"Yo! Look out!"

The epithelial cell grunted as a swarm of bacteria swam past. They were busy collecting nutrients, and the constant barrage didn't make their jobs any easier.

Intestinal Epithelial Cells

Cells lining the surface of the intestines responsible for collecting nutrients into the body and for keeping harmful substances, such as antigens, out.

The past few days had been quite taxing indeed. Recently, a constant stream of unfamiliar food made its way down to the intestines. Sure, the basic makeup was the same: carbohydrates, proteins, lipids, et cetera and so forth. It was the way they were combined that was throwing the epithelial cells off. The food seemed much… greasier than normal in the past few days. And saltier. And the water…

For some reason the water was much dirtier than usual one day. It was extremely strange, but one time water came flowing through that was filled with bacteria, viruses, and even some pieces of metal floating in it. This only happened once, and the water since had been pristine, but that one time was odd.

Unsafe Tap Water

In many parts of the world, tap water is unsafe to drink. It may contain harmful antigens, or even heavy metals. This can be due to poor infrastructure, poor filtration and water treatment, damage to the water lines, et cetera. People are often advised to only drink bottled, filtered, or boiled water in such areas. Places where the tap water is unsafe to drink include China, Mexico, and Flint, Michigan, United States, among others.

And recently, the quality of the oxygen they were getting seemed a bit off.

"Yeahahahahahah!"

"Agh!" The Epithelial Cell dodged as a swarm of small, pinkish bacteria swam past him and rounded a bend in the intestine. "Damn germs…"

"Hey, let's just focus on getting these nutrients," his colleague called over. "All this oil is making the food quite slippery. They're headed towards a Peyer's Patch anyway."

"Yeah, yeah."

The pair reeled in their nets, picked out a few bacteria that had wiggled their way in, and placed the catch into the receptacle in order to be processed.

The Epithelial Cell sighed as his goggles started to fog up.

I frickin hate this job, he thought.

…

M Cell hummed cheerily to himself as he rearranged the tables.

Perfect, he thought.

M Cell

M Cells are a special type of epithelial cell in the intestine, which lure in antigens before turning them over to the immune system. M Cells are found in "Peyer's Patches" throughout the intestine. Peyer's Patches seem like easy entrance points into the body to antigens, with thin membranes, but they are in actuality a deadly trap.

Straightening his tie, M Cell cast another cursory glance over his Peyer's Patch. A fine establishment, if he may say so himself. The tables were perfectly set, the napkins folded with the crispest of creases, the bar fully stocked with the finest of liquors.

And behind every cupboard, underneath every floorboard, immune cells were waiting.

No antigens will be getting through me, M Cell thought with a chuckle.

He looked down at his own outfit, making sure that all was crisp and clean and straight. He had to play his part, after all. He dressed as a waiter for a fine establishment, while harboring a merciless enforcer of the good of the body underneath his relaxed and personable exterior. Antigens came in expecting a feast.

It was they who would be feasted on.

Phagocytosis

The process by which immune cells, such as neutrophils and macrophages, engulf and digest antigens and infected cells. The word can be broken down into its components phago (to eat) + cyte (cell) + osis (the process of).

As if on cue, M Cell heard the relentless banging of flagella on the entrance to the Peyer's Patch.

"Xiǎo xìbāo guāiguāi, bǎ ménr kāikāi, wǒmen xiǎng jìnlái! Hahaha!"

M Cell frowned. he had never heard bacteria speak like this before. What was this strange language?

Whatever. It didn't matter. What did matter was finishing these bacteria off for the good of the body.

"Welcome, welcome, please come in!" said M Cell as he allowed the bacteria in.

"Bìzuǐ!" snapped a bacterium.

Well, this was interesting…

The bacteria were all quite small. Each had several long, tentacle-like flagella, and were covered in fine, pink, fur-like cilia. They were shaped like little pill capsules, and they had a single, bloodshot eye and a small mouth full of sharp teeth on the front of their bodies.

Salmonella Enterica

A strain of bacteria causing the disease salmonella. Commonly found in meat from cattle and poultry, as well as raw eggs. Salmonella can arise if such foods are not cooked properly, as heat kills the bacteria by denaturing their proteins.

They giggled and babbled among each other in the strange language unfamiliar to M Cell. It sounded like it had lots of "R" sounds, somewhat. It also felt almost musical, each word having a different tone, and the tones running together in full sentences with a quality that one might describe as songlike.

As expected, the bacteria started trashing the place. They flipped tables, broke bottles, and tore menus. M Cell was very experienced with bacteria. He was prepared to clean up his Peyer's Patch, once the immune cells finished cleaning up the bacteria.

"I hope you enjoy your visit. It will be the last thing you do," said M Cell as he pushed a button on a desk.

Immediately, neutrophils and macrophages jumped out of their hiding spots. Coming up through trap doors, materializing in cupboards, emerging from underneath tables, the converged on the bacteria. One neutrophil even jumped out from the grand piano in the corner.

However, these bacteria were quite slippery. They dodged, feinted, and wiggled their way away from the immune cells. M Cell grew concerned.

He broke out into a nervous sweat when a good deal of bacteria managed to break through the walls and escape into the bloodstream.

"No!" he cried.

The bacteria swam away, giggling uncontrollably.

The neutrophil who had been hiding in the piano immediately gave chase.

"This is U-4989!" he barked into his radio. "Some bacteria just escaped from a Peyer's Patch! I'm gonna need help down here, there's a lot!"

He ran out of the Patch and followed the bacteria. Several other immune cells followed after him.

"No, no, no!" lamented M Cell. "This isn't happening!"

"Don't worry, M Cell," said a macrophage with short, dark brown hair. "You did your job by luring the bacteria in. We'll do our job by killing the rest!" She smiled sweetly.

M Cell looked at the floor. On the ground were the bodies of a few bacteria. The macrophages were busy putting the dead antigens into a large pot.

"We'll take these to Dendritic-sama, hopefully he'll be able to help," said the brown-haired Macrophage. "You just stay here, clean up, and continue working hard! You did your duty, now we shall do ours."

M Cell bowed to the macrophages. "Thank you all very much. Please, hunt them down quickly!"

"Don't you worry about that one bit. It's what we do!"

M Cell picked up a broom as the macrophages all left, carrying the large pot. Bacteria flagella hung over the rim of the pot, trailing outside.

Strange…

Did he just see one of the flagella twitch as the macrophages left?

No, it must have been a trick of the light. When macrophages are called into duty, they execute it to the fullest extent.

Literally.

Author's Note: As a Cell's at Work! fan who is also studying Mandarin, I thought it would be fun to set a story in China! I have visited Beijing twice already, and it honestly felt like my second home, but let's be honest… come things about Beijing life do quite a number on our cells (air pollution, unsafe tap water, questionable street food…)

Translations for the Mandarin:

"Xiǎo xìbāo guāiguāi, bǎ ménr kāikāi, wǒmen xiǎng jìnlái!" - "Open up, good little cell, we want to come in!" (this is a reference to a children's song called "Little Rabbit." I've replaced "rabbit" with the Mandarin word for "cell," xìbāo.

"Bìzuǐ!" - "Shut up!"