title: Response to B and T cell mitogens and surface markers in human fetal lymphoid tissues.
abstract: We studied the responses to phytohemagglutinin (PHA) and Staphylococcus aureus protein A (SpA), a B cell mitogen, and surface markers in the thymus, liver and spleen of 5 human fetuses ageing from 12 to 26 gestational wk and in cord blood lymhocytes of 9 newborns. Sheep rosette forming cells appeared in all 3 organs at 17 wk; mIgM+ cells were detected in liver and spleen at 24 and 17 wk respectively. SpA and PHA stimulated the cells of all the 5 liver and all the 3 spleen samples examined. Thymus cells responded to PHA as early as the 17th wk and showed a progressive increase in stimulation indexes. An unexpected observation was the response of the thymus cells of a 15-wk fetus to SpA; this finding is discussed in the text. Cord blood lymphocytes gave results comparable to those found in normal adults.
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D005333:Fetus / Q000276:immunology*; D006801:Humans; D007075:Immunoglobulin M; D008099:Liver / Q000276:immunology; D008221:Lymphoid Tissue / Q000276:immunology; D008934:Mitogens / Q000494:pharmacology*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011247:Pregnancy; D011947:Receptors, Antigen, B-Cell; D012397:Rosette Formation; D013154:Spleen / Q000276:immunology; D013205:Staphylococcal Protein A / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology
chemical_list: D007075:Immunoglobulin M; D008934:Mitogens; D010835:Phytohemagglutinins; D011947:Receptors, Antigen, B-Cell; D013205:Staphylococcal Protein A