The subjects of Immunity

The immune system acts against invading viruses and organisms.  The invaders would drain the host of nutrients and energy if not for immunological intervention.  The first lectures assert that modern times allow for generally pathogen-free living mainly by providing clean water and public sanitation (proper sewage disposal).  Also important are vector control (mosquito abatement), food safety, and vaccination.  Pathogens are grouped in different categories beginning with acellular viruses, prokaryotic bacteria, unicellular eukaryotes including fungi, protozoans, and finally multicellular worms platyhelminthes and nematodes.  In addition to availing oneself of modern safeties listed above, the simple act of washing hands frequently can have a large beneficial health result even before considering the immune system.

The different categories of pathogens offer different surface features that allow recognition by the immune system.  These features differ from the surface features of our own cells, thus allowing evolution of a system that distinguishes invader from self.  There are two different classes of recognition in the system: the innate and the adaptive.  Innate recognition involves detecting general patterns of molecules associated with the various pathogen classes and does not require prior exposure.  Adaptive response involves recognition of specific molecules associated with specific strains within the pathogen class.  It is developed after exposure to the pathogen.

After recognition in either category, the system has different levels of responses, ranging from relatively benign to all-out war.  These responses can also be misdirected, such misdirection characterized as allergies, inflammation, and autoimmune disease.

Innate	Fast (minutes)	Always there	Recognizes patterns	Phagocytes, NK cells, proteins & barriers
Adaptive	Slower-weeks initially, 3 or more days subsequently	requires gene rearrangement	Recognizes specific proteins	B and TH and Tc cells

I am unsure about how much augmentation I need on the blog.  I could incorporate all of the notes, but that makes no sense.  Perhaps creating links external to the course will enhance my understanding and