# Exploiting the Hydrophobic Glycosyl Pocket of IgG1 for Imaging and Drug Delivery Applications

> **NIH NIH R01** · STATE UNIVERSITY OF NY,BINGHAMTON · 2022 · $308,528

## Abstract

Project Summary:
Due to the rapidly growing importance of antibody-mediated drug delivery, there is a critical need for simple and
efficient site-specific conjugation techniques that do not require extensive antibody engineering efforts. Moreover,
there is significant need to identify sites of conjugation that are protected from plasma enzymes and are useful for
the attachment of hydrophobic payloads. The goal of this proposal is to optimize conjugation technology at the
conserved Q295 residue in order to meet these challenges. In contrast to most sites of conjugation, the Q295 site is
contained within a large hydrophobic cavity that is sterically shielded from plasma and is particularly amenable to the
conjugation of large nonpolar payloads. Remarkably, the properties of this hydrophobic pocket are largely unexplored
to-date and our preliminary research shows that there are significant untapped opportunities for exploiting the unique
features of this site. The goal of this project is to demonstrate the broad utility of this site-specific conjugation
technology through the preparation and evaluation of antibody conjugates for oncology, immunology, and imaging
applications. We will accomplish this goal through the achievement of three aims. Aim#1 focuses on developing a
thorough molecular understanding of the local environment around the Q295 residue and optimizing linkers that can
place the payload within the associated hydrophobic pocket. The goal of this aim is to thoroughly understand the
chemical properties of the hydrophobic pocket that surrounds the Q295 moiety. Aim#2 focuses on demonstrating the
therapeutic utility of this technology through the preparation of ADCs that deliver a wide range of payloads –
particularly focusing on payloads that have exhibited difficulties when attached through traditional (“stochastic”)
conjugation approaches. Four particular payloads were selected: MMAE (due to its clinical relevance and known linker
stability issues), Tubulysin (due to interest in payloads with low PGP efflux and also a labile ester functionality that has
caused problems with traditional approaches), Thailanstatin A (due to its unique mechanism of action and to the labile
functional groups in its structure), and Brequinar (due to its potency as an immunosuppressive agent and its very high
hydrophobicity that has so-far prevented ADC delivery). The resulting B-cell targeting ADCs will be thoroughly evaluated
for their pharmacokinetic profile and efficacy in a B-cell xenograft model. Aim#3 focuses on using the Q295 site for
the development of Raman imaging probes that can be used for generating live-cell time lapse images. Importantly,
there have been no reported attempts to use Raman imaging to study ADC trafficking. Traditional ADC conjugation
methods cannot be employed for the attachment of the Raman tags due to their very high hydrophobicity. Successful
achievement of these aims will provide the drug-delivery community with a valuable ne...

## Key facts

- **NIH application ID:** 10458034
- **Project number:** 5R01GM140026-02
- **Recipient organization:** STATE UNIVERSITY OF NY,BINGHAMTON
- **Principal Investigator:** Lawrence Tumey
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $308,528
- **Award type:** 5
- **Project period:** 2021-08-01 → 2025-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10458034

## Citation

> US National Institutes of Health, RePORTER application 10458034, Exploiting the Hydrophobic Glycosyl Pocket of IgG1 for Imaging and Drug Delivery Applications (5R01GM140026-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10458034. Licensed CC0.

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