T. Ferkol et al., GENE-TRANSFER INTO THE AIRWAY EPITHELIUM OF ANIMALS BY TARGETING THE POLYMERIC IMMUNOGLOBULIN RECEPTOR, The Journal of clinical investigation, 95(2), 1995, pp. 493-502
Genes of interest can be targeted specifically to respiratory epitheli
al cells in intact animals with high efficiency by exploiting the rece
ptor-mediated endocytosis of the polymeric immunoglobulin receptor. A
DNA carrier, consisting of the Fab portion of polyclonal antibodies ra
ised against rat secretory component covalently linked to poly-L-lysin
e, was used to introduce plasmids containing different reporter genes
into airway epithelial cells in vivo. We observed significant levels o
f luciferase enzyme activity in protein extracts from the liver and lu
ng, achieving maximum values of 13,795+/-4,431 and 346,954+/-199,120 i
ntegrated light units (ILU) per milligram of protein extract, respecti
vely. No luciferase activity was detected in spleen or heart, which do
not express the receptor. Transfections using complexes consisting of
an irrelevant plasmid (pCMV lacZ) bound to the bona fide carrier or t
he expression plasmid (pGEMluc) bound to a carrier based on an irrelev
ant Fab fragment resulted in background levels of luciferase activity
in all tissues examined. Thus, only tissues that contain cells bearing
the polymeric immunoglobulin receptor are transfected, and transfecti
on cannot be attributed to the nonspecific uptake of an irrelevant car
rier-DNA complex. Specific mRNA from the luciferase gene was also dete
cted in the lungs of transfected animals. To determine which cells in
the lung are transfected by this method, DNA complexes were prepared c
ontaining expression plasmids with genes encoding the bacterial beta-g
alactosidase or the human interleukin 2 receptor. Expression of these
genes was localized to the surface epithelium of the airways and the s
ubmucosal glands, and not the bronchioles and alveoli. Receptor-mediat
ed endocytosis can be used to introduce functional genes into the resp
iratory epithelium of rats, and may be a useful technique for gene the
rapy targeting the lung.