Correction of B-cell development in Btk-deficient mice using lentiviral vectors with codon-optimized human BTK.
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.
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Department of Immunology, Erasmus MC, Rotterdam, The Netherlands.
Baert
M R M
MR
Pike-Overzet
K
K
Rodijk
M
M
Brugman
M H
MH
Schambach
A
A
Baum
C
C
Hendriks
R W
RW
van Dongen
J J M
JJ
Staal
F J T
FJ
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
D003062:Codon; D017931:DNA Primers; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human; C000625951:Btk protein, mouse; D002118:Calcium