Toll-Like Receptor 4 Agonistic Antibody Promotes Host Defense against Chronic Pseudomonas aeruginosa Lung Infection in Mice.

Abstract

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.

• Authors: Shigeki Nakamura, Naoki Iwanaga, Masafumi Seki, Kenji Fukudome, Kazuhiro Oshima, Taiga Miyazaki, Koichi Izumikawa, Katsunori Yanagihara, Yoshitsugu Miyazaki, Hiroshi Mukae, Shigeru Kohno
• Journal: Infection and immunity (Infect Immun) Vol. 84 Issue 7 Pg. 1986-1993 (07 2016) ISSN: 1098-5522 [Electronic] United States
• PMID: 27091927 (Publication Type: Journal Article)
• Copyright: Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Chemical References

• Antibodies, Monoclonal
• Cytokines
• Opsonin Proteins
• Toll-Like Receptor 4
• Serine Proteases

Topics

• Animals
• Antibodies, Monoclonal (pharmacology)
• Bacterial Load
• CD4-Positive T-Lymphocytes (immunology, metabolism)
• Chronic Disease
• Cytokines (metabolism)
• Disease Models, Animal
• Female
• Immunity, Innate (drug effects)
• Mice
• Mice, Knockout
• Microbial Viability (immunology)
• Neutrophils (immunology, metabolism, microbiology)
• Opsonin Proteins (immunology)
• Phagocytosis (immunology)
• Pneumonia, Bacterial (drug therapy, immunology, metabolism, microbiology)
• Pseudomonas aeruginosa (drug effects, immunology)
• Serine Proteases (metabolism)
• Toll-Like Receptor 4 (agonists)