Chapter 2: The Enemy Comes
Day (1)
"Warning. Warning. Warning. Incoming virus spores detected approaching LC676 Alveolus." A robotic voice announced amidst the screeching blares of the Klaxons. "Repeat. Incoming virus spores detected approaching LC676 Alveolus."
The words of the bacteria came back to U-1196 as loud as the wails of the sirens. She felt her mitochondrion sank at the thought that what the Streptococcus Pneumoniae might be right. This could indeed be the start of a devastating plague.
"That's… That's where we are going," the glasses-wearing erythrocyte sounded aghast. "We are supposed to exchange our carbon dioxide on that Alveolus."
His companions exchanged worried glances. Blush and Burns adjusted their hold on their CO2 packages as if to steady themselves while Sharp remained still. His expression, however, contorted ever so slightly to express his uneasiness. Freckles instinctively shuffle to stand close to the bespectacled red blood cell.
"We can just go and exchange our gas canisters on another station," stammered Blush.
"No. We can't do that." countered Sharp. "We have our orders. We must exchange our packages on the designated supply depot, or we'll cause a backlog."
This only made the five erythrocytes even more tensed.
"Don't worry, we'll escort you," U-1196 offered, gesturing to her kouhai leukocyte of her intent. "We are also heading that way."
"Then there's no time to lose," J-1178 added, unsheathing her katana blade. She then eyed the glasses-wearing erythrocyte. "Try to keep up, Rookie."
AA-2153 nodded. He exchanged one final look with his friends, who needed no further instructions.
"Alright, follow my lead."
They moved as one team with the two white blood cells leading the way, followed by the five red blood cells.
Klaxons blared from all ends of the pulmonary arterial corridor they were in. Likewise, the robotic voice talking in the PA system kept on repeating its warning of the impending virus invasion at Alveolus LC676.
Along their way, U-1196 noticed other groups of red blood cells making detours away from the affected Alveolus, crowding instead at the capillaries heading to the other adjacent Alveoli. The veteran neutrophil made a quick glance at the quiet erythrocyte named Sharp and realized how right he was to keep on their original delivery route.
The delivery of oxygen must not be hampered by any reason. This world cannot afford any system failing or operating inefficiently. With the numbers of her kind in the immune system abnormally low, they could not guarantee an all-encompassing patrol for the entire world.
She tapped in on her headset to listen on any other neutrophils responding to the alert but heard none. She made a side-glance at her kouhai leukocyte and realized they might be the only reinforcements to respond. Even with the reforms enacted by the Consciousness for the world, the soldiers of the immune system could not be afforded any rest.
From the pulmonary artery, they entered the capillary that led straight towards the lower section of Alveolus LC676. Unlike the enclosed passageway of the pulmonary artery, the capillary had a glass lining that let cells see the hollowed insides of the Alveolus.
The floor rumbled as a gust of air whooshed into the Alveolus' opening.
U-1196 stopped to peer into the window panes and saw to her horror numerous virus spores falling rapidly from the opening. Below, she saw frantic Pneumocyte cells, wearing hats with the Roman numerals 'II' etched on the front, trying to scramble away from the falling virus spores.
"By the Consciousness, those Type II Pneumocytes…" J-1178 placed a hand over her mouth, unable to finish her sentence.
U-1196 let out a curse under her breath. They were already too late. By the time they reached the inside of the Alveolus, hundreds of those pneumocytes would already be infected. There would be no prevention now, only extermination of the fallen.
She slammed a fist into the glass pane in frustration that caused the five erythrocytes to jump into attention.
"Nanahachi, help me find the switch," the veteran neutrophil growled through clenched teeth. Immediately she darted her gaze from side to side of the hallway looking for something.
"Already on it, Onee-sama," J-1178 concurred, already moving and exploring the wall panels below the glass panes for any hidden switch.
As for the five red blood cells, they stood silently, not daring to disturb the two white blood cells in their search.
AA-2153 watched his neutrophil friend growing more frustrated with each passing second. As his friend said, they were looking for some type of switch. But switch for what?
Wait…
His eyes went wide with sudden realization. He shifted his gaze towards the other end of the corridor before looking back to his neutrophil friend.
"Nee-san, are you looking for a Selectin switch?" AA-2153 asked.
Burns standing beside him, tilted his head to one side. "Selectin what?"
He was aptly ignored.
U-1196's face perked up. She immediately strode towards the bespectacled erythrocyte before placing her hands on his shoulders.
"Have you seen one?!" she asked, almost shouting to his face. "Tell me, please!"
AA-2153 seemed to shrink from the intense gaze of the veteran neutrophil. "I think it's somewhere near the supply depot if I'm not mistaken. There's a large-"
U-1196 didn't wait for him to finish his sentence before sprinting her way towards the direction of the supply depot located on the other end of the capillary hallway. J-1178 gave him a final glare before she too moved to catch up with her Onee-sama.
"What in the name of the Consciousness are they looking for?" Burns queried once more, this time visibly worried at the sudden haste of the two neutrophils.
"They're looking for a Selectin switch, so they could-"
Screams and frantic shouts screeched out of the PA system. Immediately, all five erythrocytes went to gaze out of the glass panes. To their horror, they saw dozens of pneumocytes getting infected by the falling virus spores. Their cries were being broadcast into narrow halls of the capillaries.
"Consciousness help us!" AA-2153 heard Freckles blurt out, her voice in the middle of cracking.
"We must catch up with Nee-san," the bespectacled red blood cell told his companions. "Something bad is about to happen."
"Bad what?" Burns again asked, already frustrated at being ignored.
"The Selectin switch," AA-2153 began, his face now full of dread. "Will allow Nee-san and Nanahachi-chan to transmigrate into the Alveolus in a process called-"
"Diapedesis," Sharp muttered, realization now dawning on his face. "You're right, this is bad."
Diapedesis or Neutrophil Transmigration is the process for neutrophils to squeeze out of the blood vessels and into the parts where pathogens are located. Diapedesis is only a step of a more extensive process for neutrophil response called Leukocyte Extravasation.
"It means they will open the walls of this capillary for them to get out." The bespectacled erythrocyte continued his explanation before his friend could react. "This also means we will be exposed to the outside. We could be sucked out if we're not careful."
"Wait, doesn't this sound like the start of an inflammation?" Blush chimed in. He had remained mostly silent during the whole conversation, but unease finally forced him to voice his concern.
"It is," Freckles replied before starting to run. "No more questions. We need to move now!"
=0=0=0=
U-1196's footsteps echoed against the capillary's hard floor. Pneumocyte cells wearing caps with the numerals 'I' rushed past her, desperately wanting to get as far away from this place as possible.
"Clear of the way!" she bellowed at the fleeing Pneumocytes, frustration building inside her.
"Get back to your posts!" J-1178 barked behind her. "This will be contained!"
The pneumocytes inside the Alveolus were now a lost cause. She wanted to blame herself for that, but she crushed those self-loathing thoughts before they could get her off track. Death was a constant in this world, and it was absurd to think she could save everyone from it. What she needed now was to concentrate and apply all her rage in the extermination of their enemy.
After what seemed like a long run, the two neutrophils finally reached the supply depot. Canisters of CO2 and O2 littered the floor, indicating they were left here by fleeing red blood cells. The sight somehow made her feel disgusted at the blatant dereliction of duty. Again, she quickly ignored such thoughts and focused instead in searching for the Selectin switch.
Fortunately, it didn't take long to find it. Just like what her rookie erythrocyte friend said, the switch was located exactly beside the supply depot inside a box casing labeled, 'Selectin'.
U-1196 opened the box to reveal a handprint scanner and not some levers like an actual switch. She removed her left glove and placed her left hand on the glass panel. The scanner then analyzed her hand.
"Um, Onee-sama," J-1178 tugged her sleeve. "Look!"
The junior neutrophil pointed at something outside the Alveolus.
The veteran neutrophil leaned closer to the windowpane, and what she saw made her eyes wide open with shock.
"That's…"
A figure in black inside the Alveolus caught her attention. Amidst the fleeing pneumocytes, she saw a maid wearing glasses and sporting two braided pigtails standing alone and looking up towards the falling virus spores. She wielded a broom with spikes in her gloved hands, which appeared a complete juxtaposition from the rest of her outfit.
"Hey, who's that?" her bespectacled erythrocyte friend asked, pointing at the maid below.
"An Alveolar Macrophage," U-1196 muttered, captivated by the maid and flowing elegance. "She's the one who triggered the alarm."
Alveolar Macrophages, also known as Dust cells, are macrophages found inside the millions of Alveoli of the lungs. They keep the Alveoli clean from dust, debris, and pathogens that somehow make their way inside. For many circadian years, they wore heavy black cloaks to protect themselves from the inhalation of hazardous granules caused by excessive smoking. Due to the reforms enacted by the Consciousness, the lungs have been free from the effects of tobacco, and these macrophages have returned to wearing only their usual black maid uniforms.
Aside from their designation as cleaners of the Alveoli, they also prepare the proper rituals of phagocytosis for cells that have committed apoptosis in the service of the world.
For a fleeting moment, U-1196's thought that the alveolar macrophage could handle the incoming invasion by herself. After all, the macrophages were not only known for their elegance and beauty, but also for their unbridled ruthlessness in battle. And yet, even with such a strong battle maid, U-1196 knew that this onslaught would still prove to be more than a single macrophage could handle.
The veteran neutrophil was about to move away from the glass windows when she noticed the alveolar macrophage spread her hands to her side as she stared up into the opening above. She opened her mouth.
U-1196 eyes went wide with horror as a sudden realization dawned on her. With only a fraction of a second, she swerved to look back at the junior neutrophil, her lips curling up to form a snarl.
"Brace yourse-"
But her words died on her throat as she heard a nucleus-splitting scream.
A/N:
This is more of a transition chapter. Actually, this was originally the first half of a much longer chapter, but I have to cut it for Story Beat purposes. I usually write chapters that average from 1.5k to 2.5k words, so anything above 3k gets immediately cut.
Anyways, there are plenty of medical tidbits shown in this chapter, particularly the type of cells found in the Alveolus and the Selectin. For now, I'll just explain the parts of the Alveolus and the cells that call it their home. I'll make a separate explanation for Selectin and Leukocyte Extravasation in the next chapter.
Interesting Tidbits:
Pulmonary Alveolus
As mentioned in the previous chapter, our two lovely neutrophils chased a Streptococcus Pneumoniae inside the Pulmonary Artery. The bacteria was neutralized, and another alarm blared, requesting reinforcements into a particular Alveolus. They then went from the Pulmonary Artery into the Capillary of a certain LC676 Alveolus.
In real life, this is how our red blood cells travel to the Alveolus. From the heart, these red blood cells travel into the lungs inside blood vessels that become smaller and smaller until they reach the Alveolus. It is in the Capillary that Oxygen inside the Alveolus is exchanged with Carbon Dioxide by our ever industrious red blood cells.
Now in the CAWB manga, the Alveolus is depicted as a giant 'honey-combed' dome hanging inside the lungs. In real life, an Alveolus is microscopic, and you cannot see it with the naked eye. It's perhaps even smaller than what the manga, and I am depicting it. In this story, the Alveolus is huge compared to the cells, but in reality, it could be no larger than a small room compared to an Alveolar Macrophage.
Speaking of which…
Cells in the Alveolus
In this chapter, we are introduced to some new cells that are not an erythrocyte or a neutrophil. Here, we see the two types of Pneumocytes, namely, Type I and Type II Pneumocytes, running away from the incoming virus invasion and the Alveolar Macrophage facing it.
Type I Pneumocytes - In reality, the Type I Pneumocytes are the thin endothelial lining cells that encompass the Alveolus. In this story, they are shown inside the capillary, but they are actually the walls of the Alveolus, which, to me, seem extremely creepy and horrific if depicted as a Cells at Work fanfic. Imagine a dome coated by a mesh of anthropomorphic cells stitched together, screaming and begging for release. That's some Lovecraftian level of nightmare fuel.
Type II Pneumocytes - The Type II Pneumocytes, on the other hand, are the cells that produce a substance called a Pulmonary Surfactant, which helps with the exchange of gases between the blood and Alveolar air. It also helps with the regulation of Alveolar expansion during breathing.
Alveolar Macrophage - ah yes, the ever-vigilant maids of our Alveoli. The Alveolar Macrophages serve as guardians against respiratory invaders. They are the cleaners of the lungs, and they frequently remove inhaled dust particles as well. In this story, they are depicted wearing black maid uniforms in contrast with their more general-purpose sisters that prefer wearing white dresses.
Alright, that's it for the interesting tidbits, next up, we'll tackle Leukocyte Extravasation and Cytokines.
Stay safe, everyone!
References:
1 - Wikipedia - Pulmonary Alveolus
2 - Inflammatory responses in the initiation of lung repair and regeneration: their role in stimulating lung resident stem cells - inflammregen (d0t) biomedcentral (d0t) com
3 - The Basic Inflammatory Response by Ryan Abbot
Youtube: iVCXRa8FdP0
4 - Biology Help: Pulmonary Alveoli - Cells of Alveoli - Type 1 - Type 2 - Pneumocytes - Macrophages by 5MinuteSchool
Youtube: vCvkwtsh2z0
5 - ScienceDaily article: Researchers identify cells likely targeted by COVID-19 virus
Revision History:
- Originally published on June 9, 2020
