Which immune cells are important when considering immunity?
*The slides today are an oversimplification of an intricate and nuanced system.
Your body is built to defend against invaders. After the physical barrier of your skin/mucosal lining, your innate system is the first to kick in. This system is fast and ready to go before anything even presents itself as a threat. In this post I discuss macrophages and dendritic cells because they are key for helping to signal the adaptive system. These cells are able to engulf foreign particles, destroy them, and use the debris to signal for other immune cells and proteins.
The adaptive system is the one that a vaccine is trying to prepare for future re-exposure. The adaptive system, made of B-cells and T-cells is slower and harder to activate but this is because it is secondary to the innate and it builds a strong and specific response to the presented antigen. It results in an army of cells and antibodies that recognize the antigen and can target it for neutralization quickly. These cells can also quickly scan your body for signs of cells that have already been infected with the antigen. When found, they signal them for death. The adaptive system is powerful and important for pathogens (like viruses) that our innate system tries to stop but is ultimately unable to.
Finally, in this post I briefly discuss antibodies and memory cells. After many specific B-cells and T-cells are created, a handful are set aside to wait in case the body ever encounters this antigen again (memory cells). Memory versions of these cells are kept in higher numbers than before and are also easier to activate. This makes the adaptive response faster in the chance of re-exposure. A vaccine is a way to get this memory already in place before you’ve even been exposed to the pathogen in the first place! That way when the real pathogen enters your body, your innate AND adaptive systems can jump at it immediately.
Source Material: How the Immune System Works, 4th Edition, Lauren Sompayrac, PhD
Posted on Instagram on March 12, 2021.