viruses

Question 1

how does our immune system recognise viruses it has never seen before

Answer 1

very specialised recognition proteins
ie. antibodies, B cells, T cells

Question 2

T Cells

Answer 2

identify and destroy virus cells

1. Large variety of T cells with distinct TCRS
2. T cells identify the infected cell with virus inside and matches its TCRs
3. Infected cell destroyed
4. Successful T cells proliferate
5. T cell receptors further improved
   = expanded pool of highly optimised virus specific T cells/ TCRs
   - becomes ‘immune’ –> immunological memoru

Question 3

B Cells

Answer 3

1. antibody on cell surface and secreted
2. successful B cells proliferate
3. expanded pool of highly optimised virus specific B cells/ antibodies
   - becomes ‘immune’ –> immunological memory
4. antibodies bind to the virus and
   a. blocks virus from entering new cells
   b. attract a macrophage that destroys
   the virus

Question 4

where does recognition come from

Answer 4

generic TCR from a naive T cell matures (maturation) –> large pool of randomised TCRs and T cells

in the TCR: split evenly between constant and variable part
- variable part randomly cut and stuck back together (semantic recombination)
- randomised variant –> transcription –> translation
- extra mutations increase variety further (hypermutation)
- transcription –> translation –> TCR further improved!