Vocababble: Microbiology, Immunology and Medicine

commensal = a type of symbiosis where two (or more) organisms from different species live in close proximity to one another, in which one member is unaffected by the relationship and the other benefits from it (lots of sources say neither org benefits and none is harmed, but I don't believe those definitions)
( study notes )

Vocababble: Microbiology and Immunology II

Immune system is divided into a more primitive innate immune system, and acquired or adaptive immune system of vertebrates, the latter of which is further divided into humoral and cellular components.
( B cells, T cells, etc )