In a "Fantastic Voyage" Plot, more often than not, the voyagers will have to contend with white blood cells that are instinctively trying to remove them from the bloodstream. (Hey, the white blood cells don't know the voyagers are there to help!) Either the voyagers will meet them head on and attack, or a Chase Scene will ensue.
In Real Life, white blood cells usually don't chase pathogens, they just float around and eat any threats that they bump into. Chemicals such as bacterial wastes or inflammatory secretions do attract them to the general area of infection, but most types don't actively chase any threats they find there.
- The orange blobs within the tree in Pokémon: Lucario and the Mystery of Mew are described as its equivalent to white blood cells. They specifically home in on any nearby humans.
- Cells at Work! (and by extension its spinoffs such as Cells at Work! CODE BLACK) personifies white blood cells as highly-trained pathogen killing machines.
- A variation in Druuna: Aphrodisia where Captain Williamson goes into a Journey to the Center of the Mind to find Druuna, but runs into antibodies which manifest themselves as insectoid monsters crawling out of the ground. He injected himself with a serum that causes them to ignore him at first, but later on it loses its effect and he has to make a break for it.
- Fantastic Voyage: White blood cells are mentioned but not seen until near the end, antibodies make an earlier appearance.
- Osmosis Jones anthropomorphizes the entire human body, giving all the various cells and such names and allowing them to speak and develop friendships with other cells. The white blood cells are treated like the police, so they get a lot of chase scenes with equally anthropomorphic pathogens.
- Doctor Who:
- In the story The Invisible Enemy, the Doctor and Leela travel inside the Doctor's body note to deal with an alien infection. At one point, they're attacked by white blood cells, but the Doctor uses a nearby nerve cluster to send them a fake message summoning them to a different part of the body. (This wouldn't work in a human body, where white blood cells just wander aimlessly and deal with whatever they happen to come across, but maybe a Time Lord's immune system works differently.)
- In Into the Dalek they... well, see the title. A Dalek's machinery has the equivalent of white blood cells: little seeker robot things that fly around and blast anything that causes damage, such as shrunken people.
- In The Outer Limits (1995) episode "In the Blood", a spaceship crew punches a hole into another dimension, which they assume to be hyperspace or subspace. The main character, who is descended from Magical Native Americans, starts to believe that it is actually the bloodstream of the living universe. What they originally thought to be asteroids turn out to have a similar structure to human white blood cells, except they use gravity to kill infection.
- Mario & Luigi: Bowser's Inside Story
- One room inside Bowser features a large worm boss that is eating what appear to be white knights. After you defeat the worm, the knights ambush you and send you falling. It's not explicitly stated that these are white blood cells, but Toadbert's description of their intent matches perfectly.
- There's also Alpha Kretin, who is by no means a white blood cell, but attacks in the same way, swarming Princess Peach and then taking some kind of monster form after it's spun away by Mario and Luigi. Sadly, it also appears in the Gauntlet.
- Although it's not a physical example, Censors in Psychonauts are a mental equivalent. Censors roam the psyche and censor out anything that doesn't belong, including hallucinations, paranoias... and visiting Psychonauts. In fact, one of the first signs that Boyd's mind isn't doing so well is that there are no Censors whatsoever in there. It isn't until Razputin uncovers the isolated Manchurian Agent implanted in his mind that both Censors and the G-Men, who were Good All Along and had the same goal as Raz and Boyd, show up in droves to stamp out the delusion.
- During the Teen Titans episode "Crash", Cyborg gets infected with a virus, so Gizmo and Beast Boy go micro and fight the virus. One scene shows white blood cells chasing them.
- During an episode of The Magic School Bus, "Inside Ralphie", the classroom piles into their bus and goes micro to figure out what's making Ralphie get sick. They encounter white blood cells, which identify the bus as a pathogen and start a chase scene. The white blood cells are shown "sniffing" for pathogens, even though they don't have noses. White blood cells don't actually move like they do in this episode; they mainly just float along and consume any pathogens they come across.
- In the "TV Dinner" episode of Megas XLR, Coop and company enter a planet-sized monster's body, where the titular Humongous Mecha is bacterial-sized by comparison. They get attacked by the extra-terrestrial equivalent of white blood cells.
- This happens in Archer in the episode where the crew has to destroy an aneurysm inside the brain of an important scientist. The white blood cells try to consume the ship they are in but Archer kills them with a laser gun.
- This video shows a white blood cell chasing a staphylococcus bacterium.
- Fetuses have to be protected from the mother's own white blood cells.
- Although white blood cells don't usually chase pathogens directly, they do actively migrate towards potential sites of infection in response to inflammatory compounds: the same chemicals which cause tissue to become swollen, red, hot and sore when injured. If bacteria happen to penetrate the injury site, the WBCs will at least be in the right neighborhood to gobble them up.