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Therapeutics/pharmacology
Oral
Richard James, PhD
Principal Investigator
Seattle Children's Research Institute
King Hung, BS
Seattle Children's Research Institute
Iram Khan, PhD
Seattle Children's Research Institute
Tingting Zhang, PhD
Seattle Children's Research Institute
Rene Cheng, BS
University of Washington
Swati Singh, BS
Seattle Children's Research Institute
Emmaline Suchland, BS
Seattle Children's Research Institute
Chester Jacobs, BS
Seattle Children's Research Institute
Matthew Macquivey, BS
Seattle Children's Research Institute
Claire Stoffers, BS
Seattle Children's Research Institute
David Rawlings, MD
Seattle Children's Research Institute
Injectable protein or peptide drugs now constitute ~10% of the pharmaceutical market. Recently, we developed a cell-based method to stably deliver protein drugs. To do this, we coupled CRISPR/Cas9-based nucleases with adeno-associated virus for delivery of donor homology templates to safe-harbor loci in human B cells, which we subsequently differentiate into antibody-secreting cells (ASC). A subset of these cells resembled long-lived plasma B cells (CD38hiCD138+), whereas others exhibited phenotypes (CD38+CD138-) not previously associated with longevity. We show that engineered B cells can engraft in recipient immune deficient, NOD/SCID/gc-null (NSG) mice and stably produce human antibody for >1 year. ASCs engineered to express firefly luciferase primarily migrated to the bone marrow, the endogenous location of human long-lived plasma cells. Upon provisioning NSG mice with human cytokines (IL6, and/or BAFF) that promote survival of long-lived plasma cells, we observed substantial increases in antibody production and durability of B cell grafts. BAFF preferentially promoted class-switched, CD138+ plasma cells. In contrast, IL6 promoted surface IgM-expressing CD38+CD138- ASCs, as well as CD138+ plasma cells. Finally, quantification of human ASC in the murine bone marrow and spleen showed that as few as 20,000 engineered cells/recipient was sufficient to maintain IgG titers of 10 ug/mL, levels that could be of therapeutic valuable if achieved using expression of candidate mAb reagents. Together, these studies show that engineered human B cells have the capacity to engraft long-term and function normally in vivo, strongly supporting further studies using this novel cell therapy platform for long-term delivery of protein drugs.