Ask A Scientist: What’s the Difference Between Human Monocytes and Macrophages?

Monocytes and macrophages are very closely related cells with a few important distinctions and different use cases. Put simply, monocytes are macrophages in the blood; macrophages are monocytes in tissue.

Understanding the Difference

Monocytes are the largest type of white blood cells and play an important role in the adaptive immunity process. Monocytes typically circulate through the blood for 1–3 days before migrating into tissues, where they become macrophages or dendritic cells.

Macrophages are monocytes that have migrated from the bloodstream into any tissue in the body. Here they aid in phagocytosis to eliminate harmful materials such as foreign substances, cellular debris and cancer cells. Macrophages take on various names depending on the tissue to which they migrated:

• Kidney: Intraglomerular Mesangial Cells — Specialized pericytes that monitor glucose levels
• Liver: Kupfer Cells — Phagocytic cells that express macrophage biomarkers
• Lungs: Alveolar Macrophages — Found in the pulmonary alveolus and “clean” respiratory surfaces
• Lymph Nodes: Sinus Histiocytes — Immobile macrophages found in the medullary sinuses
• Placenta: Hofbauer Cells — Thought to prevent vertical transmission of pathogens from mother to fetus
• Skin: Langerhans — Dendritic cells in the skin and mucosa associated with HIV, HPV and LCH
• Several Others

These subpopulations of macrophages have functional differences due to environmental signals but are all part of the same macrophage family.

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Use Cases for Monocytes

Charles River monocytes are purified from peripheral blood and are versatile enough to meet your exact needs. With monocytes, you can:

1. Thaw and use in an assay the same day
2. Culture dendritic cells
3. Culture to make macrophages
4. Produce a variety of cytokines and chemokines

For in vitro studies, most laboratories culture monocytes for five days in the presence of M-CSF, at which point they consider the cells to be macrophages. Monocytes can also be cultured with GM-CSF or IFNγ added to the medium. These cytokines push the cells toward a more inflammatory phenotype.

Browse Human Monocytes

Use Cases for Macrophages

Because macrophages can have suppressive effects on tumors, they are used to study various infections and immunotherapies. You can use Charles River macrophages to:

• Study chemotaxis
• Study effects of drugs on macrophage functions
• Study their role in wound healing

Browse Human Macrophages