| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
*
Department of Microbiology and Immunology, Morehouse School of Medicine, Atlanta, GA 30310;
Department of Biology, Spelman College, Atlanta, GA 30314; and
National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
The search for a chlamydial vaccine has led to the development of
several animal models for understanding the pathogenesis and
immunobiology of the disease. Current research focuses on defining the
relevant immune effectors that mediate anti-chlamydial immunity,
identify protective Ags that elicit such responses, and design
effective methods of vaccine delivery. Recent reports have indicated
that rapid, early elicitation and recruitment of certain immune
effectors (i.e., dendritic and Th1 cells) into the local genital
mucosae are crucial for reducing the intensity of and terminating a
cervico-vaginal infection and curbing ascending disease, and therefore
are important for preventing major complications of chlamydial
infection (6, 7, 8, 9). Specifically, it has been established
that specific Th1 cells and their notable cytokine, IFN-
, are
crucial immune effectors controlling Chlamydia in mice,
guinea pigs, nonhuman primates, and probably humans (7, 10, 11, 12, 13, 14, 15, 16), and these cells are recruited into the genital mucosa
during an infection. The induction of mucosal anti-chlamydial
Abs, such as secretory IgA and IgG, appears to play an ancillary role
in protective immunity (12).
The activation, recruitment, and retention as well as the effector
function of Th1 cells against microbial pathogens or tumors involve 1)
obligatory intimate interaction with accessory, infected, and
noninfected cells via cell surface molecules that include the gene
products of the MHC, addressins, coreceptors, and costimulatory and
adhesion molecules (17, 18); and 2) cytokine induction and
interaction at the afferent and efferent phases of host immune
responses. Local mucosal regulation of the expression and activity of
these cellular and molecular entities determines the outcome of the
overall host response as well as the acquisition and maintenance of
immunity that ensure vaccine efficacy. In particular, cytokines are
important mediators of immunity against microbial pathogens. The
pattern of cytokines induced following exposure to specific microbes
could determine the outcome of the infection, including the
establishment of immunity or the development of disease
(19). In this respect it has been shown that for several
intracellular pathogens (including Chlamydia,
Mycobacteria, and Leishmania), protective
immunity requires the induction of Th1 cytokines, notably IFN-,
TNF-
, and IL-2; however, pathology develops if Th2 cytokines (i.e.,
IL-4, IL-5, and IL-10) are induced (19, 20). The pattern
and interaction of Th1 and Th2 cytokines elicited could therefore
affect the outcome of an infection. Furthermore, since several
pathogens are preferentially susceptible to either Th1 or Th2 response,
the identification of immunobiologic factors that selectively regulate
Th1 or Th2 response against a given pathogen could aid in skewing
protective immune responses to the desired route as part of vaccine
design strategy.
IL-10, an anti-Th1 cytokine (21) produced during genital chlamydial infection of experimental animals and humans (22, 23), is potentially an important local factor that could control the Th1 response against Chlamydia. Thus, genetic differences in mouse strain susceptibility to C. trachomatis or Coccidioides immitis was mapped to high IL-10 producers being more susceptible to infections (22, 24). Also, increased IL-10 levels in the endocervical secretion of women with chlamydial infection could predispose to enhanced HIV-1 transmission (23). These observations suggest that the temporary or inadequate immunity commonly induced against Chlamydia (12) is at least partially due to the negative immunoregulation of IL-10, which could occur via IL-10-regulated production of relatively low frequency of chlamydial-specific Th1 cells. In such a case, genetic or biologic suppression of IL-10 activity or expression during immune elicitation against Chlamydia should lead to the induction of high levels of specific Th1 response that may mediate long term anti-chlamydial immunity. In this study we revealed that the cellular and molecular immunologic basis for the resistance of IL-10-deficient mice to chlamydial infection is associated with the potency of the APCs at inducing a Th1 response, and that an immunotherapeutic cellular vaccination strategy based on biochemical suppression of IL-10 expression in dendritic cells (DC) 3 might be a practical application of this system in vaccinating against pathogens or tumors that are controlled by Th1 immunity.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Stocks of C. trachomatis agent of mouse pneumonitis (MoPn) and the human isolate serovar D used to infect mice in vivo were prepared by propagating elementary bodies (EBs) in McCoy cells as previously described (25). Stocks were titrated by infecting McCoy cells with varying dilutions of EBs, and the infectious titer was expressed as inclusion-forming units (IFU) per milliliter. Chlamydial Ag was prepared by growing MoPn in HeLa cells and purifying EBs over renografin gradients, followed by inactivation under UV light for 3 h.
Animals, infection, and analysis of the course of the infection
Female IL-10-/- and IL-10+/+ mice on a C57BL/6J background, 5–8 wk old, were obtained from The Jackson Laboratory (Bar Harbor, ME). All animals were fed food and water ad libitum and maintained in laminar flow racks under pathogen-free conditions of 12 h of light and 12 h of darkness. Mice were infected intravaginally with 105 IFU of MoPn/mouse in a volume of 30 µL of PBS while under phenobarbitol anesthesia. The course of the infection was monitored by periodic (every 3 days) cervico-vaginal swabbing of individual animals. Chlamydia was isolated from the swabs in tissue culture according to standard methods, and inclusions were visualized and enumerated by immunofluorescence (25). The animals were monitored for at least 4–6 wk, a time period that spans the course of MoPn infection in mice (8). Infected KO mice did not show any clinical evidence of overt pathology beside the shedding of chlamydiae in their genital tracts, suggesting that the inoculum was not lethal for the animals. Experiments were repeated to include 10 or 12 animals per experimental group.
Assessment of ascending infection
MoPn was isolated from the upper genital tracts of mice at different times after infection as follows. Mice were infected intravaginally with 105 IFU of MoPn/mouse as previously described (25). At the indicated time periods after infection a portion of the reproductive system between the uterus and the ovaries of each mouse was removed and teased with forceps, and tissue homogenates were collected in 1 ml of PBS. Chlamydia was isolated from the homogenate in tissue culture according to a standard immunofluorescence staining method (25).
Cytokines, mAbs, and other reagents
ELISA kits for quantitating the amounts of murine cytokines in biological and culture fluids were purchased from BioSource (Camarillo, CA). Chlamydial isolation from cervico-vaginal swabs in tissue culture was assayed by staining infected monolayers of McCoy cells with FITC-labeled, genus-specific anti-chlamydial Abs (Kallestad Diagnostics, Chaska, MN) to detect chlamydial inclusions by direct immunofluorescence (25).
FACS analysis
Single-cell preparations from the indicated organs and tissues of IL-10-/- and IL-10+/+ mice were stained with FITC-labeled mAbs directed against murine CD3, CD4, CD8, CD54 (IL-10), CD71 (transferrin receptor), CD102 (ICAM-2), MadCAM-1, NK, MHC class II, and Mac-1 Ags, according to the manufacturer’s protocols (BioSource). Stained cells were analyzed on a FACScan flow cytometer (Becton Dickinson, Sunnyvale. CA) using controls stained with isotype-matched irrelevant Abs. The results are expressed as the proportion (percentage) of positively stained cells in the cell preparation.
Measurement of frequency of chlamydial-specific Th1 cells (Th1 frequency) after a primary infection of IL-10KO (IL-10-/-) and wild-type (IL-10+/+) mice
A modified procedure of the limiting dilution technique
(26) was used to assess Th1 frequency in infected mice.
Briefly, T cells were isolated from the genital tracts of infected mice
at the indicated times as previously described (7).
Cultures were established by seeding T cells in a serial doubling
dilution into 96-well round-bottom tissue culture plates at 24
wells/dilution. Typically, four and eight dilutions were established
for each T cell responder in the range of 1 x
105 through 8 x 102
cells/well. The T cells were stimulated with APCs from wild-type mice
(2 x 105 cells/well) and chlamydial Ag (10
µg/ml). Background cultures contained 24 wells with APCs and Ag.
After 5 days of incubation the supernatants were assayed for IFN- by
a sensitive ELISA (7). The mean and SD of all 24
replicates of background cultures were calculated. Three times the
value of the SD was added to the mean value, and the sum was the
baseline for positive experimental wells. Following determination of
the number of positive and negative wells per dilution of each T cell
preparation, the data were analyzed by a limiting dilution computer
program (LIDIA) (26, 27) that provided both the Th1
frequency and the conformity of the input data with a single-hit
Poisson model. Genital tract T cells from naive
IL-10+/+ mice have a Th1 frequency of 15 (range,
9–21).
Measurement of efficiency of Ag presentation by splenic APCs from IL-10-/- and IL-10+/+ mice
The efficiency of Ag presentation by splenic APCs from IL-10KO
mice and wild type animals was compared by assessing the ability of
gamma-irradiated whole spleen cells to present chlamydial Ags to immune
T cells from infected wild-type mice. Spleen cells from
Chlamydia-infected wild-type mice were enriched for T cells
by the nylon wool adherence method (13, 28). Purified
splenic cells contained at least 97% CD3+ cells,
as determined by FACS analysis. To assess the Ag-presenting function of
X-irradiated splenic cells from either IL-10KOs or control mice, 2
x 105 cells were cocultured with 2 x
105 nylon wool-purified T cells in the presence
or the absence of chlamydial Ag (i.e., UV-inactivated MoPn EBs at 10
µg/ml) in 96-well tissue culture plates for 24, 48, 72, 96, or
120 h. At the end of each incubation period the supernatants were
collected and assayed for IL-2 and/or IFN- content by a quantitative
ELISA (Cytoscreen Immunoassay Kit, BioSource) according to the
supplier’s instructions. The concentration of cytokine in each sample
was obtained by extrapolation from a standard calibration curve
generated simultaneously. Data were calculated as the mean values
(±SD) of triplicate cultures for each experiment. The results were
derived from at least three independent experiments.
Assessment of the effect of antisense IL-10 oligonucleotide (oligo) treatment of DC on chlamydial Ag presentation and activation of specific Th1 response
DC were isolated from the bone marrow of wild-type
(IL-10+/+) mice by a standard procedure
(29). Briefly, marrow was collected from the femurs and
tibia of naive wild-type C57BL/6 mice (6–8 wk old) and refluxed by
vigorous pipetting to dissociate the tissue and release the cells.
Approximately 2.0 x 107 cells were plated
in 100-cm2 dishes in complete RPMI 1640 medium
containing 10% FCS, HEPES, glutamine, nonessential amino acids, sodium
pyruvate, gentamicin, recombinant murine GM-CSF (10 ng/ml), and IL-4 (5
ng/ml). Following enrichment for DC (29) and washing
steps, 105 cells were plated per well in
round-bottom 96-well plates and treated for 24 h with 20 µM of
either sense or antisense oligos corresponding to nucleotides 315–333
of the murine IL-10 gene (30, 31) (i.e., sense,
5'-CCAAGCCTTATCGGAAATG-3'; and antisense, 5'-CATTTCCGATAAGGCTTGG-3').
The cells were then used to stimulate splenic T cells from immune mice
(at 105 T cells/well), in the presence or the
absence of chlamydial Ag (10 µg/ml). After 5 days of incubation, the
amounts of IFN- in the culture supernatants were measured by a
sensitive sandwich ELISA (7). Concentrations of IFN-
are expressed as the mean (picograms per milliliter) results from three
different experiments. Control cultures that contained T cells and APCs
but without chlamydial Ag did not show any measurable amount of
IFN-, so the data are not presented. Typically, DC were
characterized microscopically as loosely adherent mononuclear cells
expressing high levels of MHC class II, CD54, and CD11c but lacking
B220 surface Ags.
Adoptive immunotherapeutic vaccination with IL-10KO or IL-10 antisense oligo-treated BMDCs
DC were isolated from the bone marrow of IL-10-/- and IL-10+/+ mice as previously described above. Purified DC from IL-10+/+ mice were treated with either antisense or sense oligos. Then, IL-10KO DC and IL-10 oligo-treated DC were pulsed with C. trachomatis serovar D Ag for 12 h. Each DC preparation was adoptively transferred into 4-wk-old female C57BL/6 mice (2.5 x 107 cells/mouse) by i.v. infusion into the retro-orbital sinus in 0.2 ml of PBS. Treated mice were maintained in a laminar flow hood and were fed and maintained under a 12-h light, 12-h dark cycle. After 1 wk, the mice were infected intravaginally with 104 IFU/mouse of live C. trachomatis serovar D. The status of the infection was monitored by periodic cervico-vaginal swabbing of individual animal and isolation of chlamydiae in tissue culture (32). Experiments were repeated twice, and there were six to nine mice per group.
Statistical analysis
The levels of IL-2 or IFN- in samples from different
experiments were analyzed and compared by performing a one- or
two-tailed t test, and the relationship between different
experimental groupings was assessed by ANOVA. Minimal statistical
significance was judged at p < 0.05.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Because of the negative immunologic influence of IL-10 on the Th1
response and the fact that Chlamydia immunity in mice is
mediated by Th1 cells, we initially tested the hypothesis that
genetically engineered IL-10KO (IL-10-/-) mice
would exhibit greater resistance to genital chlamydial infection than
wild-type (IL-10+/+) mice. When the course of
genital chlamydial infection was compared in
IL-10-/- and IL-10+/+
mice by determining the intensity of shedding of chlamydiae into the
cervico-vaginal vault, the infection was less severe and of shorter
duration in IL-10-/- mice (Fig. 1
). IL-10-/- mice
exhibited between 1 and 3 log lower shedding of chlamydiae and cleared
the infection up to 3 wk earlier than IL-10+/+
mice. Moreover, IL-10-/- mice suffered a
markedly reduced ascending infection, as determined by the presence of
live organisms in the uteri and ovarian regions of the reproductive
system. These results suggested that the relevant anti-chlamydial
immune effectors are elicited more rapidly and induced in greater
amounts in IL-10KO than in wild-type mice. Also,
IL-10-/- mice are likely to suffer lesser
complications associated with ascending chlamydial infection.
|
-secreting T cells (i.e., Th1 cells) in the genital
tract T cell preparations, it was found that
IL-10-/- mice exhibited a greater and more
rapid Th1 response than control mice (Table I). Thus, there were 5- to 50-fold more
chlamydial-specific Th1 cells in the genital tracts of
IL-10-/- mice over 15–85 days of intravaginal
infection relative to those in wild-type mice. Moreover, when the mice
were challenged after 85 days of the primary infection,
IL-10-/- mice resisted the productive
establishment of a cervico-vaginal infection. In contrast, wild-type
mice were productively infected, although they suffered a milder
intensity of disease compared with the primary infection. The results
suggested that elevated frequency of chlamydial-specific Th1 cells in
the IL-10-/- mice conferred protective immunity
in these mice.
|
To understand the cellular and molecular immunologic basis for the
enhanced Th1 induction in IL-10KO mice, the study focused on the APCs
because of their central role in immune initiation and regulation. It
was hypothesized that transcriptional control of endogenous expression
of IL-10 in APCs would determine whether T cell activation is skewed
toward a Th1, Th2, or mixed Th1/Th2 response. To test this hypothesis,
the efficiency of APCs from IL-10-/-
mice at presenting chlamydial Ags to immune T cells from either
knockout or wild-type mice was investigated. When T cells from
IL-10-/- and IL-10+/+
mice were stimulated with APCs derived from
IL-10-/- mice, a greater Th1 response was
always induced compared with that produced by stimulation with APCs
from IL-10+/+ mice (Fig. 2). The Th1 response was measured by
Ag-specific IFN- secretion, as previously described
(7). APCs from IL-10-/- mice were
4 and 15 times more efficient at activating Th1 cells in T cell
preparations from IL-10-/- and
IL-10+/+ mice, respectively, than APCs
derived from IL-10+/+ mice. In addition, kinetic
studies of the Th1-inducing ability of IL-10KO APCs using either naive
or immune T cells from IL-10+/+ mice showed that
IL-10KO APCs were rapid and potent activators of both primary and
secondary Th1 responses against chlamydial Ags (Fig. 3). These results indicated that the
negative immunoregulatory effect of IL-10 on the Th1 response is
exerted at the level of the APCs, a novel finding in the immunobiology
of IL-10. Moreover, the enhanced Th1 induction by IL-10KO APCs appears
to be an active process, not just a default outcome of lack of IL-10 in
the environment. This point is substantiated by the results showing
that T cells from IL-10+/+ mice containing the
intact IL-10 gene were stimulated to express an elevated Th1 response
by IL-10KO APCs (Fig. 2). Besides, it was interesting that increased
levels of IL-2, IL-6, and IL-12 were measured in cultures
containing IL-10KO APCs as well, but IL-4 was undetected except in
those containing APC from IL-10+/+ mice (data not
shown). Although the role of IL-2 and IL-12 in Th1 development is
established (33), the reasons for the concomitant increase
in IL-6 in these cultures is unclear. However, a role for IL-6 in host
defense against C. trachomatis was suggested in a recent
analysis of IL-6KO mice (34).
|
|
Genetic or biochemical modulation of endogenous IL-10 expression
in APCs for activating a high frequency of specific Th1 cells holds
promise for ex vivo manipulation of APCs, such as DC, in adoptive
immunotherapy to vaccinate against chlamydial infection and other
pathogens controlled by the Th1 response. We investigated whether
biochemical modulation of endogenous IL-10 expression in normal DC
using an antisense oligo approach would foster Ag presentation for
enhanced specific Th1 activation. DC were isolated from the bone marrow
of wild-type mice and characterized as loosely adherent mononuclear
cells, expressing high levels of MHC class II, CD54, and CD11c, but
lacking B220 surface Ags (29). Purified DC were treated
with 20 µM of either the antisense or the sense oligo of the murine
IL-10 gene (30, 31) and used to stimulate splenic T cells
from immune mice. The results presented in Fig. 4 reveal that antisense treatment of DC
boosted their efficiency at activating a specific Th1 response against
chlamydial Ags. There was at least an 11-fold increase in Th1 induction
by antisense-treated DC over untreated DC. FACS analysis showed that
antisense oligo-treated DC expressed decreased levels of FcII/III
receptors (CD16/CD32; p > 0.0001), but the levels of
CD54, CD11b, CD11c, and MHC class II Ags were essentially unchanged.
These results favor the likelihood that antisense IL-10 oligo treatment
of APCs is a viable ex vivo approach to biochemical modulation of
endogenous IL-10 expression and enhancement of Th1 activation. However,
the ultimate goal of this phenomenon is to determine whether
IL-10-suppressed APCs can function as cellular vaccines, capable of
processing, selecting, and delivering appropriate immunogenic epitopes
to the host immune system, for activating a high frequency of specific
Th1 response in vivo and establishment of protective immunity against
an infection.
|
In exploring novel vaccine-designing strategies, it has been shown
that an immunotherapeutic cellular vaccination approach using DC as
potent inducers of a T cell response is a viable strategy for inducing
protective immunity against the complications of genital chlamydial
infection (29, 35). Therefore, using the adoptive
immunotherapeutic vaccination technique, we evaluated the ability of a
cellular vaccine, comprising chlamydial-pulsed IL-10KO or
IL-10-suppressed DC, to confer protective immunity against
genital infection by a human serovar of C. trachomatis.
The choice of a human serovar for this study include the
need to show that the proposed regimen is effective against the human
pathogen, which is the main focus of present vaccine efforts, and that
the IL-10 effect is not unique to the murine system. The hypothesis
tested is that the enhanced Th1-inducing capacity of IL-10KO DC should
activate a high frequency of chlamydial-specific Th1 cells that would
confer protective immunity against an infection. IL-10KO DC isolated
from IL-10-/- mice were pulsed with
UV-inactivated C. trachomatis serovar D EBs for 12 h,
while wild-type DC from IL-10+/+ mice were
pretreated with either the antisense or sense oligo of the murine IL-10
gene (30, 31) and then pulsed with UV-inactivated C.
trachomatis serovar D EBs for the final 12 h of a 40-h oligo
treatment. Both DC preparations were adoptively transferred into naive
female mice, and after 1 wk the mice were challenged intravaginally
with live C. trachomatis serovar D. Table II shows the results of the adoptive
transfer studies to evaluate the ability of IL-10 suppressed DC to form
the basis of a cellular vaccine for inducing a specific Th1 response
that protects against Chlamydia. All recipients of DC only
(group 1), Ag-pulsed DC (group 2), and Ag-pulsed, IL-10 sense
oligo-treated DC (group 3) were productively infected during the first
2 wk of challenge. However, only one of nine recipients of Ag-pulsed
IL-10KO DC (group 5) and Ag-pulsed, IL-10 antisense oligo-treated DC
(group 4) showed evidence of a productive infection during the same
period after challenge infection. In fact, all nine recipients of
Ag-pulsed IL-10KO DC (group 5) had resolved the infection by the second
week of challenge. In terms of chlamydial titers calculated during the
first week (day 6) of challenge, group 1 mice had an average titer of
6.4 x 103 IFU/ml, group 2 mice had an
average titer of 2.1 x 103 IFU/ml, group 4
mice had an average titer of 92.12 IFU/ml, and group 5 mice had an
average titer of 20.47 IFU/ml. The results indicated that the exquisite
ability of IL-10KO DC to rapidly induce a high frequency of specific
Th1 response may underlie the therapeutic potency of the cells in
vaccinating against genital chlamydial infection.
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
To investigate the potential application of a cellular vaccine system based on the suppression of endogenously expressed IL-10 to facilitate specific Th1 induction, we initially analyzed genital chlamydial infection in genetically engineered IL-10 knockout (IL-10-/-) and control wild-type (IL-10+/+) mice. The course of genital chlamydial infection was shorter and the disease was less severe in IL-10-/- than IL-10+/+ mice. Moreover, protective, specific anti-chlamydial Th1 cells are elicited more rapidly and induced in greater amounts in IL-10KO mice than in wild-type mice. Thus, IL-10-/- mice suffered fewer complications associated with ascending chlamydial infection. Protective immunity induced in IL-10KO was long lasting, because challenged IL-10-/- mice resisted the productive establishment of a cervico-vaginal infection. The elevated frequency of chlamydial-specific Th1 cells in the IL-10-/- mice may be responsible for the protective immunity displayed by these mice. These findings corroborate previous reports that the resistance of experimental animals to genital reinfection by Chlamydia is a function of the intensity of chlamydial-specific T cells in the genital mucosa (28). The resistance of IL-10-/- mice to experimental chlamydial lung infection was associated with an increased Th1 response (38), and elevated levels of IL-10 in the endocervical secretions of women with genital chlamydial infection could predispose the women to HIV-1 transmission (23). Therefore, a vaccine delivery system that includes a means of suppressing IL-10 would foster the induction of a high frequency of specific Th1 cells and probably lead to the establishment of long term immunity against Chlamydia and possibly other pathogens controlled by the Th1 response.
An understanding of the cellular and molecular immunologic basis of Th1
augmentation against Chlamydia in the IL-10-deficient mouse
system may furnish information on how biochemical modulation of IL-10
expression can be exploited in vaccine design against C.
trachomatis and other pathogens controlled by Th1 immunity. Since
complete abrogation of IL-10 from the host has obvious adverse
immunoregulatory and biologic consequences, the study focused on the
APCs because of their central role in immune initiation and regulation.
These studies have revealed that the negative immunoregulatory effect
of IL-10 on the Th1 response is exerted at the level of the APCs, a
novel finding in the immunobiology of IL-10. Moreover, the enhanced Th1
induction by IL-10KO APCs appears to be an active process, not just a
default outcome of a lack of IL-10 in the environment, a finding that
would underscore the basis for the ineffectiveness of anti-IL-10
Abs to enhance Th1 induction via binding and neutralization of secreted
IL-10. Although previous reports demonstrated that exogenous treatment
with IL-10 could suppress T cell activation via action on the APCs
(39, 40), the present studies have shown, for the first
time, that endogenous IL-10 production by the APCs is a crucial
regulatory step in Th1 activation. The observed increased levels of
IL-2, IL-6, and IL-12 in cultures containing IL-10KO APCs but
undetectable levels of IL-4 posed a challenging explanation. Although
the role of IL-2 and IL-12 in Th1 development is established
(33), the concomitant increase in IL-6 in these
cultures is unclear. However, a role for IL-6 in host defense
against C. trachomatis was suggested in recent analysis of
IL-6KO mice (34). Furthermore, it is important to mention
that the Th1 response measured in these studies would include cellular
immune responses mediated principally by CD4+ Th1
cells, but may also include IFN--secreting
CD8+ T cells.
These studies indicated that genetic or biochemical modulation of
endogenous IL-10 gene expression in APCs for activating a high
frequency of specific Th1 cells holds promise for ex vivo manipulation
of APCs, such as DC, in adoptive immunotherapy to vaccinate against
chlamydial infection and other pathogens controlled by the Th1
response. The findings extend previous reports by Caldwell and
co-workers (29, 35) that chlamydia-pulsed DC are potent
inducers of cell-mediated immunity and are capable of vaccinating
against genital chlamydial infection in mice. DC are prime candidates
for immunotherapeutic vaccination against several pathogens and tumors
(41, 42, 43, 44, 45, 46) because of their proclivity for activating
specific T cells against a number of Ags (47, 48, 49, 50, 51),
including chlamydial Ags (29, 52). The potency of DC as
highly efficient APCs is due in part to their high costimulatory
ability associated with an elevated density expression of costimulators
such as IL-1, LFA-3, and B7 molecules (41, 53, 54). Beside
a decrease in surface expression of FcR molecules, the high potency
of IL-10 antisense oligo-treated DC at activating the Th1 response
could not be explained by an immediate effect on the common
costimulatory molecules on the APCs. FcRs are important mediators of
the effector functions of Abs in humoral immunity associated with the
Th2 response. Suppression of FcR expression on APCs could be an
indicator of an immune response being skewed to inducing a
predominantly Th1 response. Furthermore, it is possible that the effect
of antisense treatment was manifested at a later time when the APCs are
exposed to T cells in the presence of Ag. The phenomenal efficacy of
these cellular vaccines makes them appropriate candidates for inducing
protective immunity against tumors and pathogens controlled by Th1
immunity, including Chlamydia, HIV, Mycobacteria,
as well as certain protozoan parasites. Interestingly, recent clinical
studies in humans suggested that increased IL-10 levels in the
endocervical secretion of women with chlamydial infection could
predispose to enhanced HIV-1 transmission (23), because
the condition limits the induction of a Th1 response, which is critical
for HIV-1 control.
IL-10-suppressed DC-based cellular vaccines have unique advantages that
could facilitate rapid extension of the experimental technology to
clinical applications. First, the remarkable ability of DC to process a
whole Ag or components of an Ag and select the appropriate
immunodominant epitope(s) for presentation to and activation of
specific Th1 cells is a property that may obviate the current search
for protective Ags and laborious mapping of immunogenic epitopes.
Second, the potential for clinical application of DC in immunotherapies
has resulted in the establishment of the technology and protocols for
efficient ex vivo propagation of DC from peripheral blood cells of
humans (41, 42, 45, 46). However, to be of widespread
attraction and application, IL-10 suppressed DC-based cellular vaccines
should elicit long term protective immunity, and possibly induce
cross-protection from other C. trachomatis serovars or
species. The potential to induce long term protective immunity is
predictable from results showing a high frequency of
chlamydial-specific Th1 cells (Table I
) and resistance of
IL-10-/- mice to reinfection 85 days after the
primary infection. Furthermore, in its ideal form, adoptive
immunotherapeutic cellular vaccination requires an autologous or
syngeneic system to avoid alloreactivity associated with foreign
transplantation Ags on the transferred cells. However, as in
transplantation therapy, there appears to be numerous severe disease
conditions (infectious and noninfectious) that require up-regulation of
the Th1 response, which warrants the application of an IL-10-suppressed
DC-based vaccination strategy for clinical use.
|
Footnotes |
|---|
2 Address correspondence and reprint requests to Dr. Joseph U. Igietseme, Department of Microbiology and Immunology, Morehouse School of Medicine, 720 Westview Drive S.W., Atlanta, GA 30310.
3 Abbreviations used in this paper: DC, dendritic cells; MoPn, mouse pneumonitis; EB, elementary bodies; IFU, inclusion-forming units; IL-10KO, IL-10 knockout; IL-12KO, IL-12 knockout; IL-10-/-, IL-10KO phenotype; IL-10+/+, wild-type phenotype; IL-12-/-, IL-12KO phenotype; oligo, oligonucleotide.
Received for publication September 28, 1999. Accepted for publication February 7, 2000.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
interferon-secreting T cells in the genital tract produces optimal protection against Chlamydia trachomatis infection in mice. Infect. Immun. 66:4030.: is this true for human?. Scand. J. Immunol. 46:546.[Medline]
interferon gene knockout mice. Infect. Immun. 65:2145.[Abstract]
interferon receptor-deficient mice despite a strong local immunoglobulin A response. Infect. Immun. 65:1032.[Abstract]
responses correlate with clearance of Chlamydia trachomatis mouse pneumonitis infection. J. Immunol. 156:4338.[Abstract]
-mediated inhibition. J. Immunol. 162:3541. production by T helper 1 cells. Eur. J. Immunol. 26:659.[Medline]
This article has been cited by other articles:
|
|
 |
|
  K. Breckpot, C. Aerts-Toegaert, C. Heirman, U. Peeters, R. Beyaert, J. L. Aerts, and K. Thielemans Attenuated Expression of A20 Markedly Increases the Efficacy of Double-Stranded RNA-Activated Dendritic Cells As an Anti-Cancer Vaccine J. Immunol., January 15, 2009; 182(2): 860 - 870. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. E. Kaiko, S. Phipps, D. K. Hickey, C. E. Lam, P. M. Hansbro, P. S. Foster, and K. W. Beagley Chlamydia muridarum Infection Subverts Dendritic Cell Function to Promote Th2 Immunity and Airways Hyperreactivity J. Immunol., February 15, 2008; 180(4): 2225 - 2232. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Natividad, M. J. Holland, K. A. Rockett, J. Forton, N. Faal, H. M. Joof, D. C.W. Mabey, R. L. Bailey, and D. P. Kwiatkowski Susceptibility to sequelae of human ocular chlamydial infection associated with allelic variation in IL10 cis-regulation Hum. Mol. Genet., January 15, 2008; 17(2): 323 - 329. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. S. Kornbluth and G. W. Stone Immunostimulatory combinations: designing the next generation of vaccine adjuvants J. Leukoc. Biol., November 1, 2006; 80(5): 1084 - 1102. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Kawasaki, W. J. Hubbard, M. A. Choudhry, M. G. Schwacha, K. I. Bland, and I. H. Chaudry Trauma-Hemorrhage Induces Depressed Splenic Dendritic Cell Functions in Mice J. Immunol., October 1, 2006; 177(7): 4514 - 4520. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C.-C. Chen, S. Louie, B. A. McCormick, W. A. Walker, and H. N. Shi Helminth-Primed Dendritic Cells Alter the Host Response to Enteric Bacterial Infection J. Immunol., January 1, 2006; 176(1): 472 - 483. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Kamada, T. Hisamatsu, S. Okamoto, T. Sato, K. Matsuoka, K. Arai, T. Nakai, A. Hasegawa, N. Inoue, N. Watanabe, et al. Abnormally Differentiated Subsets of Intestinal Macrophage Play a Key Role in Th1-Dominant Chronic Colitis through Excess Production of IL-12 and IL-23 in Response to Bacteria J. Immunol., November 15, 2005; 175(10): 6900 - 6908. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Q. He, T. T. Moore, F. O. Eko, D. Lyn, G. A. Ananaba, A. Martin, S. Singh, L. James, J. Stiles, C. M. Black, et al. Molecular Basis for the Potency of IL-10-Deficient Dendritic Cells as a Highly Efficient APC System for Activating Th1 Response J. Immunol., April 15, 2005; 174(8): 4860 - 4869. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Rey-Ladino, K. M. Koochesfahani, M. L. Zaharik, C. Shen, and R. C. Brunham A Live and Inactivated Chlamydia trachomatis Mouse Pneumonitis Strain Induces the Maturation of Dendritic Cells That Are Phenotypically and Immunologically Distinct Infect. Immun., March 1, 2005; 73(3): 1568 - 1577. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Q. Li, A. L. Carr, E. J. Donald, J. J. Skitzki, R. Okuyama, L. M. Stoolman, and A. E. Chang Synergistic Effects of IL-12 and IL-18 in Skewing Tumor-Reactive T-Cell Responses Towards a Type 1 Pattern Cancer Res., February 1, 2005; 65(3): 1063 - 1070. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Gervassi, M. R. Alderson, R. Suchland, J. F. Maisonneuve, K. H. Grabstein, and P. Probst Differential Regulation of Inflammatory Cytokine Secretion by Human Dendritic Cells upon Chlamydia trachomatis Infection Infect. Immun., December 1, 2004; 72(12): 7231 - 7239. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. K. Maxion, W. Liu, M.-H. Chang, and K. A. Kelly The Infecting Dose of Chlamydia muridarum Modulates the Innate Immune Response and Ascending Infection Infect. Immun., November 1, 2004; 72(11): 6330 - 6340. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. O. Eko, Q. He, T. Brown, L. McMillan, G. O. Ifere, G. A. Ananaba, D. Lyn, W. Lubitz, K. L. Kellar, C. M. Black, et al. A Novel Recombinant Multisubunit Vaccine against Chlamydia J. Immunol., September 1, 2004; 173(5): 3375 - 3382. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Mandrekar, D. Catalano, A. Dolganiuc, K. Kodys, and G. Szabo Inhibition of Myeloid Dendritic Cell Accessory Cell Function and Induction of T Cell Anergy by Alcohol Correlates with Decreased IL-12 Production J. Immunol., September 1, 2004; 173(5): 3398 - 3407. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. T. Mao, M. D. Roth, K. J. Serio, F. Baratelli, L. Zhu, E. C. Holmes, R. M. Strieter, and S. M. Dubinett Celecoxib Modulates the Capacity for Prostaglandin E2 and Interleukin-10 Production in Alveolar Macrophages from Active Smokers Clin. Cancer Res., December 1, 2003; 9(16): 5835 - 5841. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Colino and C. M. Snapper Opposing Signals from Pathogen-Associated Molecular Patterns and IL-10 Are Critical for Optimal Dendritic Cell Induction of In Vivo Humoral Immunity to Streptococcus pneumoniae J. Immunol., October 1, 2003; 171(7): 3508 - 3519. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H.-R. Jiang, E. Muckersie, M. Robertson, H. Xu, J. Liversidge, and J. V. Forrester Secretion of interleukin-10 or interleukin-12 by LPS-activated dendritic cells is critically dependent on time of stimulus relative to initiation of purified DC culture J. Leukoc. Biol., November 1, 2002; 72(5): 978 - 985. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Hawkins, R. G. Rank, and K. A. Kelly A Chlamydia trachomatis-Specific Th2 Clone Does Not Provide Protection against a Genital Infection and Displays Reduced Trafficking to the Infected Genital Mucosa Infect. Immun., September 1, 2002; 70(9): 5132 - 5139. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. J. Bontkes, T. D. de Gruijl, G. J. Schuurhuis, R. J. Scheper, C. J. L. M. Meijer, and E. Hooijberg Expansion of dendritic cell precursors from human CD34+ progenitor cells isolated from healthy donor blood; growth factor combination determines proliferation rate and functional outcome J. Leukoc. Biol., August 1, 2002; 72(2): 321 - 329. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Harizi, M. Juzan, V. Pitard, J.-F. Moreau, and N. Gualde Cyclooxygenase-2-Issued Prostaglandin E2 Enhances the Production of Endogenous IL-10, Which Down-Regulates Dendritic Cell Functions J. Immunol., March 1, 2002; 168(5): 2255 - 2263. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Darville, C. W. Andrews Jr., J. D. Sikes, P. L. Fraley, L. Braswell, and R. G. Rank Mouse Strain-Dependent Chemokine Regulation of the Genital Tract T Helper Cell Type 1 Immune Response Infect. Immun., December 1, 2001; 69(12): 7419 - 7424. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Hammad, A.-S. Charbonnier, C. Duez, A. Jacquet, G. A. Stewart, A.-B. Tonnel, and J. Pestel Th2 polarization by Der p 1-pulsed monocyte-derived dendritic cells is due to the allergic status of the donors Blood, August 15, 2001; 98(4): 1135 - 1141. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Silva, T. F. Pais, and R. Appelberg Blocking the Receptor for IL-10 Improves Antimycobacterial Chemotherapy and Vaccination J. Immunol., August 1, 2001; 167(3): 1535 - 1541. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. H. Shaw, V. R. Grund, L. Durling, and H. D. Caldwell Expression of Genes Encoding Th1 Cell-Activating Cytokines and Lymphoid Homing Chemokines by Chlamydia-Pulsed Dendritic Cells Correlates with Protective Immunizing Efficacy Infect. Immun., July 1, 2001; 69(7): 4667 - 4672. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Corinti, C. Albanesi, A. la Sala, S. Pastore, and G. Girolomoni Regulatory Activity of Autocrine IL-10 on Dendritic Cell Functions J. Immunol., April 1, 2001; 166(7): 4312 - 4318. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
