To round off a week's worth of laboratory stories, how about some dessert? I know you must be hungry, because I didn't even tell you anything about microbiology and the fun specimens that come into the lab.
My contribution this week was a cake for my coworkers. I went with Funfetti cake, because in my experience nobody hates Funfetti, and it was easier for me to use a box mix than to try my hand at a from-scratch cake. I colored some vanilla frosting so it would have a yellow tint like the plasma we work with, and then I decorated it with antibodies.
I initially thought pretzel sticks would work, but they're too inflexible. My antibodies are made out of Twizzlers Pull-and-Peel (cherry flavor), carefully peeled, cut to size, and pressed into the frosting. Several which were not cut to the right length were eaten in the process. For science.
The little guys around the edges are IgG molecules. They're made of two long "heavy chains" and two small "light chains" and look like little letter "Y"s. The upper tips of the Y, where the light chains and heavy chains are held together with sulfide bonds, is where the antibody magic happens in your immune system. Those tips will recognize and bind antigens, signalling your immune cells to attack. Variations in the amino acids at the antigen-binding region of the antibodies make your immune system capable of mounting a response to pretty much anything nature can throw at it.
The big mess at the middle is an IgM pentamer, which just means five IgM antibodies bound together into an immunological ninja star. IgM is usually the first antibody to respond to an infection. The reason you can be tested for Lyme disease and they can tell the difference between an active infection and a past infection is that the IgM will be present if your body is still fighting in its initial encounter with the bug, while the IgG antibodies will persist for life, hanging around ready to multiply if you're ever re-infected.
I'm pretty certain that cake doesn't have much effect on the immune system, but it sure made us happy.