|
|
||||||||
From the Departments of 1 Ophthalmology and 2 Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and the 3 Department of Medicine, Wayne State University, Detroit, Michigan.
| Abstract |
|---|
|
|
|---|
METHODS. Frozen sections of lacrimal glands from MRL/lpr and MRL/+ mice ages 1
through 5 months were stained with monoclonal antibodies to the
cytokines interferon (IFN)-
and interleukin (IL)-4 and to the cell
surface costimulatory molecules B7-1 and B7-2, which are associated
with Th1 and Th2 responses, respectively.
RESULTS. The median proportion of cells staining for IL-4 ranged from 30% to
67% over time for MRL/lpr mice and from 30% to 55% for MRL/+ mice.
The median proportion of cells staining for IFN-
ranged from 1% to
5% for MRL/lpr mice and from 0% to 3% for MRL/+ mice. The proportion
of cells staining positively for IL-4 was significantly greater than
for IFN-
in both MRL/lpr (mean difference, 33%; P =
0.0001) and MRL/+ mice (mean difference, 42%; P =
0.0002). The median proportion of cells staining positively for B7-2
ranged from 20% to 38% for MRL/lpr mice and from 16% to 34% for
MRL/+ mice. The median proportion of cells staining for B7-1 ranged
from 2% to 10% for MRL/lpr mice and from 2% to 5% for MRL/+ mice.
The proportion of cells staining positively for B7-2 was significantly
greater than for B7-1 for both MRL/lpr mice (mean difference, 15%;
P = 0.001) and for MRL/+ mice (mean difference, 19%;
P = 0.006).
CONCLUSIONS. On the basis of immunohistochemistry for cytokines and costimulatory molecules, inflammatory lacrimal gland lesions in MRL/lpr and MRL/+ mice appear to be a largely Th2 phenomenon.
| Introduction |
|---|
|
|
|---|
/ß+ "double-negative" T cells in the lymph
nodes.1
2
10
11
12
Although an accelerated autoimmune
disease develops in MRL/lpr mice compared with that in MRL/+ mice,
inflammatory lacrimal gland lesions, which are composed largely of T
cells (approximately 80%), the majority (approximately 63%74%) of
which are CD4+ T cells, develop in both
substrains.4
5
6
Although inflammatory lacrimal gland
lesions develop in both MRL/lpr and MRL/+ mice, there are differences
between the two substrains. Lacrimal gland disease develops earlier in
MRL/lpr mice than in MRL/+ mice, and at comparable ages MRL/lpr mice
have more severe disease. Furthermore, a late accumulation of B cells
develops in the lacrimal gland lesions in MRL/+ mice that is not seen
in MRL/lpr mice and suggests that MRL/+ and MRL/lpr mice could have
different immunologic mechanisms of autoimmune lacrimal gland disease.
CD4+ helper T (Th) cells differentiate into two
subpopulations, Th1 and Th2, with different effector
mechanisms.13
14
15
16
17
18
19
Th1 cells produce interferon (IFN)-
and tumor necrosis factor (TNF) and are primarily responsible for
cell-mediated immune responses, such as delayed-type hypersensitivity.
Th2 cells produce interleukin (IL)-4, IL-5, and IL-10 and provide
help to B cells in antibody production in humoral immune
responses.13
18
Factors involved in directing
the immune response toward Th1 or Th2 include specific cytokines; IL-12
and IFN-
induce a Th1 response, whereas IL-4 induces a Th2 response,
and IL-10 inhibits a Th1 response. Certain antigens are more likely to
induce a predominant subset as well.19
20
B7 is a
costimulatory molecule expressed on antigen-presenting cells and is
required for the effective stimulation of T cells to respond to antigen
presentation; it exists as two subtypes, B7-1 and B7-2, which appear to
stimulate Th1 responses and Th2 responses,
respectively.21
22
We report the results of immunohistochemistry to evaluate the relative roles of Th1 versus Th2 responses in the inflammatory lacrimal gland lesions of both substrains of MRL/Mp mice.
| Materials and Methods |
|---|
|
|
|---|
Immunocytochemistry
Staining of frozen sections of the lacrimal glands was performed
using a panel of monoclonal antibodies and the avidin-biotin-peroxidase
complex (ABC) technique.4
5
6
Frozen sections were fixed in
chilled (4°C) acetone, air dried, rehydrated in phosphate-buffered
saline (PBS), and incubated with the appropriate blocking agent
(Vector, Burlingame, CA) for 15 minutes. The primary antibody was
applied, and the slides were incubated for 60 minutes. A second
blocking step was then performed. The slides were washed in PBS,
incubated with a biotinylated secondary antibody for 30 minutes, rinsed
in PBS, incubated with the ABC agent for 45 minutes, washed again in
PBS, developed with 3% hydrogen peroxide and 3-amino-9-ethyl-carbazole
containing acetate buffer, and counterstained with Harriss
hematoxylin (Sigma, St. Louis, MO). The percentage of mononuclear
inflammatory cells staining with a monoclonal antibody was enumerated
using a 10 x 10-µm grid disc that covered a
0.16-mm2 area using a x25 objective and a x10
ocular mounted on a standard binocular microscope (Carl Zeiss,
Oberkochen, Germany).4
5
6
The monoclonal antibodies used were all rat anti-mouse antibodies and
were used at the following dilutions: anti-IL-4 (PharMingen, San Diego,
CA) at 1:100,23
anti-IFN-
(BioSource, Camarillo, CA) at
1:50,14
anti-B7-1 (PBL, New Brunswick, NJ) at
1:200,24
and anti-B7-2 (PharMingen) at
1:200.25
The secondary antibody was a mouse-adsorbed,
biotinylated, rabbit anti-rat immunoglobulin (Vector) at 1:100. These
antibodies have little cross reactivity. For each staining run and each
antibody, appropriate positive controls (spleen sections) and negative
controls (in which normal rat immunoglobulin was substituted for the
primary antibody) were performed to ensure quality control.
Double Staining
Double staining for IL-4 and either CD3 or CD4 was performed using
a rat anti-mouse IL-4 antibody (PharMingen), and the ABC technique
using 3-amino-9-ethyl-carbazole (Vector), as for single staining, and
then a hamster anti-mouse CD3 monoclonal antibody (gift of James P. Allison)26
or the rat anti-mouse CD4 monoclonal
antibody, anti-L3T4 (Becton Dickinson, Bedford, MA),27
and
the ABC technique, using glucose oxidase (Vector).
Statistics
The comparison of the proportion of cells staining positively for
IL-4 and IFN-
and for B7-2 and B7-1 was performed using the sign
test, a nonparametric paired analysis. The evaluation of trends over
time for cytokines or cell surface markers within a substrain was
performed using linear regression; the results are expressed as ß,
the slope of the regression line. Comparison between substrains was
performed using an analysis of covariance.28
| Results |
|---|
|
|
|---|
. Double staining performed on three
3- to 4-month-old MRL/lpr mice and on three 3- to 4-month-old MRL/+
mice confirmed that nearly all the IL-4stained cells were
CD3+ CD4+ T cells. The median proportion of
cells that stained positively for IL-4 ranged from 30% to 67% for
MRL/lpr mice, and 30% to 55% for MRL/+ mice, whereas the median
proportion of cells that stained positively for IFN-
ranged from 1%
to 5% for MRL/lpr mice, and from 1% to 3% for MRL/+ mice. The
proportion of cells staining positively for IL-4 was significantly
greater than the proportion staining positively for IFN-
(mean
difference, 33%; P = 0.001) and for MRL/+ mice (mean
difference, 42%; P = 0.002). Immunocytochemistry
for B7-1 and B7-2 revealed that a greater percentage of cells stained
for B7-2 than for B7-1 for both MRL/lpr (Fig. 3)
and MRL/+ mice (Fig. 4)
. The median proportion of cells staining positively for B7-2 ranged
from 20% to 38% for MRL/lpr mice and from 16% to 34% for MRL/+
mice, whereas the median proportion of cells staining positively for
B7-1 ranged from 2% to 10% for MRL/lpr mice and from 2% to 5% for
MRL/+ mice. There was a significantly greater proportion of cells
staining positively for B7-2 in both MRL/lpr mice (mean difference,
15%; P = 0.0001), and in MRL/+ mice (mean difference,
19%; P = 0.006). One-month-old MRL/lpr mice typically
had lesions too small to be analyzed, although in two mice staining for
IL-4 and B7-2 was evident, whereas staining for IFN-
and B7-1 was
not seen. One-month-old MRL/+ mice had no lesions.
|
|
|
|
|
in MRL/lpr mice (ß = -0.7; P =
0.29) or MRL/+ mice (ß = 0.48; P = 0.50). For B7-2
there was no significant trend over time for MRL/lpr mice (ß =
-1.96; P = 0.17), but there was a significant increase over
time in MRL/+ mice (ß = 5.45; P = 0.015). For B7-1
there was no significant trend over time for MRL/+ mice (ß =
-0.41; P = 0.80), but there was a suggestion of a decline
over time for MRL/lpr mice (ß = -2.14; P = 0.08),
which did not reach the conventional level of significance of
P = 0.05.
Comparison of MRL/lpr and MRL/+ Mice
There was no significant difference between the two substrains for
IL-4 staining. For IFN-
, there was a suggestion that MRL/lpr mice
had a greater proportion of cells staining positively than did MRL/+
mice (P = 0.078), and for B7-1, there was a suggestion that
MRL/lpr mice had a greater percentage of cells staining positively than
did MRL/+ mice (P = 0.064). However, neither of these
differences was at the conventional level of significance of P
= 0.05. Because of the significant substrain by time interaction
(different slopes on the regression lines) for B7-2 staining, the two
strains could not be compared directly for the proportion of cells
staining positively for B7-2 overall.
Age-matched control BALB/c mice showed no lacrimal gland inflammation at any of the ages studied.
| Discussion |
|---|
|
|
|---|
. Although IFN-
can be detected within a
few isolated cells in the inflammatory lacrimal gland lesions, IL-4
predominates, suggesting that the lesions are largely Th2. Our results
show that B7-2 is the major costimulatory molecule seen in the lacrimal
gland lesions of both MRL/lpr and MRL/+ mice. It has been reported by
Kuchroo et al.21
that B7-1 is the costimulatory molecule
for Th1 cells and that B7-2 is the costimulatory molecule for Th2
cells. The finding of a predominance of B7-2 within the lacrimal gland
lesions of MRL/lpr and MRL/+ mice further suggests a Th2 response at
this site.
Because of the known late accumulation of B cells in the lacrimal gland
lesions of MRL/+ mice,4
we had initially hypothesized that
the lesions in MRL/+ mice may be Th2. The predominance of IL-4 over
INF-
and B7-2 over B7-1 and the increase in B7-2 with time are all
consistent with Th2 response in this substrain. However, Murray et
al.31
and Takahashi et al.32
have
reported that the autoimmune mechanism in MRL/lpr mice spleens and
lymph nodes is Th1. As such, it was possible that the lacrimal gland
lesions in MRL/lpr mice might be predominately Th1, predominately Th2,
or mixed. Because of the accelerated lacrimal gland disease seen in
MRL/lpr mice, we initially predicted that a mixed population would be
present in MRL/lpr mice with an increasing Th1 component over time.
However, our results demonstrate a predominant Th2 response in MRL/lpr
mice. Although the numbers of positively staining cells are small, the
suggestion of an increase in staining for INF-
and B7-1 in the
lacrimal gland lesions of MRL/lpr mice compared with MRL/+ mice and the
earlier onset of disease in these mice4
are both
consistent with a mild influence on the lpr gene on the
lacrimal gland lesions in MRL/lpr mice. However, the predominant
character of the lacrimal gland lesions in MRL/lpr mice remains that of
the background MRL/Mp strain (i.e., a Th2 response).
Our results demonstrating that the lacrimal gland lesions are largely Th2 are consistent with the fact that the lacrimal gland disease is intrinsic to the MRL/Mp mice and are present in both substrains. The lpr gene accelerates the development of the autoimmune disease present in MRL/+ mice but is not required for the lacrimal gland disease. Luzina et al.33 have recently demonstrated that the infiltrating lymphocytes in the vasculitic lesions of Palmerston North mice, another autoimmune strain of mice, are largely Th2, also suggesting that Th2 responses can be responsible for autoimmune end-organ disease.
Evaluations of minor salivary biopsy specimens from patients with
Sjögrens syndrome have given inconsistent
results.34
35
Fox et al.34
reported that the
lymphocytes from minor salivary gland biopsy specimens transcribed mRNA
for IL-2, IFN-
, and IL-10, but little IL-4. The coproduction of
IFN-
and IL-10 was considered peculiar, because IFN-
generally is
associated with Th1 responses and IL-10 with Th2 responses. Conversely,
Ohyama et al.35
detected IL-2 and IFN-
mRNA
consistently in minor salivary gland biopsy specimens but also detected
IL-4 mRNA in specimens with an accumulation of B cells. These results
suggest a less clear-cut distinction between Th1 and Th2 responses in
minor salivary gland biopsy specimens of patients with Sjögrens
syndrome, at least when cytokines are evaluated by reverse
transcriptionpolymerase chain reaction for cytokine mRNA
transcription.
The autoimmune lymphoproliferative syndrome is a recently described human disorder similar to that seen in MRL/lpr mice.36 Patients with this disorder have an inherited defect of apoptosis, generally caused by a defective Fas protein, lymphoproliferation, excess numbers of CD3+ CD4- CD8- double-negative lymphocytes, autoimmune disease, and autoantibodies. Evaluations of Th1 versus Th2 responses in these patients show a prominent "skewing" toward the Th2 phenotype,36 a result similar to that seen in the lacrimal glands of MRL/Mp mice.
In conclusion, the inflammatory lacrimal gland lesions in MRL/lpr and
MRL/+ mice appear to be characterized primarily by a Th2 response. The
lesions are composed of large numbers of CD4+ T
cells staining for IL-4, but relatively few cells staining for IFN-
.
B7-1 positive antigen-presenting cells, which drive the system toward a
Th1 response, are only sparsely present, whereas B7-2 positive cells,
which drive the system toward a Th2 response, are present in
significantly greater numbers. Additional experiments, such as
evaluating the amount of mRNA for these cytokines produced in the
lacrimal gland, and/or cytokine production by inflammatory cells
isolated from the lacrimal gland, and studies blocking either IL-4 or
B7-2 with monoclonal antibodies are needed to confirm these results.
| Footnotes |
|---|
Submitted for publication May 25, 1999; revised August 17, 1999; accepted September 15, 1999.
Commercial relationships policy: N.
Corresponding author: Douglas A. Jabs, Department of Ophthalmology and Medicine, Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, 550 North Broadway, Suite 700, Baltimore, MD 21205. dajabs{at}jhmi.edu
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
D. A. Jabs, R. A. Prendergast, A. L. Campbell, B. Lee, E. K. Akpek, H. C. Gerard, A. P. Hudson, and J. A. Whittum-Hudson Autoimmune Th2-Mediated Dacryoadenitis in MRL/MpJ Mice Becomes Th1-Mediated in IL-4 Deficient MRL/MpJ Mice Invest. Ophthalmol. Vis. Sci., December 1, 2007; 48(12): 5624 - 5629. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. S. Vinay, J. D. Kim, T. Asai, B. K. Choi, and B. S. Kwon Absence of 4 1BB Gene Function Exacerbates Lacrimal Gland Inflammation in Autoimmune-Prone MRL-Faslpr Mice Invest. Ophthalmol. Vis. Sci., October 1, 2007; 48(10): 4608 - 4615. [Abstract] [Full Text] [PDF] |
||||
![]() |
M Pertovaara, J Antonen, and M Hurme Th2 cytokine genotypes are associated with a milder form of primary Sjogren's syndrome Ann Rheum Dis, May 1, 2006; 65(5): 666 - 670. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. A. Jabs, H. C. Gerard, Y. Wei, A. L. Campbell, A. P. Hudson, E. K. Akpek, B. Lee, R. A. Prendergast, and J. A. Whittum-Hudson Inflammatory Mediators in Autoimmune Lacrimal Gland Disease in MRL/Mpj Mice Invest. Ophthalmol. Vis. Sci., July 1, 2004; 45(7): 2293 - 2298. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Barabino and M. R. Dana Animal Models of Dry Eye: A Critical Assessment of Opportunities and Limitations Invest. Ophthalmol. Vis. Sci., June 1, 2004; 45(6): 1641 - 1646. [Full Text] [PDF] |
||||
![]() |
E. K. Akpek, D. A. Jabs, H. C. Gerard, R. A. Prendergast, A. P. Hudson, B. Lee, and J. A. Whittum-Hudson Chemokines in Autoimmune Lacrimal Gland Disease in MRL/MpJ Mice Invest. Ophthalmol. Vis. Sci., January 1, 2004; 45(1): 185 - 190. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Cha, A.B. Peck, and M.G. Humphreys-Beher PROGRESS IN UNDERSTANDING AUTOIMMUNE EXOCRINOPATHY USING THE NON-OBESE DIABETIC MOUSE: AN UPDATE Crit. Rev. Oral. Biol. Med., January 1, 2002; 13(1): 5 - 16. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. A. Jabs, R. A. Prendergast, E. M. Rorer, A. P. Hudson, and J. A. Whittum-Hudson Cytokines in Autoimmune Lacrimal Gland Disease in MRL/MpJ Mice Invest. Ophthalmol. Vis. Sci., October 1, 2001; 42(11): 2567 - 2571. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |