Alpha-naphthyl acetate esterase activity in human foetal lymphocytes.
Human foetal mononuclear cells from thymus, spleen, liver, bone marrow and peripheral blood at 8-24 weeks of gestation were examined for cytochemical evidence of acid alpha-naphthyl acetate esterase (ANAE) activity. The focal brownish-red ANAE reaction product (T cell staining pattern) was observed in counterstained cytocentrifuged cell smears in the cytoplasm. ANAE-positive lymphoid cells were first observed in the thymus at 9 weeks of gestation. A gradual increase in frequency of ANAE-positive cells in foetal thymus was observed, from about 10% at 14-15 weeks to about 20% at 22-24 weeks of gestation. By 14 weeks of foetal age, spleen and liver contained a few ANAE-positive cells and after 15 weeks of gestation consistent occurrence of ANAE-positive cells was observed in foetal bone marrow and peripheral blood. These results demonstrate that ANAE-positive lymphocytes first appear in the foetal thymus and are subsequently found in the foetal liver, spleen, bone marrow and peripheral blood.
D001853:Bone Marrow / Q000201:enzymology; D001854:Bone Marrow Cells; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D005260:Female; D005333:Fetus / Q000201:enzymology*; D006801:Humans; D008099:Liver / Q000166:cytology / Q000201:enzymology; D008214:Lymphocytes / Q000201:enzymology*; D009283:Naphthol AS D Esterase / Q000097:blood / Q000378:metabolism*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D013154:Spleen / Q000166:cytology / Q000201:enzymology; D013950:Thymus Gland / Q000166:cytology / Q000201:enzymology
D009283:Naphthol AS D Esterase; D002265:Carboxylic Ester Hydrolases