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Biomedical subjects

E Ribi

Publications and source records attributed to E Ribi.

At least 73 records · Page 4Linked to original sources
PubMed1970

Macrophage Migration Inhibition Studies with Cells from Mice Vaccinated with Cell Walls of Mycobacterium bovis BCG: Relationship Between Inhibitory Activity of Lung Cells and Resistance to Airborne Challenge with Mycobacterium tuberculosis H37Rv.

In an effort to evaluate the role of delayed hypersensitivity in acquired resistance of mice to airborne infection with Mycobacterium tuberculosis H37Rv, the ability of lung and peritoneal cells from mice vaccinated in various ways with mycobacterial fractions or with M. bovis BCG to inhibit, in the presence of purified protein derivative, in vitro migration of normal peritoneal cells was determined. The degree of inhibition induced by lung cells was correlated with immunity, but that induced by peritoneal cells could not be associated with enhanced resistance. Live BCG given intravenously to mice stimulated greater resistance to infection and inhibitory activity of lung cells than did live BCG given subcutaneously. Vaccines with a protective index greater than 1 also induced a significant increase in lung weight. Although a correlation between ability of lung cells to inhibit cell migration and acquired resistance of the host to airborne infection with H37Rv was demonstrated, the data do not exclude the possibility that the two phenomena are independent responses to the immunologically complex mycobacterial antigens.

Journal Article↗
PubMed1970

Aerosol-Induced Tuberculosis in Subhuman Primates and the Course of the Disease After Intravenous BCG Vaccination.

Suitability of the rhesus monkey (Macaca mulatta) as an experimental host for evaluation of vaccines against airborne infection with Mycobacterium tuberculosis strain H37Rv was investigated. Nonvaccinated monkeys were exposed to estimated doses of 12, 25, or 49 units of H37Rv in a modified Henderson apparatus, and the course of the disease was followed by chest X rays, skin testing with purified protein derivative, body-weight determinations, and autopsy 8 weeks postinfection. These animals developed progressive and extensive tuberculosis with pathological changes proportional to the infecting dose. Four of seven monkeys vaccinated intravenously with 1 mg of live BCG 8 weeks prior to challenge with 40 units of H37Rv had no gross evidence of disease at autopsy 13 weeks postinfection; the other three monkeys had minimal disease. These data demonstrated that (i) reproducible and progressive infection could be induced in rhesus monkeys infected in a manner which simulated natural infection of man and (ii) a high level of resistance to infection could be induced by BCG vaccine in the rhesus monkey, which in nature is highly susceptible to tuberculous infection.

Journal Article↗
PubMed1970

Chromatography of microbial lipids by centrifugation through microparticulate gel.

An improved apparatus and a procedure are described by which the migration of sample components in column chromatography is accelerated by centrifugal force, thereby making it possible to use beds of densely packed gel prepared with ultrafine silica. This technique was used to resolve components of certain lipid mixtures where other methods have failed, and it has been found generally useful as an adjunct to other methods for the fractionation of lipids. Biologically active phosphoglycolipids from Mycobacterium tuberculosis and a phosphatidylglycerol-like substance from Mycoplasma pneumoniae which formed single spots on thin-layer chromatographic plates were each found to contain a major and several minor components by centrifugal chromatography. The method enabled us to isolate individual components of Wax D from M. tuberculosis rather than a spectrum of components. Minor components were resolved which, although present in insufficient quantity to influence results of chemical analyses, may be responsible for biological activity. The apparatus provides an essentially closed system which reduces highly volatile solvents to minimal evaporation during the chromatographic process. Samples are applied in solution and are not allowed to dry on the columns until after separation has been achieved. Consequently, polar, labile microbial lipids can be resolved without the use of harsh reagents which destroy some of their properties. Single components may be harvested by cutting and removing appropriate segments of the larger chromatograms or by eluting them from the columns.

Centrifugation↗
PubMed1969

Relationship of footpad sensitivity to purified protein derivatives and resistance to airborne infection with Mycobacterium tuberculosis of mice vaccinated with mycobacterial cell walls.

Footpads of mice sensitized by oil-treated Bacillus Calmette-Guérin (BCG) cell walls given either intravenously, subcutaneously, intradermally, intraperitoneally, or intramuscularly became swollen and reddened after injection of purified protein derivative (PPD). This reaction, greatest after intradermal and subcutaneous sensitization, generally reached a maximum about 24 hr after challenge and was still marked at 48 hr. The histological response was characterized by infiltration with both polymorphonuclear and mononuclear cells. The proportion of mononuclear cells increased with time and they predominated at 48 hr. The footpad reaction could be detected as early as 1 week after sensitization and persisted for at least 37 weeks. Footpad sensitivity to PPD and acquired resistance to airborne infection with Mycobacterium tuberculosis H37Rv were correlated in that (i) both reached a peak approximately 1 month after sensitization of the mouse, and (ii) cell walls treated with NaOH or given without oil neither protected mice against challenge infection nor sensitized them to PPD. Although, as we reported previously, mice vaccinated subcutaneously or intradermally exhibited little or no enhanced resistance to experimental infection, mice given oil-treated cell walls by these routes were highly sensitive to footpad inoculation of PPD. Therefore, the footpad test cannot be used to determine immunity of the mouse to pulmonary infection with tubercle bacilli.

Adjuvants, Immunologic↗
PubMed1969

Preparation of cell walls and protoplasm of Neisseria with the Ribi cell fractionator.

The varied pressures required for disruption of Neisseria gonorrhoeae and other species of Neisseria when the Sorvall-Ribi refrigerated cell fractionator is used in the preparation of cell walls and cellular protoplasm are reported. Optimal disruption pressure for the gonococcus was considerably less than that required for other members of the genus Neisseria. Pressures varied from 8,000 psi for N. gonorrhoeae F62, colony type 4, to 22,000 psi for the nonpathogenic Neisseria-N. sicca, N. flava, and N. catarrhalis. Representative electron photomicrographs are shown.

Bacteriological Techniques↗
PubMed1969

Alteration of physical, chemical, and biological properties of endotoxin by treatment with mild alkali.

Treatment with alkali is one of several methods for removing fatty acids from bacterial endotoxins and, in the process, detoxifying the material. Saponification of fatty acid esters is the major detectable chemical change produced by alkali; however, kinetic studies of mild alkaline hydrolysis of endotoxin failed to correlate rates of detoxification with rates of loss of ketodeoxyoctonates, heptose, O-acetyl groups, or fatty acid esters. The alterations occurring during the critical stages of hydrolysis apparently changed the essential chemical conformation of endotoxic particles before cleavage of a significant amount of material took place. The rates of both saponification and detoxification were markedly increased by carrying out the reaction in media of ethyl alcohol or dimethylsulfoxide instead of water.

Alkalies↗
PubMed1969

Occult endotoxin in bacterial protoplasm.

Protoplasm separated from disrupted cells of gram-negative bacteria was extracted with hot phenol-water or was precipitated with ethyl alcohol after digestion with Pronase. These methods recovered about 10 times more endotoxin than was detectable in the untreated protoplasm. Inactivation of endotoxin by protoplasm also occurred in vitro when the endotoxin was first dissociated into subunits before reaction with protoplasm. Despite this increased yield from another source, the major proportion of endotoxin was still found in the cell walls.

Animals↗
PubMed1968

Immunogenicity of cell walls from various mycobacteria against airborne tuberculosis in mice.

Protective potency of oil-treated cell walls of various mycobacteria against airborne infection of mice with a few cells of Mycobacterium tuberculosis H37Rv was compared with that of viable BCG. Although less potent than BCG cell walls, the cell walls of atypical mycobacteria of Runyon's groups I to IV protected against challenge by aerosol to some degree. Protection afforded by cell walls of H37Rv and of the avirulent mutants H37Ra and Washington II was comparable to that provided by BCG cell walls. However, cell walls of a highly virulent strain of M. bovis (Bovinus I) provided the best protection yet achieved. Present evidence suggests that protective substances are shared by all mycobacteria but in differing amounts; the relationship between virulence and immunogenicity has yet to be clarified.

Animals↗
PubMed1968

Modification of selected host-reactive properties of endotoxin by treatment with sodium deoxycholate.

Endotoxin dissociated into subunits by sodium deoxycholate treatment exhibited diminished capacity to kill chick embryos, protect mice against the lethal effects of infection with Salmonella typhi, evoke hemorrhagic necrosis in skin inoculated with epinephrine, prepare for and provoke the dermal Shwartzman reaction, and induce pyrogenic tolerance. Surfactant-treated material which had been allowed to reaggregate displayed activity equivalent to that of untreated material. These findings were consistent with the working hypothesis that a macromolecular complex of critical size is required in order for endotoxin to elicit its characteristic effects in the host.

Animals↗