Innate Immune system
The innate immune
system is evolutionally older; it is the dominant but non-specific protective
system in human being. It has several
components including (1) the skin and surface barriers, (2) inflammation, (3)
complement system, and (4) others.
The outermost layer of our skin comprises
primarily one type of protective cells, keratinocytes, which serve as a general
barrier to protect us against outside invaders, including bacteria, viruses, UV
light, etc. If the outside invader
breaks into the skin (e.g., through a cut), keratinocytes can also produce
proinflammatory biomolecules, such as TNF-α, as an additional layer of protection. In one of our studies, we showed that UV
light elevated levels of TNF-α released from an artificial skin and one of
our compounds, UTL-5d, lowered TNF-α levels, indicating that it may be a potential ant-inflammatory agent. Generally, elevated TNF-α levels indicate that inflammation is on its way.
Other surface barriers
in the body include the lungs and the GI tract; each has its own way to protect
the body from outside invaders. One
specific example is mucus, which works to trap and expel outside invaders.
Another component of
the innate immune system is complement system, which assist antibodies and
phagocytic cells to clear pathogens. The
complement system comprises a number of proteins in blood. When stimulated by outside invaders, specific
protein(s) will be cleaved to release cytokines and initiate further immune
responses to protect the body.
Assuming a human body is a nation, the innate immune system is similar to a more
rigid pre-structured national defense system, air force, army, navy, and marine. In addition, the innate immune system can also
recruit immune cells to sites of infection, through the production of special
chemicals, such as cytokines. It can
also activate the complement cascade to identify bacteria, and remove foreign
substances by white blood cells.
Furthermore, the innate
immune system can also activate the adaptive immune system by antigen
presentation. This is very similar to a
real life situation wherein a special situation in a foreign country requires
Department of Defense (Innate immune system) to organize a special force
(adaptive immune system) to counter and resolve the situation.
Note:
What are Cytokines?
Cytokines are signaling proteins for cell to cell
communication and interactions. They are
important regulators of both the innate and adaptive immune systems. Examples of cytokines include interleukins
(IL), interferons, and tumor necrosis factors (TNF). Cytokines are different from hormones in that
almost all cells are capable of producing cytokines whereas hormones are
secreted by discrete glands.
© Jiajiu Shaw, 2017
Disclaimer: This blog is written solely for informational purposes. It does not constitute the practice of any medical, nursing or other medical professional health care advice, diagnosis, or treatment. All contents posted are extracted from the book I wrote, "IS CANCER IN US", published recently.
