6.3.5 Principles of Adaptive Immunity

Question 1

What is the first law of immunology?

Answer 1

Lymphocytes detect antigen in different ways:

B cell receptors detect whole antigen (protein) on pathogen surface

T cell receptors detect digested antigen (peptide) presented on other cells

Question 2

Describe T-cell mediated immunity

Answer 2

Antigen brought to lymph nodes by dendritic cells for processing and presentation

T cells express TCRs that recognise foreign peptides displayed by MHC

Question 3

What is the second law of adaptive immunity

Answer 3

MHC class I present antigen fragments from cytoplasm (ICF)

MHC class II present antigen fragments from tissue fluid (ECF)

Allows compartmentalisation of antigen presentation