Ultrastructural cytochemical characterization of alpha-naphthyl acetate esterase in chicken monocytic cell lines

In order to study the differentiation level of two chicken monocytic cell lines, IN24 and LSCC-NP1 cells, alpha-naphthyl acetate esterase (ANAE) was examined by ultrastructural cytochemical technique. Morphologically and functionally, IN24 cells showed immature character compared to LSCC-NP1 cells. In IN24 and LSCC-NP1 cells, ANAE activity was localized on the external face of the plasma membrane and coated vesicles, but not in lysosomes and phagocytic vacuoles. ANAE reactivity showed a dense linear reaction product on the entire cell surface in IN24 cells and granular reaction product in LSCC-NP1 cells. On treatment with interferon-gamma (IFN-gamma), ANAE reactivity of IN24 cells became similar to that of LSCC-NP1 cells. IN24 cells treated with lipopolysaccharide (LPS) had less amounts of ANAE surface product, and reactivity was partially dispersed on the cell surface.