# Mechanisms of impaired T-cell mechanosensing of melanoma antigens

> **NIH NIH U01** · GEORGIA INSTITUTE OF TECHNOLOGY · 2021 · $643,620

## Abstract

Project Summary
This project investigates how the tumor microenvironment (TME) impairs in situ interactions of T-cell surface
molecules with counter-molecules on the melanoma cells to suppress anti-tumor immunity. Detailed mechanistic
understanding will be obtained by an integrated approach that combines physical science (PS) based tools with
two complementary pre-clinical mouse models of melanoma T cell immunity, which will be further tested using
biospecimens from melanoma patients. The molecular focus is the T-cell receptor (TCR) that initiates the T-cell
antigen recognition upon binding to peptide-major histocompatibility complex (pMHC), and the coreceptor CD8
that co-ligates with the pMHC. The first PS tool is quantifying TCR mechanosensing by single-molecule force
probes through in situ kinetic analyses of molecular interactions with concurrent imaging of intracellular signals
on a single cell. The second PS tool is DNA-based digital tension probes that report cell generated pulling forces
on the TCR and CD8 via engaged pMHC. One animal model is a recognized standard that uses melanoma
conjugated with a chicken ovalbumin antigen recognized by the OT-I TCR. The other animal model is a
melanoma self-antigen gp100 in conjunction with JR209 humanized transgenic mice. By analyzing the
mechanically regulated two-dimensional (2D) ligand binding of TCR and/or CD8 at the T-cell membrane, we
observed that the TCR avidities for the pMHC of CD8 T cells infiltrating primary murine melanomas grown in vivo
are significantly reduced relative to T cells within non-tumor associated tissues (spleen and blood). Such
differential avidities were not detected by the conventional assay using pMHC tetramer, attesting to the power
of our mechanics-based methods for analyzing TCR–pMHC interactions. We also found melanomas to
substantially alter the force-dependent TCR–pMHC bond durability: in tumor-free animals, the TCR and pMHC
formed a catch-slip bond whose lifetime first increased and then decreased with increasing force, which we have
previously demonstrated to govern T cell signaling and effector function, whereas in melanoma-bearing animals,
the TCR–pMHC bond lifetime only decreased with increasing force, i.e., behaved as a slip bond and were
associated with reduced T cell effector functions. We hypothesize that deficient CD8 T cell immunity in melanoma
results, at least in part, from impaired antigen recognition within the TME, as manifested by the altered TCR
mechanosensing of pMHC. Three specific aims are proposed to test our hypothesis: 1) Determine the molecular
interactions crucial to T cell antigen recognition that are impaired by the TME; 2) Define the functional
consequences of suppressed T cell antigen recognition; and 3) Elucidate the mechanisms underlying the TME
suppression of T cell antigen recognition. Completing these aims has the potential to identify new
immunotherapeutic targets for the treatment of melanoma to improve the outcomes of patient...

## Key facts

- **NIH application ID:** 10136540
- **Project number:** 5U01CA214354-05
- **Recipient organization:** GEORGIA INSTITUTE OF TECHNOLOGY
- **Principal Investigator:** MICHELLE KROGSGAARD
- **Activity code:** U01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $643,620
- **Award type:** 5
- **Project period:** 2017-04-01 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10136540

## Citation

> US National Institutes of Health, RePORTER application 10136540, Mechanisms of impaired T-cell mechanosensing of melanoma antigens (5U01CA214354-05). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10136540. Licensed CC0.

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