# Characterization of an expanded set of assays for immunomodulatory proteins using targeted mass spectrometry

## TL;DR

This paper introduces a new set of assays to measure immune-related proteins in cancer, which can help predict treatment responses and improve clinical research.

## Contribution

The study expands a targeted mass spectrometry assay panel to quantify 39 immune-related proteins using novel monoclonal antibodies.

## Key findings

- A multiplexed IO-3 assay panel was developed to target 43 peptides from 39 immune- and inflammation-related proteins.
- Novel monoclonal antibodies were created and characterized for use in the assays.
- A publicly available dataset provides detailed assay performance and reagent information for implementation.

## Abstract

Immunotherapies are revolutionizing cancer care, but many patients do not achieve durable responses and immune-related adverse events are difficult to predict. Quantifying the hundreds of proteins involved in cancer immunity has the potential to provide biomarkers to monitor and predict tumor response. We previously developed robust, multiplexed quantitative assays for immunomodulatory proteins using targeted mass spectrometry, providing measurements that can be performed reproducibly and harmonized across laboratories. Here, we expand upon those efforts in presenting data from a multiplexed immuno-oncology (IO)-3 assay panel targeting 43 peptides representing 39 immune- and inflammation-related proteins. A suite of novel monoclonal antibodies was generated as assay reagents, and the fully characterized antibodies are made available as a resource to the community. The publicly available dataset contains complete characterization of the assay performance, as well as the mass spectrometer parameters and reagent information necessary for implementation of the assay. Quantification of the proteins will provide benefit to correlative studies in clinical trials, identification of new biomarkers, and improve understanding of the immune response in cancer.