Block 2 Flashcards
1
Q
IgG
A
– Monomer
- Main circulating Ig, Most abundant in serum (80%)
- Crosses placenta and provides passive immunization of fetus
- Via Brambell Receptor or Neonatal FcR - Activates Complement > Opsonization
- IgG receptors on Macrophages and Phagocytes
2
Q
IgM
A
– Pentamer in serum, Monomer as BCR
- Activates Complement (Classical)
- Pentameric form has high avidity (monomer has low affinity)
3
Q
IgA
A
– Dimer in secretions, Monomer in serum
- Main Ig secreted at mucosal surfaces
- IgA1 – α1 Heavy chains >Serum
- Activates Complement (Alternative & Lectin) - IgA2 – α2 Heavy chains Secretions (mucosal, colostrum, milk)
- Does not activate complement
4
Q
IgE
A
– Monomer
- Least abundant Ig
- Does not activate complement
- Linked to parasitic infections and allergic diseases
- Binds high-affinity IgE receptors on mast cells, eosinophils, basophils, and Langerhanns cells
- So high affinity that they bind IgE without IgE binding antigen
5
Q
IgD
A
– Monomer
-Coexpressed with IgM on surface of B cells due to differential RNA splicing
6
Q
o CD3
A
pan T Cell marker
7
Q
o CD19
A
Pan B Cell marker
8
Q
o CD56
A
NK Cell marker
9
Q
o CD45
A
Leukocyte marker
10
Q
o CD34
A
Hematopoietic Stem Cell marker
11
Q
o CD95
A
Fas Receptor marker
12
Q
12/23 rule
A
- Rearrangement is guided by flanking DNA sequences (Recombination Signal Sequences)
- RSS are madeup of 12 or 23 paring within each domain of VDJ/VJ segments
- RAG-1/2 binds RSS and cleaves DNA forming two DNA hairpins
