Jitt # 10 Activation-Induced Cytidine Deaminase Deficiency Flashcards Preview

Medical Immunology Bios 443/843 > Jitt # 10 Activation-Induced Cytidine Deaminase Deficiency > Flashcards

Flashcards in Jitt # 10 Activation-Induced Cytidine Deaminase Deficiency Deck (10):
1

AID

Activation induced cytidine deaminase; converts cytidine to uridine by deaminating cytidine; triggers a DNA breakage and repair mechanism;

2

AID deficiency

caused by mutations in AID; causes hyper IgM syndrome;

3

AID deficiency symptoms

Increased susceptibility to recurrent pyogenic infections is the only symptom, similar to X-linked agammaglobulinemia

4

UNG

Uracil-DNA glycosylase; DNA repair enzyme involved in class switch recombination;

5

What two signals are required for AID protein production?

B cells produce AID when CD40R and IL-4 R (or other cytokine receptor?) are ligated by CD40L on T cells and IL-4 (Other cytokine?) binds

6

Cytidine

Cytosine bound to Ribose; transcription is upregulated after B cell/T cell interaction; causes the separation of Double stranded DNA; Cytidine is converted to uridine; which is recognized by UNG recognizes uridine and removes them; these sites (abasic/no base) are excised by DNA endonucleases creating DNA single stranded breaks.

7

What processes does AID play a role in?

Class switching and somatic hyper mutation of B cells.

8

Somatic hypermutation

The process by which B cells undergo expansion and increased affinity for antigens by the introduction of point mutations; occurs after antigen receptor and T cell receptor are engaged on B cells; selection then occurs

9

Affinity Maturation

The process by which B cells who have antigen receptors that have high affinity for antigen receive strong survival signals. Patients with AID cannot induce point mutations and do not undergo affinity maturation.

10

MMR

Mis-match repair; DNA repair mechanism; plays a primary role in detecting DNA mismatches during meiosis and class-switch recombination; recognizes U-G mismatches made by AID; produces double stranded breaks;

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