Khan Academy
Khan Academy: Innate Immunity
The human body requires a multilayered immune system to keep it running smoothly. The two main classes of the immune system are the innate immune system and the adaptive immune system, or "acquired immunity". This article discusses the...
Other
Dalhousie University: Antibodies
A very good explanation of what antibodies are and what their functions are. Includes a list of the different types of antibodies.