Pathogen Time or, BOOM Headshot

I was going to write about cell organelles, but I DO WHAT I WANT, so it’s really Pathogen Time. Plus, this nicely mirrors Video Game You (see: https://dailyscienceblog.wordpress.com/tag/john-mayer/ ), “know thy enemy” and all that. The big bosses are bacteria, viruses, fungi and prions.

Fighting a bacterial infection is basically the same as fighting zombies. They eat everything you love  (brains/nutrients), they’re dumb and gross and there are a shit ton of them. Thankfully, a headshot (with bullets, machete or antibodies) usually does the trick. Also, for common infections, you just need time to cut through the teeming horde. Less common ones require multiplayer mode/drugs. Although out-competing you for resources is the bacteria’s main mode of attack, they may also release toxins or invade your cells. Bacteria can also form “plaques”, consisting of bacteria and nutrients they are growing on/around. These can do a LOT of damage if left unchecked; the plaque on your teeth needs to be brushed off/scraped off with that God awful metal hook by the dentist or the bacteria will destroy your teeth. Do not let them destroy your teeth. A win for bacteria is a win for zombies.

Viruses on the other hand, while not technically living, are much more sophisticated than the single-cellular zombies on your teeth. The reason why they’re not technically living is because they cannot self-maintain, reproduce or metabolize on their own. For that, they use YOU. Yup, viruses are mad spies that hijack your cells into aiding their heinous schemes. Those schemes being replication of viral DNA and synthesis of viral capsids (think capsule) for the TOTAL TAKEOVER OF YOUR BODY. Remember that chickenpox you had? It planted its DNA in your cells, waiting until you’re old to hit you with shingles. Or not, viruses get senile too. Lucky for us, cytotoxic T-Cells are always up for playing a round of spy vs. spy.

Despite what you may think, fungi are not such fungis (GET IT GET IT). Just ask my brother about the crap that grew in his lungs when he lived in a glorified closet for a year. But I will tell you more about that tomorrow.

OH THE SUSPENSE. OH THE ALLCAPS.

 

 

Source

-. 2010. GRE Subject Test: Biology 5th Ed. Kaplan, New York.

Wassenaar, T. M. 2009. “Pathogenic Bacteria: Bacterial Pathogenicity”. Virtual Museum of Bacteria. 12 Feb, 2013. <http://bacteriamuseum.org/cms/Pathogenic-Bacteria/bacterial-pathogenicity.html&gt;

More on Video Game You

Now that I’ve had my rest and about a gallon of mango juice, I’ll continue on talking about Halo 4¾ : Immunecraft. But before I move onto the specialty classes of white blood cells, I forgot to mention a few base classes. Besides macrophages, other specialized white blood cells the are part of the nonspecific immune response include neutrophils, eosinophils, basophils and mast cells. Neutrophils engulf pathogens and infected cells like macrophages, but don’t keep any trophies after (they’re not APCs, antigen presenting cells). The other two ‘Phils and the mast cells release nonspecific toxins in the presence of invaders. So they’re your buddy with the flamethrower, that can maybe get too excited and maybe burn down more buildings than you’d like. But Flamethrower Carl’s enthusiasm does attract the attention of the other players; basophils and mast cells secrete histamine to dilate the capillaries and make them leak. The leakiness allows macrophages and neutrophils to reach a given infection site and, when signaled, the special forces can move in.

B Cells and T-cells are these special forces. Both are produced in the bone marrow, but the T-cells get upgrades by maturing in the thymus. These cells arrive when an antigen presenting macrophage activates a circulating helper T-cell. This is the “go” signal and starts a chain reaction of immune responses faster than you can think about saying “domino”. Helper T-cells divide and activate B-cells and cytotoxic T-cells which in turn start dividing, kicking ass and taking names (not in that order). Cytotoxic T-cells are your hit men with machine guns that can hone in on an enemy and riddle it full of holes (literally, they use enzymes to “pop” cells). They are great for attacking viruses in infected cells. B-cells are a bit more clever, they specialize into plasma cells which produce antibodies specific to the invader in question. Besides gassing out the enemy with antibodies, B-cells can specialize into memory B-cells in order to “record” the antibodies needed for a particular pathogen. Subesequent infections of the same pathogen are then fought off much faster. Finally, there is the underappreciated suppressor T-cell, a helper T-cell that gets out and reminds everyone (via chemical signals) that the immune system does not follow a scorched earth policy so PLEASE just tone it down guys, OK???

Probably the niftiest thing about this whole immune response/video game is that the B-cells and T-cells activated are activated because they are already specific to whatever is already infecting you. Your body can tell the FUTURE. Except it can’t. There are BILLIONS of B- and T-cells in your body, each with different surface receptors that can be activated by different antigens. So it’s a probability thing, like those monkeys on typewriters, but instead of Shakespeare, they come up with billions of cell surface receptors. Of those billions, your body can single out the exact one to save you from misery or even death.

 

Source

-. 2010. GRE Subject Test: Biology 5th Ed. Kaplan, New York.