How does Neisseria meningitidis evade complement system?
Next, we discuss the diverse evasion mechanisms deployed by bacterial pathogens, using as examples two human bacterial pathogens, S. aureus and N. meningitidis, which avoid complement mainly by using secreted and surface-exposed proteins, respectively.
Why is complement important for Neisseria?
The complement system is the most important aspect of host defence against this pathogen, and the critical interaction between the two is influenced by genetic polymorphisms on both the bacterial and the host side; variations of the meningococcus may lead to increased survival in human sera, whereas humans with …
What immune defects predispose to meningococcal disease?
Examples of complement component deficiencies include C3, C5-9, properdin, factor H, and factor D. These disorders are very rare and usually genetic. People who receive complement inhibitors such as eculizumab (Soliris®) and ravulizumab (Ultomiris™) are also at increased risk for meningococcal disease.
Where is Neisseria meningitidis found?
Neisseria meningitidis exists in the nasopharynx of about 5-10% of the population and rarely causes serious disease. Severe meningococcal disease can occur when the bacterium enters normally sterile areas of the body, penetrating through the mucous membranes of the nose and throat.
What is complement evasion?
Complement Evasion: An Effective Strategy That Parasites Utilize to Survive in the Host.
What are the 3 complement pathways?
There are three pathways of complement activation: the classical pathway, which is triggered directly by pathogen or indirectly by antibody binding to the pathogen surface; the MB-lectin pathway; and the alternative pathway, which also provides an amplification loop for the other two pathways.
What are the four major functions of the complement system?
The complement system has four major function, including lysis of infectious organisms, activation of inflammation, opsonization and immune clearance. There are three different complement pathways, the classical complement pathway, the alternative complement pathway, and the mannose-binding lectin pathway.
Who is generally at highest risk for meningitis Why?
Infants, teens and young adults, and older adults have the highest rates of meningococcal disease in the United States.
Which defenses protect us from infection by Neisseria meningitidis?
Mucosal immunity constitutes the first line of defence against meningococcal infection and is generally very effective, as shown by the fact that few carriers develop clinical disease.
What causes Neisseria disease?
Meningococcal disease is caused by bacteria called Neisseria meningitidis. It can lead to serious blood infections. When the linings of the brain and spinal cord become infected, it is called meningitis. The disease strikes quickly and can have serious complications, including death.
Is Neisseria meningitidis an STD?
Neisseria meningitidis: An Emerging Sexually Transmitted Infection.
How does M protein prevent phagocytosis?
M protein is strongly anti-phagocytic and is the major virulence factor for group A streptococci (Streptococcus pyogenes). It binds to serum factor H, destroying C3-convertase and preventing opsonization by C3b.
Does IgM Opsonize?
There are no FcµRs on phagocytes, so IgM cannot opsonize in this manner. However, a single molecule of IgM can activate complement through the classical pathway, leading to the deposition of many C3b molecules that can act as opsonins.
What are the 4 functions of complement?