APC, T & B cell activation

Question 1

Where in the body & how are T Cell is first activated (primed)?

Answer 1

T cells are activated in the lymph node when DC/APC presents Ag (processed) via MHC

Question 2

Which type of Ag activates B cells?

Answer 2

B cells activated by Ag on its native form

Question 3

Process of reaching the activation of T cells (starting from encountering Ag by DC cells)

Answer 3

1. DC cells capture Ag
2. DC activate & mature & migrate twds lymph node
3. While migrating DC matures into an APC
4. DC present Ag to T cells in lymph node

Question 4

The 2 signals required for full activation of B cells

Answer 4

1. Epitope binding to BCR

2. Cytokines secreted by activated T cells

Question 5

Briefly describe how B cells get help from T cells. (2 signal activation)

Answer 5

1. B cell activated when bound to peptide Ag & presents to CD4+ T cells via MHC II
2. activated CD4+ T cells secrete cytokines (IL-4, IL-5)

Question 6

MHC class I presents [intra/extracell] Ag only to CD_+ on (type of) T cell

Answer 6

a. intracellular

b. CD8+ on cytotoxic T cells

Question 7

MHC class II presents [intra/extracell] Ag only to CD_+ on (type of) T cell

Answer 7

a. extracellular

b. CD4+ on T cells

Question 8

Describe the process of T cell activation

Answer 8

1. Pathogen activates APC
2. APC expresses co-stimulatory molecules (B7)
3. Pathogen taken up via phagocytosis
4. pathogen is processed in APC
5. APC presents peptide to naive T cells via MHC II?
6. T cell activated
7. T cells leave lymph node

Question 9

The 2 signals required for full activation of T cells

Answer 9

1. Ag via MHC bind to TCR

2. Activated APC express co-stimulatory molecules