Lecture 17

Question 1

Complement Receptors

Answer 1

Receptor Binding to Complement Fragments

Question 2

CR1(CD35)

Answer 2

1. High affinity binding to both C4b and C3b
   - Neutrophiles, Macrophages, and Monocytes
   - RBC
   - Follicular Dendritic Cells
2. Expression on B-Cells
   - Host Cell Membranes

Question 3

Neutrophils, Monocytes, Macrophages: CR1 expression on Phagocytes

Answer 3

Allows for receptor-mediated phagocytosis of C4b- and C3b-opsonized microbes

Question 4

RBCs: CR1 expression on Erythrocytes

Answer 4

1. Low density; lots of RBCs

Question 5

SSm Macrophage

Answer 5

Transfer C3b-tagged antigens to follicular dendritic cells

Question 6

Follicular Dendritic Cells (FCDs)

Answer 6

Facilitate the exposure of antigens to naive B-Cells

Question 7

Regular MACs

Answer 7

can also facilitate the exposure of C3b-tagged antigens to naive B-cells

Question 8

Expression on B-Cells

Answer 8

Facilitates uptake and processing of antigen for subsequent presentation of TH cells

Question 9

Host Cell Membranes

Answer 9

Participates in the destruction of complement components on the surface of host cells

Question 10

CR2 (CD21)

Answer 10

1. High affinity binding to C3b proteolytic products
2. Expression on B-Cells

Question 11

C3b Proteolytic Products

Answer 11

1. iC3b
2. C3d
3. C3dg

Question 12

Expression on B-cells

Answer 12

Markedly increases the avidity of antigen binding to the B-cell receptor complex

Question 13

Regulatory Proteins

Answer 13

1. Passive Regulation
2. Active Regulation

Question 14

Passive Regulation

Answer 14

1. Relative instability of Complement componenents
2. Host vs Pathogen membrane surface compositions