U937 cells are of the myeloid lineage .
U937 cells so secrete a large number of cytokines and chemokines either constitutively ( e.g. IL - 1 and GM - CSF ) or in response to soluble stimuli .
U937 cells are of the myeloid lineage and so secrete a large number of cytokines and chemokines either constitutively ( e.g. IL - 1 and GM - CSF ) or in response to soluble stimuli .