Alphabet Soup and Microscopic Bugs

Caught up in the hubbub of Peru, Vegas, and other extracurricular activities, I have yet to provide a mini introduction to Block IV: Immunology and Microbiology. I think this post is aptly appellated "Alphabet Soup and Microscopic Bugs," as Immunology is nothing short of memorizing tons of different complement factors (C1 thru C9), interleukins (IL-1 thru IL-12), receptors, chemokines, immunoglobulins (IgM, IgG, IgA, etc.), and a myriad of other biochemical molecules. And Microbiology is simply memorizing bug after bug after bug, from herpes to the HIV to the flu. Structure, classification, staining, life cycle, symptoms. However, this Block is incredibly important, as it is the only time in the first two years where we study these topics. Next year we will review anatomy and physiology as we study the pathophysiology of each organ system, but not the material covered in the next few weeks. This Block is also fairly comprehensive: these are most of the infectious organisms that we will have to know in and out as physicians. So a year from now, this will be a very important part of our first milestone, the STEP 1 exam. Plus, I find both fields fascinating and relevant (very exciting since I have struggled to find the relevance of some of the material covered so far).

To provide an example of the ridiculous amount of letters and numbers that require rout memorization, I have selected to detail the alternative complement pathway (courtesy of Wikipedia). "Complement" is a biochemical cascade that helps the antibodies in our body clear pathogens. It is part of the "innate" immune system, which means that it is one of body's first responders to infectious disease. Essentially, these molecules act as little markers on foreign cells, waiving the red flag saying, "Hey! This guy doesn't belong here! Kick him out!" They are, in more preferable vernacular, the tattle-tales of the immune system.

"The alternative pathway is triggered by spontaneous C3 hydrolysis directly due to the breakdown of the thioester bond via condensation reaction (C3 is mildly unstable in aqueous environment) to form C3a and C3b. C3b is then capable of covalently binding to a pathogenic membrane surface if it is near enough. If there is no pathogen in the blood, the C3a and C3b protein fragments will be deactivated by rejoining with each other. Upon binding with a cellular membrane C3b is bound by factor B to form C3bB. This complex in presence of factor D will be cleaved into Ba and Bb. Bb will remain covalently bonded to C3b to form C3bBb which is the alternative pathway C3-convertase. The C3bBb complex, which is "hooked" onto the surface of the pathogen, will then act like a "chain saw," catalyzing the hydrolysis of C3 in the blood into C3a and C3b, which positively affects the number of C3bBb hooked onto a pathogen. After hydrolysis of C3, C3b complexes to become C3bBbC3b, which cleaves C5 into C5a and C5b. C5b with C6, C7, C8, and C9 (C5b6789) complex to form the membrane attack complex, also known as MAC, which is inserted into the cell membrane, "punches a hole," and initiates cells lysis. C5a and C3a are known to trigger mast cell degranulation. IgA is associated with activating the alternative path."

That is one of the many pathways we had to learn for our first exam.

We started learning about microbes this past week (and my lack of an example shows you that I'm already a week behind). But we also have enjoyed a couple small group and laboratory sessions. I honestly wish I could detail what we are learning in lab (besides Gram staining), but I'm more of a "laboratory technician" than a true "scientist." After I proceeded to break half of the glassware in my drawer during Organic lab with Becky Smock, and then blew up my fair share of UNC MelTemps, I figure it's better to just do what I'm told. I'm tired of owing the Chemistry department money at the end of each semester. My partner, Austin Hester, tells me to swab the petri dish, and I swab the petri dish. If the table needs cleaning or 20 wells each need 14 drops of buffer, I do that as well. Yeah, I've never been much of a "lab" guy. I guess that's why my greatest accomplishment in my year of undergraduate research was "providing the lab with a more festive environment" - courtesy of my PI.

And so, I prefer working with macroscopic organisms instead of glassware and microbes.