# Detection of IL35+ Exosomes as a Marker for Peripheral Tolerance

> **NIH NIH R03** · UNIVERSITY OF WISCONSIN-MADISON · 2020 · $77,500

## Abstract

ABSTRACT
Interleukin 35 (IL35) has emerged as a potent immuno-suppressive cytokine in cancer, auto-immune and
transplant immunology. A member of the IL12 family of cytokines, IL35 is a heterodimeric cytokine composed
of the protein subunits Epstein Barr Virus Induced 3 (Ebi3) and p35 and is produced and secreted
predominantly by regulatory T cells (Tregs). While IL35 has been implicated in the regulation of a number of
cellular immune responses, there still exists significant debate as to whether the cytokine actually exists. This
debate is predicated on the fact that attempts to isolate IL35 from blood, physiological solutions like ascites or
lymph, or even cell culture supernatants have failed. We have recently immune-precipitated both Ebi3 and p35
with an antibody to the tetraspanin CD81 from mouse lymphocytes. Tetraspanins are membrane spanning
proteins associated with the formation of the small, extracellular vesicles, exosomes. This interesting
observation prompted us to examine whether IL35 exists as Ebi3 and p35 proteins associated with
tetraspanins and secreted and acquired as an exosome. To test the idea that IL35 exists as an exosome
dependent cytokine, we designed the following specific aims: Specific Aim 1: To test whether exosomes
isolated from serum of tolerized groups of tetraspanin knockout mice (CD81, CD63, CD9) lose Ebi3 and p35
positive exosomes. Specific Aim 2: To examine whether lymphocytes from tolerized-CD81, CD63 or CD9
knockout mice produce and release functional IL35+ immuno-suppressive exosomes. The successful
completion of the outlined specific aims in this proposal will fill a significant gap in our understanding of the
cytokine IL35, and will ideally lead to future applications that further our understanding of the therapeutic
implications of IL35 for humans.

## Key facts

- **NIH application ID:** 9978316
- **Project number:** 1R03AI146688-01A1
- **Recipient organization:** UNIVERSITY OF WISCONSIN-MADISON
- **Principal Investigator:** Jeremy A Sullivan
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $77,500
- **Award type:** 1
- **Project period:** 2020-01-01 → 2021-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9978316

## Citation

> US National Institutes of Health, RePORTER application 9978316, Detection of IL35+ Exosomes as a Marker for Peripheral Tolerance (1R03AI146688-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9978316. Licensed CC0.

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