Adaptive Immune Response

Question 1

What are two most important cells of the adaptive immune system?

Answer 1

T lymphocytes and antigen presenting cells

Question 2

What are the features of an antigen presenting cell that make it good at its job?

Answer 2

Strategic location

Pathogen capture (phagocytosis-whole microbe, macropinocytosis-soluble particles)

Diversity in pathogen sensors (PRRs)

Question 3

What are the four types of APC? Where are they found and what do they present to?

Answer 3

Dendritic cells- lymph nodes, mucous membranes and blood- naive T cells

Langerhan’s cells-skin-naive T cells

Macrophages-various tissues-effector T cells (already activated)

B cells (BCR)- lymphoid tissues- effector T cells and naive T cells

Question 4

If an antigen presenting cell comes across an extracellular microbe, what type of immunity does it result in?

Answer 4

Humoral immunity:

• antibodies (opsonisation)
• Complement (opsonisation)
• phagocytosis

Question 5

If an antigen presenting cell comes across an intracellular microbe, what type of immunity does it result in?

Answer 5

Cell-dependent immunity (cell mediated):

• cytoxic T lymphocytes
• antibodies
• macrophages

Question 6

Where are T cells made and matured?

Answer 6

Made in bone marrow

Matured in thymus

Question 7

What is the antigen receptor on a T cell called?

Answer 7

T cell receptor (TCR)

Random rearrangement leads to more TCR diversity

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Question 8

List some cytokines that are produced by T cells

Answer 8

CD4+ TH1 cells: TNFalpha, IFNgamma

CD4+ TH2 cells: IL-4, IL-5, IL-10

CD4+-TH17: IL-17

CD4+-Treg: IL-10, IL-35, TGFb

The nature of the T cell function depends on the cytokines is produces