Saline-soluble Fraction Research Articles

Studies on Japanese B Encephalitis Virus Vaccines from Tissue Culture

Abstract The virulence spectrum of isolates from the 49th HK passage of OCT-541 (JBE) virus at 37°C was examined using an infectious center technique in singly infected HK cells. Thirty per cent of that portion of the virus population that could be examined in this manner were found to be less virulent for the weanling mouse than was the parent virus. Ten per cent of the isolates were of very low virulence and one isolate designated T-11 virus was sufficiently different to be studied in depth. The T-11 virus infectivity titer for cell cultures exceeds the intracerebral LD50 for weanling mice 1 million-fold. Intracerebral inoculation of 250 TCID50 of virus produces a non-lethal immunizing infection in weanling mice. Peripheral inoculation of this host does not result in infection. T-11 virus retains complete neurovirulence for the suckling mouse when given intracerebrally. It will produce a non-lethal immunizing infection in 30% of weanling hamsters inoculated by peripheral routes. Comparison of the attenuated virus with the virulent OCT-541 virus by several methods did not reveal the mechanism or defect by which this virus is different. Thus, T-11 virus has a half-life at 38°C and pH 7.1 similar or superior to that of OCT-541 virus. The two strains are equally sensitive to interferon and T-11 virus can not be demonstrated to induce more interferon than the parent virus. Single cycle growth curves in cell culture are identical for the two viruses. T-11 virus is inhibited in multicycle growth curves and is more sensitive to the saline-soluble fraction of unpurified commerical agars. It has several other plaque markers common to other tissue culture-passaged viruses.

Highly selective in vivo ethylation of rat liver nuclear protein by ethionine

Ethionine ethylates rat liver nuclear proteins in a highly selective manner. The proteins most ethylated are those insoluble in 20–40% (NH 4) 2SO 4 in the saline soluble fraction. With L-ethionine-ethyl-1- 14C, only one peak of radioactivity was found. This peak has been tentatively identified as an ethyl analogue of methylguanidino arginine, recently reported to occur in nuclear proteins. No radioactive ethionine was found in the proteins after giving ethyl-labeled or 35S-labeled ethionine. The pattern of labeling with methionine-methyl- 14C is more complex and is presented.

Composition of Aortic Tissue from Copper-deficient Chicks

The effect of copper deficiency upon the composition of connective tissue in the vascular system of the chick was investigated. The aortas of 4-week-old chicks, which had been fed copper-deficient and control diets, were processed so as to separate soluble collagen, insoluble or mature collagen and elastin. The fractions were analyzed for nitrogen, hydroxyproline, and hexosamine. Chicks fed the deficient diet weighed approximately 30% as much as the controls fed copper but, expressed as percentage of body weight, their aortas were twice as heavy as controls. Based on wet weight, the saline-soluble fraction from copper-deficient aortas contained nearly twice as much nitrogen, nearly 4 times as much hydroxyproline and significantly more hexosamine. The percentage of nitrogen removed by autoclaving and by sodium hydroxide extraction was appreciably greater in the deficient aortas but it was not collagen. On the basis of dry weight, the control aortas contained about 47% elastin and the deficient about 26% whether determined by sodium hydroxide or formic acid purification. The copper-deficient aortas accumulated a large fraction of non-elastin, non-collagen protein and had an increased concentration of soluble collagen. The elastin isolated by sodium hydroxide treatment contained a greatly elevated concentration of lysine and significantly less desmosine and isodesmosine.

SOLUBILIZATION OF CELL ANTIGENS ASSOCIATED WITH THE REJECTION OF TRANSFERRED RABBIT LYMPH NODE CELLS.

In a study of solubilization of the cell antigens associated with the rejection of transferred rabbit lymph node cells, fragments of such cells, obtained by centrifugation of cell-wash fluids, were extracted with Triton, and the water-in-soluble part of the Triton extract was solubilized with snake venom. Two fractions were obtained by this procedure, within the same range of yield: a saline-soluble fraction of the Triton extract, and a venom-solubilized fraction. Both of these were tested for serologic activity against rabbit anti-rabbit-leucocyte serum, which can cause suppression of transferred lymph node cells, and against suppressive antibody specifically purified from such sera. Both preparations were found to give positive results in the following tests: agglutination of RBC coated with the suppressive antibody, adsorption to RBC with resulting agglutinability of the cells by the anti-leucocyte sera, and inhibition of such adsorption-hemagglutination by solutions of the antigens. Experiments were also carried out on the association of these antigens with the rejection of transferred lymph node cells. Both preparations were found to absorb from rabbit anti-rabbit-leucocyte serum the antibody which causes suppression of transferred lymph node cells. Also, sera of rabbits given secondary injections of these preparations, after primary injections of rabbit leucocytes, were found to suppress transferred lymph node cells.

CHANGES BY AGE IN THE CHEMICAL CONSTITUTIONSOF THE MOUSE BRAIN

Rise and fall in chemical components and the histochemical changes in the mouse brain from birth to 1 year 8 months were followed, and changes in cerebral vascular walls observed.Brain weight, lipids and serotonin increase with age, and also histochemically the increase in lipids is observed. But, after reaching the maturity at 10 weeks, so much increase does not take place. On the contrary, water, protein and reducing substance in the saline soluble fraction of the brain decrease with age. Total protein increases, but acid soluble protein is reduced with age. SO4 in the saline soluble fraction increases, and, histochemically metachromasic substances increase with age. Lipoprotein in paperelectrophoresis is presented by I and II peaks, and II/I quotient becomes greater with are.

Preparation, Characterization, and Antigenicity of a Saline Soluble Fraction From Shigella Types

A procedure for the extraction of a saline soluble fraction from Shigella species is described. Each of the 3 extracts protects mice against massive challenge with the homologous strain of Shigella. Heterologous protection is of low order or insignificant. A 1:10 dilution of the extracts reduces the toxicity while retaining the essential protective properties. A polyvalent extract has been prepared containing a 1:10 dilution of each of the 3 extracts. Preliminary chemical characterization indicates a nondialyzable carbohydrate-containing compound with small amounts of nitrogen present.