Immune Response and Hypersensitivity Flashcards
What are the 2 main subdivisions of the immune system?
Innate and adaptive.
What is innate immunity?
Non-specific defence mechanisms (e.g. skin, chemicals, immune cells).
-fast action
What are the main subdivisions of the innate immune system? (3)
- Barrier and chemical mechanisms (e.g. skin)
- Pattern recognition receptor (PRR)
- Cellular (phagocytes, NK cells)
What is adaptive immunity?
Antigen-specific immune response.
-slower repsonse
What are the main subdivisions of the adaptive immune system? (2)
- Humoral
- Cellular
What is humoral immunity?
Immunity mediated by macromolecules ( not cells) found in ECF such as secreted antibodies and complement proteins.
What are the main components of the innate immune system? (5)
- PRR
- Antimicrobial peptides
- Cells
- Complement components
- Cytokines
What are pattern recognition receptors (PRR)?
Antigen recognition receptors in the innate system.
Are PRRs identical?
No, there’s a diversity of type, but each cell carries identical receptors of a given type.
What do PRRs commonly recognise? (2)
- Pathogen-associated molecular patterns (PAMPs)
- Danger associated molecular patterns (DAMPs)
What are the 2 groups of PRRs?
- Transmembrane (cell suraface) and intracellular
- Fluid-phase soluble molecules
Pattern recognition receptors:
What molecule does TLR4 recognise?
LPS.
Pattern recognition receptors:
What molecule does TLR5 recognise?
Flagellin.
Pattern recognition receptors:
What molecule does TLR9 (intracellular) recognise?
MyD88.
What are antimicrobial peptides (AMPs)?
Proteins produced in secretions»_space; break down proteins in microbes.
Give some examples of antimicrobial peptides.
Defensins
Protegrin
Granulysin
Histatin
Give some examples of cells that play a role in the innate immune system.
Macrophages Dendritic cells NK cells Neutrophils Eosinophils
What are the complement components of the innate immune system?
- Classic and alternative complement pathway.
- Proteins that bind components
What are cytokines?
Molecules that mediate host defence and inflammation, and regulate the adaptive immune response.
-autocrine/paracrine/endocrine
What does autocrine mean?
Relating to a cell-produced substance that has an effect on the cell by which it is secreted.
What does paracrine mean?
Relating to a hormone which has effect only in the vicinity of the gland secreting it.
What does endocrine mean?
Relating to glands which secrete hormones or other products directly into the blood.
What is a fluid-phase recognition molecule?
Collectins.
- C-type lectin family
- Mannan-bindng lectin
- Surfactant protein A / D
What is the function of fluid-phase recognition molecules? (3)
- Recognise carbohydrates
- Neutralisation of pathogens
- Recruitment of adaptive response
What do fluid-phase recognition molecules bind via?
Carbohydrate-recognition domains (CRDs).
How many carbohydrate-recognition domains does mannose-binding lectin have?
2-6 clusters.
What are the main innate immune pathways? (3)
- Classical
- Mannose-binding lectin
- Alternative
What is the role of IL1?
Initial cytokine»_space; unwell, muscle ache, etc.
What does IL1 target? (3)
- Endothelia
- Hepatocytes
- Hypothalamus
When are TNF and IL6 produced?
Early infection.
What does TNF target? (4)
- Endothelia
- Hepatocytes
- Hypothalamus
- Neutrophils
Adaptive immune response; what happens when a lymphocyte comes into contact with its specific antigen?
Clonal expansion.
What happens in primary lymphoid organs?
Lymphocytes develop and mature.
What are the primary lymphoid organs? (2)
- Bone marrow (B cells)
- Thymus (T cells)
What happens in secondary lymphoid organs?
Initiate adaptive immune response and lymphocyte activation.
What are the secondary lymphoid organs? (3)
- Spleen
- Lymph nodes
- Mucosal surfaces
What is the range of antigenic variability?
10^9.
How many genes does the human genome contain?
30,000.
How is diversity increased in human antigen receptors?
VDJ recombination.