Lecture 44-T cells

Question 1

what is the cell which triggers T-cells when pathogen are detected in the body?

Answer 1

dendritic cells

Question 2

what are the input and output of the process of signalling T-cells during an infection?

Answer 2

input: pathogen or vaccine
output: anitbodies and cytotoxic T-cells

Question 3

what occurs to signal T-cells when infection is detected?

Answer 3

• pathogens enter body
• dendritic cells sample and breakdown the pathogen
• peptides are formed which are loaded onto MHC
• MHC-peptide complex taken to lymph nodes where they meet T-cells
• T-cells initiate immune response
• output (antibodies and cytotoxic T-cells) released

Question 4

what happens to endogenous antigens?

Answer 4

• proteins from virus in cytoplasm broken up into short peptides
• peptides transported to ER
• loading onto MHC-I occurs in ER
• MHC-peptide complex is sent to cell surface

Question 5

what happens to exogenous antigens?

Answer 5

• antigens are brought into cell by phagocytosis
• MHC-II made and imported to phagolysosome
• MHC-II loading occurs inside phagolysosome
• complex exported to cell surface