What is the link between the innate and acquired immune systems?
Macrophages. They phagocytose the invaders and present them to T0 cells
What do macrophages secrete that turns a To into a Th1 cell?
IL-12
What does the Th1 cell secrete after it has been converted from a To cell?
Interferon gamma which feeds back to the macrophage (along with NK and other cells in the IIS) and IL-2 which also feeds back on itself
What effect does gamma interferon (secreted by Th1) have on macrophages?
It enhances its activity within the innate immune system
What is the IL-12 gamma interferon axis?
Macrophage secretes IL-12 which turns T0 cells into Th1 cells. They then secrete gamma interferon which stimulates the macrophage
What other effect does the IL-2 secreted by the Th1 cell have besides enhancing itself?
It activates cytotoxic T cells which kill cells infected with the pathogen
How does a cytotoxic T cell know a cell has a pathogen?
It attaches to a MHC1 on the surface of the cell
What is MHCII?
It is a surface protein on all APCs that shows the antigen (of an exogenous pathogen) to the rest of the immune system
What are the antigen presenting cells?
Macrophages
B cells
Dendritic cells
What kind of cells in the body have MHCI?
All nucleated cells
What cytokine will convert T0 to Th2?
What cell produces this cytokine?
IL-4
It is produced by an unknown cell in the immune system
What cytokines does Th2 secrete and what cell do they in turn act on?
IL-4 and IL-5
They act on B cells
Once a B cell is activated by Th2 what does it become? What does it then produce?
A plasma cell
It produces immunoglobulins
