Attack of the Macrophage
In this scanning electron micrograph a human macrophage, a type of cell found in blood that helps confer immunity and ward off infection, homes in on a chain of nasty Streptococcus bacteria. Hitching a ride aboard the macrophage is sphere-shaped lymphocyte. Both macrophage and lymphocyte can be found near the site of an infection, and the two act in concert to help eliminate it. The macrophage works be "eating" the invader. That act begins a complex process of biochemical communication that involves "helper cells" like lymphocytes, which help stimulate antibody production and make it easier for the invading germs to be consumed.

You, too, can learn about immunology and lots of other cellular-mediated events of nature by going to Cells Alive, a way cool page with lots of pretty scientific pictures of things we can't otherwise see. A big thanks to James A. Sullivan for lending us this CSI.