Gene expression and immune response kinetics using electroporation-mediated DNA delivery to muscle.
BACKGROUND
Injection of DNA encoding exogenic proteins into muscle tissue combined with electroporation often results in a transient increase of the encoded protein concentration in the muscle and the blood. The reduction is normally due to an immune response against the exogenic protein but other factors may also be involved. How various electroporation parameters affect the concentration kinetics of syngenic and exogenic proteins is studied in relation to immune response and muscle damage after electroporation-mediated DNA transfer to muscle.


METHODS
Electroporation was applied to mouse quadriceps and rat tibialis anterior muscles after injection of DNA encoding either secreted alkaline phosphatase (SEAP), beta-galactosidase (beta-gal), luciferase or a mouse IgG molecule. Protein concentrations in blood or muscle and antibody responses were measured for a period up to 3 months. Tissue inflammation and muscle cell damage were studied on muscle cross-sections and assessed by measuring the concentrations of creatine phosphokinase (CPK) in blood.


RESULTS
Mice with the highest SEAP concentration in blood at day 7 also had the highest rate of decrease afterwards, the strongest antibody responses against SEAP and the highest acute levels of CPK in blood. DNA-transfected muscle fibers were significantly reduced in number from days 7 to 14. Mononuclear cells surrounded the reporter gene expressing muscle fibers, thus indicating a cellular immune response. When using DNA encoding a syngenic protein the protein concentration in blood was relatively stabile over a 3-month period, but showed different kinetics for various electroporation parameters.


CONCLUSIONS
Our findings suggest that the optimal electroporation parameters for DNA vaccination may be different from the optimal parameters for long-term expression of genes encoding syngenic proteins.
Grønevik
Eirik
E
Department of Physiology, University of Oslo, Box 1103 Blindern, 0316 Oslo, Norway. e.gronevik@inovio.com
von Steyern
Fredik Vult
FV
Kalhovde
John Magne
JM
Tjelle
Torunn Elisabeth
TE
Mathiesen
Iacob
I
D000469:Alkaline Phosphatase / Q000097:blood / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000917:Antibody Formation / Q000276:immunology*; D003402:Creatine Kinase / Q000097:blood; D004247:DNA / Q000276:immunology / Q000378:metabolism*; D017931:DNA Primers; D018274:Electroporation / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000235:genetics; D006651:Histocytochemistry; D007074:Immunoglobulin G / Q000097:blood / Q000235:genetics / Q000378:metabolism; D007146:Immunoglobulin lambda-Chains / Q000235:genetics; D007167:Immunotherapy / Q000379:methods*; D007700:Kinetics; D008156:Luciferases / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D001616:beta-Galactosidase
D017931:DNA Primers; D007074:Immunoglobulin G; D007146:Immunoglobulin lambda-Chains; D004247:DNA; D008156:Luciferases; D003402:Creatine Kinase; D000469:Alkaline Phosphatase; D001616:beta-Galactosidase