title: Immunosuppression in murine malaria: a soluble immunosuppressive factor derived from Plasmodium berghei-infected blood.
abstract: Mice infected with Plasmodium berghei have a depressed immune response to a variety of antigens. We report the extraction, purification, and characterization of a soluble immunosuppressive substance derived from P. berghei-infected mouse blood. A crude extract, prepared by solubilization of infected erythrocytes in a Parr cell disruption bomb, reduced the anti-DNP PFC response of mice injected with the extract 1 day before immunization. Purification of the immunosuppressant was accomplished by precipitation with 50% saturated ammonium sulfate followed by chromatography on Sephadex G-150 in the presence of 6 M guanidine hydrochloride. The immunosuppressive activity was recovered in the last fraction eluted from the Sephadex G-150 column that contained low m.w. components. The activity was abrogated by trypsin digestion, but not by periodate oxidation. Volume for volume, the purified immunosuppressant had a 100-fold greater activity than the crude extract from which it was derived. It suppressed the response to the T-dependent antigens DNP-KLH and SRBC, but not to the T-independent antigen DNP-Ficoll.
mesh_terms: D000818:Animals; D004136:Dinitrobenzenes / Q000276:immunology; D005260:Female; D006433:Hemocyanins / Q000276:immunology; D007075:Immunoglobulin M / Q000096:biosynthesis; D007165:Immunosuppression Therapy; D007166:Immunosuppressive Agents / Q000302:isolation & purification / Q000494:pharmacology*; D008288:Malaria / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D008970:Molecular Weight; D010962:Plasmodium berghei / Q000276:immunology; D012995:Solubility
chemical_list: D004136:Dinitrobenzenes; D007075:Immunoglobulin M; D007166:Immunosuppressive Agents; D006433:Hemocyanins