# Modulating extracellular TCR-CD3 interactions to identify new melanoma immunotherapy targets

> **NIH NIH R21** · NEW YORK UNIVERSITY SCHOOL OF MEDICINE · 2021 · $237,724

## Abstract

ABSTRACT
Melanoma is one of the deadliest and aggressive form of skin cancer. Main treatment options in metastatic
melanoma involve T cell immunotherapy using checkpoint blockade (anti-PD-1, anti-CTLA-4 and others) or
adoptive T cell therapy (ACT) with modified patient T cells. Although, durable response is only observed in a
fraction of patients. Further progress can be made by studying and targeting different T cell signaling
pathways. One such pathway is the T cell receptor (TCR) signaling pathway. T cell recognition of antigen by
the TCR and the resulting proximal signaling through the surrounding CD3 subunits are key steps in the
initiation of tumor-killing. Identification of the specific extracellular contacts between the TCR and CD3 subunits
gives precise guidance for immunotherapeutic strategies that modulate T-cell immunity by targeting signaling
through the TCR-CD3 complex. Previous studies that targeted the antigen binding site for enhancing T-cell
responses to tumor antigens often lead to off-target effects and toxicity. Based on our recent TCR-CD3
structure, we mutated specific CD3 interacting TCR-residues that resulted in different T cell cytokine
responses. Our hypothesis is that by modulating TCR-CD3 interactions in specific ways, immune-mediated
cytotoxicity to tumor antigens can be increased without losing specificity for the cancer antigen. To test our
hypothesis, in Aim 1, an in vitro retroviral TCR display method and a novel CD3-tetramer assay will be used to
mutate specific TCR-residues and identify TCRs that interact with CD3 with increased affinity, resulting in T
cells that mediate more effective functionality. In Aim 2, a structure-based TCR design will be used to identify
TCR mutants with enhanced CD3 binding ability in silico. In both instances, identified mutations will be
introduced into gp100-specific TCRs and their in vitro/in vivo tumor killing efficacy will be analyzed to validate
the anti-tumor potential of new TCRs with the goal of developing new wave of effective T cell therapies against
melanoma.

## Key facts

- **NIH application ID:** 10290708
- **Project number:** 1R21CA263378-01
- **Recipient organization:** NEW YORK UNIVERSITY SCHOOL OF MEDICINE
- **Principal Investigator:** Aswin Natarajan
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $237,724
- **Award type:** 1
- **Project period:** 2021-06-01 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10290708

## Citation

> US National Institutes of Health, RePORTER application 10290708, Modulating extracellular TCR-CD3 interactions to identify new melanoma immunotherapy targets (1R21CA263378-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10290708. Licensed CC0.

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