I doubt the immune system is controlled by the brain. But we have a nervous system, which lets our brain know where the sense of touch or pain comes from. And it also passes brain commands to muscles, etc.

Is the nervous system an active part of the brain? Is it the nervous system which makes headless chickens run for hours? Who knows…

Calin said:
how is the body location transmitted throughout the body? … response command center (which I assume is the brain)?

There are a ton of systems in the body. Anything driven by nerves isn't driven JUST by the brain. We have nerve processing in the spinal cord, and in at a few other “second brain” nerve bundles, like the Auerbach's Plexus. That's the place you feel when you get ‘butterflies in your stomach' or certain other responses.

The lymph system is a parallel distribution system to blood and runs all through your body. That's actually the system that does a ton of distribution work with the immune system. The spleen, thymus gland, and a few other organs run the juice to lymph nodes all around your body. It isn't as active as the heart and blood vessels, but it still gets distributed everywhere in your body. It isn't location based, it floods the entire body with the immune response.

There are some immune responses that are local, like mast cells, that react to things like cuts and scratches that trigger inflammation and swelling. They play a part in a lot of things like allergies, and they play a role in the form of pneumonia that kills people with Covid-19, but they aren't directly part of your question.

Calin said:
If a person has covid that`s a virus located in the lungs, how is the virus presence, type and location within the body transmitted to the infection response command center (which I assume is the brain)? Once the response center has that location he has to detach the remedy (in our case citochines) to the location in question. How does the remedy (which I assume are some type of cells) know how to find the place where they are sent to? The remedy travels in the blood, so it travels throughout our entire body, how does it know where to stop/deploy?

Many body systems — including the immune system — don't rely on location. You've got a lot of assumptions there that really don't hold true. Viruses don't stay put exclusively in the lungs, but can spread anywhere through any circulation system. Viruses have areas they can attack more strongly than others, but they can travel everywhere. Cytokines are a messenger protein, and several immune system cells can dump them out. They flow through the blood and lymph systems, and other cells detect the message and respond. Some cells respond by repeating the alarm, some respond by taking action. When it gets into the blood it takes under a minute to spread around the entire body. Exactly how the cells respond to the chemical is beyond me, but I know they use the chemicals to communicate, and it doesn't take long for that signal to travel everywhere.

The lymph system is involved with a lot of immune response, and flows everywhere. An extra feature is that lymph vessels are meshed just below the skin and easily break, so if you get a cut the area will instantly be flooded with lymphocytes, a big part of the body's immune response. The body has a bunch of responses and many of them are spread throughout the body. The spleen produces a bunch of immune system cells, and distributes them through the lymph. White blood cells get distributed and can attack any virus, can move everywhere in the body (including between various body barriers) and serve as a rapid response. Bone marrow is all around your body and it participates both through manufacture of various cells and many B-cells that work as a memory and help control what antigens are made, including T-cells. T-cells fight more specific infections like viruses and can also flow everywhere, distributed mostly by the lymph system, but they're not a first response. There are lots of other cells in the immune system for fighting all kinds of infections beyond just viruses.

There are lots of other types of cells involved in immune response, and they're all spread everywhere in the body. Some are embedded in tissues, some free-floating, some in blood plasma, some in lymph, some embedded in organs and tissues. The response is everywhere in the body, and your entire body keeps fighting either until the infection is addressed or your body dies.