# Increasing the efficacy of non-activated CAR T cells by modulating IFN1 signaling

> **NIH NIH R01** · UNIVERSITY OF PENNSYLVANIA · 2024 · $587,108

## Abstract

Chimeric antigen receptor (CAR) T cells have demonstrated their efficacy in treating blood-based cancers.
However, the durability of responses is often hindered by challenges related to long-term T cell persistence and
engraftment. The success of CAR T cell immunotherapy relies on the differentiation status and overall fitness of
the CAR T cell product. Current protocols involve the activation and ex vivo expansion of patient T cells, however,
activation leads to irreversible differentiation, compromising their therapeutic potency.
Our recent work showed that a manufacturing protocol utilizing non-activated T cells results in superior
differentiation characteristics and reduced exhaustion, with concordant benefits in long-term tumor control.
Nevertheless, as quiescent T cells are highly resistant to lentiviral infection, CAR T manufacturing yield is a
significant limitation with non-activated T cells. The goal of this study is to harness the intrinsic stemness qualities
of non-activated CAR T cells and improve their transduction efficiency and effector function, thereby enhancing
their durable efficacy following infusion.
Quiescent T cells initiate a type I interferon (IFN1)-mediated innate response upon lentiviral vector transduction,
which limits CAR T cell transduction efficiency. Our preliminary data indicate that pre-treatment of non-activated
T cells with an IFN1-binding protein enhances CAR T cell transduction efficiency, and promotes a more naïve
and central memory phenotype. This research will delve into the impact of IFN1 blockade on CAR lentivirus
transduction and function of non-activated T cells, both in vitro and in xenograft models in vivo. Given that
sustained type I IFN signaling facilitates tumor immune escape and resistance to therapies, we hypothesize that
continuous IFN1 blockade not only enhances T cell fitness by inhibiting the innate response to the lentiviral vector
but also amplifies the therapeutic efficacy of T cells in tumors reliant on IFN-mediated immune evasion. To
explore this further, we will evaluate the effect of sustained IFN1 blockade by constructing lentiviral transfer
plasmids encoding both a CAR and a secreted anti-IFN1 binding protein in various xenograft models of cancer.
Another key aspect of our investigation is the interplay between SAMHD1 and IFN1 signaling pathways in
quiescent T cells. SAMHD1 restricts nucleotide availability for reverse transcription and is upregulated by IFN1.
Given that Vpx, a component of natural HIV, degrades SAMHD1, we will assess the impact of Vpx incorporation
on the efficiency of reverse transcription and vector integration of CAR lentivirus in non-activated T cells. Our
hypothesis is that restoring Vpx, which targets rate-limiting steps of the viral transduction pathway,
will synergize
with IFN1 inhibition in quiescent T cells, ultimately enhancing lentiviral transduction efficiency and bolstering the
function in non-activated CAR T cells.
These studies represent a signif...

## Key facts

- **NIH application ID:** 10943418
- **Project number:** 1R01CA292680-01
- **Recipient organization:** UNIVERSITY OF PENNSYLVANIA
- **Principal Investigator:** Saba Ghassemi
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $587,108
- **Award type:** 1
- **Project period:** 2024-08-01 → 2029-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10943418

## Citation

> US National Institutes of Health, RePORTER application 10943418, Increasing the efficacy of non-activated CAR T cells by modulating IFN1 signaling (1R01CA292680-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10943418. Licensed CC0.

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