Hu8F4-Car T Cells With Mutated FC Spacer Segment Improve Target Specificity and Mediate Anti-leukemia Activity In Vivo

Authors

Hong He
Rolando A Vedia
Sijie Lu
Qiaochuan Li
Kathryn R Cox
Lisa St John
Anna Sergeeva
Karen Clise-Dwyer
Gheath Alatrash
Elizabeth J Shpall
Qing Ma
Jeffrey J Molldrem

Language

English

Publication Date

11-1-2024

Journal

Cytotherapy

DOI

10.1016/j.jcyt.2024.06.010

PMID

39033444

PMCID

PMC11471379

PubMedCentral® Posted Date

11-1-2025

PubMedCentral® Full Text Version

Author MSS

Abstract

Background aims: Hu8F4 is a T-cell receptor-like antibody with high affinity for the leukemia-associated antigen PR1/HLA-A2 epitope. Adapted into a chimeric antigen receptor (CAR) format, Hu8F4-CAR is composed of the Hu8F4 single-chain variable fragment, the human IgG1 CH2CH3 extracellular spacer domain, a human CD28 costimulatory domain and the human CD3ζ signaling domain. We have demonstrated high efficacy of Hu8F4-CAR-T cells against PR1/HLA-A2-expressing cell lines and leukemic blasts from patients with acute myeloid leukemia in vitro. Previous studies have shown that modification of the Fc domains of IgG4 CH2CH3 spacer regions can eliminate activation-induced cell death and off-target killing mediated by mouse Fc gamma receptor-expressing cells.

Methods: We generated Hu8F4-CAR(PQ) with mutated Fc receptor binding sites on the CH2 domain of Hu8F4-CAR to prevent unwanted interactions with Fc gamma receptor-expressing cells in vivo.

Results: The primary human T cells transduced with Hu8F4-CAR(PQ) can specifically lyse HLA-A2+ PR1-expressing leukemia cell lines in vitro. Furthermore, both adult donor-derived and cord blood-derived Hu8F4-CAR(PQ)-T cells are active and can eliminate U937 leukemia cells in NSG mice.

Conclusions: Herein, we demonstrate that modification of the IgG1-based spacer can eliminate Fc receptor binding-induced adverse effects and Hu8F4-CAR(PQ)-T cells can kill leukemia in vivo.

Keywords

Humans, Animals, Mice, Receptors, Chimeric Antigen, T-Lymphocytes, Immunotherapy, Adoptive, HLA-A2 Antigen, Xenograft Model Antitumor Assays, Leukemia, Myeloid, Acute, Cell Line, Tumor, Single-Chain Antibodies, Mutation, Immunoglobulin G, Receptors, Antigen, T-Cell, Leukemia, Mice, Inbred NOD, PR1, Hu8F4, CAR-T cell, AML

Published Open-Access

yes

Recommended Citation

He, Hong; Vedia, Rolando A; Lu, Sijie; et al., "Hu8F4-Car T Cells With Mutated FC Spacer Segment Improve Target Specificity and Mediate Anti-leukemia Activity In Vivo" (2024). Faculty, Staff and Student Publications. 6219.
https://digitalcommons.library.tmc.edu/uthgsbs_docs/6219