Innate immunity: defence mechanisms that are non-specific and ubiquitous. These are the cells that are often first on the scene, and charge in blindly, attacking everything left, right and center,
and then die.
Includes cells such as neutrophils,
monocytes, macrophages, dendritic cells, and very importantly, the entire complement system.
Aquired immunity: also called adaptive immunity, comes from exposure to immunogens.
Includes B cells and T cells. B cells make antibodies after being exposed to an immunogen. Encountering that foregin body
again (now called an "antigen") will cause the adaptive immune system to react faster than it did previous (because it has this
antibody memory, now. Thats why its adaptive, or aquired).
Cell-mediated immunity, also known as cellular immunity, is one of the two types of the adoptive immune system inside the body. It is mostly responsible for fighting microbes and antigens or foreign substances inside the cells. The T lymphocytes, or thymus-derived lymphocytes, are a key part of cell-mediated immunity.
Humoral immunity is a means by which the body protects itself from infection by producing antibodies that target foreign
material in the bloodstream that is seen as potentially dangerous, marking it for destruction. It is part of the adaptive immune system, which is activated in
response to a specific threat, as opposed to the innate immune system, which is continually active but less effective.