title: Some physicochemical characteristics of an immune lymphocyte product which inhibits the multiplication of toxoplasma within mouse macrophages.
abstract: In response to antigenic stimulation, the splenic lymphocytes from Toxoplasma-infected mice produce a factor which is called by the authors the Toxoplasma growth inhibitory factor (Toxo-GIF) and which inhibits the multiplication of Toxoplasma within nonimmune macrophages in vitro. In this study, partial characterization of murine Toxo-GIF was examined using Sephadex G-100 gel-filtration, isoelectric focusing, zonal electrophoresis and heat and enzymatic treatment. Peak activity of Toxo-GIF was found in a Sephadex G-100 fraction with a similar molecular size to that of the ovalbumin. The molecular weight of Toxo-GIF was calculated to be between 38,000 and 55,000. Toxo-GIF was stable to heating at 56 C for 30 min but lost its activity at 80 for 30 min or by exposure to pH values of 5 and 2. Exposure of Toxo-GIF to water-insoluble chymotrypsin or neuraminidase markedly decreased its ability to induce enhanced microbicidal activity of cultured macrophages, suggesting that Toxo-GIF was a glycoprotein. Furthermore, Toxo-GIF migrated in a region cathodal to mouse albumin on agar zone electrophoresis. Isoelectric focusing of active Sephadex fractions showed a well-defined peak of Toxo-GIF activity with an isoelectric point of pH 4.9 to 5.9.
mesh_terms: D000645:Ammonium Sulfate / Q000494:pharmacology; D000818:Animals; D005591:Chemical Fractionation; D055598:Chemical Phenomena; D002621:Chemistry; D002846:Chromatography, Affinity; D004586:Electrophoresis; D007525:Isoelectric Focusing; D008214:Lymphocytes / Q000276:immunology; D008222:Lymphokines / Q000096:biosynthesis; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008970:Molecular Weight; D013696:Temperature; D014122:Toxoplasma / Q000201:enzymology / Q000254:growth & development*
chemical_list: D008222:Lymphokines; D000645:Ammonium Sulfate