5' Natural protection against meningococcal disease

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5. Natural protection against meningococcal
disease
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..Antibodies
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What do these antibodies do?
Serum bactericidal antibody (SBA) enhances
clearance of organisms from the bloodstream and
spinal fluid

• 1. by complement mediated killing
• 2. by enhancing phagocytosis
• Process called phagocytosis phago means to
  eat or engulf
• Antibodies attach to the meningococci and
  specialised cells engulf and digest the complex

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Antibodies in the blood do protect

• E.g. Very high rate of meningococcal disease
  (Group C) in army recruits.
• 14744 new recruits were bled during 1st week of
  basic training.
• Later, there were 60 cases of meningococcal
  disease.
• Only 5.6 of the cases had SBA activity compared
  to 82.2 of controls.
• disease
  no disease
• SBA 4 3/54
  444/540
• (6)
  (82)

Goldschneider et al J Exp Med 1969
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The problem for babies

• Protection from disease depends upon serum
  bactericidal activity (SBA).
• 50 of newborn babies have anti-meningococcal
  bactericidal activity from Mum disease is rare
  at this age
• Immunity falls rapidly after birth to bottom out
  between 6-12 months.
• This serum bactericidal activity then increases
  through childhood so that by adulthood 65-85 of
  individuals have this protection