The collection, purification and characterization of canine peripheral blood monocytes

Peripheral blood leukocytes from 11 adult healthy dogs were obtained by continuous flow filtration leukophoresis. Initial cell eluates were composed predominantly of polymorphonuclear leukocytes (81%) and monocytes (11%). Purified populations of monocytes (> 95%) were obtained by incubating the cell eluate in suspension culture for 72 hr and then allowing them to attach to glass for 24 hr. Monocytes were identified by morphologic criteria, positive staining for nonspecific esterase activity, their ability to phagocytose carbon particles and their ability to form rosettes with opsonized sheep red blood cells. Peripheral blood monocytes obtained by this technique were cytotoxic to xenogeneic and allogeneic tumor cells in vitro.