Affiliation:
1. Division of Biology
2. Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas 66506
Abstract
ABSTRACT
This study investigates Toll-like receptor 4 (TLR4)-positive macrophages in early recognition and clearance of pulmonary bacteria. TLR4 is a
trans
-membrane receptor that is the primary recognition molecule for lipopolysaccharide of gram-negative bacteria. The
TLR4
Lps-del
mouse strains C57BL10/ScN (B10) and STOCK
Abb
tm1
TLR4
Lps-del
Slc11a1
s
(B10 × C2D) are susceptible to pulmonary infections and develop pneumonia when naturally or experimentally infected by the opportunistic bacterium
Pasteurella pneumotropica.
Since these mice have the
TLR4
Lps-del
genotype, we hypothesized that reconstitution of mice with TLR4-positive macrophages would provide resistance to this bacterium. A cultured macrophage cell line (C2D macrophages) and bone marrow cells from C2D mice were adoptively transferred to B10 and B10 × C2D mice by intraperitoneal injection. C2D macrophages increased B10 and B10 × C2D mouse resistance to
P. pneumotropica
. In C2D-recipient mice there was earlier transcription of tumor necrosis factor alpha and chemokines JE and macrophage inflammatory protein 2 (MIP-2) in the lungs of B10 and B10 × C2D mice, and there was earlier transcription of KC and MIP-1α in B10 × C2D mice. In addition, the course of inflammation following experimental
Pasteurella
challenge was altered in C2D recipients. C2D macrophages also protected B10 × C2D mice, which lack CD4
+
T cells. These data indicate that macrophages are critical for pulmonary immunity and can provide host resistance to
P. pneumotropica.
This study indicates that TLR4-positive macrophages are important for early recognition and clearance of pulmonary bacterial infections.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Cited by
36 articles.
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