Effector T Lymphocytes

Question 1

Broadly speaking, how do Cytotoxic T Lymphocytes kill infected cells?

Answer 1

Inducing apoptosis

Question 2

What are the two mechanisms by which CTLs kill cells?

Answer 2

Granzyme + perforin – perforin makes a pore in the cell membrane through which granzyme can enter and trigger apoptosis
Fas ligand on T cell binds to Fas receptor on infected cell
When Fas has been engaged – it releases CASPASES
Both pathways upregulate CASPASES which drives apoptosis

Question 3

What are the four main effector functions of CD4+ T Lymphocytes?

Answer 3

Macrophage Activation
B cell Activation
Delayed Type Hypersensitivity
Regulation

Question 4

What are the two phases involved in Delayed Type Hypersensitivity?

Answer 4

Sensitisation – initial exposure to the antigen

Effector – delayed response

Question 5

What are the five T helper cell subsets?

Answer 5

Th1 – inflammatory responses
Th2 – boosts anti-multicellular organism responses
Th17 – important in control of bacteria
Follicular T helper cells – essential for generation of isotype-switched antibodies
Treg – regulation of T cell responses

Question 6

What is the main difference between T cell memory and B cell memory?

Answer 6

T cell memory doesn’t undergo isotype switching or affinity maturation – it does not get better