Download GROWTH MEDIA OCULAR INFECTION

BASIC IMMUNE
FUNCTIONS
• CELL MEMORY-IMMEDIATLY
RECOGNIZE INVADERS ON
SECOND EXPOSURE
• CELL SPECIFICITY- ANTIGENS
• RECOGNITION OF SELF-DETECTS
SELF FROM NONSELF
GENETIC BASIS OF
IMMUNOLOGY
• HUMAN LEUKOCYTE ANTIGEN
– DETERMINES SELF FROM NONSELF
– HLA A,B,C FOUND ON ALL
NUCLEATED CELLS
– HLA D FOUND ONLY ON
LYMPHOCYTES
MAJOR
HISTOCOMPATIBILITY
COMPLEX
• GENETIC REGION THAT
CONTROLS HLA EXPRESSION
• CLASS I GENES A,B,C
– IMMUNOSURVEILLANCE
• CLASS II GENES D
– IMMUNE REGULATION
• CLASS III GENES C2,C4,B
– COMPLEMENTREGULATION
MACROPHAGES
• INDUCTION OF T LYMPHOCYTES
• SITE OF IMMUNE GENE CONTROL
• AUGMENTS KILLING AND
PHAGOCYTOSIS
• SECRETES A VARIETY OF
CYTOKINES
T-LYMPHOCYTES
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T-HELPER (T4)
CYTOTOXIC T CELL
SUPPRESSOR T CELL (T8)
DELAYED SENSITIVITY T
B-LYMPHOCYTES
• PRECURSOR TO PLASMA CELLS
• SOURCE OF IMMUNOGLOBULINS
– ANTIBODIES
• TYPICALLY REQUIRE T CELL
INDUCTION
• MAY PRODUCE MULTIPLE
ANTIBODIES
IMMUNOGLOBULINS
• IgA
– PRINCIPLE OCULAR SURFACE
ANTIBODY
– IMMUNOLOGIC PAINT
– SECRETORY PROTECTS FROM LYTIC
ENZYMES
• IgD
– POORLY UNDERSTOOD
– MAY REACT EARLIER THAN IgM
IMMUNOGLOBULINS
• IgM
– PRIMARY ANTIBODY DURING FIRST
EXPOSURE
– IMPORTANT IN RETINAL/CHOROIDAL
• IgG
– PRIMARY ANTIBODY IN SECOND
EXPOSURE
• IgE
– MEDIATOR OF ALLERGY
OTHER IMMUNE CELLS
• K CELLS
– NON T NON B LYMPHOCYTES
– DIRECT CELL DESTRUCTION
• NK CELLS
– LARGE GRANULAR LYMPHOCYTE
– ADCC
– TUMORS, PARASITES
IMMUNE CELLS
• POLYMORPHONUCLEAR
LEUKOCYTES(PMN’S, POLYS,
NEUTRAPHILS)
– PRIMARY PHAGOCYTIC CELL
– ENZYMATIC
DESTRUCTION(MYELOPEROXIDASE,
PEROXIDASE, SUPEROXIDE
• LANGERHAN CELL
– NONMACROPHAGE ANTIGEN
PRESENTOR
IMMUNE CELLS
• BASOPHILS/MAST CELLS
– MEDIATORS OF ALLERGIC REACTION
– GRANULATION PRODUCTS
• EOSINOPHILS
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PHAGOCYTIZE IgE COMPLEXES
PROTEINS(MBP)
ENZYMES
SLOWS ALLERGIC RESPONSE
COMPLEMENT
• ACTIVATED BY ANTIBODY
• ACTIVATED BY BACTERIAL
ENDOTOXIN
• +ANTIBODY FOR CELL LYSIS
• ACTIVATES CLOTTING
• ACTIVATES PHAGOCYTIC CELLS
• +PHAGOCYTIC CELLS FOR LYSIS
• CELL LYSIS
Autoimmune Disease
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Type I Acute Allergic Conjunctivitis
Type II Stevens-Johnson
Type III Arteritis, Marginal Ulcers
Type IV GPC
Ocular Immunology
• The Eye Composed of Three Immune
Systems
• Eyelids-similar responses to skin
• Conjunctiva- mucosal system similar to
gut, nasopharynx
• Internal structures-Immune Privilege
Eyelids
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Lid responses are identical to skin
Primarily a cellular response
Activated T-cells (Th1)
Marked swelling, redness
Example: Hordeolum
Conjunctiva
• Conjunctiva Associated
LymphaticTissue(CALT/MALT)
• APC ‘s to nearest lymph node
• T-cell proliferation via CD2
pathway(Th2)
• Elicit plasma cell production
• Example Viral Conjunctivitis
Immunological Components
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Lymphocytes, Plasma cells, PMN’s
IgG, IgM, IgA
Langerhans, Macrophages
No Mast cells, No Eosinophils
Few if any cells in the central cornea
More at limbus and conjunctiva
Tears
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IgG , IgM, SIgA, IgA
Il’s 1(Th-1), 1B(Th-1), 4(Th-2), 8(Th-2)
TGF(cell growth)
TNF(nuclear factor–B signal
transduction pathway)
• Endothelin(vasoconstrictor) ,
fibronectin(wound healing cell adhesion)
• GM-CSF
S-IgA
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Produced by lacrimal gland
Influenced by tear flow rate
>Flow <S IgA
At night <flow > S IgA
>S IgA > PMN
Protects against overnight infection with
closed eye
S-IgA
• Hormonal Control
– Androgens reduce production
– Insulin required for SC component
production
• Neural Control
– Sympathetic and Parasympathetic pathways
Immune Privilege
• To some extent in cornea
• All internal structures
Immune Privilege
• Extreme form of regional immunity
– Internal structures are recognized as foreign by conj
and lids
• Occurs within brain, eye, reproductive organs,
fetoplacental tissues
• anterior chamber, subretinal space, retinal
pigment epithelium, vitreous cavity
• Immune response is minimal
IMMUNE PRIVILEGE
WHY?
• Is it the Anatomy? No lymphatics
• A/C Macrophages present to spleen as normal
• Differences 1)high level of transforming
growth factor beta(downregulator) 2) don’t
produce IL-12 3) don’t express CD40
• But systemic immune response do develop
WHY DO WE NEED
IMMUNE PRIVILEGE?
• Preserve sight
• Immune Responses are Th1 or Th2
mediated
• Th1 primarily cellular with a great deal
of adjacent tissue damage
• Th2 primarily humoral less collateral
tissue damage
IMMUNE PRIVILEGE
How Does it Work?
• Blood Ocular Barrier-difficult for blood
born mediators to enter the eye; iris
ciliary body, retina, RPE/choriocapillaris
• Drainage through venous system force to
spleen- humoral responses
• APC’s are unique
Reasons for low immunity
• Class I and II MHC are poorly expressed
on ocular tissue --antigen is presented to
T cells with MHC
• Activated T-Cells express FAS effectively kills other T cells by apoptosis
• Complement is downregulated by CD59,
CD46, MCP(membrane co-factor
protein) all expressed on ocular tissue
Cornea
• No lymphatic, No
vascular supply,
perilimbal
• FAS ligand active
• Examples ulcer
central and
peripheral
• Variety of Cytokines
present
• IL-1, IL-6, IL-8, IL10, MAPK(mitogen
activated protein
kinase)
• IL-1 most important
• Overstimulation of
Il-1 in Corneal melt
• IL-10 important in
clearing herpes
Wound Healing
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Matrix Metalloproteinase(MMP)
Extracellular protein
 MMP > Cancer and Emphysema
Tissue Inhibitor of MMP(TIMP)
Wound Il-1 with  MMP
MMP “resurfaces” wound
Excessive MMP chronic
ulcer/neovascularization
Dry Eye
• 37% of US population have dry eye
symptoms
• Two main types evaporative and
• Starts with hyper-osmolarity
• Il-1 TNF are upregulated
• Proinflammatory on the ocular surface
are up regulated
• Recruit other proinflammatory T cells
secreted through the lacrimal gland
Evaporative
Tear Secretion (Collagen and Inflammatory)
Hyperosmolality
TNF-α
Upregulation of MAPK and NF-kB
IL-1
TNF-α
IL-8
MMP’s
INF-γ
↓Goblet cells
Dendritic Cells recruited
Fas Inactivated
Corneal &
Conjunctival
Cell Death
APC to Lymph Nodes
T cells to ocular surface-chronic inflammation
Anterior Chamber
• 50% of acute anterior uveitis is HLA B-27 associated
• May be associated with systemic inflammatory disease
– Spondyloarthropathies
– Sarcoid
• Most knowledge is from animal models not hman
• NK cells don’t work (tumors)
• TGF-B
• MIF(migration inhibitory factory)
• ACAID (anterior chamber associated immune
deviation)
• Immune reactions that do develop, develop slowly
Table 2
The role of cytokines in experimental autoimmune uveitis
Cytokine Effect
IL-1 Cytokine involved in breakdown of the retinal–blood barrier and an enhancer of inflammation [8,9]
IL-2 Cytokine involved in activation of uveitogenic cells and its blockade can ameliorate uveitis [10,11]
IL-3 Cytokine important in the development of experimental autoimmune encephalomyelitis (EAE) and
possibly EAU [13]
IL-4/IL-13 Associated with a change in the cytokine profile of cells infiltrating the eye and regulatory
mechanisms [14]
IL-5 Marker of a Th2 response and associated with amelioration of the symptoms [17–24].
IL-6 Associated with a deviant immune response in CCR5-deficient mice [26,27]
IL-7 Breakdown of the retinal-blood barrier and an enhancer of inflammation. This cytokine has been
reported to be important in the development of IRBP-specific CD8+ T cells [8,31]
IL-8 This cytokine is thought to be the principal chemokine responsible for tissue infiltration in patients with
Behcet’s disease [28,29]
IL-10 Cytokine associated with decreased immune responses [14–16]
IL-12/23/27 Cytokine which plays an essential role in the development of EAU [30]
IL-15 Cytokine important in the development of IRBP-specific CD8+ cells [31]
IL-17 Proinflammatory cytokine important for the development of EAE [34]
IL-18 Cytokine not required for the development of EAU in normal mice, but associated with disease in
certain transgenic strains [33]
IL-27 Suppression of development of Th17 cells in EAE [36]
IFN-g Associated with autoimmune uveitis and used as a marker of disease development and severity
[15,25,37]
TNF-a Marker of inflammation and tissue damage in normal animals [40]
TGF-b Linked to a decreased inflammatory response in EAU [45]
a-MSH Neuropeptide involved in immune privilege in the eye which has been reported to have an effector
role in decreasing inflammation during EAU [47].
Immune Therapy
• Steroids
• Infliximab, Entanercept, Adalimumab –
antibodies against TNF-α
• Daclizumab anti-CD25 receptor antibody
on T-cells
• Inteferon-α 2a (pegylated interferon)antiviral activity used in HIV and
Hepatitis C, Behcet’s/toxicity
RETINA
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Mueller Cells play key role in immune privilege
Lack MHC II genes
Don’t express IL-1
T-cells enter retina –APC’s on vascular
endothelial Class II recruit inflammatory cells
then downrgulated
• FAS or TNF-alpha downregulation
• Opens door for transplants
Retina and MMP’s
• MMP’s found in retina, vitreous, RPE
•  TIMP and  MMP-1,MMP-2,
– MMM-9 in Diabetic Retinopathy
• Sorsby’s Dystrophy  TIMP
• **Clinical Trials underway with MMP
– Inhibitors**
Normal Retina
Toxoplasmosis/Inflammation
Macular Degeneration
Interferon retinopathy
Macular Degeneration
• Two forms wet and dry
• Dry 80%
• Wet most of the blindness
Early Steps in ARMD
Drusen
• Central core of
glycoproteins
• Surround of
crystallins,
chaperone
proteins, APOE,
amyloid, and
complement 5-9
Dendritic cell
melanosome
s
lysosomes
Phagosomes with
absorbed outer segments
Nucleus
drusen
Bruch’s membrane
Choriocapillaris
Giant cell
Lysosomes cant handle all the accumulated waste, results in low
grade inflammatory response, lipid built up within Bruch’s
Drusen
Intact Bruch’s
membrane and
fenestrated
choriocapillaris
Physiological VEGF-secretion and
signaling
Senescence
Oxidative damage
Cellular dysfunction
Free radicals
Sub-RPE deposits
Complement
Atrophy of the RPE
Macrophage infiltration
Reduced VEGF signaling
Atrophy of the choriocapillaris
Progressive cell death
Inflammation
Degrades Bruch’s membrane
Enables increases in VEGF signalling
Vascularization
Macular degeneration
Retina and VEGF
• VEGF increases angiogenesis
• PEDF(pigment epithelium derived
factor) antiangiogenesis factor
• Chronic inflammation
• Released factors up regulate VEGF leads
to choroidal neovascularization
Complement Factor H
• Complement factor H is a protein that cleaves C3b into
an inactive form CB3i
• It weakens the complex that forms between C3b and
Factor B (proinflammatory)
• A mutation in the gene responsible for Complement
Factor H production may be associated with 50% of all
wet ARMD
• Smoking and increased C-Reactive protein levels
increase the risk in those with the mutation
• 90% of those with the altered gene develop ARMD by
age 90
Treatment of Macular
degeneration
• Verteporfin(Visudyne)
– Binds to neovascular endothelium, light activates
releases leukotrienes and thromboxanes which
induce clotting
• Macugen(Pengaptanib)
– Vascular endothelial growth factor inhibitor, done
by intravitreal injection about evry six weeks
• Anecortave acetate(Retaane)
– Antiangiogenic steroid, the steroid properties of
raising pressure and cataract formation have been
engineered out, given as a peribulbar injection
• Ranibizumab(Lucentis) –anti VEGF-A
• Bevacizumab (Avastin) anti-VEGF,
developed for colon cancer used for
ARMD and diabetes and corneal neo
• Squalamine lactate( Evizon)- endothelial
cell migration and proliferation
Hyperglycemia, AGEs
Hypoxia
GPCRs (chemokines)
RTKs (HGF, IGF, VEGF)
Cytokine receptors
NOX2
Glucose
p22
p47
NOS3
Rac-1
Sorbitol
AR
PKC
NADP-H
oxidase
ROS
RNS
RAGE
Mitochondrial Oxidase
Modulation of redox-dependent
Transcriptional and post transcriptional
events
VEGF