adaptive immunity

Question 1

what works under a humoral response

Answer 1

• b cell response
• secretion of antibodies

Question 2

what works under a cell mediated response

Answer 2

• t cells
• go to the pathogen to kill it

Question 3

what is drained into the tissue

Answer 3

• cells
• cytokines
• pathogen antigens
• enters lymphatics and moves to the lymph

Question 4

what are the parts of the lymph node

Answer 4

• Afferent lymph vessel (ARRIVING)
• Efferent lymph vessel (LEAVING)
• Artery and vein
• Subcapsular sinus
• Cortical sinus
• Medullary sinus
• Particortical area
• Primary lymphoic follice (b cells)
• Germinal centre
• High endothelial vessels

Question 5

how is the spleen involved in adaptive immunity

Answer 5

• splenic macrophages - use receptors to see bacteria and phagocytose bacteria
• detects if there is anything in the blood stream that is not meant to be there
• recycles rbcs

Question 6

what do MCHI shows

Answer 6

things that it is producing from inside the cell and then checks to see if it is self and ok

Question 7

what do MCHII show

Answer 7

they have engulfed something and then present to check if it is non self

Question 8

what are the types of t cells

Answer 8

• cytotoxic T cell - CD8+ t cells
• t helper cell - CD4+ t cells

Question 9

recirculation of t cells

Answer 9

1. t cell enter the lymph node via the high endothelial venules into the paracortical area
2. in the paracortical are t cells that interact with dendritic cells presenting antigens
3. if they don’t encounter the antigen, they move out of the efferent end of the lymph

Question 10

how do t cells recognise the antigen

Answer 10

1. t cell receptors recognise and CD4 binds to the MHCII molecule
2. co stimulation occurs B7.1 and B7.2 bonds and signals to CD28, this induces CD40L on the T cell which signals back to CD40
3. cytokine release then instructs the T cell what kind of T cell to differentiate into
4. the T cell produces IL-2 to act on itself and replicate - autocrine signalling

Question 11

co stimulatory molecules in adaptive immunity

Answer 11

• dendritic cells need to also express co-stimulatory molecules and chemokine receptor to reach the lymph
• induce pro-inflammatory cytokines TLR recognition induce co-stimulatory molecule upregulation and chemokine receptor expression
• intracellular infections INFa and INFb expression induces same effect

Question 12

t cell anergy

Answer 12

• cell not activated if there is no B7.1 and 2 on its surface
• become anergenic if there is no recognition

Question 13

what is the TH1 response

Answer 13

• enhance phagocytosis
• help macrophages
• IL12 secreted
• antigen restricted
• INFy produced - upregulates MHC molecules

Question 14

what is the TH2 response

Answer 14

• repair
• IL4 - turn macrophages down/ off
• IL5 - recruits eosinophils which degranulate and kill helminths
• IL13 - turn macrophages down/ off, enhance mucus secretion and gut peristalsis

Question 15

what is the TH17 response

Answer 15

• develop in response to pro-inflammatory cytokines
• activated by IL-21 and IL6
• stimulated by fungus and damages and apoptotic cells
• release IL-17 and IL-22

Question 16

what is the Treg response

Answer 16

• turn off the immune system
• stop the polarisation and make anti-inflammatory signals

Question 17

what do cytotoxic CD8 t cells do

Answer 17

• directly kill cells which express non-self-antigen on MHCI
• need helper t cell to also be bound to dendritic cell
• need IL2 from the neighbouring CD4+ t cell
• looks for the infected tissue and recognise the antigen bound to MCHI