Skin Immunology and Biochemistry Flashcards
what 4 factors contribute to the skin’s effectiveness as a first line defence system?
structure - stratification, keratin layer
cell types - immune cells, keratinocytes
cytokines, chemokines, antimicrobial peptides
genetics
what are the 2 components of immune defence?
non-specific (innate)
- first line
specific (adaptive)
- self limiting
name 3 types of pathogenic immune responses
hypersensitivity
autoimmunity
immunodeficiency
autoinflammation
what is the difference between autoimmunity and autoinflammation
autoimmunity = problem with adaptive immune system where it senses part of self as harmful and attacks autoinflammation = problem with innate immune system where it reacts without cause or stimulation
how does the keratin layer form?
lipid rich barrier formed by differentiation of keratinocytes to corneocytes
what is present in the keratin layer?
filaggrin, involucrin, keratin,
Langerhans cells
what are keratinocytes and where are they mainly found?
structural and functional cells of the epidermis
what are 3 functions of keratinocytes?
- sense pathogens via receptors on cell surface and mediate an immune response
- produce antimicrobial peptides that directly kill pathogens
- produce cytokines and chemokines
what are Langerhans cells?
type of dendritic cell found amongst keratinocytes in epidermis
main skin immune cell
what is the function of Langerhans cells and how are they characterised?
antigen presenting cells
characterised by birbeck granules
what type of T cells are found in the epidermis and the dermis?
epidermis = mainly CD8 T cells
Dermis = CD4 and CD8 T cells
other T cells like NK cells also found
CD4 T cells become helper T cells, which ones are associated with psoriasis and atopic dematits?
psoriasis = TH1
atopic dermatitis = TH2
Combination of both = TH17
where do T cells come from and where do they mature?
produced in the bone marrow
mature in the thymus
what is involved in antigen recognition and T cell activation?
interaction with T cell receptor and MHC which is enhanced by co-receptors CD4 and CD8
what is the role of CD4 cells?
helper T cells
TH1 = activate macrophages, IL2, IFN gamma
TH2 = help B cells make antibodies, IL4, IL5, IL6
what is the role of CD8 cells?
cytotoxic T cells
directly kill infected cells
protect against viruses and cancer