Presentation mastic gravity

1. Neuroimmunology and Inflammation
Tom Lane, Ph.D.
University of California, Irvine
1) Immunology overview
2) Multiple sclerosis (MS) - neuroinflammatory
demyelinating disease in humans
3) Models of MS
• EAE - autoimmune model
• TMEV
• MHV
Viral models

2. Figure 1-11

3. Figure 6-9

4. Figure 6-20

5. Figure 6-26

6. Figure 8-46

7. Figure 8-47

8. Multiple Sclerosis:
epidemiology
• Affects 350,000 in US
• 70% Women
• Onset 30 years of age

9. Myelin sheath
Oligodendrocyte
Neuron
Axon
Axon
Myelin
sheath
Axoplasm
Node
of
Ranvier
Adapted from Snell R.S. Clinical Neuroanatomy 3rd edition 2001. Lippincott Williams & Wilkins.

10. Normal myelinated
axons

11. Types of disease progression
Relapsing-remitting MS
Secondary progressive
MS
< 5
%
Adapted from Waubant L.E. et al. Pathophysiology of Multiple Scerosis Lesions. Science and Medicine 1997 ; 4 (6): 32-41.
Noseworthy J.H. et al. Medical Progress: Multiple Sclerosis N Engl J Med 2000; 343: 938-52.
10 %
Primary progressive
MS
Progressive relapsing
MS

12. MS pathogenesis:
Complex disease process
in which many potential
interrelated mechanisms
contribute to myelin
damage/destruction

14. Active lesion - histology
(human and mouse)

15. Multiple sclerosis - early medical view
‘There is no known means of combating the [underlying] disease [of MS] nor
inducing a remission. There is therefore no justification whatsoever for subjectin
patients to expensive and often unpleasant forms of therapy. It is better that the
should husband their financial resources against the days of disablement which
ahead. A placebo may be given as a vehicle of hope.’
F. Elliot et al., Clinical Neurology, 1952

16. Frohman et al., NEJM, 2006

17. Animal models have provided important insight into underlying
molecular, cellular, and immunopathological mechanisms that ma
be important in immune-mediated demyelinating diseases e.g. M

18. Experimental autoimmune encephalomyelitis (EAE)
• Autoimmune model of MS
• Autoreactive T cells (both CD4+ and CD8+) are thought
to be important in driving disease
• Other cells/factors also considered important

19. EAE and development of MS treatments
Similarities between EAE and MS
Characteristic EAE MS
Genetic susceptibility Strong association with MHC II Strong association with MHC II
Females more susceptible in certain strains Females more susceptible
Environmental triggers Relapses with earlier infection; superantigens trigger relapses Association with earlier infection
White matter pathology Th1 T cells, B cells, CD4 and CD8 T cells, B cells Th1 T cells, B cells, CD4 and
and antibodies to myelin in lesions CD8 T cells, B cells and antibodies to
myelin in lesions
Clonal CD4 and CD8 T cells reactive to myelin components Clonal CD4 and CD8 T cells reactive to
Macrophages Macrophages
Microglia Microglia
a4b1 integrin a4b1 integrin
Complement Complement
Grey matter pathology Axonal degeneration Axonal degeneration
Clinical presentation Optic neuritis, myelitis, periventricular Optic neuritis, myelitis, periventricular
white matter inflammation white matter inflammation
Clinical forms Relapsing remitting Relapsing remitting
Progressive Progressive

20. Potential mechanisms by which EAE occurs

21. Therapeutic Prevents EAE Reverses ongoing EAE Efficacy in MS
Glatiramer acetate Yes (used with adjuvants) Not tested, in approval package Approved for relapsing remitting MS
IFN-b Yes Yes Approved for relapsing remitting MS,
APL to MBP Yes Yes Phase 2b; reduced magnetic resonance a
Native peptide for MBP Yes Yes Reduces anti-MBP antibody levels in spi
Anti-a4b1 integrin,
Natalizumab Yes Yes Approved but withdrawn after cases of P
Statins Yes Yes Early clinical trial
Quinolines Yes Yes Quinoline carboxamide reduced MR acti
Tolerizing DNA vaccine Yes Yes Phase 1–2 trial in progress
Prevention and reversal of EAE predicts clinical success in some c
…. but not always, why?
1) Drug delivery - need to find drugs that can penetrate into CNS
2) Use of knock-out mice to study autoimmunity
3) Reliance on models of EAE driven by CD4+ T cells
Notable failures:
Blocking TNF-a signaling
Treatment with recombinant IFN-g Both led to increased clinical/histologic disease

22. Evidence for an Infectious Etiology of Multiple
Sclerosis
• Only a 25-35% concordance of disease in identical twins – implies
an overlying environmental effect
• Post-World War II epidemics of MS – Iceland, and the Faroe,
Orkney and Shetland Islands
• Migration studies – indicate high and low risk areas for MS
• Purported association of MS with various infectious agents over
the last 40 years – supported by epidemiologic and twin studies

24. Infectious Agent and Autoimmune Disease
Induction
Infectious Agent Trigger – virus infection strongly implicated by epidemiological
studies as a trigger of T cell-mediated autoimmune disease, particularly in MS
– Infectious Agent Encoded Superantigen – leads to the activation of a wide range of T cell
specificities including anti-self directed responses
– Direct or indirect release of self epitopes – leading to activation of autoreactive T and/or B
cells
• Direct – infectious agent-induced necrotic or apoptotic tissue destruction
• Indirect – bystander tissue destruction by tissue-localized, infectious agent-specific
immune response leading to release of self antigens (Epitope Spreading)
– Molecular Mimicry – activation of autoreactive T and/or B cells by immunologic cross-
reactivity between an infectious agent-encoded epitope and an epitope on a self protein

25. Immune-Mediated Demyelination in SJL Mice Infected
with Wildtype TMEV is a CD4+ Th1 Disease
2 4 6 8 10 12 14
TMEV
0
Weeks Post Infection
Relative
Disease
Severity
i.c.
C57BL/6
SJL
Hi DTH
Hi IgG2a
Hi IFN-g, IL-2
Low CTL Response
Low DTH
Hi IgG1
Low IFN-g, IL-2
Potent CTL Response
Rapid Virus Clearance
Persistent CNS virus - Mf, MG
• Picornavirus – single strand,
+ sense RNA
• Natural endemic disease of mice
• Susceptibility associated with
virus persistence in CNS
microglia/Mfs; resistance
with virus clearance
SJL.b2M-/
(lack CD8+ T)
• CD4+ T cell-mediated
pathology
CD8
Th1

26. Clinical Symptoms in an SJL Mouse with TMEV-
Induced Demyelinating Disease (80 d PI)
Grading Scale
1 – waddling gait
2 – severe waddling gait
3 – impaired righting reflex
4 – spastic hind limb paralysis

27. Demyelinating Histopathology of TMEV-Induced
Demyelinating Disease – 80 Days PI

28. Myelin-Specific CD4+ Autoreactive T Cells are Activated
During Chronic Stages of TMEV-IDD
DAYS POST-INFECTION
CLINICAL
SEVERITY
DISEASE
20 40 100
80 120 140
TMEV
i.c.
a TMEV
a PLP139-151
a TMEV
60
a TMEV
ONSET
LATE
CHRONIC
EARLY
CHRONIC
•Autoimmunity in chronic TMEV-IDD is induced by epitope spreading
– there is no apparent mimicry between TMEV and myelin epitopes
•Late phase autoimmune response has pathologic consequences
as myelin-specific tolerance ameliorates disease progression
Hi Dose i.v. tolerance using
MP-4 (MBP-PLP fusion protein)
containing 6 encephalitogenic epitopes
a PLP139-151
aPLP56-70
aPLP178-191
aMOG92-106
aMBP84-104

29. Viral Peptide
Self-Tissue
Destruction
Self-Tissue
Peptides
Persistent
Viral Infection
Epitope Spread from
viral to self-peptides
1
2
3
4
5
6
Self-Tissue
Destruction
Self-Tissue
Peptide Mimic
Inflammatory
Cytokines
1
2
3
4
vTh1
Virus
Particles
Mf
APC APC
vTh1
Th1
Mf
Mf
Inflammatory
Cytokines
Potential Mechanisms of Infection-Induced
Autoimmune Disease
Viral peptide
Self-peptide 1
Self-peptide 2
Molecular Mimicry Epitope Spreading
Self-peptide Mimic

30. • Mouse hepatitis virus enveloped, (+) strand RNA virus; 32 kb genome; replicates in
cytoplasm of host cell
• Neuroadapted strains cause an acute encephalomyelitis which may lead to chronic
demyelination
• Clinical: mice develop abnormal gait and hindlimb paralysis
• Histology: viral persistence in CNS, mononuclear cell infiltration and myelin
destruction
• MHV-induced demyelination used as model for human demyelinating disease
Multiple Sclerosis
M Protein (M133-14
CD4+ T cell
S Protein (S510-518
CD8+ T cell
N Protein
RNA Genome
MHV - inject i.c.
Evaluate host defense/
disease
MHV infection as model for immune-mediated demyelination