# Enhanced MR reporter for immuno-imaging.

> **NIH NIH P41** · JOHNS HOPKINS UNIVERSITY · 2020 · $261,376

## Abstract

SUMMARY for TR&D 2
TR&D 2 of the BTRC will develop novel synthetic, non-metallic reporter genes that can be detected with chemical
exchange saturation transfer (CEST) MRI for precise visualization and pinpointing of biological processes in
living organisms. Using a lysine-rich protein (LRP) as such a prototype gene, we have previously demonstrated
that 1) We can image rapidly dividing tumor cells without the limitation of a label dilution effect that currently
exists with conventional MR contrast agents; 2) We can image promoter-driven specific gene expression; and
3) we can image oncolytic virotherapy. In this TR&D, we aim to dramatically improve the CEST contrast and
biocompatibility of LRP for further dissemination to the scientific community, and to create a pathway towards
eventual clinical translation. Using advanced, rational design-based molecular-genetic engineering approaches,
we will first develop a so-called “enhanced” LRP, or eLRP (Aim 1a). Enhancement is defined by transcription
and translation efficiency, protein refolding, optimal proton exchange rate, and strongest CEST contrast. For the
latter, a custom-designed high-throughput screening methodology will be used to determine optimal peptide
sequence configurations. Next, we will “humanize” eLRP to create heLRP, using an array of immunological
assays (Aim 1b). We will use established algorithms to identify epitopes that induce a T cell and/or humoral
response in reverse. Re-engineered LRPs will undergo reiterated screening processes until all immunogenicity
has been eliminated without compromising CEST contrast. Alternatively, we will use human protamine-1
(hPRM1) as a starting template to create chimeric LRP/hPRM1 constructs through DNA shuffling. The absence
of serum polyclonal antibodies from heLRP-immunized rabbits will be used as a final key criteria for TR&D 2
dissemination. During this immunological screening process, we will simultaneously identify the counterpart of
heLRP, i.e., an “immunogenic” LRP or iLRP. Following in vivo transfection, this iLRP will be used as a new
theranostic vector to simultaneously induce an anti-tumor immune response and visualize subsequent tumor cell
regression (Aim 2). Finally, we aim to demonstrate how eLRP can be used to provide a unique dynamic insight
into biological processes and as defined by cell-cell interactions. We have chosen dendritic cell (DC)
immunotherapy as an example. Following a validation study to confirm that constitutively expressed eLRP DCs
can be detected in vivo when migrating to lymph nodes following vaccination (Aim 3a), we will investigate when
and where DC activation occurs upon presenting antigen to CD4+ cells. We aim to accomplish this using IL-12
promoter-driven specific expression (Aim 3b). Concurrently, we will assess the time course and biodistribution
of activated, Ova-specific CD4+ transgenic cells using BLI in an Ova-expressing melanoma mouse model. Our
LRP reporters will have many applications in the stu...

## Key facts

- **NIH application ID:** 9984356
- **Project number:** 5P41EB024495-04
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Jeff W. Bulte
- **Activity code:** P41 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $261,376
- **Award type:** 5
- **Project period:** 2017-09-15 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9984356

## Citation

> US National Institutes of Health, RePORTER application 9984356, Enhanced MR reporter for immuno-imaging. (5P41EB024495-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9984356. Licensed CC0.

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