My Own Private Army

If you don't already know I'm a research scientist here in Dallas. My job focuses on immunological research and some of the areas that I study are cellular therapies to combat autoimmunity (i.e. Lupus, Arthritis) and cellular based cancer vaccines. I thought I'd show you one of the technologies that I use at work on a daily basis. Its called Flow Cytometry, commonly referred to as flow.

Last friday at work I volunteered my blood for an experiment I was running. Although I had used flow many times before, I had never use my blood as a control for an experiment and being the nerd I am I could hardly contain my excitement to see my own blood on the cytometer.



So in order to analyze blood an instrument called a Flow Cytometer is used. Basically it sucks up a blood sample and injects it into a fluid stream that carries the cells in a line one by one to a fixed laser. The cells intercept the laser and scatter the laser light. Big cells, like Monocytes, scatter more light than smaller cells, like Lymphocytes. So the horizontal axis in this graph measures the size of cells. The vertical axis measures the internal complexity of cells, like granularity. Granulocytes have more stuff inside them so they are higher on the vertical axis than Lymphs and Monos. I posted a picture that illustrates this process well. With a flow cytometer I am able to characterize cells in the blood at a rate of 40,000 cells per second.


Okay I know it looks like a bunch of dots but each dot that you see is representative of one of my blood cells. I have circled three populations of cells. Lymphocytes, the one in the lower left corner, are composed of my B Cells (the cells that make antibodies) and my T Cells (Half of these cells kill other cells that are infected with something nasty and the other half helps infected cells kill something that is inside of it. HIV Infects T Cells).

Granulocytes, located kinda above the Lymphs, are also known as Neutrophils. These cells exist solely to eat bacteria and digest them with enzymes. Typically these cells only last about 3 days and I am constantly replenishing them, as you should be yours as well. If I had an infection I'd see a much larger amount of these cells.

Monocytes, on the right, circulate in my blood waiting to be called on. When I get an infection they get signals from other cells at the site of the infection and migrate out of the blood to tissue that is infected at which point they become a Macrophage. They then engulf bacteria or virus, chew it up, migrate to the thymus, and present chewed up nastiness to T Cells or B Cells so that I can have a specialized (adaptive) response to my infection. So you know when you get sick and your Lymph nodes swell up? Thats because you have a bunch of macrophages, and other cells that present chewed up nastiness, flowing into your lymph nodes. The T and B cells wait in the Lymph nodes to be shown chewed up nastiness and then become trained to recognize nastiness at which point they multiply and go out and fight the infection. T cells either kill or help infected cells and B cells make proteins that stick to the nastiness (known as antibodies). Antibodies are like tags that other immune cells can then use to recognize nastiness faster and thus kill it faster.

Training T and B cells results in the production of memory cells so that when you get the same infection again you have antibodies, T killer and T helper cells ready to go immediately. This allows you to fight off infection faster the second time around. Your B and T memory cells are with you for your whole life and eventually you build up a kind of immunity portfolio. Isn't that badass!!! I think so.

To appreciate how powerful the immune system is you have to look at the two extremes of malfunction of immunity. Some children are born without an immune system or the ability to produce one. This condition is called SCID (Severe Combined Immune Deficiency). Without an immune system the life expectancy of these infants is next to nothing. On the other extreme your immune system cannot distinguish foreign nastiness from your own tissue or it thinks that your own tissue is foreign. This results in autoimmune disorders like Lupus or Arthritis. It is quite possible for your immune system to literally eat you alive.

I use this technology every day but it still amazes me. If you have any more questions about this or want to know more about this technology, T cell counts, or how the body fights infection let me know. I'm a big geek and I love talking about my work.