Lecture 26 symbiosis on health and disease

Question 1

gnobiotic animals

Answer 1

sterile in utero
birth canal colonisation
sterile upbringing intestine, immunity defects

Question 2

human neonate intestine colonisation development bacteria trend

Answer 2

facultative anaerobes
weaning obligate anaerobes (into adulthood dominate)
correlate intestinal capillary development

Question 3

mutualistic bacteroides relationship with human

Answer 3

host intestinal epith develop

extensive SA, nutrient rich for colonisation

Question 4

gnobiotic immune system defects and how to fix

Answer 4

susceptible infection
cytokine low
innate (myeloid lin.) low
serum Ig low
CD4 low

intestinal colonisation can restore

Question 5

CD4 gnobiotic vs conventional (missing what bacteria and what is immune effect)

Answer 5

bacteroides

lower splenic CD4

Question 6

why bacteroides increase CD4 levels

Answer 6

PSA
(bacteroides capsular antigen peptide derived from polysaccharide)
CD4 TCR recognise PSA, expand

(CD4 recognises MHC2)

Question 7

macrophage activation

Answer 7

MHC-2 of CD4