Basic Skin Immunology Flashcards
What about the structure of skin contributes to skin as an immunological system?
Keratin layer (stratum corneum)
Stratification
What about the cell types of skin contributes to skin as an immunological system?
Immune system cells
Keratinocytes
Which chemical signals/molecu;es influence cell beahaviour in the skin and help target pathogens?
Cytokines
Chemokines
Eicosanoids
Antimicrobial Peptides
What is the stratum corneum?
The keratin layer of the skin
tough, lipid rich, physical barrier
(formed by the terminal differentiation of keratinocytes to corneoctes)
Which important structural portiens are found in the kerait layer and epidermis of the skin?
Filaggrin, Involucrin, keratin
What are AMPs?
Antimicrobial Peptides
What do Keratinocytes (KCs) produce that can directly kill pathogens?
Antimicrobial peptides (AMPs)
What type of peptides have been found in high levels in skin of patients with psoriasis?
AMPs
antimicrobial peptides
What can keratinocytes be activated by?
UV (sunlight)
Sensitizers (e.g. allergic contact dermatitis)
What do keratinocytes (KCs) produces that recruit and regulate cells of the adaptive and innate immune system?
(e.g. in psoriasis)
Cytokines and chemokines
What do the cytokines and chemokines produced by the keratinocytes do?
Recruit and regulate cells of the adaptive and innate immune system (e.g. in psoriasis)
What type of cells are Langerhans cells foudn in the epidermis?
A type of dendritic cell
(interspersed with keratinocytes in the epidermis)
Main skin resident immune cell
Antigen presenting cells (APC), characterised by the Birbeck granule
What do Langerhans cells do in the epidermis?
They act as guarda in the epidermis
They process lipid Ag and microbial fragments and present to effector T cells
They help to activate T cells
What main type of T cells are found in the epidermis?
Mainly CD8+ T cells are found in the epidermis
What type of T cells are found in the dermis?
CD4 + and CD8+ T cells are found in the dermis
Other subsets of T cells (eg. Natural Killer (NK) cells) are also found
Which CD4+ TH cells are associated with psoriasis? (2)
TH1
TH17
Which CD4+ TH cells are associated with atopic dermatitis? (2)
TH2
TH17
Where are T cells produced?
In Bone Marrow
Where are T cells sesitised?
Thymus
What happens (T cells) in bone marrow.
T cells are produced in bone marrow
What happens to T cells in the thymus?
T cells are sensitised in thymus
What cells are the basis of cell-mediateed immunity?
T cells
Helper T cells= CD__ cells
TH
CD4+ cells
Cytoxic T cells = CD__ cells
CD8+ cells.
The T helper cells assist other cells of the ______ system to carry our their roles buy the realease of chemical mediators including substances such as _________ and _________.
The T helper cells assist other cells of the immune system to carry our their roles buy the realease of chemical mediators including substances such as interferons and interleukins.
What are the roles of the cytotoxic T cells (CD8+)?
Can kill infected cells directly
Important protection against viruses and cancer
What is the role of TH1 cells?
Activate macrophages to destroy microorganisms
IL2, IFNgamma
What is the role of Th2 cells?
Hep B cells to make Antibodies
IL4, IL5, IL6
What do Dermal Dendritic Cells, found in the dermis do?
Involved in Antigen presenting and secreting cytokines/chemokines
What do plasmacytoid Dendritic Cells (pDC) produce?
IFNα (Found in diseased skin)
What do dendritic cells do in the dermis in terms of sntigen presentation?
Transmit information to T (&B) cells
What type of immune response are mast cells effecotrs of?
IgE-mediated immune response (allergy)
What is a MHC?
Major Histocombatibility Complex
What are the two forms of MHC?
Class I
Found on almost all cells
Present Antigen cytotoxic T cells
Class II
Found on Anitgen presenting Cells (B cells, macrophages)
Presnt exogenous Ag
What is the MHC involved in?
Immunological recognition and trnsplant rejection
Control the immune response through recognition of “self” and “non-self”
What are pDC?
plasmacytoid Dendritic Cells
In psoriasis, what happens when KC under stress?
release factors that stimulate pDC to produce IFNα
release IL-1β/IL-6 and TNF
In psoriasis, what happens when chemical signals activate DC?
DCs migrate to skin draining lymph node to present to and activate T cells
(TH1 and Th17)
In psoriasis, T cells are attracted to the dermis by ______ and secrete ______.
Stimulates: (3)
In psoriasis, T cells are attracted to the dermis by chemokines and secrete IL-17A/17F/22
Simulates KC proliferation,
AMP release
and nuetrophil-attracting chemokines..
Mutations in which gene are assoiate with sever/onset atopic eczema?
Filagrin gene
AMP is increased/decreased in skin of person with stopic eczema.
AMP is decreased in skin of person with stopic eczema.
Type II and type III hypersensitivity are mediated by which antibodies?
IgG and IgM
Type IV hypersensitivity is mediated by which cells?
TH1 cells
In type IV hypersensitivity, when does reaction peak?
24-48 hours after contact with allergen
What are the non-immune cells in the epidermis?
Keratinocytes
What are the immune cells in the epidermis?
Langerhans Cells
T cells (especially CD8+)
What layer of the skin are melanocytes found in?
Epidermis
What are the immune cells in the dermis?
Dendritic cells
Macrophages
T Cells (CD4+ & CD8+)
Natural Killer Cells
What cells (other than the immune cells) are found in the dermis?
Fibroblasts
Lymph/vasculature (transport/access)
