IL-12 gene therapy protects mice in lethal Klebsiella pneumonia.
IL-12 is a proinflammatory cytokine that has recently been shown to have beneficial effects in the setting of acquired host immunity. To determine the role of IL-12 in innate immunity against Gram-negative bacterial organisms, CBA/J mice were challenged with 10(2) CFU of Klebsiella pneumoniae intratracheally (i.t.), resulting in the time-dependent expression of IL-12 mRNA (p35 and p40) and protein within the lung. Passive immunization of animals with anti-IL-12 serum i.p. at the time of K. pneumoniae inoculation resulted in a 12-fold increase in K. pneumoniae CFU in lung homogenates at 48 h, as compared with animals receiving control serum. In addition, treatment of Klebsiella-infected mice with anti-IL-12 Abs significantly decreased both short and long term survival. To assess the effect of compartmentalized IL-12 overexpression on outcome in Klebsiella pneumonia, animals were treated i.t. with 5 x 10(8) PFU of a nonreplicating adenoviral vector containing a human cytomegalovirus promoter and cDNAs coding for the p35 and p40 subunits of IL-12 inserted into the E1 and E3 domains (Ad5mIL-12), respectively. In vivo transfection with Ad5mIL-12 resulted in 45% long term survival in Klebsiella pneumonia, whereas no animals with Klebsiella pneumonia receiving control adenovirus survived. Moreover, treatment with anti-IFN-gamma Abs or soluble TNF receptor:Ig construct partially and completely attenuated survival benefits observed in animals receiving Ad5mIL-12, respectively. In conclusion, endogenous IL-12 is a critical component of antibacterial host defense, and the compartmentalized overexpression of IL-12 using recombinant adenoviral gene therapy represents a safe and effective approach to deliver IL-12 to the lung in the setting of murine Klebsiella pneumonia.
Greenberger
M J
MJ
Department of Medicine, University of Michigan Medical School, Ann Arbor 48109, USA.
Kunkel
S L
SL
Strieter
R M
RM
Lukacs
N W
NW
Bramson
J
J
Gauldie
J
J
Graham
F L
FL
Hitt
M
M
Danforth
J M
JM
Standiford
T J
TJ
D000260:Adenoviruses, Human / Q000235:genetics; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D001483:Base Sequence; D003587:Cytomegalovirus / Q000235:genetics; D005260:Female; D015967:Gene Expression Regulation, Viral; D005822:Genetic Vectors / Q000235:genetics; D007116:Immunization, Passive; D007371:Interferon-gamma / Q000037:antagonists & inhibitors / Q000276:immunology; D018664:Interleukin-12 / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use*; D007710:Klebsiella Infections / Q000628:therapy*; D007711:Klebsiella pneumoniae / Q000276:immunology / Q000302:isolation & purification; D008168:Lung / Q000378:metabolism / Q000382:microbiology; D051379:Mice; D008808:Mice, Inbred CBA; D008969:Molecular Sequence Data; D018410:Pneumonia, Bacterial / Q000628:therapy*; D011401:Promoter Regions, Genetic; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis*; D013047:Specific Pathogen-Free Organisms; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors
D000911:Antibodies, Monoclonal; D018124:Receptors, Tumor Necrosis Factor; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12; D007371:Interferon-gamma