The Immune System

The environment consists of numerous pathogens, which are agents, usually microorganisms, that cause diseases in their hosts. A host is the organism that is invaded and often harmed by a pathogen. Pathogens include bacteria, protists, fungi and other infectious organisms. We are constantly exposed to pathogens in food and water, on surfaces, and in the air. Mammalian immune systems evolved for protection from such pathogens; they are composed of an extremely diverse array of specialized cells and soluble molecules that coordinate a rapid and flexible defense system capable of providing protection from a majority of these disease agents. Components of the immune system constantly search the body for signs of pathogens. When pathogens are found, immune factors are mobilized to the site of an infection. This pathway provides an in-depth look at innate immune response, adaptive immune response, antibodies, and disruptions in the immune system. The pathway also provides vocabulary support for these topics, as well as opportunities for learners to self-assess their understanding by analyzing figures and answering questions.

Topics

adaptive immunity
affinity
allergy
antibody
antigen
antigen-presenting cell
APC
autoantibody
autoimmune response
autoimmunity
avidity
B cell
basophil
cell-mediated immune response
clonal selection
complement system
cross reactivity
cytokine
cytotoxic T lymphocyte
CTL
dendritic cell
effector cell
eosinophil
epitope
granzyme
helper T lymphocyte
TH
host
humoral immune response
hypersensitivities
immune tolerance
immunodeficiency
inflammation
innate immunity
interferon
lymph
lymphocyte
macrophage
major histocompatibility class
MHC I/II molecule
mast cell
memory cell
monocyte
mucosa-associated lymphoid tissue
MALT
natural killer
NK cell
neutrophil
opsonization
passive immunity
pathogen
pathogen-associated molecular pattern
PAMP
pattern recognition receptor
PRR
perforin
plasma cell
regulatory T
Treg cell
T cell