In vitro properties of diffuse cytoplasmic esterase-positive canine mononuclear leukocytes

Depletion of cytoplasmic esterase-positive canine peripheral blood monocytes from mononuclear cell suspensions was attempted using plastic adherence, carbonyl iron ingestion and/or Sephadex G-10 filtration. An esterase-positive, nonadherent, nonphagocytic subpopulation was identified and further characterized by the presence or absence of cell membrane receptors for the Fc portions of immunoglobulin and the activated third component of complement. The majority of these nonadherent cells lacked these receptors. The data suggests that canine peripheral blood monocytes are a heterogenous cell population.