Evolution of the Immune System Flashcards
How does the immune system evolve during a person’s lifetime?
Immune cells continuously evolve and adapt within weeks
How did food influence immune system evolution?
The need to ingest food safely helped drive the evolution of immune mechanisms
What is fixed immunity?
Immunity by epithelial cells
What is mobile immunity?
Immunity by leukocytes that patrol blood or residue in tissues
What are the three ways worms defend against infections?
- Anti-microbial proteins
- Pattern recognition receptors
- Melanisation reactions
What are the three types of fly immune cells and their functions?
- Plasmatocytes - phagocytosis
- Crystal cells - melanisation and clotting
- Lamellocytes - encapsulation of pathogens
Who discovered TLRs?
Janeway and Medzhitov
Who discovered TLR4?
Bruce Beutler
What three features make phagocytes special?
- Surveillance via PRRs
- Containment
- Destruction
What is NETosis?
A dying neutrophil releases DNA strands like a net coated in antimicrobial proteins to trap and kill pathogens
What are the five key innate immune cells in jawed vertebrates?
- Neutrophils
- Monocytes
- Eosinophils
- Basophils
- Mast cells
What are heterophils?
Are neutrophil like cells found in birds, reptiles and some mammals
What is the immunological Big Bang?
The rapid emergence of adaptive immunity in jawed vertebrates
What organs developed alongside adaptive immunity?
- Thymus
- Spleen
- Lymph nodes in mammals
What is the function of RAG1 and RAG2 genes?
Encode the V(D)J recombinase essential for rearranging DNA segments in developing B and T cells to generate receptor diversity
What is activation induced cytidine deaminase?
An enzyme that introduces mutations for somatic hypermutation and enables class switching in activated B cells
Why can’t fish undergo class switching?
Fish lack lymph nodes which are needed to concentrate T cell help signals for class switching
What mechanisms prevent autoimmunity?
- Sequestration (hiding) of self antigens
- Anergy specific unresponsiveness
- Regulatory immune mechanisms
What is the difference between autoimmunity and autoimmune disease?
Autoimmunity is the presence of self reactive cells while autoimmune disease causes tissue damage due to immune attack
What is a holobiont?
Is a host and its associated microbiota functioning together as an ecological unit
Why is understanding holobionts important in immunology?
It can inform vaccine engineering by highlighting how microbial communities influence immune responses
