title: Influence of a bovine spleen extract on immunological responses in mice.
abstract: The presence of immunological stimulatory and inhibitory activities has been detected in a bovine spleen extract F prepared by acetic extraction of an acetonic powder. F was fractioned after water dilution, by ultrafiltration on an Amicon PM-10 membrane. Two successive ultrafiltrates (mol. wt. less than 10,000) are obtained: U1 which contained the largest pool of the low molecular weight substances, and U2 which was shown previously to be enriched in an immunosuppressive peptide. The biological activities of U1 have been studied compared to those of U2: 1. Added to mouse spleen cells culture, U1, at low dose, stimulated 3H-thymidine incorporation into the DNA of the cells, but inhibited it when large dose was added. In this test, U2 was devoid of stimulatory action. 2. When injected into mice sensitized with sheep red blood cells, three distinct activities were detected: U1 was inhibitory at the sensitization period; at the last step of differentiation of the lymphocyte, U1 was stimulatory at low dose and inhibitory at large dose. As assessed by Biogel P-2 chromatography, this last activity was attributed to the presence in fraction U1 of the immunosuppressive peptide previously characterized in U2.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D000921:Antibody-Producing Cells / Q000276:immunology; D002417:Cattle; D005591:Chemical Fractionation; D002850:Chromatography, Gel; D004247:DNA / Q000378:metabolism; D004306:Dose-Response Relationship, Immunologic; D007166:Immunosuppressive Agents; D008214:Lymphocytes / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D013154:Spleen / Q000276:immunology*; D013936:Thymidine / Q000378:metabolism
chemical_list: D007166:Immunosuppressive Agents; D004247:DNA; D013936:Thymidine