Hu8F4-CAR T cells with mutated Fc spacer segment improve target-specificity and mediate anti-leukemia activity in vivo .
Jeffrey J MolldremHong HeRolando VediaSijie LuQiaochuan LiKathryn CoxLisa St JohnAnna SergeevaKaren Clise-DwyerGheath AlatrashElizabeth ShpallQing MaPublished in: Research square (2024)
Hu8F4 is a T cell receptor (TCR)-like antibody with high affinity for leukemia-associated antigen PR1/HLA-A2 epitope. Adapted into a chimeric antigen receptor (CAR) format, Hu8F4-CAR is comprised of the Hu8F4 scFv, 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 AML patients 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 (FcgR)-expressing cells. We generated Hu8F4-CAR(PQ) with mutated Fc receptor binding sites on the CH2 domain of Hu8F4-CAR to prevent unwanted interactions with FcgR-expressing cells in vivo . 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. 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 .
Keyphrases
- acute myeloid leukemia
- endothelial cells
- induced apoptosis
- cell cycle arrest
- cell death
- bone marrow
- cord blood
- induced pluripotent stem cells
- room temperature
- pluripotent stem cells
- ejection fraction
- binding protein
- endoplasmic reticulum stress
- type diabetes
- adipose tissue
- oxidative stress
- diabetic rats
- cell proliferation
- chronic kidney disease
- immune response
- metabolic syndrome
- prognostic factors
- regulatory t cells