Chigbu: Immuno of Conj Flashcards
Does the conjunctiva epithelium contain more CD8 or CD4 T-cells?
CD8 T-cells
This effect aids in clearing away antigens, dust and cell debris found on the ocular surface.
Mechanical Washing Effect
What are the 3 proteins found in the tight junctions of the epithelial cells?
- Occludins
- Claudins
- JAMs
Antigens that are left behind after blinking are subject to what types of AMPs found in mucin?
- Lysozymes
- Lactoferrin
- Defensins
These receptors provide an external alarm system by detecting non-cells on the epithelial surface.
Pattern Recognition Receptors
TLRs are a type of PRR found on the conjunctiva and corneal epithelial layer which detect _____.
PAMPs
Lipopolysaccharide (LPS) is a PAMP of ____?
gram (-) bacteria
Peptidoglycan (PGN) is a PAMP of _____?
gram (+) bacteria
What TLR is responsible for LPS?
TLR 4
What TLR is responsible for PGN?
TLR 1 and 2
What TLR is responsible for Viral RNA and Bacterial DNA?
TLR 3 and 8
What TLR is responsible for Flagellin (pseudomonas)?
TLR 6
When PRR/TLRs engage w/ PAMPs, an immune response is initiated w/ the use of?
- AMPs
- Cytokines: IL-1, IL-6, TNF-a, IFN-y
- Chemokines
The conj lamina propria (2nd layer) consist of what 4 cells that form the basis of CALT?
- lymphocytes: t/b cells, NK
- Macrophages
- Mast Cells
- DCs
Plasma cells account for ___ of conjunctival lymphocyte and secrete ___?
20%
IgA
This immunoglobulin neutralizes infectious without causing inflammation bc it cannot activate complements.
IgA
Does the lamina propria contain more CD8 or CD4 T-cells?
Neither.
It contains equal numbers of both
What are the 3 cells that are conjunctival APCs?
- Langherhans
- DCs
- Macrophages
Where do the APCs present antigens?
T-cells and Conjunctival follicles
This is the site of localized immune processing of antigens that pass through the conj. epithelium.
Conjunctival follicles
What are follicles composed of?
Naive T and B cells, APCs
Why do follicles enlarge?
Enlarge in response to ocular surface infection (viral) or inflammation
What are the effector immune cells of the conj.?
- Mast Cells
- T/B cells
- Plasma Cells
- Neutrophils
This effector cell provides immune surveillance to the cornea while we’re sleeping
Neutrophils
Are eosinophils found on the conjunctiva?
NO
This immunoglobulin prevents binding of microbes and antigens to the epithelial surface?
sIgA
What are the main cells found in the EFFERENT arm of the CALT? In what layer of the epithelium are they found?
CD8 and CD4 Tcells
Basal Layer
What are the main cells found in the AFFERENT arm of the CALT?
T and B cells
This lymphoid tissue functions to maintain balance between immune tolerance and immune-mediated ocular surface inflammatory processes.
Eye Associated Lymphoid Tissue
Does the EALT favor immune-mediated inflammation or immune tolerance?
Immune tolerance - provides afferent and efferent protection to ocular surface
This arm of EALT does uptake and presentation of antigen, while also generating effector T cells. `
The afferent arm of EALT
What are the main cells of the AFFERENT arm of EALT?
T and B-cells
This arm of EALT is the regulator of immune tolerance?
Efferent Arm
More lymphoid follicles are found where?
- upper conjunctiva
- tarsal plate
- peripheral zone (temp/nasally)
Which infection is known to induce follicles around the limbus?
Trachoma (chlamydia)
How does the CALT provide immune surveillance for the cornea?
- Windscreen when blinking
2. Generates AMPs that suppress bacterial growth when we sleep
What 2 cells do CALT favor when upregulating factors from neutrophils to suppress bacterial growth during sleep?
TH2 –> activates B cells –> activates plasma cells that secrete IgA
Tregs –> activate TGF-beta (anti-inflammatory)
What 4 effector cells does CALT generate?
TH1, TH2, TH17, Tregs
Trachoma presents as what type of immune response?
Type 1
Irritation, dryness or infection can damage epithelial cells and TJs causing CALT to ___?
Generate more proinflammatory immune cells
Immune cells activate fibroblast which causes them to express which complement components? What do they activate?
Express C1, C2, C4 and HLAII
Activates C5a and C3a
Ocular surface trauma by an epithelial defect and allows entry of an nonpathogenic antigen is known as ?
Ocular Allergy
Ocular surface trauma by an epithelial defect and allows entry of an pathogenic antigen is known as ?
Microbial Conjunctivitis
Allergens produce _____ which binds to ______ in conjunctival epithelium
protease
Protease-Activated Receptor 2 (PAR-2)
Protease bound to PAR-2 causes what?
Breakdown of TJ proteins (occludins) and separates epithelial cells to allow access of the allergen into tissue
What are the main 2 immune cells involved in allergic conjunctivitis?
Mast cell (innate) Th2 (adaptive)
What type of immune response is allergic conjunctivitis? But, what type of hypersensitivity response is it?
Type 2 immune response
Type 1 hypersensitivity response
Histidine Decarboxylase and Histaminase breaks down ____?
Histamine
What drug inhibits 4. Histidine Decarboxylase and Histaminase ?
Alrex 0.2%
What allergic conjunctivitis does not have eosinophils?
SAC
Histamine hits H1 receptors on sensory nerve fibers and causes ___?
Itching
Fibroblast DO NOT play a major role in which 2 allergies?
SAC and PAC
Which ocular allergy has an innate response with TH1 and TH2 cells?
AKC
In which condition will you have more eosinophils?
VKC and AKC
When IL-4 induces fibroblast to produce more collagen we get what?
Papillary hypertrophy
Any ulceration found in the cornea due to allergies are caused by fibroblasts producing too many __ and ___?
MMPs and Eosinophils
VKC is mediated by what?
Th2 cells
In VKC, ulceration is usually due to what 3 things?
- Mechanical abrasion from papillae
- Eosinophils
- MMPs
What are the 4 presenting signs of VKC?
- Trantas Dots
- Papillary Hypertrophy
- Shield Ulcer
- Limbal Hypertrophy
This VKC finding contains degenerated eosinophils and epithelial cells
Trantas Dots
This VKC finding is caused by mast cells found around the limbus and can lead to PEE.
Limbal hypertrophy
This VKC finding is noninfectious and is caused by mechanical rubbing.
Shield Ulcer
This VKC finding presents when fibroblast become activated and undergo proliferation
Papillae hypertrophy
What is the best way to manage VKC?
Antihistamine/MCS agent
Where are shield ulcers found in VKC?
Superior 1/3 of cornea
Dosing of Lastacaft, Pazeo and Pataday?
QD
Dosing of Zatidor?
BID
Dosing of Alocril?
BID
Dosing of Alomide
QID
FML/Lotemax/Pred Forte is used for what AC?
VKC
Dosing for Lotemax
QID minimum
What cell is the first responder in infectious conjunctivitis? What do they produce
Th1 Cells: produce IFN-y to fight pathogens