Lecture 4- co-ordinated communication in the immune system

Question 1

how do Cells of the immune system work together to protect the host?

Answer 1

1 - resident cells recruit innate leukocytes and initiate inflammation
2 - DCs carry antigen to lymphoid organs
3 - DCs activate antigen-specific T cells
4 - CD4 T cells help B cell response
5 - T cells and plasma cells migrate from lymph node to infected tissue
6 - lymphocytes help innate cells clear infection

Question 2

what do innate response deal with?

Answer 2

most infections
Innate responses are first to encounter pathogens (including epithelial cells, mucous, etc)
Tissue-resident cells secrete chemokines to attract other cells

Question 3

what is present in Confocal microscopy of DC Migration

Answer 3

-capillaries, lymphatic vessels and dendric cells

T cells migrate towards DC in lymph nodes

Question 4

what do chemokines do?

Answer 4

control immune cell movement

CCR7 = chemotactic cytokine receptor 7
CCL21 = ‘chemokine with specific structural motif’ 21

Cyto (cell) -kinesis (affect)
Small proteins secreted to regulate functions of the immune system
Local and systemic effects

Include:
Interleukins (inter-leukocyte signalling)
Interferons (interfere with viral reproduction)
Chemokines (Chemical movement)

Question 5

how do CD4+ ‘helper’ T cells also shape tissue response?

Answer 5

TH1 cells are specialised for helping clear intracellular pathogens eg IgG production, macrophage activation, cytotoxicity

TH2 cells are specialised for helping clear multicellular parasites eg mucous production, IgE production, Eosinophil activation

Question 6

how do chemokines control immune cell movement?

Answer 6

Lymph nodes contain separate areas for T and B cells. Chemokines and their receptors help the immune cells move to where they need to be.
The image shows where cells are located in LNs and that chemokines are important in this positioning

Fibroblasts in the T cell zone secrete chemokines that attract T cells and DCs
T cells and DCs express chemokine receptors to move into T cell zone

Follicular dendritic cells secrete chemokines to attract B cells
B cells express chemokine receptors to direct them to B cell follicles

Question 7

what do DCs activate?

Answer 7

antigen-specific T cells

Question 8

what do DC cytokines drive?

Answer 8

T cell differentiation