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Animal Models |
From the Department of Immunobiology,*
Biomedical
Primate Research Centre, Rijswijk, The Netherlands; Institute of
Neurology,
University of Vienna, Vienna,
Austria; Bijvoet Centre and Image Sciences
Institute,
Utrecht University, Utrecht, The
Netherlands; TNO-PML, Pharmacology Research
Group,§
Prins Maurits Laboratory, Rijswijk, The
Netherlands; and Department of Neurological and Psychiatric
Sciences,¶
University of Florence,
Florence, Italy
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Magnetic resonance imaging (MRI) is presently the diagnostic imaging modality of choice in MS.2-4 T2-weighted sequences are especially sensitive to structural alterations of CNS tissue. All lesion stages, from early inflammation to late chronic stages, are visualized as hyperintense regions. Therefore, T2-weighted MRI is usually applied to assess the spatial distribution of plaques and to determine the total lesion load.5 Active lesions can be distinguished from inactive ones by increased permeability of the blood-brain barrier (BBB) for intravenously injected gadolinium. This results in local enhancement of the signal intensity of T1-weighted images. Lesions with contrast-induced regional signal enhancement correlate well with disease activity both in MS6-9 and in the experimental model experimental autoimmune encephalomyelitis (EAE).10 However, limited information is available on pathological characteristics of MRI-detectable lesions.
The objectives of this study were to investigate the histopathological basis of MRI-detectable lesions in the EAE model in marmoset monkeys. The obvious advantage of any EAE model is that MR images can be recorded before and at defined time points after disease onset. When regions of interest appear in MRI, animals can be sacrificed immediately after in vivo MRI analysis to characterize regions of interest by immunohistopathological techniques. The EAE model in marmosets is of particular interest in view of the close similarity between the human and marmoset immune systems.11-15
The present study shows that the development of lesions in the marmoset brain white matter can be very well visualized with MRI techniques similar to those used for diagnosis of MS. Moreover, for histopathological characterization of MRI-detectable lesions, the same reagents could be used as those applied for the stage characterization of lesions in the CNS of MS patients. Our present pathological investigation reveals the presence of both active and inactive, as well as remyelinating, plaques in the CNS of EAE-affected marmosets that strongly resemble the plaques in the CNS of MS patients. Correlation of MRI and pathology revealed that the number of lesions in tissue sections equalled those found by T2-weighted MRI. Furthermore, none of the pathologically defined inactive lesions displayed gadolinium enhancement. Nearly all lesions that did show gadolinium enhancement of the T1-weighted nuclear magnetic resonance (NMR) signal could be classified as early active. In summary, we demonstrate here that the present EAE model resembles MS not only in its clinical expression, but also in radiological and histopathological aspects of the lesions that are found in the CNS white matter.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Eleven marmosets (Callithrix jacchus) were used for this study. The sex and birth dates (month/year) of the monkeys were: EB: male, 4/1992; EC: male, 8/1990; ED: female, 6/1992; EE: male, 4/1992; EG: female, 8/1992; EH: male, 6/1992; EI: male, 8/1992; EJ: male, 4/1993; EK: male, 4/1993; EL: male, 4/1993; and GY: male, 7/1994. The body weight of the monkeys at the start of the experiment ranged between 295 and 320 g. The monkeys were bred and raised at the Biomedical Primate Research Centre (Rijswijk, The Netherlands). Marmosets of either sex can be used, because there is no sex-linked difference in susceptibility to EAE. During the experiments, the monkeys were individually housed in spacious cages with padded shelter on the bottom. The daily diet consisted of commercial food pellets for nonhuman primates (Hope Farms, Woerden, The Netherlands), supplemented with rice and fresh fruit. Drinking water was provided ad libitum.
EAE Induction
Myelin was isolated as described16 from human brain white matter, which was kindly provided by Dr. Rivka Ravid of the Dutch Brain Bank (Amsterdam, The Netherlands). The myelin concentration in the stock solution was 30 mg/ml on a dry-weight basis and 1.3 mg/ml protein on a protein basis as measured according to Bradford.17
In a first group of five monkeys (EB, EC, ED, EE, and EG), EAE was induced essentially as described earlier.18,19 The myelin stock solution was emulsified in an equal volume of enriched complete adjuvant. Enriched complete adjuvant was prepared by mixing incomplete adjuvant (DIFCO Laboratories, Detroit, MI) with 6 mg/ml desiccated mycobacteria (Mycobacterium tuberculosis, H37A, DIFCO) followed by brief sonication. Under ketamine anesthesia, each monkey was injected intradermally on the back with 600 µl of emulsion divided over four spots, two in the inguinal and two in the axillary region. In addition, 1 ml phosphate-buffered saline (pH 7.4) containing 1010 heat-inactivated B. pertussis particles was injected immediately after immunization and 48 hours later.
In a second group of six monkeys, the original immunization protocol was modified in two respects. First, the Mycobacterium concentration in the antigen-adjuvant emulsion was reduced from 1.5 to 0.5 mg/ml to diminish the severity of ulceration around the injection sites. Secondly, B. pertussis administration as second adjuvant was omitted to obtain a milder EAE in which patterns of EAE reactivity can be associated with the presence of certain mhc alleles and cytokine profiles.20,21
Clinical Diagnosis
The clinical course of EAE was recorded daily by a trained observer using semiquantitative scoring: 0 = no clinical signs; 0.5 = apathy, loss of appetite, altered walking pattern without ataxia; 1 = lethargy and/or anorexia; 2 = ataxia; 2.5 = para- or monoparesis and/or sensory loss and/or brain stem syndrome; 3 = para- or hemiplegia; 4 = quadriplegia; 5 = spontaneous death attributable to EAE. The highest per-day scores were averaged over 1 week. Moreover, each monkey was weighed at least three times per week to obtain a more objective score of the clinical wellbeing.
MRI
MRI was performed at the Bijvoet Center of Utrecht University, The Netherlands. For each monkey, T2- and T1-weighted magnetic resonance (MR) images were recorded, the latter also with contrast enhancement after intravenous injection of gadolinium-diethylenetriamine-penta-acetic acid (DTPA) (triple dose). The time points for performing MRI after immunization were chosen during periods of clinically active EAE.
In Vivo MRI
In preparation for the experiment, the monkeys were anesthetized with ketamine/Vetranquil (9/1 v/v). During scanning, each monkey was placed on a 37°C water-filled heating pad (Granulab International BV, Amersfoort, The Netherlands) to prevent hypothermia. The head of the monkey was fixed in a custom-built stereotactic apparatus made of metal-free plastics to ensure reproducible positioning in the magnetic field and to minimize movement artifacts. The stereotactic apparatus was placed inside a saddle-type radiofrequency coil. MRI was performed on a SISCO 200-MHz spectrometer (Varian, Palo Alto, CA) equipped with an actively shielded gradient (maximum gradient 3.2 G/cm, 33 cm inner diameter).
Postmortem MRI
T2-weighted MR images were recorded from formalin-fixed brains to enable the determination of the exact localization of the lesions that were detected in vivo. In both scannings the same orientation points were chosen for slice localization (see below). Because movement artifacts were absent and long acquisition times can be used, images of very high contrast can be obtained.
Slice Orientation and Scanning Procedure
First, a sagittal scout scan was made. The posterior and anterior positions of the corpus callosum were chosen as orientation markers for precise localization of the slices for the in vivo and postmortem MRI. A T2 (echotime (TE)/repetition time (TR), 60/2500 ms)-weighted multislice scan (20 slices of 1 mm thickness) was obtained followed by a T1-weighted scan (TE/TR, 25/1000 ms) with the same spatial prescription. Gadolinium-DTPA (Magnevist; Schering AG, Berlin, Germany) was injected intravenously (0.3 mmol/kg) and allowed to circulate for 10 minutes to ensure adequate distribution. Next, the T1-weighted MRI was repeated to attain a postcontrast data set. Each slice was recorded with a matrix of 256 x 128 data points and a field of view of 5 x 5 cm. The data set was analyzed on an Apple Macintosh Performa 630 using the public domain NIH Image program.
The T1-weighted MR images had an unexpected gray-white matter contrast. In images recorded with the NMR machines that are now used in clinical settings, which are 1.5 Tesla or less, a contrast conversion of the white and gray matter is normally seen on T1-weighted versus T2-weighted images. In T1-weighted images the NMR signal of the white matter is hyperintense in comparison with that of the gray matter, whereas in T2-weighted images the white matter signal is hypointense compared with that of the gray matter. In both the T1- and T2-weighted images recorded on our 4.7-Tesla machine, white matter is hypointense as compared with gray matter, and lesions are visible as hyperintensities. This is not a unique feature of the marmoset brain, given that it was also observed in cat brains (unpublished observation). The most likely explanation for this discrepancy is that with the high magnetic field used, T1 values of gray and white matter converge, whereas T2 values are unaffected by the strength of the field. In our T1-weighted images, the intensities of white and gray matter are most likely determined by the longer T2 value of gray matter and the different proton densities of both tissues. This phenomenon did not affect the detection of gadolinium enhancement, because even long TR/short TE images ("proton-density" weighted) contrast enhancement can be observed.22
Histopathology Analysis
The brain and spinal cord of sacrificed monkeys were excised and fixed in toto for 3 days in 4% buffered formalin and subsequently stored at 4°C in phosphate-buffered saline, pH 7.4, containing sodium azide until analysis. In some experiments the fresh brain hemispheres were separated with a surgical blade, after which one hemisphere was fixed in buffered formalin and the other snap frozen in liquid nitrogen for immunohistological analysis. The analysis of the frozen brains has been published separately.23 Formalin-fixed brains were embedded in paraffin. For the exact localization of lesions that were MRI detectable in vivo, use was made of the postmortem images. Because high-contrast images were made in the coronal and axial directions using the same orientation parameters as for the in vivo images, this enabled an accurate three-dimensional positioning of each lesion. From this material, coronal sections with a thickness of 3 to 5 µm were cut.
The extent of inflammation, demyelination, and axonal pathology was evaluated on tissue sections stained for hematoxylin and eosin to visualize infiltrated cells, with Klüver Barrera stain (Luxol Fast Blue (LFB) combined with periodic acid-Schiff (PAS)) for staining myelin and myelin degradation products and with Bielschowsky silver impregnation for staining axons. Immunocytochemistry was performed with a biotin-avidin system as described earlier.24 T cells were stained with anti-human CD3 antibodies (Dakopatts, Glostrup, Denmark). Astrocytes were stained with polyclonal anti-glial fibrillary acidic protein (Dakopatts). Macrophages were detected by staining with the antibodies 27E10 and MRP14, which are both commercially available from BMA Biomedicals (Augst, Switzerland).25 Myelin and oligodendrocytes were stained with antibodies recognizing 2'-3'-cyclic nucleotide-3'-phosphodiesterase (CNP; Affinity Research, Nottingham, UK), proteolipid protein (PLP) and myelin oligodendrocyte glycoprotein (MOG) which were kindly provided by Dr. S. Piddlesden (University of Cardiff, UK). Immunoglobulin (Ig) depositions in the lesions were detected using biotinylated anti-(human) Ig (Amersham, Buckinghamshire, UK) as a primary antibody. Depositions of complement factor C9 were detected by a polyclonal antibody as described earlier.26
Lesional Staging
The maturation stage of a certain lesion was assessed using previously published criteria for the classification of MS lesions.27 In this classification scheme, lesions are staged as follows: 1) early active lesions, presence of LFB and MOG myelin degradation products in macrophages and/or the presence of macrophages stained for macrophage antigen MRP14; 2) late active lesions, presence of myelin degradation products LFB and PLP but not MOG in macrophages and/or the presence of macrophages stained for macrophage antigens by 27E10 but not MRP14; 3) inactive lesions, presence of PAS-positive myelin degradation products but without LFB, PLP, or MOG degradation products in macrophages; and 4) remyelinated lesions, presence of thin LFB-positive myelin.
Ethics
According to Dutch law on animal experimentation, the experimental procedures of this study have been reviewed and approved by the Institute's Animal Care and Use Committee.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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, the axons were completely disrupted,
suggesting that the lesions were formed by a destructive inflammatory
process rather than by selective demyelination. For these reasons we
chose to further investigate EAE induced without administration of
B. pertussis and using a reduced Mycobacterium
dose in the inoculum.
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The clinical course of EAE was monitored using semiquantitative
criteria (Figure 1a)
and body weight
measurement as a surrogate disease parameter (Figure 1b)
. All six
monkeys developed a protracted form of EAE, but substantial
interindividual variation of disease courses was observed. Monkey EH
experienced several relatively mild attacks, maximally reaching score
2.0 (ataxia), with episodes of complete remission in between. This
monkey went into remission in the 49th week and remained free of
clinical signs up to week 76, when it was sacrificed for pathological
examination. In the five other monkeys (EI, EJ, EK, EL, and GY),
disease episodes of higher severity alternated with episodes of
incomplete remission, as was particularly apparent from body weight
measurements (Figure 1b)
. In the advanced stages of EAE, clinical
remission in these monkeys was incomplete. Clinical signs progressed to
paraparesis (EI) and hemiplegia (EJ) or paraplegia (EK, EL, and GY).
Monkey EI was sacrificed after a long period of chronic ataxia, monkey
EJ with one paralyzed leg and monkeys GY, EK, and EL with both legs
paralyzed. Importantly, none of the monkeys in this experimental group
died spontaneously.
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In Vivo MRI
To visualize abnormalities in the brain white matter, T1- and
T2-weighted MR data sets were recorded during episodes of active EAE.
The first MR images were made of all monkeys in the 17th week after
immunization. At that stage, regions with hyperintense signal intensity
were found around the ventricles on T2-weighted images. Comparison with
the T1-weighted images at that stage with those recorded before EAE
induction, showed that the ventricles themselves were not enlarged.
This observation points to periventricular edema (not shown). MRI
recorded at later disease stages showed a number of circumscribed
hyperintense regions within white matter tracts such as the corpus
callosum, but also in cerebral gray matter ((Figure 2
, c and d.
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To assess the total lesion load in the brain, a T2-weighted data
set from all fixed brains was attained. These postmortem MR images were
compared with the data from in vivo MR images, which were
recorded 1 hour before the monkey was sacrificed. Because of the
absence of movement artifacts, the postmortem images showed very high
quality and contrast (Figure 2
, a and b). As reported previously, the
contrast in T2-weighted MR images of brain tissue before and after 6
weeks of fixation in buffered formalin is comparable.28,29
In accordance with this, all hyperintensities that were detectable
in vivo (Figure 2
, c and d), were found in the postmortem
images (Figure 2
, a and b). Using the combined data from MR images made
in the coronal (Figure 3
, a and b) and
axial (Figure 2
, a and b) directions, the exact localization of each
individual lesion in the fixed brain could be determined.
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Pathological investigation of animals with EAE induced without
usage of Bordetella revealed the presence of inflammatory
lesions with predilection sites in the cerebral white matter and spinal
cord (Table 1)
. Except for some perivascular lesions, the cerebellum
and medulla oblongata in these animals were practically devoid of
inflammation. The cerebral lesions contained lymphocytes and
macrophages, whereas accompanying granulocytes were sparsely found in
some infiltrates in the brain of animal EK. In general, the
demyelination in these animals led to the formation of large confluent
plaques, which were visualized by Klüver Barrera stain (Figure 3
, c to f) or immunocytochemical staining for the myelin proteins PLP
(Figures 4e and 5a)
, CNP, and MOG. The CNS of animals EH,
EJ, and EK also contained, in addition to the plaques, a large number
of small demyelinated perivascular lesions. Staining by Bielschowsky
impregnation revealed axonal reduction in active demyelinating plaques
which, because almost no spheroids were present, occurred because of
edema and the infiltration of large numbers of inflammatory cells
(Figures 4h and 5e)
. In most older inactive plaques, axons were very
well preserved. In a small minority of plaques, however, a highly
reduced axonal density was seen (Table 2)
.
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and LFB- and
PAS-positive degradation products in phagocytic macrophages, as well as
on astrocytic scar formation, we concluded that in all animals, active
as well as inactive lesions were present (Tables 1 and 2)
. In addition
to the standard histopathology, a fine characterization of each lesion
was made by analyzing the presence of certain macrophage subpopulations
by staining with the antibodies 27E10 and MRP14 and for intracellular
presence of MOG and PLP protein degradation products. Inactive
demyelinated lesions, showing absence of LFB-positive material (Figure 5d)
and only a moderate amount of PAS-positive myelin breakdown
products in macrophages, also lacked staining with the macrophage
markers 27E10 and MRP14. The macrophages in these lesions did not
contain detectable amounts of MOG and PLP. In contrast, active lesions
contained many macrophages that stained positively with the antibody
27E10 (Figure 4
, a and b) and contained LFB-positive material.
Macrophages expressing MRP14 (Figure 4d)
and containing the myelin
degradation product MOG (Figure 4g)
were found only in some of the
active lesions. The MOG and PLP staining showed that all KLB- and
27E10-positive lesions contained macrophages with intracellular
inclusions of PLP-positive degradation products (Figure 4f)
.
Because Ig- and complement-mediated mechanisms are involved in myelin
degradation in rodent EAE models, and possibly also in
MS,25,30
we have investigated the presence of Ig and
complement factor C9 in demyelinated lesions. Ig deposition was found
in a variety of lesions ranging from inactive to active. In some of the
early active lesions, such as lesions D and I of animal EI, punctate Ig
deposition was found on myelin sheaths, pointing to active myelin
destruction (Figure 4i)
. Although Ig molecules were
present in both active and inactive lesions, complement factor C9 could
only be demonstrated in the (early active) lesions in a similar
distribution as that of the punctate Ig deposition described above
(Figure 4j)
.
Besides active and inactive demyelinated lesions, remyelinated plaques
were also found (Figure 5)
. Remyelinated lesions, or shadow plaques due
to the presence of very thin LFB-positive myelin sheaths (Figure 3e and 5c)
, showed strong staining of myelin and oligodendrocytes by
immunocytochemistry for CNP (Figure 5h)
. Remyelinating activity was
found not only in inactive lesions, but also in early and late actively
demyelinating lesions. In situ hybridization for PLP mRNA
revealed that areas of active remyelination contained high numbers of
oligodendrocytes that expressed PLP mRNA in their cytoplasm (Figure 5
,
a, b, f, and g).
MRI-Pathology Correlation
High-contrast T2-weighted MR images of fixed brains were recorded using the same parameters for slice orientation as used for in vivo MRI. The postmortem images were used to study the possible MRI-pathology correlation of lesions.
In animals EI and GY, virtually all confluent lesions that could be
detected by histopathology were also visible in the postmortem
T2-weighted MRI. However, no clearly diverse T2 signal intensities
could be detected between lesions with different histopathological
aspects (Figure 3
and Table 3
). We
are currently planning quantitative T2 measurements to investigate this
issue in more detail. In animals EH, EJ, and EK, the correlation
between pathology and MRI was more difficult. Many of the very small
perivascular or periventricular lesions could not be retrieved in the
corresponding MRI. Moreover, the majority of the small hyperintense
regions in the T2-weighted MR images, eg, those in the corpus callosum
of animal EK, were not found at the same place by pathological
investigation. However, the total number of lesions that were found
with pathology and MRI in the corresponding areas was similar (Table 4)
. This suggests that the discrepancy in
correlation of pathology and MRI has a technical reason, such as small
differences in the plane of sectioning, rather than that these lesions
differ in T2 characteristics from larger "pathological" lesions
that could be traced easily in MRI. Little is known on the MRI
appearance of remyelinated lesions. Our present data show that, as
predicted by Barkhof,31
the shadow plaque K (Figures 3c and 5f)
appears as a hyperintense region in T2-weighted MRI (Figure 3a)
.
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. A false negative score may occur when the amount
of extravasated gadolinium is too low to cause a detectable change of
the T1-weighted NMR signal intensity (partial volume effect). This may
take place when extravasation occurs only in peripheral parts of a
lesion. Hence, lesions that were peripheral parts of a
gadolinium-enhancing lesion were analyzed as a separate group within
the pathologically defined demyelinating lesions (Table 3)
. With this
precaution in mind, all gadolinium-positive lesions could be classified
as early demyelinating lesions, containing high numbers of MOG-positive
macrophages (Tables 3 and 5)
.
Gadolinium-negative lesions that are closely associated with
gadolinium-positive lesions were shown to be early active lesions too.
However, gadolinium-negative lesions that were not associated with
gadolinium-positive lesions contained PLP-positive or 27E10-positive
macrophages, but MOG- or MRP14-positive macrophages were absent, and
these were, therefore, classified as late active (Tables 3 and 5)
. None
of the pathologically defined inactive lesions
(n = 58) displayed gadolinium enhancement of the
T1-weighted NMR signal intensity (Table 5)
.
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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The current histopathological characterization of demyelinating activity in lesions is based on the presence of material positive for LFB, PAS, or Oil Red O (for neutral lipids) in phagocytic macrophages. However, especially PAS and Oil Red O positivity in macrophages can be found for more than 6 months after a new demyelinating lesion has developed, which implies that the presence of PAS- and Oil Red O-positive material may not always reflect ongoing demyelination.25 Recent studies have shown that the presence of myelin protein breakdown products, such as MOG, myelin basic protein, or PLP, in macrophages gives a more accurate characterization of the stage of demyelinating lesions.27,32 Early stages of demyelination can also be distinguished by the expression of the macrophage activation markers MRP14 or 27E10.27 By combination of the classical and the new markers, a stringent stage characterization of demyelinating lesions can be made. By using these criteria for lesional staging, we were able to demonstrate that essentially all types of lesions present in MS brain (perivascular, paraventricular, active, and inactive demyelinating and remyelinating) are also present in EAE-affected marmoset brains. We conclude therefore that in the present model the main characteristics of MS pathology can be found. The fact that the same set of markers can be used for the pathological characterization of the lesions in the CNS of MS patients as in the marmoset model is of great value for extrapolation of experimental and patient data.
This report documents the correlation of radiological (MRI) and histopathological characteristics of the CNS white matter lesions in the marmoset EAE model. Normal brain tissue is highly organized, determining the typical MR relaxation times. The standard T2-weighted sequences are very sensitive to structure disturbances representing all stages of lesion formation as hyperintense regions. Therefore, in human brain, T2-weighted MR images are very suitable for assessing the spatial lesion distribution, but because of the inherent low specificity the images provide only little information on the nature of lesions.29 Our data show that the shape and localization of the MRI-detectable lesions in the brain of marmosets developing EAE resembles the situation in the CNS of MS patients. In accordance with data from others, the T2-weighted MR images made of formalin-fixed brains do not essentially differ from the T2-weighted images made in vivo.28,31 We have used high-contrast postmortem MRI for exact three-dimensional localization of lesions of interest for further characterization with histology. In the pathology and MRI analysis of marmoset brains, similar numbers of lesions were counted, indicating that, as in humans, T2-weighted MRI can be used to determine the total lesion load.
Extravasation of intravenously injected gadolinium is a radiological criterion for active lesions that can be seen as focal enhancement of T1-weighted signal intensity. By using a whole set of histopathological parameters, we were able to demonstrate 1) that all early active lesions display gadolinium enhancement in T1-weighted MRI and 2) that, with the exception of one lesion (K), all nonenhancing lesions could be characterized as inactive or late active lesions. A discrepancy exists in a subgroup of pathologically defined active lesions, which are located very close to gadolinium-enhancing lesions in adjacent scans, but which displayed no detectable extravasation of gadolinium. The discrepancy between the histological and radiological markers for BBB leakage may have a technical reason, ie, that gadolinium extravasation in only a small part of a lesion may yield an insufficient concentration of the paramagnetic molecule to exert a visible effect on the T1-weighted NMR signal intensity of the whole lesion (partial volume effect). Another explanation for the detection of albumin and the absence of gadolinium is that leakage of molecules such as albumin and Igs from serum to the brain is a continuous phenomenon, whereas gadolinium-DTPA is given in a single injection and therefore may reach concentrations too low to detect in the late active lesions.
As indicated in Table 5
, many lesions appear as hyperintensities in our
in vivo T1-weighted images. Given the virtual lack of axon
pathology, structures such as "black holes" could not be expected.
Moreover, no apparent correlation with certain stages of lesion
differentiation could be found. We have no explanation for the observed
phenomenon, and comparable to the different T1 values of gray and white
matter (see Slice Orientation and Scanning Procedure, in Materials and
Methods), we like to attribute it to the high magnetic field.
Experiments are now in preparation to quantitate NMR signal intensities
of individual lesions to correlate these data with quantitative
immunohistochemical criteria of demyelination, remyelination, and
axonal loss. We are also investigating whether administration of a
higher Gadolinium dosage than the currently used triple dose may
increase the numbers of detectable lesions with BBB leakage or
demyelinating activity.
In summary, the new marmoset EAE model is a valid experimental model for human MS in which lesion formation can be investigated with MRI and pathology. In view of the central role of autoimmune factors in the etiopathogenesis of MS, the high similarity of the human and marmoset immune systems is of great importance. In this respect, a high degree of homology in the genes encoding for T-cell receptor subunits15 and major histocompatibility complex molecules (Ref. 16 and S.G. Antunes et al, submitted), as well as significant immunological cross-reactivity of lymphocyte surface markers and cytokines, have been documented.11-13,23 These collective data make this model a unique tool for basic research in MS and EAE and for preclinical evaluation of new therapies for MS.
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Acknowledgements |
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Footnotes |
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Supported by the European Union (EU) Human Capital and Mobility program (ERBCHGECT 940071, "Nonhuman Primates as Models for Human Biology and Disease"), by the EU Concerted Action on T-Cell Autoimmunity in Multiple Sclerosis, by the Dutch MS Foundation (Stichting Vrienden MS Research; grant 95-221MS), by an EU grant for the Scheikundig Onderloeu in Nederland-NMR Large-Scale Facility for Biomolecular NMR, and by the EU shared-cost project "CD40 Immunotherapy in Marmosets" (contract BMH4-CT.97-2131).
Bert A. 't Hart and Jan Bauer contributed equally to this study.
Accepted for publication May 2, 1998.
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S. M. Kerfoot, E. M. Long, M. J. Hickey, G. Andonegui, B. M. Lapointe, R. C. O. Zanardo, C. Bonder, W. G. James, S. M. Robbins, and P. Kubes TLR4 Contributes to Disease-Inducing Mechanisms Resulting in Central Nervous System Autoimmune Disease J. Immunol., December 1, 2004; 173(11): 7070 - 7077. [Abstract] [Full Text] [PDF]
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H. P. M. Brok, M. van Meurs, E. Blezer, A. Schantz, D. Peritt, G. Treacy, J. D. Laman, J. Bauer, and B. A. 't Hart Prevention of Experimental Autoimmune Encephalomyelitis in Common Marmosets Using an Anti-IL-12p40 Monoclonal Antibody J. Immunol., December 1, 2002; 169(11): 6554 - 6563. [Abstract] [Full Text] [PDF]
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A. F. de Vos, M. van Meurs, H. P. Brok, L. A. Boven, R. Q. Hintzen, P. van der Valk, R. Ravid, S. Rensing, L. Boon, B. A. 't Hart, et al. Transfer of Central Nervous System Autoantigens and Presentation in Secondary Lymphoid Organs J. Immunol., November 15, 2002; 169(10): 5415 - 5423. [Abstract] [Full Text] [PDF]
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J W Pan, P K Coyle, K Bashir, J N Whitaker, L B Krupp, and H P Hetherington Metabolic differences between multiple sclerosis subtypes measured by quantitative MR spectroscopy Multiple Sclerosis, June 1, 2002; 8(3): 200 - 206. [Abstract] [PDF]
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F. Barkhof, J.-H. T. M. van Waesberghe, M. Filippi, T. Yousry, D. H. Miller, D. Hahn, A. J. Thompson, L. Kappos, P. Brex, C. Pozzilli, et al. T1 hypointense lesions in secondary progressive multiple sclerosis: effect of interferon beta-1b treatment Brain, July 1, 2001; 124(7): 1396 - 1402. [Abstract] [Full Text] [PDF]
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H. I. McFarland, A. A. Lobito, M. M. Johnson, G. R. Palardy, C. S. K. Yee, E. K. Jordan, J. A. Frank, N. Tresser, C. P. Genain, J. P. Mueller, et al. Effective Antigen-Specific Immunotherapy in the Marmoset Model of Multiple Sclerosis J. Immunol., February 1, 2001; 166(3): 2116 - 2121. [Abstract] [Full Text] [PDF]
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