CD14CD16

CD14CD16 refers to monocytes that express both CD14 and CD16 on their surface. In humans, monocytes are commonly subdivided by these markers into classical (CD14++CD16−), intermediate (CD14++CD16+), and non-classical (CD14+CD16++). The intermediate subset, often defined as CD14++CD16+, is sometimes described as CD14CD16+ when emphasizing dual positivity for CD14 and CD16.

CD14 is a co-receptor for lipopolysaccharide and part of the Toll-like receptor 4 signaling complex, whereas CD16 is Fc gamma receptor III, which binds the Fc portion of IgG. Cells expressing both markers thus represent a distinctive monocyte population with characteristic functional traits.

Functionally, CD14+CD16+ monocytes display a pro-inflammatory profile, producing higher levels of cytokines such as TNF-α and IL-1β upon stimulation, and they possess antigen-presenting and phagocytic capacities that differ from classical monocytes. They are often considered more inflammatory and may exhibit distinct migratory and tissue-homing properties.

In health, these cells are a minority of circulating monocytes, and their frequency can shift with age, infection, and inflammatory states. In various diseases, including HIV infection, sepsis, and cardiovascular disease, CD14+CD16+ monocytes are often expanded and can correlate with disease activity or progression, making them a subject of ongoing clinical and translational research.

Nomenclature and interpretation: because marker expression can vary with technical and biological factors, researchers may use different definitions for the CD14+CD16+ subset. The term “CD14CD16” is thus context-dependent and may refer to the intermediate monocyte population or dual-positive cells in a given study.