Etc.

Question 1

FcRn

Answer 1

Neonatal Fc receptor that transports Abs from the mom to the fetus. It protects IgGs from intracellular catabolism.

Question 2

Types of Fc receptors (4)

Answer 2

FcyRI (CD64) - high affinity, phagocytosis and cell activation.
FcyRII (CD32) - low affinity, feedback inhibition.
FcyRIII (CD16) - low affinity, Ab-dependent cell-mediated cytotoxicity (NK cells only).
FceRI - high affinity, cell activation (mast cells)

Question 3

Most efficient opsonization mechanism:

Answer 3

IgG3 and IgG1 binding FcyRI (CD64)

Question 4

Polymorphism in FcyRIIB gene is linked to:

Answer 4

Systemic lupus erythematosus

Question 5

Antibody-dependent cellular cytotoxicity (ADCC)

Answer 5

Ab binds FcyRIII on NK cells, caused cross-linking, NK kills target cell.

Question 6

C5 convertase equals what in the alternative pathway?

Answer 6

C3bBb3b

Question 7

C5 convertase equals what in the classical pathway?

Answer 7

C4b2a3b

Question 8

CR1 (CD35) function

Answer 8

A high affinity receptor for C3b and C4b

Promotes phagocytosis and clearance of immune complexes.

Question 9

CR2 (CD21) function

Answer 9

High affinity for C3d, C3dg and iC3b.

Enhance B cell responses.

Question 10

How does EBV enter B cells?

Answer 10

Via CR2 and remains latent for life.

Question 11

CR3 (Mac-1)

Answer 11

An integral that functions as a receptor for iC3b.
Also involved in the recruitment of leukocytes to infection.
CR4 functions similarly.

Question 12

Factor I

Answer 12

Cleaves C3b and C4b.

Inhibition.

Question 13

Factor H

Answer 13

Binds C3b and displaces Bb.

Cofactor for factor I.

Question 14

MCP

Answer 14

Cofactor for factor I-mediated cleavage of C3b and C4b.

Question 15

DAF

Answer 15

Causes dissociation of C3 convertase.

Question 16

C1 INH

Answer 16

Terminated classical activation.

Question 17

CD59 and plasma S protein

Answer 17

Inhibit MAC formation.

Question 18

Microbes on which complement is activated become coated with what?

Answer 18

C3b, iC3b or C4b and are phagocytosed.

Question 19

What complement fragments induce acute inflammation?

Answer 19

C5a, C4a, C3a.

Question 20

C3d binds what on B cells?

Answer 20

CR2 (CD21)

Question 21

C1q, C2 and C4 deficiencies are associated with:

Answer 21

SLE

Question 22

C3, propirden, and factor D deficiency is associated with:

Answer 22

Pyogenic bacterial infections

Question 23

C5, C6, C7, C8, C9 deficiencies cause:

Answer 23

Neisseria bacteria infections

Question 24

what Igs does an infant have access to?

Answer 24

IgG from mom via placenta

IgA via brest milk

Question 25

Transcytosis

Answer 25

Process of transports Abs from milk across gut epithelium.

Question 26

First level of resistance to infections by infants depends on:

Answer 26

Activity of the phagocytic system.

Question 27

Reasons IgG is most protective:

Answer 27

``` Higher acts in blood. binds avidly to Ag. Activates complement system. Good at opsonizing. Relatively small and penetrates easily to tissues. ```

Question 28

Timeline of fetal Ab production

Answer 28

Some IgM is produced in utero. IgG is produced at high levels after birth. At 6 mo old, mom's Abs are gone and newborns are on their own.

Question 29

Tfh secrete what? Causing what?

Answer 29

IL-21 which is needed for GC development (isotype switching, affinity maturation, Ab production) and generation of plasma cells. IFN-y or IL-4 which controls isotope switching.

Question 30

Tfh express:

Answer 30

ICOS PD-1 IL-21 Bcl-6

Question 31

CD40 engagement induces:

Answer 31

AID