AUTHOR=Whiteaker Jeffrey R. , Zhao Lei , Schoenherr Regine M. , Huang Dongqing , Lundeen Rachel A. , Voytovich Ulianna , Kennedy Jacob J. , Ivey Richard G. , Lin Chenwei , Murillo Oscar D. , Lorentzen Travis D. , Colantonio Simona , Caceres Tessa W. , Roberts Rhonda R. , Knotts Joseph G. , Reading Joshua J. , Perry Candice D. , Richardson Christopher W. , Garcia-Buntley Sandra S. , Bocik William , Hewitt Stephen M. , Chowdhury Shrabanti , Vandermeer Jackie , Smith Stephen D. , Gopal Ajay K. , Ramchurren Nirasha , Fling Steven P. , Wang Pei , Paulovich Amanda G. TITLE=A multiplexed assay for quantifying immunomodulatory proteins supports correlative studies in immunotherapy clinical trials JOURNAL=Frontiers in Oncology VOLUME=13 YEAR=2023 URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2023.1168710 DOI=10.3389/fonc.2023.1168710 ISSN=2234-943X ABSTRACT=Introduction

Immunotherapy is an effective treatment for a subset of cancer patients, and expanding the benefits of immunotherapy to all cancer patients will require predictive biomarkers of response and immune-related adverse events (irAEs). To support correlative studies in immunotherapy clinical trials, we are developing highly validated assays for quantifying immunomodulatory proteins in human biospecimens.

Methods

Here, we developed a panel of novel monoclonal antibodies and incorporated them into a novel, multiplexed, immuno-multiple reaction monitoring mass spectrometry (MRM-MS)-based proteomic assay targeting 49 proteotypic peptides representing 43 immunomodulatory proteins.

Results and discussion

The multiplex assay was validated in human tissue and plasma matrices, where the linearity of quantification was >3 orders of magnitude with median interday CVs of 8.7% (tissue) and 10.1% (plasma). Proof-of-principle demonstration of the assay was conducted in plasma samples collected in clinical trials from lymphoma patients receiving an immune checkpoint inhibitor. We provide the assays and novel monoclonal antibodies as a publicly available resource for the biomedical community.