Cellular immunity of late 1960s and 1970s that followed on discovery of the importance of lymphocytes (re experiments on removal of bursa [in birds] and thymus [in mice]) in acquired immune response

“Cells of the immune system not only communicated with each other; they produced, especially when aroused, a roar of white noise in the form of molecules passing back and forth. These signals acted like hormones, in the sense that they either stimulated white blood cells to multiply or emphatically suppressed their activity; attracted other cells to the scene of immunological insult or inhibited the usual suspects from crashing that scene; induced profound changes locally or issued a generalized alarm that could affect the entire organism, such as molecules that traveled to the brain and induced fever. In 1974 Stanley Cohen proposed the word ‘cytokine’ as an umbrella term under which all these homeless factors could huddle; he defined them as the family of molecules manufactured and secreted by a variety of cells engaged in immunological or inflammatory responses” (Hall, 196).