Our immune system can be divided into epithelial barriers, and cellular and humoral constituents, also known as the innate (unspecific) immunity or adaptive (specific) immunity. 
Innate immunity, also known as genetic or natural immunity, is the defence system with which we were born and is our first line of defence. It is fast acting, non-specific and offers lifelong protection.
Innate immunity involves barriers that keep harmful materials from entering our body and protects us against all pathogens (i.e. viruses, bacteria, fungi, worms, protists).
Adaptive immunity, also known as the acquired immunity, is the second line of defence against non-self pathogens and is only found in vertebrates. It is not immediate, highly specific, but not always last throughout an entire life, although it can.
B lymphocytes are like the body's military intelligence system — they find their targets and send defences to lock onto them (make antibodies and lock onto specific antigens).
T cells are like the soldiers — they destroy the invaders that the intelligence system finds (destroy antigens tagged by antibodies).
The above process usually causes the area around the infection to swell, heat up and redden, and inflammation results. A fever may develop as well. 
We develop adaptive immunity naturally when we're exposed to diseases or artificially when we're immunized against them with vaccines. 
Maintain Our Tribe
How amazing to know we have a whole tribe of soldiers inside our body to defend and protect us! Nutrients, however, are like supplies to soldiers and leaders, supporting our entire immune system to function properly.
Let’s learn how different nutrients contribute to our immune system!