CD4+ t cells

Question 1

Main cell type linking adaptive and innate arms

Answer 1

dendritic cells

Question 2

Changes that enhance DC antigen presentation to t cells

Answer 2

Upregulation of MHC and increased cytokine production when DCs take in antigens

Question 3

TLRs recognising pathogens and sending signals leads to what in DCs?

Answer 3

Upregulation of chemokine receptor CCR7
Upregulation of MHH class II
Upregulation of co-stimulatory molecules

Question 4

Priming (activation) and differentiation of naive cells

Answer 4

DCs present antigens to naive T cells in the lymph nodes and upon exposure to the MHCII/peptide complex they are activated and given a message to survive + signalled to differentiate into subtypes of T helper cells

Question 5

Subtypes of T helper cells (five)

Answer 5

Th1 - proinflammatory, produce IFN-gamma
Th2 - anti-inflammatory, produce IL-4 and IL-10
Tfh - follicular helper cells (follicles of lymph nodes)
Th17 - proinflammatory, produce IL-1
Treg cells - regulatory CD4+ t cells, inhibit activation of CD4s

Question 6

What determines what type of subset a Th0 differentiates into?

Answer 6

Cytokines produced by DCs in response to pathogen determines the programme of CD4+ t cell differentiation

Question 7

Functions of CD4+ T cell subsets

Answer 7

different substrates of CD4+ t cell provide help to different targets to help control infection by different classes of pathogens, except for Tregs <- inhibitory of other CD4+ cells

Question 8

How does Th2 negatively regulate development of Th1?

Answer 8

Produce IL-4, which binds to receptors on Th1 cells and inhibit differentiation

Question 9

CD4+ t cells and autoimmune disease

Answer 9

autoimmune diseases often linked to HLA class II alleles -> implicates CD4+
Excessive Th1, Th2, or Th17 can lead to autoimmune diseases
Excessive Th2 can lead to allergy