title: Ontogeny of the immune system: fetal lamb as a model.
abstract: We examined adult sheep lymphocytes for the following surface markers: Surface membrane immunoglobulin, antigen identified by anti-sheep thymocyte globulin and complement receptors. We quantitated sheep peripheral blood mononuclear leukocyte proliferative responses to mitogens and alloantigens, and demonstrated a neutrophil-directed chemotactic factor (N-LDCF) liberated by mitogen-stimulated sheep mononuclear cells. A comparison of adult and fetal sheep from 120-150 d of gestation demonstrated that 1) fetal sheep had adult proportions of surface membrane Ig+ and T+ lymphocytes but a significant decrease in FcIgG receptor+ lymphocytes, 2) proliferative responses of fetal sheep blood mononuclear cells to mitogens and alloantigens were comparable to adult responses, and 3) fetal mononuclear leukocytes failed to produce the lymphokine, N-LDCF, in response to mitogen stimulation.
mesh_terms: D000367:Age Factors; D000818:Animals; D002630:Chemotactic Factors / Q000032:analysis; D005333:Fetus / Q000276:immunology*; D005455:Fluorescent Antibody Technique; D005865:Gestational Age; D007141:Immunoglobulin Fc Fragments / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D016209:Interleukin-8; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000276:immunology; D008222:Lymphokines / Q000096:biosynthesis; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D017452:Receptors, IgG; D011971:Receptors, Immunologic / Q000032:analysis; D012397:Rosette Formation; D012756:Sheep / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D002630:Chemotactic Factors; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D016209:Interleukin-8; D008222:Lymphokines; D011947:Receptors, Antigen, B-Cell; D017452:Receptors, IgG; D011971:Receptors, Immunologic