2.2 - Chronic inflammation

Question 1

what complex do T cells use for antigen surveillance?

Answer 1

TCR complex

Question 2

the TCR complex is comprised of ____ and ____

Answer 2

TCR and CD3

Question 3

what are the two signals for CD4 Th cell activation?

Answer 3

• EXTRAcellular antigen presented on MHC II by APCs

- B7 on APC binds CD28 on CD4 Th cell

Question 4

Th1 subset T cells secrete what cytokines? what are their roles?

Answer 4

• IFNy: activates macrophage, promotes B cell class switching from IgM to IgG, promotes Th1 phenotype, inhibits Th2 phenotype
• IL-2: T cell growth factor and CD8 T cell activator

Question 5

IL-2 secreted by Th1 is responsible for what 2 major processes?

Answer 5

• T cell growth factor

- CD8 T cell activator

Question 6

Th2 subset T cells secrete what cytokines? what are their roles?

Answer 6

• IL-4: facilitates B cell class switching to IgE
• IL-5: eosinophil chemotaxis and activation, class switching to IgA
• IL-10: inhibits Th1 phenotype

Question 7

what are the two signals for CD8 T cell activation?

Answer 7

• INTRAcellular antigen presented on MHC I

- IL-2 from CD4 Th1 provides 2nd signal

Question 8

CD8 cytotoxic T cell killing occurs via what two mechanisms?

Answer 8

• perforin and granzyme

- FasL binding to Fas on target cells (apoptosis)

Question 9

what are the two signals for B cell activation? what occurs after activation?

Answer 9

• antigen binding by surface IgM or IgD
• CD40r on B cell binds CD40L on Th cell
• secretion of IL-4 and IL-5: isotype switching, hypermutation, maturation of plasma cells

Question 10

what are the roles of IL-4 and IL-5 following B cell activation?

Answer 10

• istotype switching
• hypermutation
• maturation of plasma cells

Question 11

• istotype switching
• hypermutation
• maturation of plasma cells

following B cell activation are due to what cytokines?

Answer 11

IL-4 and IL-5

Question 12

a granuloma is a collection of what type of cells?

Answer 12

epithelioid histiocytes

Question 13

“stellate” shaped granuloma - diagnosis?

Answer 13

cat scratch disease

Question 14

what is the pathogenesis of granuloma formation?

Answer 14

• macrophages process and present antigen via MHC II to CD4 Th cells
• interaction leads macrophages to secrete IL-12, including CD4 Th cells to differentiate into Th1 subtype
• Th1 cells secrete IFNy, which converts macrophages to epithelioid histiocytes and giant cells

Question 15

what cell type is responsible for formation of epithelioid histiocytes and giant cells in granuloma formation? what cytokine is released?

Answer 15

IFNy secreted by Th1 cells - converts macrophages to epithelioid histiocytes and giant cells

Question 16

what induces CD4 Th cells to differentiate into Th1 subtype in granuloma formation?

Answer 16

IL-12 secreted by macrophages