Immuno Flashcards

1
Q

Kid comes in with swollen red knee and fever and recurrent ear and throat infections. He’s an immigrant, not up to date on vaccinations. A gram (-) coccobacillus is found when grown with the addition of hematin and NAD+ in lysed blood agar. What is the bacteria responsible for his infection? What is it’s main virulence factor?

A
H. Flu (type B) 
Polysaccharide capsule (that it anti-phagocytic) 

This kid didn’t get vaccinated and H flu is a routine childhood vaccine. It can cause septic arthritis. Remember, H flu needs NAD+ aka nicotinamide (factor V) and hematin (factor X) to grow in lysed blood agar (chocolate agar).

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2
Q

What media is H. Flu grown on? What 2 factors must be added to the culture plate to enable its growth (give the synonyms too)?

A

Chocolate agar aka lysed blood agar
Needs factor V (5) aka NAD+ aka nicotinamide
AND needs factor X (10) aka hematin

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3
Q

What kind of antibodies protect a person from re-infection with influenza?

A

Anti-hemagluttinin antibodies

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4
Q

What 3 cell types are antigen presenting cells (APCs)?

A
  1. Macrophages
  2. Dendritic cells
  3. B-cells
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5
Q

Explain how wheal and flare reactions come about.

A

You get exposed to an antigen (ex: bee sting). This antigen promotes class switching of IgM antibodies to IgE. Upon 2nd exposure to the antigen, IgE antibodies will cross-link and cause degranulation of mast cells—> release of Histamine—> vasodilation and increased vascular permeability.

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6
Q

What causes angioedema?

A
Mast cell activation (like from Ig-E mediated type I hypersensitivity/ allergy or opioids) OR
Excess bradykinin (like from being on an ACE inhibitor that prevents breakdown of bradykinin by ACE or from C1 inhibitor deficiency where you have overactivation of complement—> excess inflammation, including bradykinin)
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7
Q

What is C1 inhibitor deficiency and what is a clinical manifestation of it?

A

C1 inhibitor is usually present to prevent overactivation of the complement cascade (it stops the C1 complement protein). If you are deficient in this, you get overactivation of complement and excess inflammation. This includes excess bradykinin and angioedema (swelling of the face).

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