#macrophages

Propaganda!

Macrophages (abbreviated Mφ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris, and foreign substances, which do not have proteins that are specific to healthy body cells on their surface. This process is called phagocytosis, which acts to defend the host against infection and injury. Macrophages are found in essentially all tissues, where they patrol for potential pathogens by amoeboid movement. They take various forms (with various names) throughout the body (e.g., histiocytes, Kupffer cells, alveolar macrophages, microglia, and others), but all are part of the mononuclear phagocyte system. Besides phagocytosis, they play a critical role in nonspecific defense (innate immunity) and also help initiate specific defense mechanisms (adaptive immunity) by recruiting other immune cells such as lymphocytes.

The lung-cell type that’s most susceptible to infection by SARS-CoV-2, the virus that causes COVID-19, is not the one previously assumed to be most vulnerable. What’s more, the virus enters this susceptible cell via an unexpected route. The medical consequences may be significant. Stanford Medicine investigators have implicated a type of immune cell known as an interstitial macrophage in the critical transition from a merely bothersome COVID-19 case to a potentially deadly one. Interstitial macrophages are situated deep in the lungs, ordinarily protecting that precious organby, among other things, engorging viruses, bacteria, fungi and dust particles that make their way down our airways. But it’s these very cells, the researchers have shown in a study published online April 10 in the Journal of Experimental Medicine, that of all known types of cells composing lung tissue are most susceptible to infection by SARS-CoV-2. SARS-CoV-2-infected interstitial macrophages, the scientists have learned, morph into virus producers and squirt out inflammatory and scar-tissue-inducing chemical signals, potentially paving the road to pneumonia and damaging the lungs to the point where the virus, along with those potent secreted substances, can break out of the lungs and wreak havoc throughout the body.

The Immune System's All-Star Team: The Mighty Cells That Protect You

Your body is like a bustling city, constantly facing threats from outside invaders like viruses and bacteria. Thankfully, you have a team of dedicated defenders keeping you safe: your immune cells! Our immune system is a marvel of biological defense, tirelessly safeguarding our bodies from harmful invaders like bacteria, viruses, and parasites. At the forefront of this defense are numerous types of immune cells, each with its unique functions and capabilities. Did you know the average adult has about 2 trillion white blood cells, which contain most immune cells? That's more people than live in China! These tiny warriors come in different shapes and sizes, each with unique superpowers to protect you. Let's meet some of the key players:

The Innate Force: First up, we have the innate immune system. This frontline defense acts fast and nonspecifically, providing immediate protection against any threat. The key players: 1. Neutrophils: Think of these guys as the city's SWAT team. They're the first responders, rushing to attack invaders with toxic chemicals and swallowing them whole with their arsenal of enzymes! These are the most abundant immune cells, are short-lived but highly effective. Unfortunately, they die in the fight, leaving behind a green gooey mess (pus) that signals infection.

2. Macrophages: These are the veterans, the wise generals of the immune system. They go beyond mere engulfing, processing antigens (foreign molecules) and presenting them to other immune cells for recognition and attack. They also act as scavengers, cleaning up debris and orchestrating healing. These are the cleaners and recyclers. They gobble up dead neutrophils, debris, and even worn-out cells, keeping your city sparkling clean.

3. Natural Killer (NK) Cells: These are the ninjas of the immune system. They silently patrol, sniffing out suspicious cells infected with viruses or even cancer and eliminating them with a swift punch. The Adaptive Arsenal:

The Adaptive Arsenal: If the innate system fails, the adaptive immune system steps in. This highly specific defense remembers past encounters and tailors its response to each unique threat. The cells of adaptive immune system are:

B Cells: These are the antibody factories, producing highly specific proteins called antibodies that neutralize pathogens and toxins. Each B cell produces a unique antibody, like a lock and key, targeting specific invaders. They whip up special proteins called antibodies that lock onto specific invaders, like sticky notes, marking them for destruction.

T Cells: These are the generals, coordinating the entire defense. There are different types of T cells:

Helper T Cells: These are the commanders, directing and coordinating the immune response through chemical signals. They activate B cells, macrophages, and other immune cells, orchestrating a multi-pronged attack.

Cytotoxic T Cells: These are the elite soldiers, directly targeting and eliminating infected cells or cancer cells. They recognize and bind to specific enemy markers, unleashing a lethal attack.

Memory T Cells: These are the veterans, remembering past encounters with invaders and helping the immune system respond faster next time.

The Unsung Heroes: Beyond these main players, numerous other immune cells contribute to our defense. These include:

Dendritic cells: These antigen-presenting cells capture and process pathogens, presenting their fragments to T cells for activation. They're like the scouts, gathering enemy intel and relaying it to the command center.

Mast cells: These cells reside in tissues and release inflammatory chemicals in response to allergens or parasites. They're like the alarm system, alerting the immune system to local threats.

Eosinophils: These specialize in fighting parasitic infections, releasing toxic chemicals to neutralize them.

Basophils: These are involved in allergic reactions and contribute to wound healing.

The beauty of the immune system lies in its intricate collaboration. These diverse cell types work together in a complex and beautiful dance, each playing a specific role to achieve a common goal: protecting our health. They communicate extensively through chemical signals, creating a complex network of interactions. Imagine B cells producing antibodies that bind to a pathogen, flagging it for destruction. Macrophages engulf and eliminate the tagged pathogen, while T cells coordinate the attack and eliminate any infected cells. Dendritic cells present captured fragments to T cells, priming them for future encounters. This seamless cooperation ensures a swift and effective response to any threat.

Inspired by that one fic on Ao3 except this AU is focusing on just platonic because my Aroace self is incapable of writing romance + I need more of just silly friends being silly friends

We will bring the floods, the pain and the violence

We’ll summon the soldiers of russet and violet

To sound the sirens and slay the giant

And when the battle is over, in the damage we’ve wrought

We’ll call upon the sentinels