Subset Classical Intermediate Non-Classical
Stimulation/Differentiation CD14hi CD16- CD14hi CD16lo CD14lo CD16hi
Scavenger Receptor expression CD163+ CD163+ CD163-
Cytokine expression TNFα, IL-12, IL-10higher  - TNFαhigh IL-12high IL-10low
Chemokine recruitment CCL2/MCP-1  - CX3CL-1/Fractalkine CCL2-refractory
Antigen Presentation  - HLA-DRlow HLA-DRhigh
Tryptophan metabolism iNOS Arg+ iNOS
Function Anti-microbial Pro-inflammatory Tissue-damage Th1CMI response Anti-Tumoural Anti-parasitic Allergic response Tissue repair Th2 response Anti-parasitic Allergic response Humoral immun. Th2 response
Table 2: Monocyte subset functional phenotypes. Classical CD16-negative and CD16-positive non-classical monocytes can be classified according to their functional phenotype of scavenger receptor (CD163), cytokine expression, chemokine responsiveness, antigen presentation capacity (HLA-DR) and arginine metabolism (iNOS or Arg I). The combination of such phenotypes defines monocyte function as proinflammatory, CMI-inducing or tissue reparative, induction of humoral immunity. One point to be noted is that the classical and non-classical subsets express iNOS whereas the intermediate monocyte subset expresses arginase. Refer to macrophage table 1 earlier. This table has been adapted from [91,93,94,96,98,101,103,104].