21. Neisseria Flashcards
Which Neisseria species has no vaccine available and is multidrug-resistant?
N.gonorrhoeae
Gram and shape of Neisseria?
Gram-negative, diplococci
What unique protective thing does N.meningitidis have?
Polysaccharide CAPSULE
- anti-phagocytic
- display sialic acid residues from host to look like “self”
Basis of N.meningitidis vaccines?
Capsule
What antibiotic is effective against N.meningitidis if caught early enough?
Penicillin
Why is there no effective humoral immune response in N.g infections?
Antigenic variation of type IV pili, LOS, Opa, PorA
Difference between phase and antigenic variation
Phase = can be turned on/off at level of transcription/translation
Antigenic = aa sequence of protein/sugars can cahnge => host can’t launch effective immune response = poor vaccine candidates
Neisseria virulence factors are ______ variable and ________ variable
antigenically, phase
2 reasons N.g doesn’t have any good vaccines by N.m does?
- No capsule = no effective humoral immune response
- Antigenic variation of Type IV pili, lipooligosaccharide, Opa, PorA
Subunit of Type IV pili?
PilE
What part of TbpA is thought to directly coordinate with the bound iron?
L3 helix finger
Example of a periplasm carrier protein?
FbpA
Ideal vaccine candidate against both N.m and N.g?
The iron transporter system TbpA/B (crtically conserved surface protein)
Function of TbpB co-receptor?
Enhances iron acquisition by TbpA
3 ways Neisseria subvert host immune system?
- Pili undergo antigenic/phase variation (pilus turned on/off)
- Resistance to oxidative killing by PMNs (catalase,superoxide dismutase, peroxidases, etc quenching system)
- Hypervariable region of type IV pilus mimics “self” carbs
