Hall MS, Teer JK, Yu X, Branthoover H, Snedal S, Rodriguez-Valentin M, Nagle L, Scott E, Schachner B, Innamarato P, Hall AM, Blauvelt J, Rich CJ, Richards AD, Ceccarelli J, Langer TJ, Yoder SJ, Beatty MS, Cox CA, Messina JL, Abate-Daga D, Mule JJ, Mullinax JE, Sarnaik AA, and Pilon-Thomas S
Background: Adoptive cell therapy (ACT) with tumor-infiltrating lymphocytes (TILs) is a promising immunotherapeutic approach for patients with advanced solid tumors. While numerous advances have been made, the contribution of neoantigen-specific CD4 + T cells within TIL infusion products remains underexplored and therefore offers a significant opportunity for progress., Methods: We analyzed infused TIL products from metastatic melanoma patients previously treated with ACT for the presence of neoantigen-specific T cells. TILs were enriched on reactivity to neoantigen peptides derived and prioritized from patient sample-directed mutanome analysis. Enriched TILs were further investigated to establish the clonal neoantigen response with respect to function, transcriptomics, and persistence following ACT., Results: We discovered that neoantigen-specific TIL clones were predominantly CD4 + T cells and were present in both therapeutic responders and non-responders. CD4 + TIL demonstrated an effector T cell response with cytotoxicity toward autologous tumor in a major histocompatibility complex class II-dependent manner. These results were validated by paired TCR and single cell RNA sequencing, which elucidated transcriptomic profiles distinct to neoantigen-specific CD4 + TIL., Conclusions: Despite methods which often focus on CD8+T cells, our study supports the importance of prospective identification of neoantigen-specific CD4 + T cells within TIL products as they are a potent source of tumor-specific effectors. We further advocate for the inclusion of neoantigen-specific CD4 + TIL in future ACT protocols as a strategy to improve antitumor immunity., Competing Interests: Competing interests: Moffitt Cancer Center has licensed Intellectual Property (IP) related to the proliferation and expansion of tumor infiltrating lymphocytes (TILs) to Iovance Biotherapeutics. MSH, JEM, SP-T and AS are coinventors on such Intellectual Property. AS and SP-T are coinventors on a patent application with Provectus Biopharmaceuticals. MSH, DA-D, AS and SP-T are coinventors in provisional patent applications filed by Moffitt Cancer Center, including one resulting from the work described in this manuscript. MSH and AMH report common stock holdings in AbbVi, Amgen, BioHaven Pharmaceuticals, and Bristol Myers Squibb. JKT, XY, AS and SP-T participate in a sponsored research agreement with Turnstone Biologics. JJM is Associate Center Director at Moffitt Cancer Center and founder of Piranha Oncology, has ownership interest in Aleta Biotherapeutics, CG Oncology, Turnstone Biologics, AffyImmune, Aleta BioTherapeutics, Ankyra Therapeutics, and is a paid consultant/paid advisory board member for ONCoPEP, CG Oncology, Mersana Therapeutics, Turnstone Biologics, Aleta BioTherapeutics, Iovance Biotherapeutics, Vault Pharma, ORI Capital, UbiVac, Vycellix, AffyImmune, and Ankyra. JEM participates in sponsored research agreements with Intellia Therapeutics and SQZ Biotech that are not related to this research. JEM has received research support that is not related to this research from the following entities: Ocala Royal Dames and V Foundation. JEM has received ad hoc consulting fees from Iovance Biotherapeutics, Lyell Therapeutics, and Merit Medical. AS has received Ad hoc consulting fees from Iovance Biotherapeutics, Guidepoint, Defined Health, Huron Consulting Group, KeyQuest Health Inc, Istari, and Gerson Lehrman Group. AS has received speaker fees from Physicians’ Educational Resource (PER), Medscape and Medstar Health. Moffitt has also licensed IP to Tuhura Biopharma. SP-T is an inventor on such Intellectual Property. SP-T participates in sponsored research agreements with Provectus Biopharmaceuticals, Intellia Therapeutics, Dyve Biosciences, and Iovance Biotherapeutics that are not related to this research. SP-T has received consulting fees from Seagen and KSQ Therapeutics., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)