Am. J. Respir. Cell Mol. Biol.,
Volume 25, Number 2, August, 2001 203-211
Vitronectin and Fibronectin Function as Glucan Binding Proteins
Augmenting Macrophage Responses to Pneumocystis carinii
Robert
Vassallo,
Theodore J.
Kottom,
Joseph E.
Standing,
and
Andrew H.
Limper
Thoracic Diseases Research Unit, Division of Pulmonary, Critical Care and Internal Medicine, and Department of Biochemistry and
Molecular Biology, Mayo Clinic and Foundation, Rochester, Minnesota
-glucans represent major structural components of fungal cell
walls. We recently reported that Pneumocystis carinii -glucans stimulate alveolar macrophages to release proinflammatory
cytokines. Macrophage activation by -glucan is augmented by
serum, implying the presence of circulating factors that interact with -glucans and enhance their ability to stimulate macrophages. Using -glucan-enriched cell wall fractions from P. carinii and Saccharomyces cerevisiae, two prominent proteins
were precipitated from serum and demonstrated to be vitronectin (VN) and fibronectin (FN) by immune analysis. Preincubation of -glucan with VN or FN enhanced macrophage
activation in response to this cell wall component. Because VN
and FN accumulate in the lungs during P. carinii pneumonia,
we further investigated hepatic and pulmonary expression of
VN and FN messenger RNA during infection. P. carinii pneumonia in rodents is associated with increased hepatic expression of VN and FN as well as increased local expression of FN in
the lung. Because interleukin (IL)-6 represents the major regulator of VN and FN expression during inflammatory conditions,
we measured macrophage IL-6 release in response to stimulation with P. carinii -glucan. Stimulation of macrophages with
P. carinii -glucan induced significant release of IL-6. Elevated
concentrations of IL-6 were noted in the blood of infected animals compared with uninfected control animals. These studies indicate that VN and FN bind to -glucan components of P. carinii and augment macrophage inflammatory responses. P. carinii cell wall -glucan stimulates secretion of IL-6 by macrophages, thereby enhancing hepatic synthesis of both VN and
FN, and lung synthesis of FN during pneumonia.
Abbreviations: complementary DNA, cDNA; enzyme-linked immunosorbent assay, ELISA; fibronectin, FN; Harlan Sprague-Dawley, HSD; interleukin, IL; lipopolysaccharide binding protein, LBP; messenger RNA,
mRNA; polymerase chain reaction, PCR; severe combined immunodeficiency, SCID; sodium dodecyl sulfate polyacrylamide gel electrophoresis,
SDS-PAGE; standard error of the mean, SEM; Tris-buffered saline, TBS;
tumor necrosis factor, TNF; vitronectin, VN.
This article has been cited by other articles:

|
 |

|
 |
 
A. Rouhiainen, S. Tumova, L. Valmu, N. Kalkkinen, and H. Rauvala
Analysis of proinflammatory activity of highly purified eukaryotic recombinant HMGB1 (amphoterin)
J. Leukoc. Biol.,
January 1, 2007;
81(1):
49 - 58.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
E. M. Carmona, R. Vassallo, Z. Vuk-Pavlovic, J. E. Standing, T. J. Kottom, and A. H. Limper
Pneumocystis Cell Wall beta-Glucans Induce Dendritic Cell Costimulatory Molecule Expression and Inflammatory Activation through a Fas-Fas Ligand Mechanism
J. Immunol.,
July 1, 2006;
177(1):
459 - 467.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
F. McCann, E. Carmona, V. Puri, R. E. Pagano, and A. H. Limper
Macrophage Internalization of Fungal {beta}-Glucans Is Not Necessary for Initiation of Related Inflammatory Responses
Infect. Immun.,
October 1, 2005;
73(10):
6340 - 6349.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C. F. Thomas Jr. and A. H. Limper
Pneumocystis Pneumonia
N. Engl. J. Med.,
June 10, 2004;
350(24):
2487 - 2498.
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
S. D. Swain, S. J. Lee, M. C. Nussenzweig, and A. G. Harmsen
Absence of the Macrophage Mannose Receptor in Mice Does Not Increase Susceptibility to Pneumocystis carinii Infection In Vivo
Infect. Immun.,
November 1, 2003;
71(11):
6213 - 6221.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
F. E. Lund, K. Schuer, M. Hollifield, T. D. Randall, and B. A. Garvy
Clearance of Pneumocystis carinii in Mice Is Dependent on B Cells But Not on P. carinii-Specific Antibody
J. Immunol.,
August 1, 2003;
171(3):
1423 - 1430.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
S.-J. Yong, Z. Vuk-Pavlovic, J. E. Standing, E. C. Crouch, and A. H. Limper
Surfactant Protein D-Mediated Aggregation of Pneumocystis carinii Impairs Phagocytosis by Alveolar Macrophages
Infect. Immun.,
April 1, 2003;
71(4):
1662 - 1671.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
M. C. McElroy, D. J. Cain, C. Tyrrell, T. J. Foster, and C. Haslett
Increased Virulence of a Fibronectin-Binding Protein Mutant of Staphylococcus aureus in a Rat Model of Pneumonia
Infect. Immun.,
July 1, 2002;
70(7):
3865 - 3873.
[Abstract]
[Full Text]
[PDF]
|
 |
|
Copyright © 2001 American Thoracic Society.
|
|
|