Toll-Like Receptor 4 Agonistic Antibody Promotes Host Defense against Chronic Pseudomonas aeruginosa Lung Infection in Mice.
Chronic lower respiratory tract infection with Pseudomonas aeruginosa is difficult to treat due to enhanced antibiotic resistance and decreased efficacy of drug delivery to destroyed lung tissue. To determine the potential for restorative immunomodulation therapies, we evaluated the effect of Toll-like receptor 4 (TLR4) stimulation on the host immune response to Pseudomonas infection in mice. We implanted sterile plastic tubes precoated with P. aeruginosa in the bronchi of mice, administered the TLR4/MD2 agonistic monoclonal antibody UT12 intraperitoneally every week, and subsequently analyzed the numbers of viable bacteria and inflammatory cells and the levels of cytokines. We also performed flow cytometry-based phagocytosis and opsonophagocytic killing assays in vitro using UT12-treated murine peritoneal neutrophils. UT12-treated mice showed significantly enhanced bacterial clearance, increased numbers of Ly6G(+) neutrophils, and increased concentrations of macrophage inflammatory protein 2 (MIP-2) in the lungs (P < 0.05). Depletion of CD4(+) T cells eliminated the ability of the UT12 treatment to improve bacterial clearance and promote neutrophil recruitment and MIP-2 production. Additionally, UT12-pretreated peritoneal neutrophils exhibited increased opsonophagocytic killing activity via activation of the serine protease pathway, specifically neutrophil elastase activity, in a TLR4-dependent manner. These data indicated that UT12 administration significantly augmented the innate immune response against chronic bacterial infection, in part by promoting neutrophil recruitment and bactericidal function.
Department of Respiratory Diseases, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan shigekinak@nih.go.jp.|Department of Chemotherapy and Mycoses, National Institute of Infectious Diseases, Tokyo, Japan.
Shigeki
S
Nakamura
Department of Respiratory Diseases, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Naoki
N
Iwanaga
Division of Respiratory Medicine and Infectious Control Measures Room, Tohoku Pharmaceutical University Hospital, Sendai, Japan.
Masafumi
M
Seki
Department of Life Science, Saga University Organization for General Education, Saga, Japan.
Kenji
K
Fukudome
Department of Respiratory Diseases, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.|Unit of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Kazuhiro
K
Oshima
Department of Respiratory Diseases, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.|Unit of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Taiga
T
Miyazaki
Unit of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Koichi
K
Izumikawa
Department of Laboratory Medicine, Nagasaki University Hospital, Nagasaki, Japan.
Katsunori
K
Yanagihara
Department of Chemotherapy and Mycoses, National Institute of Infectious Diseases, Tokyo, Japan.
Yoshitsugu
Y
Miyazaki
Department of Respiratory Diseases, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Hiroshi
H
Mukae
Department of Respiratory Diseases, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Shigeru
S
Kohno
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D058491:Bacterial Load; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002908:Chronic Disease; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D007113:Immunity, Innate / Q000187:drug effects*; D051379:Mice; D018345:Mice, Knockout; D050296:Microbial Viability / Q000276:immunology; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D009895:Opsonin Proteins / Q000276:immunology; D010587:Phagocytosis / Q000276:immunology; D018410:Pneumonia, Bacterial / Q000188:drug therapy / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000276:immunology*; D057057:Serine Proteases / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000819:agonists*
D000911:Antibodies, Monoclonal; D016207:Cytokines; D009895:Opsonin Proteins; D051197:Toll-Like Receptor 4; D057057:Serine Proteases