# Mapping tumor specific immunopeptidome for antibody-based targeted therapy

> **NIH NIH F32** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2024 · $74,284

## Abstract

Project Summary
Antibody-based immunotherapies have become an established paradigm for treating cancers. Only a small
portion of patients have benefited from these agents, though, and many are only effective for treating a small set
of tumors. This is due, in part, to a lack of validated cell surface targets. Only a dozen of surface proteins has
been approved for antibody intervention, and most are not truly exclusive to malignant cells. There has been
growing interesting in searching the cellular immunopeptidome for tumor-exclusive targets. The
immunopeptidome is a pool of peptides generated from proteolysis of intracellular proteins and displayed on the
cell surface as a complex with the human leukocyte antigens (HLA). It is thought that this peptide repertoire
reflects the status of the intracellular proteome and can be modulated by driver oncogenes. Epitopes harboring
driver mutations, or neo-antigens, have been detected as peptide-HLA complexes (pHLAs) from tumor samples.
However, the mechanism of how oncogene signaling shape the immunopeptidome remains uncharacterized.
The goals of this proposal are to develop technologies to map changes in the immunopeptidome unique to
specific ongene, and tools to mount an immune response against them. These findings will ultimately aid in
developing antibody-based biologics with better safety profile and more applicable to diverse types of cancers.
Here, we hypothesized that proliferative oncogenes globally alter the immunopeptidome via transcriptional
remodeling and alternative splicing, and induce unique pHLAs beyond mutated fragments of parent
oncoproteins. To test this hypothesis, we will first develop a new mass spectrometry technique to map diseased
immunopeptidome in an allele-specific manner. Next, we will combine this technique with a reductionist cell
model approach to study the immunopeptidome of isogenic cell lines overexpressing specific oncogene. The
immunopeptidomics data will be complemented by protein databases and transcript analyses to reveal key
contributors of oncogene-specific pHLAs. Collectively, the proposed work will provide insight to how a single
genetic alteration can impact mechanisms of antigen presentation and produce neo-antigens on the cell surface.
To build on these discoveries, we will also engineer antibodies to recognize pHLAs of interest with high affinity
and peptide specificity. These reagents will be further elaborated into chimeric antigen receptors to arm cytotoxic
T cells and mount antitumor response against cells displaying oncogene-specific pHLAs. These reagents will be
tested in cultured cells, and humanized mice models. In the long term, the basic biological insights and antibody
tools generated from the proposed studies will bolster ongoing efforts to understanding the cancerous
immunopeptidome and lay the foundation for future therapeutics targeting neo-antigens.

## Key facts

- **NIH application ID:** 10904631
- **Project number:** 5F32GM149084-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** Zi Yao
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $74,284
- **Award type:** 5
- **Project period:** 2023-05-01 → 2025-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10904631

## Citation

> US National Institutes of Health, RePORTER application 10904631, Mapping tumor specific immunopeptidome for antibody-based targeted therapy (5F32GM149084-02). Retrieved via AI Analytics 2026-06-08 from https://api.ai-analytics.org/grant/nih/10904631. Licensed CC0.

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