Fetal thymic differentiation in Down's syndrome.
Phenotypic features and proliferative ability of thymocytes, splenocytes and peripheral blood lymphocytes of 20-22 weeks human fetuses affected by Down's syndrome (DS) were studied and compared to those of fetuses of the same gestational age with a normal karyotype. In the thymus of both DS and normal fetuses, the great majority of cells was CD1+, CD2+, CD5+, CD4+, CD8+; using double fluorescence analysis, these markers could be detected on the same cell. About 50-60% showed CD3 antigen and about 40-50% presented the alpha beta T cell receptor. Thymocytes with NK markers (CD16, CD57, CD56) were not found. After stimulation with phytohemagglutinin, thymocytes showed a low but detectable proliferative capability, while splenocytes and peripheral blood lymphocytes showed a high responsiveness to the mitogen. These data show that the impaired immune system in DS is not associated with gross abnormalities of phenotypic T cell development in the fetal thymus or with an inability of such fetal cells to proliferate after a mitogenic stimulus.
Cossarizza
A
A
Institute of General Pathology, University of Modena School of Medicine, Italy.
Monti
D
D
Montagnani
G
G
Forabosco
A
A
Dagna-Bricarelli
F
F
Franceschi
C
C
D015703:Antigens, CD / Q000032:analysis; D002454:Cell Differentiation; D004314:Down Syndrome / Q000196:embryology / Q000276:immunology*; D005260:Female; D005333:Fetus / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation; D011247:Pregnancy; D013950:Thymus Gland / Q000196:embryology* / Q000276:immunology
D015703:Antigens, CD