Adaptive Immunity

Question 1

What are the two types of microbes and which responses do they activate

Answer 1

Extracellular - humoral immunity

Intracellular - cell dependent immunity

Question 2

Name some features of antigen presenting cells - location, process of capture and receptors

Answer 2

Strategic locations

• SALT, GALT, NALT, BALT
• Lymphoid organs (lymph nodes, spleen)
• Blood circulation

Pathogen capture

• Phagocytosis
• Macropinocytosis

Diversity in PRR allows them to detect

• Extracellular pathogens
• Intracellular pathogens

Question 3

Name some types of APCs, their location and what they present to

Answer 3

Dendritic - lymph nodes, mucous membranes, blood - Naive T cells

Langerhans - skin - naive T cells

Macrophages - various tissues - effector T cells

B cells - lymphoid tissues - effecort T cells and naive T cells

Question 4

What component on the APC displays the antigen

Answer 4

Major Histocompatibility Complex (MHC)

Question 5

What responses are actived in humoral immunity

Answer 5

Antibodies

Complement

Phagocytosis

Question 6

What responses are activated in cell-dependent immunity

Answer 6

Cytotoxic T lymphocytes

Antibodies

Macrophages

Question 7

What does HLA stand for and what are the two types of molecules and where are they found

Answer 7

Human Leukocyte Antigen

Class 1 molecules - all nucleated cells

Class 2 molecules - macrophages, dendritic and B cells

Question 8

What are the types of HLA class 1 molecules and what peptides do they present

Answer 8

HLA-A

HLA-B

HLA-C

Intracellular microbe peptides

Question 9

What are the types of HLA class 2 molecules and what types of peptides do they present

Answer 9

HLA-DR

HLA-DQ

HLA-DP

Extracellular microbe peptides

Question 10

What cells recognise MHC class I

Answer 10

CD8+ve T cells

Question 11

What cells recognise MHC class II

Answer 11

CD4+ve T cells

Question 12

What clinical problems do MHC molecules cause

Answer 12

Major cause for organ transplant rejection

HLA association and autoimmune disease

Question 13

How are extracellular microbes processed and what cells do they stimulate

Answer 13

Processed via exogenous pathway

Stimulate CD4+ve T cells - TH2 (T helper)

Question 14

How are intracellular microbes processed and what cells are stimulated

Answer 14

Endogenous and exogenous pathways

Stimulate CD4+ve T cells - TH1 (T helper)

Stimulate CD8+ve T cells -> cytotoxic T cells

Question 15

What stimulatory signals are needed for T helper cell activation, what are the signals and what do they communicate with

Answer 15

Cytokines - from APC to T cell

CD80/86 on APC interacts with CD28 on T cell

MHC II interacts with TCR and CD4 on T cell

Question 16

What cells are activated in response to intracellular microbes, how are they stimulated and what do they do

Answer 16

Cytotoxic T lymphocytes - activated from CD8 by TH1 and APC, secrete perforins granzymes to kill virus infection cells

B cell - TH1 produces IFNg to stimulate, B cells undergo isotype switching and produced antibodies, help kill opsonized cells

Macrophages - TH1 produces IFNg to stimulate, undergo phagocytic activities to kill opsonized cells

Question 17

What cells are activated in response to extracellular microbes, what activates them and what do they do

Answer 17

Eosinophils - TH2 produces IL-5 which stimulates them, cells kill parasites

B cells - TH2 produces IL-4 which stimulates, produces antibodies

Mast cells - TH2 produces IL-4 which stimulates them, they cause local inflammation allergies - produce IgE

Neutrophils - TH17 produces IL-17 which stimulates them, they phagocytose microbes