Types of macrophages (reviewing)

The types of macrophages

M1 the classically activated macrophage (CAM) which participates in the Th1 pathway (IgG, IgM, and IgA...non hidden infections)

M2 the alternatively activated macrophage (AAM) which participates in the Th2 pathway (IgE hidden infections)  triggered by Il-4

TAM macrophages which have the TAM arms and are involved in the viral pathway
     http://angelabiggs.blogspot.com/2017/02/tam-receptors-and-ifns.html

TAM stands for : TYRO3, AXL, and MER

IFN alpha, MER, and TLR7 /TLR9 (mitochondria and nucleus)
https://arthritis-research.biomedcentral.com/articles/10.1186/ar4517

IFN beta, TYRO3, and TLR3 (cytosol)
https://www.ncbi.nlm.nih.gov/pubmed/26085147

IFN gamma, AXL, and natural killer cells (also TLR8 which is the ER)
https://www.ncbi.nlm.nih.gov/pubmed/18840707

MDSC are considered M2-like. Myeloid- Derived Suppressor Cells are triggered by the Natural killer pathway. They are not true macrophages. This pathway is triggered by the destruction of ER  by a virus within the cell...no markers are available at the infected cell's surface and these "naked" cells will be destroyed.

IFN gamma is critical in activating MDSC to suppress.
https://www.ncbi.nlm.nih.gov/pubmed/18607390

Note that the IFN gamma also suppresses the Th2 pathway where infectious pathogens are hiding (like parasitic worms) as well as stimulating the AXL hands of the TAM macrophages.

IFN gamma is made by TLR8 the nets of infected ER or Natural Killer cells....when surface proteins are not available to bind with AXL and very little HLA-C mailboxes will make it to the surface because the ER of the cell has a virus infection.