By
From the * Centenary Institute of Cancer Medicine and Cell Biology, Royal Prince Alfred Hospital,
Sydney, New South Wales, 2050 Australia; and the Department of Medicine (Neurology),
University of Sydney, Sydney, New South Wales, Australia
Tumor necrosis factor (TNF)-dependent sites of action in the generation of autoimmune inflammation have been defined by targeted disruption of TNF in the C57BL/6 mouse strain.
C57BL/6 mice are susceptible to an inflammatory, demyelinating form of experimental autoimmune encephalomyelitis (EAE) induced by the 35-55 peptide of myelin oligodendrocyte
glycoprotein. Direct targeting of a strain in which EAE was inducible was necessary, as the location of the TNF gene renders segregation of the mutated allele from the original major histocompatibility complex by backcrossing virtually impossible. In this way a single gene effect was
studied. We show here that TNF is obligatory for normal initiation of the neurological deficit,
as demonstrated by a significant (6 d) delay in disease in its absence relative to wild-type (WT)
mice. During this delay, comparable numbers of leukocytes were isolated from the perfused
central nervous system (CNS) of WT and TNF/
mice. However, in the TNF
/
mice, immunohistological analysis of CNS tissue indicated that leukocytes failed to form the typical mature perivascular cuffs observed in WT mice at this same time point. Severe EAE, including paralysis and widespread CNS perivascular inflammation, eventually developed without TNF.
TNF
/
and WT mice recovered from the acute illness at the same time, such that the overall
disease course in TNF
/
mice was only 60% of the course in control mice. Primary demyelination occurred in both WT and TNF
/
mice, although it was of variable magnitude. These
results are consistent with the TNF dependence of processes controlling initial leukocyte
movement within the CNS. Nevertheless, potent alternative mechanisms exist to mediate all
other phases of EAE.
Studies in vivo point to the importance of TNF in the
pathogenesis of autoimmune inflammation (for review
see reference 1). Experimental autoimmune encephalomyelitis (EAE), a central nervous system (CNS) autoimmune
inflammatory disease, is particularly well studied in this
context. EAE follows the recognition of myelin antigen in
the CNS by specific autoreactive TH1 CD4+ T cells (2, 3).
This recognition leads to T cell and macrophage infiltration
of the CNS; cytokine secretion, including TNF, lymphotoxin (LT)- Inhibitors of TNF consistently prevent or attenuate the
clinical course of EAE (5). The mechanism of inhibition
remains undefined, as TNF has the potential to contribute
to CNS injury at many levels, including via effects on cell
adhesion (3), by macrophage activation (9), and by direct
cytolysis of oligodendrocytes, the myelinating cell of the
CNS (10). The complex interactions between TNF, its homologue LT- Mice lacking TNF and/or LT- To explore in detail the role of TNF in autoimmune inflammation in the CNS, TNF gene-deleted C57BL/6
mice normally susceptible to EAE induced by the 35-55
peptide of myelin oligodendrocyte glycoprotein (MOG)
were generated (15). Analysis of these mice points to a particular dependence on TNF for the early inflammatory phase of EAE, and specifically to the processes involved in
the formation of perivascular cuffs within the CNS. The
existence of potent alternative pathways of CNS inflammation and demyelination is demonstrated.
Generation of C57BL/6-strain TNF Induction of EAE.
EAE was actively induced in adult (8-12-wk-old) TNF Assessment of T Cell Activation and Antibody Production.
Groups of
WT and TNF Flow Cytometry.
Flow cytometric analysis of CNS-associated
leukocytes was performed on collagenase-digested tissue after heparin-saline perfusion of animals. Isolation and purification steps
were adapted from a previously described method (17). Antibodies used in flow cytometry were FITC-conjugated hamster anti-
murine Immunohistology and Neuropathology.
Tissue specimens from various regions of the CNS of nonperfused mice were embedded in
Tissue Tek OCT compound (Sakura Finetek, Torrance, CA) and
6-µm serial cryostat sections were prepared. Sections were
stained via the immunoperoxidase technique using HRP-conjugated rabbit anti-rat Ig (DAKO, Carpenteria, CA), and counterstained with hematoxylin. Rat mAb reactive with mouse cell- surface antigens were: GK1.5 (CD4); M1.70 (CD11b/Mac-1);
YBM142.2.2 (CD45, supplied by Dr. S. Cobbold, Oxford University, Oxford, UK); 429 (vascular cellular adhesion molecule
[VCAM]-1; PharMingen); and isotype control reagents R-35-95
(rat IgG2a, PharMingen) and YKIX16.13 (rat IgG2b, supplied by
Dr. S. Cobbold). Neuropathological assessment for demyelination was performed on CNS tissue obtained from animals perfused with warm PBS, followed by 4% paraformaldehyde and
2.5% glutaraldehyde in PBS. Tissue was post-fixed in Dalton's chrome osmium solution and dehydrated in graded concentrations of ethanol and acetone. Transverse sections of spinal cord
(0.25 µm) were stained with toluidine blue. All sections were examined and photographed using standard bright-field optics.
A combination of
cell-mediated and humoral immune responses is considered
important for the full manifestation of EAE, particularly in
relation to demyelination, in which a clear role for antibody to myelin components, including MOG (18), has
been demonstrated. To determine whether mice lacking
TNF were deficient in their immune responsiveness to
MOG peptide, mice were immunized and analyzed for
MOG peptide-specific T cell proliferation, IFN- Upon challenge with the encephalitogenic MOG
35-55 peptide, WT mice exhibited signs of clinical disease
from day 10 (Fig. 1 A), manifest as symmetrical ascending
motor deficits. Disease severity then increased rapidly to
reach a peak at day 20, followed by gradual recovery over
the next 20 d to a relatively mild deficit that persisted for
the life of the mouse (data not shown). Although TNF
The clear conclusion that can be drawn from these results is that TNF is required for the normal initiation of the
neurological deficit in EAE, but is not a necessary factor for
disease progression or for recovery from the acute clinical
illness.
Since TNF appeared to be an essential participant in the early events leading to the development of EAE, a series of experiments was
performed to establish how the absence of TNF affected
the CNS inflammatory process, using the time point at which
the discrepancy between the clinical scores of TNF When this observation was extended to an investigation
of the immune response throughout the entire CNS, the kinetics of total inflammatory cell accumulation in the CNS
were found to be remarkably similar in WT and TNF These studies support the view that MOG peptide-reactive T cells are generated normally in TNF At the peak of the disease there was extensive
inflammation in the CNS of both WT and TNF
From this study of the course of EAE, clear conclusions
can be derived regarding the critical roles for TNF. Of the
three stages of the inflammatory process: initiation, tissue
injury, and recovery, TNF appears to play a unique role
only in the first. Unexpectedly, the altered characteristics of
the inflammatory disease process in TNF A variety of TNF-dependent processes may underlie this
unusual phenotype. However, a likely explanation is that
the delayed movement of leukocytes within the tissue to
form perivascular cuffs reflects a general inability of leukocytes to move correctly in the absence of TNF-inducible
chemotactic factors, notably chemokines (21). Consistent
with this concept is the defect of cell movement manifest
in the altered microarchitectural T and B cell arrangements in lymphoid tissues of TNF An important outcome of these studies is the demonstration of a potent, but TNF-independent, mechanism producing tissue injury in EAE. The results of studies of collagen arthritis in mice administered TNFR-IgG fusion
protein or lacking TNFR-1 (24) are strikingly similar to
those reported here in TNF Soluble LT- The requirement for TNF in the normal initiation of autoimmune inflammation, as demonstrated in this study,
may help to explain the therapeutic effectiveness of TNF
blocking agents when administered before rather than after
disease onset in several disease models (7, 24, 26, 27). Conversely, there is evidence from other models (notably in the
rat) that TNF may act as a downstream effector of tissue injury (8, 28, 29), while in this study, once the disease was
established, it progressed normally without TNF. Reconciling these apparent discrepancies must await a more detailed understanding of the role of TNF in cell movement
within tissues, but also an appreciation of the role that TNF
may play in induction of alternative effector pathways.
, and IFN-
(4); loss of blood brain barrier integrity; and, in some cases, antigen-specific tissue damage in
the form of demyelination (2).
, and their receptors (11), have prevented
the precise definition of the critical points of action for
TNF in any stage of CNS autoimmune inflammation, or
indeed in any inflammatory process.
can now be applied to
this problem. In a recent report, 129 strain mice lacking
both TNF and LT-
, and interbred with C57BL/6-strain
mice or crossed to the EAE-susceptible SJL mouse strain
(12), were shown to be susceptible to a CNS inflammatory
disease after immunization with a number of different myelin antigens. Some autoantigen combinations induced a
rapidly lethal atypical form of disease. The authors concluded that neither TNF nor LT-
was required for EAE
induction. Some properties of the mice used in Frei et al.
(12) study render an interpretation of the experimental
outcome difficult. First, these mice lack all lymph nodes as
a result of the absence of LT-
(13). Second, the TNF/LT
gene loci reside within the MHC, a region strongly linked
to autoimmune disease susceptibility (14) and comprising
not only genes encoding for MHC class I and II and the
TNF and LT molecules, but also complement components and molecules involved in antigen processing. Thus, attempts to backcross the TNF/LT mutations onto another
strain will create individually variable congenic segments,
the majority of which will maintain the MHC locus profile
linked to the mutated allele. For this reason, the use of a directly targeted, disease-susceptible mouse strain represents a
major theoretical advantage.
/
Mice.
Construct design,
use of the BL/6 III C57BL/6 embryonic stem cells, and generation and characterization of C57BL/6-strain TNF
/
mice have
been previously described (15). TNF
/
specific pathogen free
mice were maintained as a homozygous colony in the Centenary
Institute animal facility (Sydney, Australia). Control wild-type
(WT) C57BL/6J-strain mice were bred in-house or obtained
from CULAS Ltd. (Sydney, Australia).
/
and WT C57BL/6 mice by subcutaneous tail-base injection of 50 µg MOG peptide (35-MEVGWYRSPFSR-
VVHLYRNGK-55; reference 16) in CFA containing 1 mg of
heat-inactivated H37RA Mycobacterium tuberculosis (DIFCO Laboratories, Inc., Detroit, MI). 200 ng of pertussis toxin (LIST Biol.
Labs., Inc., Campbell, CA), was injected intravenously on days 0 and 2. Neurological deficits were quantified according to an arbitrary clinical scale: 0, normal; 1, flaccid tail; 2, hind limb weakness
or abnormal gait; 3, severe hind limb weakness, with loss of ability to right from supine; 4, hind quarter paralysis; 5, forelimb
weakness, moribund; 6, death. All animal procedures were approved by the Animal Care and Ethics Committee of the University of Sydney (Sydney, Australia).
/
mice were immunized (day 0) with MOG
peptide/CFA as above, but without the pertussis toxin injection. For assessment of T cell proliferation and IFN-
production,
draining lymph node cells were harvested on days 9 and 5, respectively, after MOG peptide/CFA. Proliferation was assessed
using 2 × 105 viable cells/well in the presence of MOG peptide
(10 µg/ml final concentration) or control antigens. T cell proliferative responses were quantified at 96 h after a 14-h pulse with
[3H]thymidine. Supernatants for IFN-
determinations were generated by culture of cells at 0.5-1 × 107/ml with MOG peptide
(20 µg/ml), or no antigen, for 60 h. IFN-
was quantitated by
sandwich ELISA. For examination of humoral responses, groups
of MOG peptide/CFA-challenged mice were secondarily immunized with MOG/IFA on day 9 and were bled for serum collection on day 14. MOG peptide-specific IgG responses were evaluated by ELISA using plates coated with avidin and biotinylated
peptide and by detection of antibody with alkaline-phosphatase-
conjugated sheep anti-mouse IgG (Sigma Chemical Co., St.
Louis, MO).
/
-TCR (H57-597), PE-conjugated rat anti-CD45
(30F11.1; PharMingen, San Diego, CA) and relevant isotype
control reagents (to set compensation levels and analysis gates).
Flow cytometry was performed on a FACStarPlusTM using CellQuest
analysis software (Becton Dickinson, San Jose, CA).
TNF/
Mice Exhibit Normal MOG Peptide-specific Cell-mediated and Humoral Immune Responses.
production, and IgG production, as detailed in Materials and
Methods. No significant differences in any of these parameters were observed between TNF
/
and WT mice (data
not shown).
/
C57BL/6 Mice Is Substantially
Delayed.
/
mice did develop EAE after MOG peptide challenge, the
onset of clinical disease was substantially and reproducibly
delayed (Fig. 1 A). The rate of progression once disease became established and the eventual peak severity of disease
in TNF
/
mice were comparable to WT mice. Both WT
and TNF
/
mice recovered simultaneously despite the
initial delay in disease onset in mice lacking TNF. Thus,
the overall disease course was reduced to 60% of the course
in control mice in the absence of TNF (Fig. 1 B). Like WT
mice, mice lacking TNF maintained a mild level of disability for an extended time after resolution of the initial peak
clinical deficit.
Fig. 1.
Natural history of EAE in WT and TNF/
C57BL/6 mice.
(A) Mean clinical EAE scores (± SEM) of WT mice (
, n = 6) and
TNF
/
mice (
, n = 8) after immunization with MOG/CFA. The
horizontal bar at days 13-15 indicates a time point of closer examination, referred to in Fig. 2 and in the text. (B) As a measure of the relative susceptibility of WT and TNF
/
mice to neurological deficits induced by
immunization with MOG, areas under the curves in A were determined.
Results are representative of four separate time course studies.
[View Larger Version of this Image (16K GIF file)]
Fig. 2.
Characterization of the early CNS inflammatory infiltrate in
WT and TNF/
mice. (A) Leukocyte inflammation (CD45+) and
VCAM-1 expression at day 15 (Fig. 1 A, horizontal bar). Tissue sections
were derived from brain stem and cerebellum and are representative of
tissues throughout the CNS of several WT and TNF
/
mice at this time
point. (Inset) VCAM-1 expression of unimmunized C57BL/6J-strain CNS.
Bar = 60 µm. (B) Total cell recoveries from the perfused CNS of normal
and immunized mice over the course of disease. Replicates concentrated
on the early disease phase when TNF
/
mice were not showing signs of
clinical disease. For simplicity, individual mice from days 13-15 are all
shown at the day 15 time point. Each data point represents a single
mouse. +, WT unimmunized.
, WT MOG immunized.
, TNF
/
MOG immunized. (C) T cell accumulation in the CNS of normal and MOG-immunized WT and TNF
/
mice at day 15. Pooled cells obtained from two mice in each case were stained and analyzed by flow cytometry. Percentage of total cells in each preparation as defined by populations 1, 2, and 3 (see text) are shown in the inset. CD45
TCR
cells
are undefined but would represent nonhematopoietically derived cells including neurons, endothelial cells, astrocytes, and oligodendrocytes.
[View Larger Versions of these Images (31 + 104K GIF file)]
/
and
WT mice was maximal (Fig. 1 A, days 13-15, horizontal
bar). Immunohistological analysis of mice at this time revealed small but frequently detectable accumulations of
leukocytes (CD45+) in TNF
/
mice (Fig. 2 A, upper panels), but a marked reduction in discrete perivascular cuffs of
leukocytes relative to WT. On the other hand, no detectable accumulations of leukocytes (CD45+) were found in
the CNS of normal nonimmunized mice (data not shown).
Clear evidence for the existence of immunological activation within the CNS was revealed by staining for the adhesion molecule VCAM-1 (Fig. 2 A, lower panels), which was
substantially upregulated on vascular endothelium throughout the CNS of TNF
/
mice.
/
mice (Fig. 2, B and C). Cells isolated from PBS-perfused
CNS tissue of WT and TNF
/
mice were quantified at
intervals after immunization (Fig. 2 B) and phenotyped by
flow cytometry using criteria previously developed (17).
Flow-cytometric analysis at day 15 (Fig. 2 C) revealed the
presence of equivalent numbers of
/
T cells (population 1, CD45hi
/
TCR+), non-T inflammatory cells (population 2, CD45hi
/
TCR
), the majority of which were
macrophages (data not shown), and microglia (population 3,
CD45low
/
TCR
). Relative to other populations isolated
(T cells, and microglia), there were more inflammatory
macrophages in the CNS of WT than TNF
/
mice (Fig. 2
C, population 2). A small number of T cells and macrophages were isolated from the CNS of nonimmunized WT
mice (Fig. 2 C, upper panel), as expected, although resident
microglial cells (population 3, CD45low
/
TCR
) were
readily detectable (17).
/
mice, migrating to and distributing throughout the CNS vasculature and leading to endothelial activation, as evidenced by
VCAM-1 upregulation
all outcomes that are not dependent on TNF. However, in the absence of TNF, formation
of discrete mature perivascular cuffs of inflammatory cells is
significantly retarded.
/
Mice.
/
mice
(Fig. 3 A), characterized by perivascular and submeningeal infiltrates of CD45+ cells and microglial activation (Fig. 3
A, arrows). Serial section staining revealed a predominance
of macrophages and CD4+ T cells (data not shown). A
general feature of the immunopathology in TNF
/
mice
was a more limited expansion of cells from the perivascular cuff into the parenchyma. Primary demyelination, involving loss of myelin from otherwise viable axons, is a hallmark of the human disease multiple sclerosis, for which
EAE serves as an experimental model (2). Primary demyelination was a relatively late event, detected in WT and
TNF
/
mice from ~30 d after MOG peptide/CFA immunization and most clearly apparent after the bulk of inflammatory cells had dissipated (Fig. 3 B, day 35). Naked
axons of otherwise normal appearance were seen, consistent with the specificity of the immune insult (Fig. 3 B, arrows). A degree of variability in magnitude of demyelination was observed in TNF
/
mice with from one of five
mice examined exhibiting few if any demyelinated axons
(data not shown), to the one mouse illustrated here (Fig. 3
B, day 40) with a level of demyelination indistinguishable from WT mice. A more extensive comparison of WT and
TNF
/
mice is currently underway to determine whether
the levels of demyelination in mice lacking TNF are reduced overall. Nevertheless, TNF is not an obligatory mediator in the demyelinating process.
Fig. 3.
Peak disease inflammation and demyelination. (A)
Leukocyte infiltration and formation of perivascular cuffs. Sections
were derived from spinal cord of
animals harvested at day 19 (WT)
and day 23 (TNF/
) and stained
for CD45. CD45+ filamentous
processes within the CNS parenchyma (arrows) indicate activated
microglia. Comparable infiltration was found at all levels of the
spinal cord, brain stem, and cerebellum. Bar = 60 µm. (B) Primary demyelination in WT and
TNF
/
mice. Sections were derived from spinal cord of mice
harvested at day 35 (WT) and
day 40 (TNF
/
). Tissues from
WT and TNF
/
mice show a
region of comparable perivenous
(v) demyelination and gliosis beneath the meningeal surface (m).
Arrows indicate naked (demyelinated) axons. In these mice, a
similar histological picture was
obtained at all levels of the spinal
cord. Bar = 12 µm.
[View Larger Version of this Image (124K GIF file)]
/
mice are consistent with the inefficient movement of cells within the
CNS, while normal upregulation of VCAM-1 and the
identification of recruited cells at the time of disease delay
suggest there are no major deficiencies in vascular adhesion
in the absence of TNF. While the precise location of leukocytes within the CNS of TNF
/
mice is unknown during the delayed preclinical phase of EAE (Fig. 2 A, upper
right panel), the data nevertheless support the view that extravasation of leukocytes, localization to the perivascular space throughout the CNS, and antigen recognition by
MOG-reactive T cells at that site (19, 20) have occurred
normally. This conclusion is based on the observation of
VCAM-1 upregulation as well as accumulation of leukocytes other than T cells in TNF
/
mice during the preclinical phase (Fig. 2, A and C), events almost certainly necessitating CNS antigen recognition by infiltrating T cells.
/
mice (15, 22). The potential role of secondary mediators in this process is highlighted by a recent description of mice in which deletion of
the gene encoding a putative chemokine receptor, blr1, resulted in splenic B cell architecture not unlike that seen in
TNF
/
mice (23).
/
mice with EAE. In particular, in TNFR1-deficient mice, arthritis was of a reduced
overall severity, but, once established in an individual joint,
progressed in a manner similar to WT mice. Therefore, the
processes that lead to tissue damage in EAE and collagen
arthritis, once it is initiated, and the eventual peak severity
of the diseases, are not due to the actions of TNF alone.
homotrimer, a predominantly T cell cytokine with some functional similarities to TNF and binding the same receptors as TNF (11), remains a possible mediator of demyelination as well as of the acute EAE phase.
A full analysis of the role of LT-
and -
in EAE in gene-targeted C57BL/6 mice prepared in parallel to the TNF
/
mice is ongoing. These studies are cumbersome, requiring
the use of irradiation bone marrow chimeras (13) to generate mice which carry lymphoid tissues but are deficient in
LT-
. Lymph nodes were lacking in TNF/LT-
double-deficient mice shown recently to be susceptible to autoimmune CNS inflammation (12). Likely alterations to normal
immunological regulation, and the absence of a switched
humoral response in these mice (25) have the potential to
significantly influence the disease outcome after immunization. As the experiments here have shown, TNF appears to
play a critical role in the early inflammatory process in
EAE. This same TNF dependency was not revealed in
mice lacking both TNF and LT-
(12). Thus, it is difficult
to say with certainty at this stage that LT-
plays no role in
the EAE disease process in immunologically intact mice.
Address correspondence to Dr. Jonathon D. Sedgwick, Centenary Institute of Cancer Medicine and Cell Biology, Bldg 93, Royal Prince Alfred Hospital, Missenden Rd., Camperdown, Sydney NSW 2050, Australia. Phone: 61-2-9565-6116; FAX: 61-2-9565-6103; E-mail: j.sedgwick{at}centenary.usyd.edu.au
Received for publication 17 June 1997 and in revised form 18 August 1997.
Thanks are extended to Professor Antony Basten for critical analysis of the manuscript, to Dr. Philip Hodgkin for providing reagents for IFN-These studies were supported by grants from the National Health and Medical Research Council (NHMRC) and the National Multiple Sclerosis Society of Australia. D.H. Strickland is supported by an Elizabeth Albiez Fellowship from the National Multiple Sclerosis Society of Australia, D.S. Riminton by an NHMRC postgraduate Scholarship, and J.D. Sedgwick by a Wellcome Trust Senior Research Fellowship in Australia (1992-1996) and an NHMRC Fellowship.
1. | Körner, H., and J.D. Sedgwick. 1996. Tumour necrosis factor and lymphotoxin: molecular aspects and role in tissue-specific autoimmunity. Immunol. Cell Biol. 74: 465-472 [Medline]. |
2. | Raine, C.S.. 1984. Biology of disease. Analysis of autoimmune demyelination: its impact upon multiple sclerosis. Lab. Invest. 50: 608-635 [Medline]. |
3. |
Baron, J.L.,
J.A. Madri,
N.H. Ruddle,
G. Hashim, and
C.A. Janeway Jr..
1993.
Surface expression of ![]() |
4. | Olsson, T.. 1995. Critical influences of the cytokine orchestration on the outcome of myelin antigen-specific T-cell autoimmunity in experimental autoimmune encephalomyelitis and multiple sclerosis. Immunol. Rev. 144: 245-268 [Medline]. |
5. | Ruddle, N.H., C.M. Bergman, K.M. McGrath, E.G. Lingenheld, M.L. Grunnet, S.J. Padula, and R.B. Clark. 1990. An antibody to lymphotoxin and tumor necrosis factor prevents transfer of experimental allergic encephalomyelitis. J. Exp. Med. 172: 1193-1200 [Abstract]. |
6. | Selmaj, K., C.S. Raine, and A.H. Cross. 1991. Anti-tumor necrosis factor therapy abrogates autoimmune demyelination. Ann. Neurol. 30: 694-700 [Medline]. |
7. | Baker, D., D. Butler, B.J. Scallon, J.K. O'Neill, J.L. Turk, and M. Feldmann. 1994. Control of established experimental allergic encephalomyelitis by inhibition of tumor necrosis factor (TNF) activity within the central nervous system using monoclonal antibodies and TNF receptor-immunoglobulin fusion proteins. Eur. J. Immunol. 24: 2040-2048 [Medline]. |
8. | Körner, H., A.L. Goodsall, F.A. Lemckert, B.J. Scallon, J. Ghrayeb, A.L. Ford, and J.D. Sedgwick. 1995. Unimpaired autoreactive T-cell traffic within the central nervous system during tumor necrosis factor receptor-mediated inhibition of experimental autoimmune encephalomyelitis. Proc. Natl. Acad. Sci. USA. 92: 11066-11070 [Abstract]. |
9. |
Philip, R., and
L.B. Epstein.
1986.
Tumour necrosis factor as
immunomodulator and mediator of monocyte cytotoxicity
induced by itself, ![]() |
10. | Selmaj, K.W., and C.S. Raine. 1988. Tumor necrosis factor mediates myelin and oligodendrocyte damage in vitro. Ann. Neurol. 23: 339-346 [Medline]. |
11. |
Bazzoni, F., and
B. Beutler.
1996.
The tumor necrosis factor
ligand and receptor families.
N. Engl. J. Med.
334:
1717-1725
|
12. |
Frei, K.,
H.P. Eugster,
M. Bopst,
C.S. Constantinescu,
E. Lavi, and
A. Fontana.
1997.
Tumor necrosis factor ![]() ![]() |
13. | De Togni, P., J. Goellner, N.H. Ruddle, P.R. Streeter, A. Fick, S. Mariathasan, S.C. Smith, R. Carlson, L.P. Shornick, J. Strauss-Schoenberger, et al . 1994. Abnormal development of peripheral lymphoid organs in mice deficient in lymphotoxin. Science (Wash. DC). 264: 703-707 [Medline]. |
14. | Theofilopoulos, A.N.. 1995. The basis of autoimmunity: part II. Genetic predisposition. Immunol. Today. 16: 150-159 [Medline]. |
15. | Körner, H., M. Cook, D.S. Riminton, F.A. Lemckert, R.M.
Hoek, B. Ledermann, F. Köntgen, B. Fazekas de St. Groth,
and J.D. Sedgwick. 1997. Distinct roles for lymphotoxin-![]() |
16. | Gardinier, M.V., P. Amiguet, C. Linington, and J.M. Matthieu. 1992. Myelin/oligodendrocyte glycoprotein is a unique member of the immunoglobulin superfamily. J. Neurosci. Res. 33: 177-187 [Medline]. |
17. |
Ford, A.L.,
A.L. Goodsall,
W.F. Hickey, and
J.D. Sedgwick.
1995.
Normal adult ramified microglia separated from other
central nervous system macrophages by flow cytometric sorting. Phenotypic differences defined and direct ex vivo antigen presentation to myelin basic protein-reactive CD4+ T
cells compared.
J. Immunol.
154:
4309-4321
|
18. | Linington, C., M. Bradl, H. Lassmann, C. Brunner, and K. Vass. 1988. Augmentation of demyelination in rat acute allergic encephalomyelitis by circulating mouse monoclonal antibodies directed against a myelin/oligodendrocyte glycoprotein. Am. J. Pathol. 130: 443-454 [Abstract]. |
19. | Hickey, W.F., and H. Kimura. 1988. Perivascular microglial cells of the CNS are bone marrow-derived and present antigen in vivo. Science (Wash. DC). 239: 290-292 [Medline]. |
20. | Ford, A.L., E. Foulcher, F.A. Lemckert, and J.D. Sedgwick. 1996. Microglia induce CD4 T lymphocyte final effector function and death. J. Exp. Med. 184: 1737-1746 [Abstract]. |
21. | Butcher, E.C., and L.J. Picker. 1996. Lymphocyte homing and homeostasis. Science (Wash. DC). 272: 60-66 [Abstract]. |
22. |
Pasparakis, M.,
L. Alexopoulou,
V. Episkopou, and
G. Kollias.
1996.
Immune and inflammatory responses in TNF-![]() ![]() |
23. | Forster, R., A.E. Mattis, E. Kremmer, E. Wolf, G. Brem, and M. Lipp. 1996. A putative chemokine receptor, blr1, directs B cell migration to defined lymphoid organs and specific anatomic compartments of the spleen. Cell. 87: 1037-1047 [Medline]. |
24. | Mori, L., S. Iselin, G. De Libero, and W. Lesslauer. 1996. Attenuation of collagen-induced arthritis in 55-kDa TNF receptor 1 (TNFR1)-IgG1-treated and TNFR1-deficient mice. J. Immunol. 157: 3178-3182 [Abstract]. |
25. |
Eugster, H.-P.,
M. Muller,
U. Karrer,
B.D. Car,
B. Schnyder,
V.M. Eng,
G. Woerly,
M. Le Hir,
F. di Padova,
M. Auget, et al
.
1996.
Multiple immune abnormalities in tumor necrosis factor and lymphotoxin ![]() |
26. |
Yang, X.D.,
R. Tisch,
S.M. Singer,
Z.A. Cao,
R.S. Liblau,
R.D. Schreiber, and
H.O. McDevitt.
1994.
Effect of tumor
necrosis factor ![]() |
27. | Körner, H., F.A. Lemckert, S. Etteldorf, B.J. Scallon, and J.D. Sedgwick. 1997. Tumor necrosis factor blockade in actively-induced experimental autoimmune encephalomyelitis prevents clinical disease despite activated T-cell infiltration to the central nervous system. Eur. J. Immunol. 27: 1973-1981 [Medline]. |
28. | Dick, A.D., P.G. McMenamin, H. Körner, B.J. Scallon, J. Ghrayeb, J.V. Forrester, and J.D. Sedgwick. 1996. Inhibition of tumor necrosis factor-activity minimizes target organ damage in experimental autoimmune uveoretinitis despite quantitatively normal activated T cell traffic to the retina. Eur. J. Immunol. 26: 1018-1025 [Medline]. |
29. |
Klinkert, W.E.F.,
K. Kojima,
W. Lesslauer,
W. Rinner,
H. Lassmann, and
H. Wekerle.
1997.
TNF-![]() |