Autoimmune Diseases Flashcards
What are the cells involved in innate immunity?
- Macrophages
- Dendritic cells
- Mast cells
- Neutrophils
- Complement
What are the cells involved in adaptive immunity?
B cells and T cells
What cells are involved in both innate and adaptive immunity?
T cells and natural killer T cells
What is innate immunity responsible for?
Inflammation in target tissues
it has pattern recognition against broad classes of antigen
What are the characteristics of the innate immune response?
What is the duration and response time like?
- No memory
- No amplification
- Little regulation
Fast response (hours to days) and short duration
What is adaptive immunity responsible for?
Learned responses in immune organs
it is highly specific and involves T and B cell receptors
What are the characteristics of the adaptive immune response?
What is the duration and response time like?
- Strong memory and amplification component (e.g. vaccines, previous infection)
- Many regulatory mechanisms
Slow response (days to weeks for initial exposure)
Responses may last from months to years
What is the first stage involved in the interaction between innate and adaptive immune systems?
Innate immune cells directly detect and attack antigenic targets
this occurs at sites of infection e.g. barrier organs
it involves phagocytosis, cytotoxicity, inflammatory mediators and chemokines to attract other cells
What is the second stage in the interaction between the innate and adaptive immune systems?
Dendritic cells present antigens to T cells
What is the third stage in the interaction between the innate and adaptive immune systems?
Crosstalk between dendritic cells, T cells and B cells
This occurs in lymphoid tissues
Immune memory determines specific learned responses
What is the fourth and final stage in the interaction between the innate and adaptive immune systems?
Adaptive immune cells activate innate immune cells, directing tissue inflammation to specific targets
T cell cytokines activate monocytes and macrophages
B cell antibodies activate complement
What are the 5 main components of the innate immune system inflammation?
- Phagocytic cells
- Histamine-producing cells
- Complement
- Cytokines
- Chemokines
What are the 3 phagocytic cells involved in innate immune system inflammation?
What are their other roles?
Neutrophils:
- eat and destroy pathogens
Macrophages:
- also produce chemokines to attract other immune cells
Dendritic cells:
- also present antigens to the adaptive immune system
What are the histamine producing cells involved in innate immune system inflammation?
What is their role?
Mast cells, basophils and eosinophils
they produce histamine and other chemokines and cytokines
this attracts other immune cells and causes vasodilatation
histamine also is involved in defence against parasites and wound healing
It is also involved in allergy and anaphylaxis
What is the role of complement in innate immune system inflammation?
How may they be activated?
Directly attacks pathogens via alternative and lectin pathways
may be activated by adaptive immune system via antibodies
What is the role of cytokines and chemokines in innate immune system inflammation?
Cytokines:
- signal between different immune cells (e.g. innate to adaptive, adaptive to innate)
Chemokines:
- attract other immune cells to sites of inflammation
How do T cells cause inflammation?
By inflammatory cytokines or by helping B cells make autoantibodies
Label the diagram showing how T cells cause inflammation
What are the problems with autoantibodies produced by plasma cells during T cells causing inflammation?
Some autoantibodies directly interfere with normal physiological function rather than causing inflammation and tissue damage
What is the definition of autoimmunity and its defining characteristic?
The adaptive immune system recognises and targets the body’s own molecules, cells and tissues
(instead of infectious agents and malignant cells)
What are the 3 main characteristics of autoimmunity?
- T cells that recognise self antigens
- B cells and plasma cells that make autoantibodies
- Inflammation in target cells, tissues and organs is secondary to actions of T cells, B cells and autoantibodies
What are the 4 main characteristics of autoinflammation?
- Seemingly spontaneous attacks of systemic inflammation
- No demonstratable source of infection as precipitating cause
- Absence of high-titre autoantibodies and antigen-specific autoreactive T cells
- No evidence of auto-antigenic exposure
Complete the table comparing autoinflammation and autoimmunity
What is meant by autoimmunity?
What characteristics is it defined by?
A theoretical concept involving breakdown of self-tolerance
many cells of the immune system have capacity for autoimmune functions
there is overlap with normal immune functions such as anti-tumour immunity
some people have autoantibodies without any symptoms
What is meant by autoimmune disease?
How is it related to autoimmunity?
Distinct clinical entities
environmental factors acting on favourable genetic background
wide variety of pathogenic mechanisms between diseases
autoimmunity, leading to inflammation, organ dysfunction and damage