Fiery Defender
This seemingly red-hot macrophage is one of the key components of the human immune system. These cells identify, engulf, and destroy pathogens and allergens that enter our bodies and clean up cellular detritus to keep it from accumulating in our bodies.
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This seemingly red-hot macrophage is one of the key components of the human immune system. These cells identify, engulf, and destroy pathogens and allergens that enter our bodies and clean up cellular detritus to keep it from accumulating in our bodies.
What am I looking at?
This is a colored scanning electron microscopy image of a human macrophage – a type of white blood cell. The term macrophage comes from the Greek words makro, meaning big, and phagein, meaning “to eat.”
Click on the right arrow to see another image of a macrophage.
Biology in the background
Macrophages are what many people think of when they think of a white blood cell. Though there are many different types of white blood cells, macrophages play several important roles in the immune system. They can identify viruses, bacteria, and allergens as foreign and then use a process called phagocytosis to engulf and destroy these pathogens. Then once they identify a pathogen, they can secrete antimicrobial chemicals and pro-inflammatory chemicals (such as chemoattractants, like histamine) to recruit more immune cells to the location of the pathogen.
In addition, besides defending us from outside pathogens, they also play a key role in homeostasis by clearing dead cells and debris from our bodies.
A macrophage is about 20 micrometers in diameter, or roughly four times smaller than the width of a human hair.
Technique
This image was created using electron microscopy.
TagsNational Institute of Allergy and Infectious Diseases, NIH