donor specific Tregs. The specific but
multifaceted requirements for B cell differentiation, including the nature of the niche impairing expansion and
differentiation of CpG-ProBs, in the acquisition of tolerance will be analyzed through use of a panel of carefully
selected gene knockout mice. The role of T and B regs in the induction and maintenance of tolerance will be
determined through time course protocols that selectively destroy Tregs or the mature progeny of CpG activate
pro cells. The diversity of CpG-ProB progeny and their expression of a regulatory module that is IL-10 inclusive
will be examined by single cell RNAseq of CpG-ProBs and their progeny at the transplant.

## Key facts

- **NIH application ID:** 9985717
- **Project number:** 5P01AI129880-03
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** TERRY B. STROM
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $437,500
- **Award type:** 5
- **Project period:** 2018-08-01 → 2023-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9985717

## Citation

> US National Institutes of Health, RePORTER application 9985717, Immunoregulation by TLR-activated TIM-1+ ProB Cells in Transplantation (5P01AI129880-03). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9985717. Licensed CC0.

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