[HTML][HTML] CD19 CAR-targeted T cells induce long-term remission and B Cell Aplasia in an immunocompetent mouse model of B cell acute lymphoblastic leukemia

ML Davila, CC Kloss, G Gunset, M Sadelain - PloS one, 2013 - journals.plos.org
ML Davila, CC Kloss, G Gunset, M Sadelain
PloS one, 2013journals.plos.org
Although many adults with B cell acute lymphoblastic leukemia (B-ALL) are induced into
remission, most will relapse, underscoring the dire need for novel therapies for this disease.
We developed murine CD19-specific chimeric antigen receptors (CARs) and an
immunocompetent mouse model of B-ALL that recapitulates the disease at genetic, cellular,
and pathologic levels. Mouse T cells transduced with an all-murine CD3ζ/CD28-based CAR
that is equivalent to the one being used in our clinical trials, eradicate B-ALL in mice and …
Although many adults with B cell acute lymphoblastic leukemia (B-ALL) are induced into remission, most will relapse, underscoring the dire need for novel therapies for this disease. We developed murine CD19-specific chimeric antigen receptors (CARs) and an immunocompetent mouse model of B-ALL that recapitulates the disease at genetic, cellular, and pathologic levels. Mouse T cells transduced with an all-murine CD3ζ/CD28-based CAR that is equivalent to the one being used in our clinical trials, eradicate B-ALL in mice and mediate long-term B cell aplasias. In this model, we find that increasing conditioning chemotherapy increases tumor eradication, B cell aplasia, and CAR-modified T cell persistence. Quantification of recipient B lineage cells allowed us to estimate an in vivo effector to endogenous target ratio for B cell aplasia maintenance. In mice exhibiting a dramatic B cell reduction we identified a small population of progenitor B cells in the bone marrow that may serve as a reservoir for long-term CAR-modified T cell stimulation. Lastly, we determine that infusion of CD8+ CAR-modified T cells alone is sufficient to maintain long-term B cell eradication. The mouse model we report here should prove valuable for investigating CAR-based and other therapies for adult B-ALL.
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