Describe and discuss the 2 pathways for antigen processing: exogenous and endogenous.
Solution
Answer :
Exogenous antigens: Exogenous antigens are produced outside of the host cell and enters the cell
by endocytosis or phagocytosis. These antigens includes bacteria and bacterial toxins, parasitic
worms, inhaled pollen or dust, Antigen presenting cells (macrophages, dendritic cells, and B
cells) degrade ingested exogenous antigen into peptide fragments within the endocytic
processing pathway. APCs then present the fragments to T helper cells (CD4+) by the use of
class II histocompatibility molecules on their surface.
Endogenous antigens are forgein antigens which are synthesised inside the body cells which
includes the viral proteins produced after a virus infects the cell or the abnormal prteins
synthesisd by cancerous cells. Fragments of endogenous antigens are processed and presented by
antigen presenting cells through class I MHC molecules. T cells displaying CD8 recognize
antigen associated with class I MHC molecules and thus are said to be class I MHC restricted..
Describe and discuss the 2 pathways for antigen processing exogenou.pdf
1. Describe and discuss the 2 pathways for antigen processing: exogenous and endogenous.
Solution
Answer :
Exogenous antigens: Exogenous antigens are produced outside of the host cell and enters the cell
by endocytosis or phagocytosis. These antigens includes bacteria and bacterial toxins, parasitic
worms, inhaled pollen or dust, Antigen presenting cells (macrophages, dendritic cells, and B
cells) degrade ingested exogenous antigen into peptide fragments within the endocytic
processing pathway. APCs then present the fragments to T helper cells (CD4+) by the use of
class II histocompatibility molecules on their surface.
Endogenous antigens are forgein antigens which are synthesised inside the body cells which
includes the viral proteins produced after a virus infects the cell or the abnormal prteins
synthesisd by cancerous cells. Fragments of endogenous antigens are processed and presented by
antigen presenting cells through class I MHC molecules. T cells displaying CD8 recognize
antigen associated with class I MHC molecules and thus are said to be class I MHC restricted.
