autoimmune diseases Flashcards
Innate immunity
- Inflammation
- More WBC’s
- No memory
- Fast response short duration
Adaptive immunity
- T cells and B cells
- Highly specific receptors
- Strong memory
- Slow response long duration
What cells of the innate immune system are required in the adaptive system
- Dendritic cells (APC’S) present antigen to T cells
- T cell cytokines activate innate cells to cause inflammation
Phagocytic cells
Neutrophils - destroy pathogens
Macrophages - produce chemokines
Dendritic cells - present antigen to T cells
Histamine producing cells
Mast cells, basophils, eosinophils
- Produce histamine - vasodilation and attract other immune cells
Complement
Directly attacks pathogens via alternative and lectin pathways
- Activated by antibodies
Cytokines
Signal between different immune cells
Chemokines
Attract other immune cells to sites of inflammation
What is autoimmunity
The adaptive immune system recognizes and targets the body’s own cells
Main characteristics of autoimmunity
- T cells that recognise self antigens
- B cells and plasma cells that make autoantibodies
- Inflammation in target cells as secondary response
What is autoinflammation
- No component of immune system
- Dysregulation of innate system
Main characteristics of autoinflammation
- Spontaneous attacks of systemic inflammation
- No source of infection
- Absence of high-titre autoantibodies
Causes of autoimmune disease
Genes - lag in presentation
Immune regulation - checks to control the system
Environment - specific factors for diseases
Central tolerance in the thymus
- T cells in the thymus have to develop many receptors so they are auto-immune
- If receptors in the thymus match the body’s it is an auto-reactive T cell and it gets deleted
- If it doesn’t match self antigens, T cell released into circulation
How are T cells made
Develop in bone marrow from haematopoietic stem cells and mature in the thymus
What is +/- selection in the thymus
T cells with self antigens are deleted as negative selection. vice versa
What forms T regulatory cells
T cells with intermediate recognition with self-antigens - Regulate the suppression and expression of different T cells
Overcoming tolerance =
Autoimmune disease
What genes cause genetic susceptibility
genes in the MHC
- Major histocompatibility complex
MHC class 1
On all nucleated cells
- puts antigens inside cell on surface to be read
- Presents to CD8 cell - T killer
MHC class 2
Only in immune syst. (APC’s)
- cells find antigen in environment and presents to CD4 T helper cell
Mutation of FoxP3
Causes failure to develop regulatory T cells - severe autoimmunity from birth
Mutation of PTPN22`
Causes T cells to be activated more easily - stronger general immune response
Other causative autoimmunity associations
- Sex/hormonal influence
- Age
- Sequestered antigens
- Environmental triggers
