title: Immune regulatory factors in sheep fetuses.
abstract: After an antigenic stimulus in vitro, a fraction was found in the supernatant fluids of spleen (S-1) and thymus (T-1) cell cultures of 70 to 80-day-old sheep fetuses infected with ovine adenovirus in utero. The fraction agreed with alpha-1-fetoprotein in mobility and its molecular weight was 67 000. Injected into adult sheep, S-1 and T-1 had a suppressive effect on the humoral immune response to both adenovirus and Clostridium perfringens D vaccine. Tests with peripheral lymphocytes suggested that fetal cell supernatants do not affect blastogenesis but markedly inhibit Ig synthesis as it could be demonstrated by immunofluorescence tests.
mesh_terms: D000256:Adenoviridae / Q000276:immunology; D000818:Animals; D000917:Antibody Formation; D003016:Clostridium perfringens / Q000276:immunology; D005260:Female; D005333:Fetus / Q000276:immunology*; D007166:Immunosuppressive Agents / Q000494:pharmacology; D011247:Pregnancy; D012756:Sheep; D013154:Spleen / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology; D014611:Vaccination
chemical_list: D007166:Immunosuppressive Agents