ABSTRACT
Plasmodium berghei-infected erythrocytes were solubilized with the nonionic detergent n-octyl glucoside and membrane-containing P. berghei fragments with either n-octyl glucoside or the ionic detergent sodium deoxycholate. Unsolubilized material was separated by centrifugation, and the detergent was removed from the respective supernatants by gel filtration. Reaggregated components in the respective void volume eluates acted as a specific vaccine in recipient mice, resulting in a dose-related accelerated elimination of infection and increased survival after challenge with the homologous parasite.
Subject(s)
Antigens, Surface/isolation & purification , Malaria/prevention & control , Plasmodium berghei/pathogenicity , Vaccines , Animals , Antigens, Surface/immunology , Detergents , Erythrocytes/physiology , Female , Malaria/immunology , Mice , Mice, Inbred A , SolubilityABSTRACT
Treatment of HeLa cells with 1.0 mM theophylline significantly reduced the growth rate of the cell cultures without affecting cellular viability. When methotrexate was added to the theophylline-treated cultures at a concentration of 0.5 microgram/ml, the cytotoxic activity of methotrexate was enhanced. The rate of cell loss in these cultures was over 2.5 times greater than in those cultures receiving only methotrexate. This enhancement of methotrexate activity was also observed when the concentration of methotrexate was reduced to 0.1 microgram/ml. It was concluded that treatment of cells with an agent which prolongs the cell cycle, such as theophylline, may aid in the development of more effective chemotherapy.
Subject(s)
Cell Division/drug effects , Cell Survival/drug effects , HeLa Cells/drug effects , Methotrexate/pharmacology , Theophylline/pharmacology , HeLa Cells/cytology , HumansABSTRACT
A fraction was obtained from Plasmodium berghei which induced hemolysis of the erythrocytes of mice and hamsters. This fraction, called lytic factor (LF), was found to be composed of a large amount of lipid material. An examination of the lipids showed the major lipids to be monoglycerides, diglycerides, triglycerides, fatty acids, long-chain alcohol, sterol, sterol ester, sterol glycoside, and two cerebrosides. The most abundant component found in the LF was sterol ester, followed in order by cerebrosides, sterol, and sterol glycoside. Lytic activity was found to be lost when samples were boiled for 5 min. An examination of the lipid composition of LF before and after boiling showed changes which may be useful in studies on the mechanism of activity of this factor. The fatty acid composition of the total lipid fraction of LF was examined by gas-liquid chromatography. The major fractions were 18:1 and 16:0 in unheated LF and 16:0 in the heated LF.
Subject(s)
Hemolysin Proteins/analysis , Lipids/analysis , Plasmodium berghei/analysis , Animals , Cerebrosides/analysis , Cricetinae , Esters/analysis , Fatty Acids/analysis , Hemolysis , Mice , Sterols/analysisSubject(s)
Disease Models, Animal , Freund's Adjuvant , Malaria/prevention & control , Vaccines , Animals , BCG Vaccine , Drug Synergism , Female , Haplorhini , Macaca , Malaria/immunology , Male , Plasmodium/isolation & purification , Poly A-USubject(s)
Erythrocytes , Malaria/immunology , Plasmodium/immunology , Vaccines , Animals , Antigens/administration & dosage , Erythrocytes/microbiology , Hot Temperature , Injections, Intraperitoneal , Malaria/blood , Malaria/prevention & control , Mice , Mice, Inbred Strains , Plasmodium/isolation & purification , Spleen/immunology , Splenectomy , VaccinationABSTRACT
Plasmodium berghei were released from mouse erythrocytes by passage through a French pressure cell. The released organisms were washed and disintegrated; the soluble portion was chromatographed on a Sephadex (G-200) column. The void-volume eluate contained an erythrocyte-free plasmodial fraction which behaved as a vaccine, preventing parasitemia, anemia, and death in mice subsequently challenged with living Plasmodium berghei.
