The immune system: what is it?

How the immune system works

I am not a scientist! I’m trying to make this understandable for non-scientists like me. If I can get these basics down, so can anyone!

The first thing to know is that it’s not like other systems in the body in that it doesn’t consist of specific organs, like the digestive system, nervous system, cardiovascular system, etc. It’s bigger than that.

The immune system spreads throughout the body through the blood, bone marrow, lymph nodes, and mucosa (both mucous membranes and that surrounding organs), and more specifically, it is a key function of the thymus gland and the spleen.

The immune system works to prevent pathogens such as viruses from causing harm. There are two branches of the immune system, innate and adaptive.

The innate immune system responds first to invading pathogens. The innate response is rapid but not specialized. There are many different types of cells involved.

The adaptive immune system responds to pathogens that slip past the innate immune system, and it remembers them if exposed again. The main cell types of the adaptive immune system are T cells and B cells, which are produced in the bone marrow from stem cells. They are also called lymphocytes.

T cells recognize invaders and coordinate immune responses. They consist of killers, helpers, and messengers. They kill infected damaged cells. They produce cytokines that fight pathogenic viruses, bacteria, and fungi. When they find pathogens, they send messages to activate the rest of the immune system.

B cells produce antibodies, called Immunoglobulins (Ig) of various types. These are specific proteins in our blood that respond to and counteract specific antigens (substances in pathogens that provoke an immune response).

Both T cells and B cells can become memory cells, which persist and can recognize when an antigen appears again and create a rapid, antigen-specific immune response. For instance, having had the measles once confers immunity — if exposed again, you don’t get the measles again because your adaptive immune system recognizes and defends against it successfully. You can prove it with a blood test for measles antibodies.

This is also how vaccines work. Introduce just enough of an antigen for the body to produce antibodies, and the body becomes immune to that antigen.

We don’t have any specific immune cells for SARS-CoV-2 (the actual name of the virus; COVID-19 is the name of the illness) yet, because it is novel — new. It’s one of many coronaviruses (which can cause the common cold). Immunity to one coronavirus does not confer immunity to others…and the nature of viruses is that they mutate.

So, it seems to me, developing a vaccine against SARS-CoV-2 is like trying to hit a moving target. There are labs around the world working on a vaccine — but testing one to see if it works well and is safe enough to offer everywhere takes time, about a year from what I’ve heard…so next spring…if the virus doesn’t mutate, possibly becoming even more contagious and severe.

Medical people in the trenches are currently trying to find out whether and when people who have recovered from COVID-19 have produced enough antibodies in their blood plasma to inject in critically ill people and turn it around.

Scientists around the world are also working on a simple blood test for SARS-CoV-2 antibodies. This test would not require as much testing as a vaccine, and it could be readily available in a much shorter time frame, telling us who’s had it and who hasn’t.

Since up to 25 percent of COVID cases may be symptomless (this is the largest figure I read), many more people many have had it and become immune than we now know.

For a fascinating look at the differences between the bat immune system and humans’ immune systems that explains immunity more eloquently than I while still being understandable to non scientists, read this: https://get21stnight.com/2020/03/30/why-do-we-keep-getting-diseases-from-bats/.

The role of lifestyle

Your lifestyle is a major factor in supporting your immune system, making you healthier, possibly even conferring the ability to have that symptomless version of COVID-19 that I’m sure we all wish we had (but knowing we have it and self-quarantining so as not to spread it to people with weaker immune systems)…and having complete immunity afterwards.

Maybe even being able to donate blood plasma full of antibodies to save lives!

A healthy immune system might make the difference between a mild case and a serious case.

But since it’s new, we’re still learning.

Hygiene, diet, sleep, fresh air, exercise, the parasympathetic nervous system, and supplements all play roles in keeping your immune system working well. I intend to explore these in the coming days.

Defend yourself with impeccable hygiene

Humans got way healthier when we started washing our hands and utilizing public sewage systems and drinking clean water. Before these practices became common, a lot of people suffered and died miserably from cholera, dysentery, diarrhea, hepatitis, typhus, and other diseases spread from poor sanitation.

In the time of the coronavirus, the actions you can take to improve hygiene and reduce transmission of the virus include hand washing, coughing or sneezing into your elbow, not touching your face with unwashed hands, wearing gloves, wearing a mask, self-quarantining if exposed or ill (whether you test positive or not, given the shortage of tests), social distancing, sheltering in place, lockdowns.

This virus is very contagious! Please take care not to get exposed and not to spread it. Wash.Your.Hands and Wear.A.Mask.When.You.Go.Out.

Current coronavirus stats from Austin

This is day 4 of sheltering in place. As of last night, we had 160 cases here and one death, a woman in her 70s with significant underlying health conditions. Blessings to her family. 💚🙏🏽

It’s still affecting more people in the 20-40 age group than older people in this city with a young-skewing population.

One person at a homeless shelter has tested positive. That person is being isolated at a hotel and the 19 others exposed are also isolated and being monitored.

I’m hearing reports of customers being abusive to employees at to-go restaurants and grocery store cashiers. I hope management protects their employees and bans these people for a few days so they will be more appreciative.

New finding: Sanitation practices may play a bigger role than antibiotics in gut microbial diversity

Just sharing a link to a story on NPR News covering new studies on the gut microbiome.

Here’s a summary: Modern Western guts are missing microbes that exist in the guts of hunter-gatherer people.

Western diets and modern-day hygiene have wiped a few dozen species right out of our digestive tracts. One missing microbe helps metabolize carbohydrates. Other bygone bacteria act as prebiotics. And another communicates with our immune system.

The big question is why.  Continue reading