title: Correction of B-cell development in Btk-deficient mice using lentiviral vectors with codon-optimized human BTK.
abstract: X-linked agammaglobulinemia (XLA) is the most common primary immunodeficiency (PID) in man and caused by mutations in the Bruton's tyrosine kinase (BTK) gene. XLA is characterized by a B-cell differentiation arrest in bone marrow, absence of mature B cells and immunoglobulins (Igs), and recurrent bacterial infections. We used self-inactivating lentiviral vectors expressing codon-optimized human BTK under the control of three different ubiquitous or B cell-specific promoters. Btk-/- mice engrafted with transduced cells showed correction of both precursor B-cell and peripheral B-cell development. Lentiviral vectors containing the wildtype BTK sequence did not correct the phenotype. All treated mice with codon-optimized BTK exhibited the recovery of B1 cells in the peritoneal cavity, and of serum IgM and IgG3 levels. Calcium mobilization responses upon B-cell receptor stimulation as well as in vivo responses to T cell-independent antigens were restored. Viral promoters overexpressing BTK >100-fold above normal resulted in erythro-myeloid proliferations independent of insertional mutagenesis. However, transplantation into secondary Btk-/- recipients using cellular promoters resulted in functional restoration of peripheral B cells and IgM levels, without any adverse effects. In conclusion, transduction of human BTK corrects B-cell development and antigen-specific antibody responses in Btk-/- mice, thus indicating the feasibility of lentiviral gene therapy for XLA, provided that BTK expression does not vastly exceed normal levels.
authors.affiliation: Department of Immunology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Ng
authors.forename: M R M
authors.initials: MR
authors.lastname: Baert
authors.forename: K
authors.initials: K
authors.lastname: Pike-Overzet
authors.forename: M
authors.initials: M
authors.lastname: Rodijk
authors.forename: M H
authors.initials: MH
authors.lastname: Brugman
authors.forename: A
authors.initials: A
authors.lastname: Schambach
authors.forename: C
authors.initials: C
authors.lastname: Baum
authors.forename: R W
authors.initials: RW
authors.lastname: Hendriks
authors.forename: J J M
authors.initials: JJ
authors.lastname: van Dongen
authors.forename: F J T
authors.initials: FJ
authors.lastname: Staal
mesh_terms: D000077329:Agammaglobulinaemia Tyrosine Kinase; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D001483:Base Sequence; D016026:Bone Marrow Transplantation; D002118:Calcium / Q000378:metabolism; D003062:Codon; D017931:DNA Primers; D005434:Flow Cytometry; D005822:Genetic Vectors; D006801:Humans; D016086:Lentivirus / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016254:Mutagenesis, Insertional; D016133:Polymerase Chain Reaction; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D014161:Transduction, Genetic
chemical_list: D003062:Codon; D017931:DNA Primers; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human; C000625951:Btk protein, mouse; D002118:Calcium