Adaptive immunity

Question 1

what are the main cells involved in adaptive immunity?

Answer 1

antigen presenting cells (dendritic, langerhans, macrophages, B cells)
T cells

Question 2

how do APC function?

Answer 2

• MHC II complexes are expressed on dendritic cells, B-cells and macrophages and they present microbial peptides from extracellular microbes
• MHC I complexes exist in all nucleated cells and present microbial peptides from intracellular microbes

Question 3

what is the ednogenous pathway of antigen presentation?

Answer 3

intracellular pathogens are processed by both non APCs and APCs
antigen is presented at surface via MHC I molceules but only APCs can stimulate immune system response via CD8 receptors on T cells

Question 4

what is the exogenous pathway of antigen presentation?

Answer 4

presentation of the microbial peptides from extracellular microbes via MHC II complexes occurs only on APCs – the APCs activate CD4+ T cells