evasion

Question 1

Host mimicry

Answer 1

○ e.g. S. pyogenes hyaluronic acid
○ N. meningitis Sialic acid
H pylori changes O antigen to mimic Lewis X and Y antigens on gastric epithelial cells

Question 2

evading innate immunity

Answer 2

• capsule, host mimicry, living intracellularly, biofilms, evasion of complement

Question 3

phase variation

Answer 3

• Salmonella suppresses some flagella while others are being expressed. Once they are recognised by adaptive immunity, salmonella can phase shift. This involves producing a DNA invertase that will flip the producer for fligA and B.
  Hin invertase

Question 4

Antigenic variation

Answer 4

pil genes
Neisseria gonerreae will bind to a surface, then recombine their pilus genes via allelic recombination.