T cell activation

Question 1

what is the only type of antigen T cells are able to recognise

Answer 1

peptide antigens

Question 2

describe what a TCR is in relation to a T cell

Answer 2

TCR = T cell receptor, a single T cell expresses 1000s of copies of a single TCR

Question 3

what else is required for T cells to be able to detect peptide antigens

Answer 3

MHC(Major Histocompatibility Complex) molecules need to present the peptide antigens to the T cell

Question 4

describe what an MHC molecule is

Answer 4

function = to display peptide antigens to T cells
also referred to as HLA(Human Leucocyte Antigens), able to present many different peptides, 2 classes

Question 5

describe the differences between Class 1 and Class 2 MHC molecules

Answer 5

Class 1 = expressed on all nucleated cells, present peptide antigens to CD8+T cells
Class 2 = expressed only on professional APCs(Antigen Presenting Cells), present peptide antigen to CD4+T cells

Question 6

give some examples of APCs(Antigen Presenting Cells)

Answer 6

dendritic cells, macrophages and B cells

Question 7

like B cells, T cells require another signal to become fully activated(not MHC) what is it and what do the T cells do once fully activated

Answer 7

other signal = co-stimulatory molecules expressed by DCs

once fully activated the T cells begin to clonally proliferate and differentiate into different types of effector cells