To test if the reduced cytokine release has an effect on in vivo anti-tumor activity, we used ET190L1-AbTCR-T cells to treat a patient-derived xenograft (PDX) mouse model of primary B-ALL (CHP105R1, negative for both CD80 and CD86) and observed similar tumor inhibition between mice treated with the ET190L1-AbTCR- and CTL019-T cells (Fig. 5c). Here, CD80 is linked to precursor B-cell acute lymphoblastic leukemia.