Cell recognition and the immune system

Question 1

describe the non-specific immune response

Answer 1

1. Phagocyte e.g. macrophage recognises foreign antigens on the pathogen and
   binds to the antigen
2. Phagocyte engulfs pathogen by surrounding it with its cell surface membrane /
   cytoplasm
3. Pathogen contained in vacuole/vesicle/phagosome in cytoplasm of phagocyte
4. Lysosome fuses with phagosome and releases lysozymes (hydrolytic enzymes)
   into the phagosome
5. These hydrolyse / digest the pathogen
6. Phagocyte becomes antigen presenting and stimulates specific immune response

Question 2

Importance

Answer 2

Lysozymes are extremely important as they are needed in order to hydrolyse the pathogen. If the pathogen was not hydrolysed then there would be no way to present its antigen on its cell surface membrane. If no there are no antigen presenting cells then it would be impossible to start the cellular response as T lymphocytes have to recognise the foreign antigen on the APC to allow it to bind and stimulate the B cell production to undergo clonal expansion and selection to secrete antibodies from plasma cells. Enzymes such as reverse transcriptase is also important for viruses as it produces a complimentary viral DNA strand from viral RNA template. This enzyme is important for the survival of HIV as it uses host enzymes to make viral proteins from viral DNA