Week 5: Neisseria

Question 1

Neisseria gonorrhoae profile

Answer 1

• Can be transmitted sexually
• An obligate human pathogen + very specialised to its host, so it survives poorly outside the host
• Can be asymptomatic in people
• Resides in genital mucosa niche
• Can cause damage without evidence of endotoxins or inflammation

Question 2

Neisseria genus profile

Answer 2

• Generally a commensal microbe + highl evolved for multiplication in humans
• Dynamic genome leads to extensive cell surface variation + evasion of host immune system
• DIfficult to model due to its adaptation to life in humans

Question 3

Type 4 pili structure + assembly

Answer 3

• Composed of PilE subunits subunits
• Assembled at innermembrane via prepilin subunit (PilE) processing (PilD), a 7 residue allowing methylation of terminal Phe
• Has a dynamic structure that is continually extended when constructed, and can be retracted via PilT ATPase that allows twitching motility
• Essential to initial adhesion + infection
• Also promotes microcolony formation via pili-pili interactions

Question 4

Pili host interaction requirements

Answer 4

• PilCl - Required for adhesion
• PilE - The major subunit
• PilV - Supposedly to be involved

Question 5

Outer membrane Opacity proteins (Opa)

Answer 5

• 11 variants per cell
• Has differences in surface loops
• Binds to different Carcinoembryonic Antigen-related Adhesion Molecule (CEACAMs) + can have varying affinity to each CEACAM

Question 6

Host CEACAM receptors

Answer 6

• 4 different CEACAMs named through 1, 3, 5, 6
• Differ in surface + signaling domains
• Also varies in host cell