QNS from 2021 Mid yr

Question 1

Sugges how (bacteria) evades the immune system.

Answer 1

1. _ stay inside the host cells, host CSM may disguise the bacteria as self/ anitgen not exposed and immune cells are not able to recognise the antigen
2. _ inhibit clonal expansion of helpter T-lymphocyes -> reduce activation of the cytotoxic T-lymphocytes and B-lymphocytes/ reduce cytokines required to activate the B-lymphocytes
3. (w/o free antigens) It is difficult to generate a large enought B-lymphoctes response
4. Large degree of variation / change in pathogen/bacterial antigens due to short replication time for binary fission (higher rate of mutation due to higher rate of DNA replication, errors can occur during the DNA replication);

Question 2

Explain how the use of vaccines in the control of infectious diseases differs from the use of antibiotics.

active vs passive

Answer 2

1. Vaccines (generally) are preventive / not a treatment / not a cure but Antibiotics (generally) not preventive / are a treatment / cure;
   2.