The location of non-specific esterase in human lung macrophages. An ultrastructural study

The non-specific carboxyl (serine) esterase of the human pulmonary alveolar macrophage was localized ultrastructurally using alpha-naphthyl acetate and hexazotized pararosanilin. The reaction product principally outlined the outer side of the plasma membrane. Consequently, this esterase is an ectoenzyme which may function as mediator of cell response to injurious agents from the outside.