Antigen presentation

where are the cells of adaptive immune response held

in the LNs, antigens are presented to them there

3 examples of APCs

• They can process pathogens and display their antigens on its surface  

(macrophages, dendritic cells, B cells) 

• Dendritic cells take antigen from the tissue to the draining lymph nodes to present to naive T cells

how do DCs enter lymph

inflamed tissue drains into lymph vessels, DCs follow to LNs to activate T cells

difference between MHC I and MCH II

All nucleated cells in the body have MHCI and use it to show that the cell is healthy  

• Proteins are broken into peptides by the proteasome  

• These are funnelled to the ER and loaded onto the MHCI to be sent to the surface of the cell 

Only antigen presenting phagocytic cells can present on MHCII, and show parts of what they have phagocytosed 

(macrophages, dendritic cells, B cells) 

• Phagocytosis breaks down things using enzymes from the lysosome  

• Small peptides from them are placed onto MHCII which is found in vesicles 

• These are presented on the cell surface  

what do TLRs do when activating dendritic cells

stimulates co-stimulatory molecule upregulation, chemokine receptor expression and pro-inflammatory chemokine production

for intracellular infections, what can induce co-stimulatory molecule expression

IFNa and IFNB expression

what is the primary response for:

• extracellular pathogens

• intracellular pathogens

• For extracellular pathogens, the primary response is phagocytosis 

• For intracellular pathogens, the NK cells cause apoptosis and the debris is phagocytosed