Interaction With Streptococcus Pneumoniae
Both H. influenzae and S. pneumoniae can be found in the upper respiratory system of humans. In an in vitro study of competition, S. pneumoniae always overpowered H. influenzae by attacking it with hydrogen peroxide and stripping off the surface molecules H. influenzae needs for survival.
When both bacteria are placed together into a nasal cavity, within 2 weeks, only H. influenzae survives. When either is placed separately into a nasal cavity, each one survives. Upon examining the upper respiratory tissue from mice exposed to both bacteria species, an extraordinarily large number of neutrophils (immune cells) was found. In mice exposed to only one bacterium, the cells were not present.
Lab tests showed neutrophils exposed to dead H. influenzae were more aggressive in attacking S. pneumoniae than unexposed neutrophils. Exposure to dead H. influenzae had no effect on live H. influenzae.
Two scenarios may be responsible for this response:
- When H. influenzae is attacked by S. pneumoniae, it signals the immune system to attack the S. pneumoniae
- The combination of the two species triggers an immune system response that is not set off by either species individually.
It is unclear why H. influenzae is not affected by the immune response.
Read more about this topic: Haemophilus Influenzae
Famous quotes containing the words interaction with and/or interaction:
“Just because multiples can turn to each other for companionship, and at times for comfort, don’t be fooled into thinking you’re not still vital to them. Don’t let or make multiples be parents as well as siblings to each other. . . . Parent interaction with infants and young children has everything to do with how those children develop on every level, including how they develop their identities.”
—Pamela Patrick Novotny (20th century)
“Here is this vast, savage, howling mother of ours, Nature, lying all around, with such beauty, and such affection for her children, as the leopard; and yet we are so early weaned from her breast to society, to that culture which is exclusively an interaction of man on man,—a sort of breeding in and in, which produces at most a merely English nobility, a civilization destined to have a speedy limit.”
—Henry David Thoreau (1817–1862)