B Cell Activation

Question 1

If the antigen is Thymus-dependant (TD), is it a soluble or insoluble protein?

Answer 1

Soluble

Question 2

What are the differences in the 2 types of Thymus-Independent (TI) antigen?

Answer 2

Type 1 - Bacterial cell wall components eg LPS

Type 2 - Repeating proteins or polysaccharide cross link mIg

Question 3

What are the differences in TI-1 and TI-2 antigens?

Answer 3

1- TI-2 not polyclonal activators
2- TI-2 only activate mature B cells
3- TI-2 require cytokines from Th to amplify response

Question 4

S……….. antigen binds to antibody but only provides signal …. = resulting in ……..

Answer 4

Soluble antigen binds to antibody but only provides signal 1 = resulting in ANERGY

Question 5

What does LPS provide? (Type 1 TI)

Answer 5

Signal 1 - antigen binding to antibody

Signal 2 - mitogenic component

Question 6

What does Ag provide? (Type 2 TI)

Answer 6

Signal 1 - cross-links Ab

Signal 2 - autocrine activity on IL-1)

Question 7

Which thymus antigens are strong, have formed a B memory and have a switching Ab class?

Answer 7

Thymus - dependant

Question 8

Which thymus antigen is weak, has no B memory and IgM of low affinity?

Answer 8

Thymus Independent

Question 9

Where is the Germinal Centre?

Answer 9

A region in the lymphoid tissue

Question 10

What is the Germinal Centre?

Answer 10

Micro-environment in which B cells undergo rapid and clonal expansion