Immunology 1-2 Flashcards
How are bacteria and viruses able to evade the immune system?
Fast replication times so are able to evolve at a much fast rate.
How does strategy 1 work and what receptors are involved?
Recognises molecular patterns using pattern recognition receptors (PRRs) such as PAMPs and DAMPs.
Which strategy is germ-line encoded?
Strategy 1
How does strategy 2 work?
Recognises precise structures with specific antigen receptors on lymphocytes.
Which strategy has a wider diversity of receptors?
Strategy 2 - receptors are formed by random recombination of gene segments creating large diversity.
What makes up the T cell receptors?
Two protein chains (alpha and beta) that are expressed by the T cell.
What are the features of innate immunity?
- Independent of exposure
- Fast
- Limited specificity
- Depends on pre-formed compounds
- Buys time whilst adaptive immunity begins response
What cells are involved in innate immunity?
Neutrophils, basophils and eosinophils (polymorphonuclear leukocytes)
How does innate immunity work?
Destroys invading nucleic acids in the cytoplasm and activates inflammatory pathways. Also stimulates type 1 interferons (anti-viral defence).
What are the features of adaptive immunity?
- Adaptation to exposure
- Slow
- Highly specific
- Can form memory cells
What cells are involved in adaptive immunity?
B cells (humoral) and T cells (cellular)
Where are lymphocytes found in the body?
98% in lymph and remaining are found in the blood.
When do lymphocytes enter the lymph?
When they enter high endothelial venules. T cell receptors on the surface of the T cell recognise chemokines present on the surface of HEVs causing a conformational change, arrest and trans-endothelial migration.
What is the process that produces lymphocytes and where does it take place (adults)?
Lymphopoiesis and in primary lymphoid organs such as the bone marrow and thymus gland.
Where does lymphopoeisis also take place in children?
Spleen, liver and bones.
