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Infection and Immunity, October 2001, p. 6401-6410, Vol. 69, No. 10
Departments of
Anesthesiology,1 Genomics and
Pathobiology,2 and Physiology and
Biophysics,3 Schools of Medicine and Dentistry,
University of Alabama at Birmingham, Birmingham, Alabama 35294
Received 22 February 2001/Returned for modification 9 May
2001/Accepted 11 June 2001
We previously reported that congenic C57BL/6 inducible nitric oxide
synthase
0019-9567/01/$04.00+0 DOI: 10.1128/IAI.69.10.6401-6410.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Cyclophosphamide Decreases Nitrotyrosine Formation and
Inhibits Nitric Oxide Production by Alveolar Macrophages in
Mycoplasmosis
/
(iNOS
/
) mice infected with
Mycoplasma pulmonis developed higher bacterial numbers
and lung lesion scores than C57BL/6 iNOS+/+ controls but
had similar lung nitrotyrosine levels. The present studies investigated
the role of inflammatory cells in nitrotyrosine formation during
mycoplasmal infection. iNOS+/+ and iNOS
/
mice were injected with cyclophosphamide (CYP) and inoculated with
107 CFU of M. pulmonis. CYP pretreatment of
M. pulmonis-infected iNOS+/+ and
iNOS
/
mice reduced polymorphonuclear cells (PMNs)
within bronchoalveolar lavages (BALs) by 88 and 72%, respectively, and
whole-lung myeloperoxidase levels by 80 and 78%, respectively, at
72 h postinfection but did not alter the number of alveolar
macrophages (AMs) in BALs. CYP treatment also significantly decreased
nitrate and nitrite (NOx) levels in BALs and plasma of infected
iNOS+/+ mice, whereas neither CYP nor mycoplasmal infection
altered NOx in iNOS
/
mice. CYP reduced lung
nitrotyrosine levels in both iNOS+/+ and
iNOS
/
mice to uninfected-control levels as shown by
immunohistochemical staining and enzyme-linked immunosorbent assay and
inhibited mycoplasmal killing by iNOS+/+ mice in vivo. CYP
inhibited the production of gamma interferon-inducible NOx by
iNOS+/+ AMs in vitro but did not alter the number of
iNOS-positive AMs, as detected by immunocytochemistry. In addition, AMs
from CYP-treated iNOS+/+ mice had significantly decreased
ability to kill mycoplasmas in vitro. These results demonstrate that
reactive species generated by inflammatory cells as well as PMN
myeloperoxidase are important contributors to nitrotyrosine formation
during mycoplasmal infection and that treatment with CYP decreases
NO· production by AMs and inhibits mycoplasmal killing.
*
Corresponding author. Mailing address: Department of
Anesthesiology, University of Alabama at Birmingham, 619 South 19th
St., THT 940, Birmingham, AL 35294. Phone: (205) 934-4231. Fax: (205) 934-7437. E-mail: Sadis.Matalon{at}ccc.uab.edu.
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