American Association for Cancer Research
10780432ccr191874-sup-223683_2_supp_5872797_q07pgk.xlsx (23.96 kB)

Supplementary Data from Antigen Experienced T Cells from Peripheral Blood Recognize p53 Neoantigens

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posted on 2023-03-31, 21:25 authored by Parisa Malekzadeh, Rami Yossef, Gal Cafri, Biman C. Paria, Frank J. Lowery, Mohammad Jafferji, Meghan L. Good, Abraham Sachs, Amy R. Copeland, Sanghyun P. Kim, Scott Kivitz, Maria R. Parkhurst, Paul F. Robbins, Satyajit Ray, Liqiang Xi, Mark Raffeld, Zhiya Yu, Nicholas P. Restifo, Robert P.T. Somerville, Steven A. Rosenberg, Drew C. Deniger

Table 1: Antibodies used in the study. Table 2: Normalized initial screening data from PBL with a T cell response to mutated TP53. Table 3: TCRB tracking of p53 neoantigen-reactive cells before and after IVS, co-culture, 41BB/OX40 sorting and REP.



The purpose of this study was to evaluate antigen experienced T cells in peripheral blood lymphocytes (PBL) for responses to p53 neoantigens. PBLs from patients with a mutated TP53 tumor were sorted for antigen-experienced T cells and in vitro stimulation (IVS) was performed with p53 neoantigens. The IVS cultures were stimulated with antigen-presenting cells expressing p53 neoantigens, enriched for 41BB/OX40 and grown with rapid expansion protocol. T-cell responses were not observed in the PBLs of 4 patients who did not have tumor-infiltrating lymphocyte (TIL) responses to mutated TP53. In contrast, 5 patients with TIL responses to mutated TP53 also had similar T-cell responses in their PBLs, indicating that the PBLs and TILs were congruent in p53 neoantigen reactivity. CD4+ and CD8+ T cells were specific for p53R175H, p53Y220C, or p53R248W neoantigens, including a 78% reactive T-cell culture against p53R175H and HLA-A*02:01. Tracking TCRB clonotypes (clonality, top ranked, and TP53 mutation-specific) supported the enrichment of p53 neoantigen–reactive T cells from PBLs. The same T-cell receptor (TCR) from the TIL was found in the IVS cultures in three cases and multiple unique TCRs were found in another patient. TP53 mutation–specific T cells also recognized tumor cell lines bearing the appropriate human leukocyte antigen restriction element and TP53 mutation, indicating these T cells could recognize processed and presented p53 neoantigens. PBL was a noninvasive source of T cells targeting TP53 mutations for cell therapy and can provide a window into intratumoral p53 neoantigen immune responses.See related commentary by Olivera et al., p. 1203