Gastroenterol Clin Biol. 2009 Jun;33 Suppl 3:S137-44.
Defensin-immunology in inflammatory
bowel disease.
Wehkamp J, Stange EF, Fellermann K.
Source
Dr. Margarete Fischer-Bosch - Institute of Clinical Pharmacology, and Robert Bosch
Hospital; Internal Medicine I, Auerbachstr. 112, 70376 Stuttgart, Germany.
jan.wehkamp@ikp-stuttgart.de
Abstract
Defensins are endogenous antibiotics with microbicidal activity against Gram-negative and
Gram-positive bacteria, fungi, enveloped viruses and protozoa. A disturbed antimicrobial
defense, as provided by Paneth- and other epithelial cell defensins, seems to be a critical
factor in the pathogenesis of inflammatory bowel diseases. Conspicuously, there is a relative
lack of Paneth cell beta-defensins HD-5 and HD-6 in ileal Crohn's disease, both in the
absence of a pattern recognition receptor NOD2 mutation and, even more pronounced, in its
presence. This deficit is independent of concurrent active inflammation and results in a
diminished antibacterial killing by the mucosa. The Crohn's disease mucosa has not only a
significant lack in killing different Escherichia coli but also an impaired ability in clearing
Staphylococcus aureus as well as anaerobic micro-organisms. Thus, this dysfunction in
antibacterial barrier seems to be broad and is not restricted to a single bacterial strain. In
addition to directly controlling barrier function, Paneth cell defensins also regulate the
composition of the bacterial stool flora. In the majority of patients, the Paneth cell deficiency
is mediated by WNT signalling which suggests a disturbed Paneth cell differentiation in ileal
Crohn's disease. In contrast, colonic Crohn's disease is characterised by an impaired induction
of mucosal beta-defensins, partly due to a low copy number of the beta-defensin gene cluster.
Therefore it seems plausible that bacteria take advantage of a niche formed by defensin
deficiency. This would represent a paradigm shift in understanding Crohn's disease and
provides a target for future therapeutic strategies.
Copyright 2009 Elsevier Masson SAS. All rights reserved.
Supplemental Content
J Clin Microbiol. 2004 Mar;42(3):1203-6.
Antibiotic-associated diarrhea accompanied
by large-scale alterations in the composition
of the fecal microbiota.
Young VB, Schmidt TM.
Source
Department of Microbiology and Molecular Genetics, Infectious Diseases Unit, National
Food Safety and Toxicology Center, Michigan State University, East Lansing, Michigan
48824, USA. youngvi@msu.edu
Abstract
Alterations in the diversity of the gut microbiota are believed to underlie the development of
antibiotic-associated diarrhea (AAD). A molecular phylogenetic analysis was performed to
document temporal changes in the diversity of fecal bacteria of a patient who developed
AAD. Antibiotic administration was associated with distinct changes in the diversity of the
gut microbiota, including a marked decrease in the prevalence of butyrate-producing bacteria.
Following the discontinuation of the antibiotic, resolution of diarrhea was accompanied by a
reversal of these changes, providing the first direct evidence linking changes in the
community structure of the gastrointestinal bacteria with the development of AAD.
Comment in

Rev Gastroenterol Disord. 2004 Fall;4(4):216-7.
Supplemental Content
Antimicrob Agents Chemother. 2010 Jul;54(7):2960-4. Epub 2010 May 10.
Emergence of resistant Klebsiella
pneumoniae in the intestinal tract during
successful treatment of Klebsiella
pneumoniae lung infection in rats.
Kesteman AS, Perrin-Guyomard A, Laurentie M, Sanders P, Toutain PL, Bousquet-Mélou A.
Source
UMR181 Physiopathologie et Toxicologie Expérimentales, INRA, ENVT, Ecole Nationale
Vétérinaire de Toulouse, 23 chemin des Capelles, BP 87 614, 31076 Toulouse Cedex 3,
France.
Abstract
Antibiotic treatment of lung infections may lead to the emergence of resistance in the gut
flora. Appropriate dosing regimens could mitigate this adverse effect. In gnotobiotic rats
harboring intestinal Escherichia coli and Enterococcus faecium populations, a lung infection
by Klebsiella pneumoniae was instigated with two different sizes of inoculum to represent an
early or a late initiation of antibiotic treatment. The rats were treated with marbofloxacin, an
expanded-spectrum fluoroquinolone, by a single-shot administration or a fractionated regimen
over 4 days. Intestinal bacterial populations were monitored during and after treatment. At the
infection site, bacterial cure without any selection of resistance was observed. Whatever the
dosage regimen, fluoroquinolone treatment had a transient negative impact on the E. coli gut
population but not on that of E. faecium. The intestinal flora was colonized by the pathogenic
lung bacteria, and there was the emergence of intestine-resistant K. pneumoniae, occurring
more often in animals treated with a single marbofloxacin dose than with the fractionated
dose. Bacterial cure without resistance selection at the infection site with fluoroquinolone
treatment can be linked to colonization of the digestive tract by targeted pulmonary bacteria,
followed by the emergence of resistance.
Supplemental Content
Infect Immun. 2009 Jul;77(7):2691-702. Epub 2009 May 11.
Perturbation of the small intestine
microbial ecology by streptomycin alters
pathology in a Salmonella enterica serovar
typhimurium murine model of infection.
Garner CD, Antonopoulos DA, Wagner B, Duhamel GE, Keresztes I, Ross DA, Young VB,
Altier C.
Source
Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY
14853, USA.
Abstract
The small intestine is an important site of infection for many enteric bacterial pathogens, and
murine models, including the streptomycin-treated mouse model of infection, are frequently
used to study these infections. The environment of the mouse small intestine and the
microbiota with which enteric pathogens are likely to interact, however, have not been well
described. Therefore, we compared the microbiota and the concentrations of short-chain fatty
acids (SCFAs) present in the ileum and cecum of streptomycin-treated mice and untreated
controls. We found that the microbiota in the ileum of untreated mice differed greatly from
that of the cecum of the same mice, primarily among families of the phylum Firmicutes. Upon
treatment with streptomycin, substantial changes in the microbial composition occurred, with
a marked loss of population complexity. Characterization of the metabolic products of the
microbiota, the SCFAs, showed that formate was present in the ileum but low or not
detectable in the cecum while butyrate was present in the cecum but not the ileum. Treatment
with streptomycin altered the SCFAs in the cecum, significantly decreasing the concentration
of acetate, propionate, and butyrate. In this work, we also characterized the pathology of
Salmonella infection in the ileum. Infection of streptomycin-treated mice with Salmonella
was characterized by a significant increase in the relative and absolute levels of the pathogen
and was associated with more severe ileal inflammation and pathology. Together these results
provide a better understanding of the ileal environment in the mouse and the changes that
occur upon streptomycin treatment.
Supplemental Content
Arch Intern Med. 2002 Oct 28;162(19):2177-84.
The spectrum of pseudomembranous
enterocolitis and antibiotic-associated
diarrhea.
Hurley BW, Nguyen CC.
Source
Division of Hospital Internal Medicine, Mayo Clinic, 13400 E Shea Blvd, Scottsdale, AZ
85259, USA.
Abstract
Pseudomembranous (entero)colitis is primarily caused by Clostridium difficile infection. The
most common predisposing factor is prior use of antibiotics, including vancomycin and
metronidazole, which themselves are therapy for C difficile colitis. Other risk factors have
also been described. The presence of C difficile in the gastrointestinal tract leads to a
spectrum of manifestations from the asymptomatic carrier state to fulminant colitis.
Successful treatment of C difficile colitis requires prompt treatment with appropriate
antibiotics, withdrawal of the suspected predisposing antibiotics, and, in rare cases, total
colectomy. Preventive measures of adequate infection control and judicious use of antibiotics
are necessary means in attempting to control the spread of C difficile infection. Attempts at
making an effective human vaccine are currently under way.
Supplemental Content
JPEN J Parenter Enteral Nutr. 2006 Sep-Oct;30(5):395-8; discussion 399.
Influences of long-term antibiotic
administration on Peyer's patch
lymphocytes and mucosal immunoglobulin
A levels in a mouse model.
Yaguchi Y, Fukatsu K, Moriya T, Maeshima Y, Ikezawa F, Omata J, Ueno C, Okamoto K,
Hara E, Ichikura T, Hiraide H, Mochizuki H, Touger-Decker RE.
Source
Department of Surgery I, National Defense Medical College, Tokorozawa, Japan.
Abstract
BACKGROUND:
Long-term antibiotic administration is sometimes necessary to control bacterial infections
during the perioperative period. However, antibiotic administration may alter gut bacterial
flora, possibly impairing gut mucosal immunity. We hypothesized that 1 week of
subcutaneous (SC) antibiotic injections would affect Peyer's patch (PP) lymphocyte numbers
and phenotypes, as well as mucosal immunoglobulin A (IgA) levels.
METHODS:
Sixty-one male Institute of Cancer Research mice were randomized to CMZ (cefmetazole 100
mg/kg, administered SC twice a day), IPM (imipenem/cilastatin 50 mg/kg x 2), and control
(saline 0.1 mL x 2) groups. After 7 days of treatment, the mice were killed and their small
intestines removed. Bacterial numbers in the small intestine were determined using sheep
blood agar plates under aerobic conditions (n = 21). PP lymphocytes were isolated to
determine cell numbers and phenotypes (CD4, CD8, alphabetaTCR, gammadeltaTCR, B220;
n = 40). IgA levels in the small intestinal and bronchoalveolar washings were also measured
with ELISA.
RESULTS:
Antibiotic administration decreased both bacterial number and the PP cell yield compared
with the control group. There were no significant differences in either phenotype percentages
or IgA levels at any mucosal sites among the 3 groups.
CONCLUSIONS:
Long-term antibiotic treatment reduces PP cell numbers while decreasing bacterial numbers in
the small intestine. It may be important to recognize changes in gut mucosal immunity during
long-term antibiotic administration.
Supplemental Content
Sex Transm Infect. 2009 Sep;85(5):348-53. Epub 2009 Mar 26.
Prospective study of correlates of vaginal
Lactobacillus colonisation among high-risk
HIV-1 seronegative women.
Baeten JM, Hassan WM, Chohan V, Richardson BA, Mandaliya K, Ndinya-Achola JO, Jaoko
W, McClelland RS.
Source
Department of Global Health, University of Washington, Seattle, Washington 98104, USA.
jbaeten@u.washington.edu
Abstract
OBJECTIVE:
Vaginal colonisation with Lactobacillus species is characteristic of normal vaginal ecology.
The absence of vaginal lactobacilli, particularly hydrogen peroxide (H(2)O(2))-producing
isolates, has been associated with symptomatic bacterial vaginosis (BV) and increased risk for
HIV-1 acquisition. Identification of factors associated with vaginal Lactobacillus colonisation
may suggest interventions to improve vaginal health.
METHODS:
We conducted a prospective cohort study of correlates of vaginal Lactobacillus colonisation
among Kenyan HIV-1 seronegative female sex workers. At monthly follow-up visits, vaginal
Lactobacillus cultures were obtained. Generalised estimating equations were used to examine
demographic, behavioural and medical correlates of Lactobacillus isolation, including
isolation of H(2)O(2)-producing strains.
RESULTS:
Lactobacillus cultures were obtained from 1020 women who completed a total of 8896
follow-up visits. Vaginal washing, typically with water alone or with soap and water, was
associated with an approximately 40% decreased likelihood of Lactobacillus isolation,
including isolation of H(2)O(2)-producing strains. Recent antibiotic use, excluding
metronidazole and treatments for vaginal candidiasis, reduced Lactobacillus isolation by
approximately 30%. H(2)O(2)-producing lactobacilli were significantly less common among
women with Trichomonas vaginalis infection and those who were seropositive for herpes
simplex virus type 2. In contrast, H(2)O(2)-producing lactobacilli were significantly more
common among women with concurrent vaginal candidiasis.
CONCLUSIONS:
Modifiable biological and behavioural factors are associated with Lactobacillus colonisation
in African women. Our results suggest intervention strategies to improve vaginal health in
women at high risk for HIV-1.
Supplemental Content
Proc Natl Acad Sci U S A. 2011 Mar 29;108(13):5354-9. Epub 2011 Mar 14.
Microbiota regulates immune defense
against respiratory tract influenza A virus
infection.
Ichinohe T, Pang IK, Kumamoto Y, Peaper DR, Ho JH, Murray TS, Iwasaki A.
Source
Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520,
USA.
Abstract
Although commensal bacteria are crucial in maintaining immune homeostasis of the intestine,
the role of commensal bacteria in immune responses at other mucosal surfaces remains less
clear. Here, we show that commensal microbiota composition critically regulates the
generation of virus-specific CD4 and CD8 T cells and antibody responses following
respiratory influenza virus infection. By using various antibiotic treatments, we found that
neomycin-sensitive bacteria are associated with the induction of productive immune
responses in the lung. Local or distal injection of Toll-like receptor (TLR) ligands could
rescue the immune impairment in the antibiotic-treated mice. Intact microbiota provided
signals leading to the expression of mRNA for pro-IL-1β and pro-IL-18 at steady state.
Following influenza virus infection, inflammasome activation led to migration of dendritic
cells (DCs) from the lung to the draining lymph node and T-cell priming. Our results reveal
the importance of commensal microbiota in regulating immunity in the respiratory mucosa
through the proper activation of inflammasomes.
Comment in

Nat Rev Immunol. 2011 May;11(5):304-5.
Supplemental Content
Gut. 2005 Nov;54(11):1546-52. Epub 2005 Jun 29.
Influence of intestinal bacteria on induction
of regulatory T cells: lessons from a transfer
model of colitis.
Strauch UG, Obermeier F, Grunwald N, Gürster S, Dunger N, Schultz M, Griese DP, Mähler
M, Schölmerich J, Rath HC.
Source
Department of Internal Medicine I, University of Regensburg, D-93053 Regensburg,
Germany. Ulrike.Strauch@klinik.uni-regensburg.de
Abstract
BACKGROUND:
The resident flora plays a critical role in initiation and perpetuation of intestinal inflammation,
as demonstrated in experimental models of colitis where animals fail to develop disease under
germ free conditions. However, the importance of exposure to commensal bacteria before the
onset of colitis is unclear. Our aim was to investigate the influence of previous exposure of
donor animals to bacterial antigens on colitis development using a transfer model.
METHODS:
Clinical course and histology were evaluated after transfer of CD4(+)CD62L(+) lymphocytes
from germ free and conventionally housed donor mice into SCID recipients. Cotransfer of
CD4(+)CD62L(+) cells with CD4(+)CD62L(- )lymphocytes from both groups of mice was
initiated. Lymphocytes were analysed by FACS, polarisation potential of cells determined,
and cytokines measured within the supernatant by enzyme linked immunosorbent assay.
RESULTS:
Animals that received cells from germ free donors developed an earlier onset of colitis
compared with mice reconstituted with lymphocytes from conventionally housed animals.
Additionally, CD4(+)CD62L(- )cells from germ free mice were not able to abrogate colitis
induced by cotransfer with CD4(+)CD62L(+) lymphocytes whereas CD4(+)CD62L(- )T cells
from normal mice ameliorated disease. The higher percentage of CD4(+)GITR(+) expressing
lymphocytes and the production of interleukin 10 after priming by dendritic cells suggests the
presence of T(reg) cells within the CD4(+)CD62L(+) lymphocyte subset derived from
conventional housed mice and assumes a lack of T(reg) cells within germ free mice.
CONCLUSION:
The results indicate that bacterial antigens are crucial for the generation and/or expansion of
T(reg) cells in a healthy individual. Therefore, bacterial colonisation is of great importance in
maintaining the immunological balance.
Supplemental Content
Commensal microbiota and CD8+ T cells
shape the formation of invariant NKT cells.
Wei B, Wingender G, Fujiwara D, Chen DY, McPherson M, Brewer S, Borneman J,
Kronenberg M, Braun J.
Source
Department of Pathology and Laboratory Medicine, David Geffen School of Medicine,
University of California, Los Angeles, CA 90095, USA.
Abstract
Commensal bacteria play an important role in formation of the immune system, but the
mechanisms involved are incompletely understood. In this study, we analyze CD1d-restricted
invariant NKT (iNKT) cells in germfree mice and in two colonies of C57BL/6 mice termed
conventional flora and restricted flora (RF), stably bearing commensal microbial communities
of diverse but distinct composition. In germfree mice, iNKT cells were moderately reduced,
suggesting that commensal microbiota were partially required for the antigenic drive in
maintaining systemic iNKT cells. Surprisingly, even greater depletion of iNKT cell
population occurred in RF mice. This was in part attributable to reduced RF levels of
intestinal microbial taxa (Sphingomonas spp.) known to express antigenic glycosphingolipid
products. However, memory and activated CD8(+) T cells were also expanded in RF mice,
prompting us to test whether CD8(+) T cell activity might be further depleting iNKT cells.
Indeed, iNKT cell numbers were restored in RF mice bearing the CD8alpha(-/-) genotype or
in adult wild-type RF mice acutely depleted with anti-CD8 Ab. Moreover, iNKT cells were
restored in RF mice bearing the Prf1(-/-) phenotype, a key component of cytolytic function.
These findings indicate that commensal microbiota, through positive (antigenic drive) and
negative (cytolytic depletion by CD8(+) T cells) mechanisms, profoundly shape the iNKT cell
compartment. Because individuals greatly vary in the composition of their microbial
communities, enteric microbiota may play an important epigenetic role in the striking
differences in iNKT cell abundance in humans and therefore in their potential contribution to
host immune status.
Supplemental Content
Eur J Immunol. 2011 May;41(5):1321-33. doi: 10.1002/eji.201040730. Epub 2011 Mar 21.
Secondary CD8+ T-cell responses are
controlled by systemic inflammation.
Wirth TC, Martin MD, Starbeck-Miller G, Harty JT, Badovinac VP.
Source
Department of Microbiology, University of Iowa, Iowa City, IA, USA.
Abstract
Repeated infections and experimental prime-boost regimens frequently result in the
generation of secondary (2°) CD8(+) T-cell responses. In contrast to primary (1°) CD8(+) T
cells, the parameters that influence the abundance and phenotype of 2° effector and memory
CD8(+) T-cell populations are largely unknown. Here, we analyze the impact of different
booster infections, Ag curtailment, and systemic inflammation on the quality and quantity of
secondary CD8(+) T-cell responses. We show that similar to 1° CD8(+) T-cell responses, the
phenotype of 2° effector and memory CD8(+) T-cell populations is critically dependent on the
nature of the infectious pathogen and the inflammatory milieu early after infection. In
addition, systemic inflammation increases the number of 2° effector and memory CD8(+) T
cells after booster infections and immunizations. Therefore, our data reveal new means to
boost the number of 2° effector and memory CD8(+) T cells in prime-boost regimens and
show a surprisingly high degree of plasticity in 2° memory CD8(+) T-cell phenotype that is
controlled by systemic inflammation.
Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Supplemental Content
Blood. 2004 Jan 1;103(1):340-6. Epub 2003 Sep 11.
Reduced stem cell mobilization in mice
receiving antibiotic modulation of the
intestinal flora: involvement of endotoxins
as cofactors in mobilization.
Velders GA, van Os R, Hagoort H, Verzaal P, Guiot HF, Lindley IJ, Willemze R, Opdenakker
G, Fibbe WE.
Source
Laboratory of Experimental Hematology, Leiden University Medical Center, Leiden, the
Netherlands.
Abstract
Since endotoxins are potent inducers of stem cell mobilization, we hypothesized that their
presence in the gut may play a role in cytokine-induced mobilization. To address this
possibility we added ciprofloxacin and polymyxin B to the drinking water of Balb/c mice
mobilized with either interleukin-8 (IL-8), granulocyte colony-stimulating factor (G-CSF), or
flt3 ligand (FL). The yield of colony-forming units (CFUs) was significantly reduced in all
mice treated with these antibiotics when compared with controls (IL-8: 192 +/- 61 vs 290 +/64, P <.05; G-CSF: 1925 +/- 1216 vs 3371 +/- 1214, P <.05; FL: 562 +/- 213 vs 1068 +/- 528,
P <.05). Treatment with ciprofloxacin eliminated only aerobic Gram-negative bacteria from
the feces without effect on mobilization. Polymyxin B treatment did not result in
decontamination but significantly reduced the number of mobilized hematopoietic progenitor
cells (HPCs) most likely due to the endotoxin binding capacity of polymyxin B. More than
90% of the gastrointestinal flora consists of anaerobic bacteria. Elimination of the anaerobic
flora by metronidazol led to a significantly reduced number of mobilized HPCs when
compared with controls (IL-8: 55 +/- 66 vs 538 +/- 216, P <.05). Germ-free OF1 mice showed
a significantly reduced mobilization compared with their wild-type controls (IL-8 controls:
378 +/- 182, IL-8 germ free: 157 +/- 53, P <.05). Finally, we performed reconstitution
experiments adding Escherichia coli-derived endotoxins to the drinking water of
decontaminated mice. This resulted in partial restoration of the IL-8-induced mobilization (67
+/- 28 vs 190 +/- 98.1, P <.01). Our results indicate that endotoxins serve as cofactors in
cytokine-induced mobilization. Modification of the endotoxin content by antibiotic treatment
may affect the yield of cytokine-induced mobilization.
Supplemental Content