Adaptive Immunity

Question 1

What are leukocytes?

Answer 1

Minor constituents of blood but they are the main cells involved in immunity
Found in skin, kidney and brain

Question 2

What are cytotoxic T cells?

Answer 2

They can kill cancer cells or cells effected with virus

Question 3

What are antibodies?

Answer 3

Result of vaccination, protect against pathogens

Question 4

What are the most potent antigen presenting cells?

Answer 4

Dendritic cells - able to sample what comes into system, present in major organs

Question 5

Where does T cell and B cell activation occur?

Answer 5

Lymph node or spleen

Question 6

What are the function of dendritic cells?

Answer 6

They phagocytise antigen and process it down to peptides
DC migrate from organs to draining lymph node
They present peptides on MHC to other white blood cells

Question 7

What happens when an antigen enters a DC?

Answer 7

Synapses on CD4+ which is activated by MHC-II and peptide
CD4+ synapses on B cell which is responsible for making antibody
Antibody is produced and secreted by plasma cell

Question 8

What happens when a cytotoxic cell is engulfed by a DC?

Answer 8

CD8+ produces CTL which kills virus cell through MHC interaction

Question 9

What is adaptive immunity?

Answer 9

Dendritic cells present peptides on MHC to T cells
CD4 T cells help B cells make antibody
CD8 T cells become cytotoxic and kill virus infected cells and cancer cells

Question 10

What is the purpose of antigen uptake?

Answer 10

Clearance of pathogens -> destroys ‘bug’, sterilising immunity - bug destroyed (innate response)
Presentation to T cells (adaptive response)

Question 11

When did the adaptive immune response begin?

Answer 11

500 million years ago

Question 12

What type of immunity do invertebrates and vertebrates have?

Answer 12

Invertebrates have innate immunity only
Vertebrates have both innate and adaptive systems

Question 13

How are endogenous antigens processed? (MHC-I)

Answer 13

Antigenic proteins are degraded to peptides in cytoplasm
Peptides are imported into endoplasmic reticulum
Peptides loaded onto MHC-I molecules for immune surveillance

Question 14

How are exogenous antigens processed? (MHC-II)

Answer 14

Phagocytosis of exogenous antigen
Antigenic proteins are degraded in acidic phagolysosome
Peptides loaded onto MHC-II molecules for immune surveillance