Previous Article | Next Article ![]()
Infect Immun, April 1998, p. 1342-1348, Vol. 66, No. 4
Department of Microbiology and
Immunology,1 and
Department of
Pathology,2 Albert Einstein College of
Medicine, Bronx, New York 10461-1602
Received 10 April 1997/Returned for modification 29 May
1997/Accepted 22 September 1997
Shigella spp. are the major cause of bacillary
dysentery worldwide. To identify immune effectors associated with
protection of the naive host during infection, the susceptibility to
pulmonary Shigella infection of each of various mouse
strains that have a targeted deletion in a specific aspect of the
immune system was evaluated. Our results demonstrate that mice
deficient in gamma interferon are 5 orders of magnitude more
susceptible to Shigella than are wild-type mice, whereas
mice deficient in B and T lymphocytes or in T lymphocytes alone exhibit
no difference in susceptibility. Significantly lower numbers of
shigellae were recovered from immunocompetent compared with
gamma-interferon-deficient mice after infection. While immunocompetent
mice were able to clear a sublethal Shigella inoculum by
day 5 postinfection, progressively increasing numbers of shigellae were
cultured from the lungs of gamma interferon-deficient mice over the
same period. Histopathology of the lungs from immunocompetent mice
infected with a sublethal Shigella inoculum showed mild
inflammatory changes, whereas the lungs from gamma interferon-deficient
mice demonstrated progressively worsening acute bronchiolitis with
ulceration. Further, the time to death in gamma interferon-deficient
mice correlates inversely with the size of the Shigella
inoculum. To identify the cellular source of gamma interferon, we
infected SCID mice, T-cell-receptor-deficient mice, beige mice (a mouse
strain deficient in natural killer [NK] cell activity), and mice
depleted of NK cells using anti-asialo-GM1. Each NK
cell-deficient mouse strain exhibited a 10-fold-greater susceptibility
to Shigella infection than immunocompetent mice. To test
the protective effects of gamma interferon in vitro, survival of
intracellular Shigella was examined in primary macrophages from wild-type mice, primary macrophages from gamma
interferon-deficient mice, a macrophage cell line, and a fibroblast
cell line. Following activation with gamma interferon, each cell type
eradicated intracellular Shigella, while nonactivated
macrophages fostered Shigella replication and nonactivated
fibroblast cells fostered both Shigella replication and
intercellular spread. Taken together, these data establish that NK
cell-mediated gamma interferon is essential to resistance following
primary Shigella infection.
0019-9567/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
An Essential Role for Gamma Interferon in Innate
Resistance to Shigella flexneri Infection
*
Corresponding author. Mailing address: Department of
Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461-1602. Phone: (718) 430-2118. Fax:
(718) 430-8711. E-mail: mgoldber{at}aecom.yu.edu.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|