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G P YOUMANS

Publications and source records attributed to G P YOUMANS.

At least 19 recordsLinked to original sources
PubMed1965

IMMUNOGENIC ACTIVITY OF A RIBOSOMAL FRACTION OBTAINED FROM MYCOBACTERIUM TUBERCULOSIS.

Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.), and Guy P. Youmans. Immunogenic activity of a ribosomal fraction obtained from Mycobacterium tuberculosis. J. Bacteriol. 89:1291-1298. 1965.-The highly immunogenic particulate fraction obtained from mechanically ruptured cells of the H37Ra strain of Mycobacterium tuberculosis was suspended and centrifuged at 20,360 x g. The supernatant liquid from this centrifugation was centrifuged at 56,550 x g to remove the larger particles, and the supernatant liquid from this was centrifuged at 144,000 x g to obtain a ribosomal fraction. The sediments from the first two centrifugations were highly immunogenic, but the ribosomal fraction showed only slight capacity to immunize mice. However, when the ribosomal fraction was mixed with Freund's incomplete adjuvant, the immunogenic activity was equivalent to the particulate fraction from which it was prepared. To test the hypothesis that some membranous substance in the particulate fraction was acting as an adjuvant for the smaller particles in the ribosomal fraction, portions of the particulate fraction were treated separately with each of the membrane-disrupting agents, sodium deoxycholate, sodium lauryl sulfate, and 1 m sodium chloride. The treated materials were then centrifuged at 144,000 x g, and the sediments were tested for immunogenicity both with and without the addition of Freund's incomplete adjuvant. Without the adjuvant, the immunizing activities were very weak or absent; with the adjuvant, they were equivalent to that of the particulate fraction from which they were prepared. Other factors which have been found to damage or destroy membranes, such as freezing and thawing, and heat, also significantly decreased the immunogenic activity of the particulate fraction unless it was incorporated into Freund's incomplete adjuvant. The larger particles which sedimented at 56,550 x g were also treated with sodium lauryl sulfate and sodium chloride. Again, immunogenicity was greatly reduced but was fully restored by use of Freund's incomplete adjuvant. The data suggest, then, that the immunizing component of the particulate fraction is a substance (ribosomal?) which sediments at 144,000 x g, but for maximal immunizing activity a labile, possibly membranous, moiety of the mycobacterial cell, which has the properties of an adjuvant, is required.

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PubMed1964

FURTHER STUDIES ON A LABILE IMMUNOGENIC PARTICULATE SUBSTANCE ISOLATED FROM MYCOBACTERIUM TUBERCULOSIS.

Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.), and Guy P. Youmans. Further studies on a labile immunogenic particulate substance isolated from Mycobacterium tuberculosis. J. Bacteriol. 87:278-285. 1964.-A particulate fraction which was highly immunogenic for mice was collected by ultracentrifugation from mycobacteria disrupted in 0.25 m sucrose buffer. The active immunogenic material was present in the gelatinous pellet obtained after centrifugation at 40,000 rev/min (144,000 x g) for 3 hr. This active material could be prepared free from whole cells and cell walls. This was done either by several centrifugations at lower speeds, or by filtering the supernatant fluid from the 10,000 rev/min centrifugation through a Millipore filter (porosity 0.5 mu). No microorganisms were found on slides or in cultures made from these filtrates. The immunogenic moiety in the particulate fraction was found to be very labile. Temperatures higher than 0 to 4 C inactivated the immunogenic activity. There was an irreversible linear decrease in activity as the temperature increased. If fractions were frozen or lyophilized, the activity remained as high as the original material for 4 weeks, and then rapidly decreased. The immunogenic material also was very sensitive to the hydrogen-ion concentration; the optimal activity was found at pH 6.8 to 7.0. The activity decreased rapidly at more acid or alkaline pH values. Also, particulate fraction prepared in sucrose buffer at pH 7.3 and 7.6 was much less active than that prepared in sucrose buffer at pH 7.0. Immunogenic activity was decreased if the particulate fraction was dialyzed overnight against 0.01 m phosphate buffer or distilled water at 4 C. The detergent sodium lauryl sulfate inactivated immunogenic activity. Moreover, the use of a Waring Blendor to blend the ruptured cell mass before centrifugation decreased the activity. Finally, a markedly lower activity resulted if both the 20,000 and 40,000 rev/min centrifugations were done the day after the rupture of the cells. Some refinements in technique which are used now in the preparation of the particulate fraction are detailed.

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PubMed1964

EFFECT OF MITOCHONDRIAL STABILIZERS ON THE IMMUNOGENICITY OF THE PARTICULATE FRACTION ISOLATED FROM MYCOBACTERIUM TUBERCULOSIS.

Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.), and Guy P. Youmans. Effect of mitochondrial stabilizers on the immunogenicity of the particulate fraction isolated from Mycobacterium tuberculosis. J. Bacteriol. 87:1346-1354. 1964.-A number of substances which have been used to stabilize mammalian mitochondrial preparations were tested to determine whether they would similarly affect the immunogenicity of a particulate fraction prepared from ruptured viable attenuated mycobacterial cells. The use of 0.44 m sucrose and the presence of 3 x 10(-2)m MgCl(2) during the preparatory processes markedly increased the immunogenicity of the particulate fraction. The increase was so great that immunogenic preparations were then consistently obtained which, in adequate dosage, were more immunogenic in CF-1 male mice than were viable attenuated mycobacterial cells. On the other hand, adenosine triphosphate (ATP), citrate, and polyvinylpyrrolidone when present during the preparatory processes reduced the immunogenicity. The addition of MgCl(2), ethylene-diaminetetraacetate, or ATP to the particulate fraction after it had been prepared did not increase its immunogenicity. When the particles were prepared in the 0.44 m sucrose buffer alone, incorporated in Freund's adjuvant, and injected intraperitoneally, immunogenicity was increased. However, this increase was not significantly greater than that obtained when the particles were prepared in the sucrose buffer containing MgCl(2). The immune state engendered in mice by the intraperitoneal injection of the particulate fraction persisted for at least 12 weeks.

Adenosine Triphosphate↗
PubMed1964

NATURE OF THE LABILE IMMUNOGENIC SUBSTANCE IN THE PARTICULATE FRACTION ISOLATED FROM MYCOBACTERIUM TUBERCULOSIS.

Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.), and Guy P. Youmans. Nature of the labile immunogenic substance in the particulate fraction isolated from Mycobacterium tuberculosis. J. Bacteriol. 88:1030-1037. 1964.-Deoxyribonuclease had no effect on the immunogenic activity of the labile particulate fraction isolated from ruptured viable cells of the H37Ra strain of Mycobacterium tuberculosis, but decreased the ropiness of the ruptured cellular mass. Ribonuclease, in a high concentration, decreased the immunogenic activity slightly. Addition of yeast ribonucleic acid to particulate fraction incubated at 37 C prevented the decrease in immunogenic activity which normally occurs at this temperature, suggesting that endogenous ribonuclease may be involved in the reduction of activity. Differential centrifugation by the use of Brodie's (1962) method showed that the particles which sedimented at 56,550 x g were immunogenically active. Experiments were done to determine whether the integrity of the structure of the particle was necessary for immunogenic activity. It was found that sonic oscillation, freezing and thawing several times, the addition of surface-active agents (sodium lauryl sulfate or deoxycholate), and preparation of the particulate fraction in hypotonic solutions either decreased or destroyed immunogenic activity. This strengthens the evidence that a structural unit is necessary for activity. In addition, both a waxy sediment and the smallest particles which sedimented only at 144,000 x g were highly immunogenic if incorporated into Freund's incomplete adjuvant. In the absence of adjuvant, neither produced any immunity.

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PubMed1962

Effect of mycosuppressin on the course of experimental tuberculosis in mice.

Youmans, Guy P. (Northwestern University Medical School, Chicago, Ill.) and Anne S. Youmans. Effect of mycosuppressin on the course of experimental tuberculosis in mice. J. Bacteriol. 84:701-707. 1962.-When mycosuppressin was administered to normal mice prior to infection with virulent tubercle bacilli, no indication of a favorable effect on the course of the infection could be obtained. However, when suspensions of virulent tubercle bacilli were exposed to mycosuppressin for from 1.25 to 3.25 hr prior to infection, survival of the mice was greatly prolonged in comparison with mice receiving untreated tubercle bacilli. Microbial enumeration studies with bovine serum agar medium revealed that the number of viable particles of tubercle bacilli in the mycosuppressin-treated suspensions did not differ significantly from the number in untreated suspensions. When the microbial enumeration studies were conducted using the same medium without serum, the number of viable particles in the mycosuppressin-treated suspensions appeared to be (1/5) to 1/20 of the number in the untreated suspensions. It was concluded that, under the conditions of these experiments, the action of mycosuppressin was primarily bacteriostatic and that this bacteriostasis persisted for a time in vivo following infection of the mice. The possible relation of these findings to the phenomenon of acquired immunity to tuberculosis also is discussed.

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PubMed1962

Effect of mycosuppressin on the respiration and growth of Mycobacterium tuberculosis.

Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.) and Guy P. Youmans. Effect of mycosuppressin on the respiration and growth of Mycobacterium tuberculosis. J. Bacteriol. 84:708-715. 1962.-A substance, called mycosuppressin, was found in the lungs of guinea pigs and rabbits vaccinated with BCG or with a particulate immunizing fraction isolated from mycobacterial cells, and was not found in lungs of unvaccinated animals. Mycosuppressin inhibited the endogenous respiration and the growth of the virulent H37Rv strain of Mycobacterium tuberculosis. It also inhibited the endogenous respiration of the avirulent H37Ra strain and the saprophyte, M. smegmatis, but it increased the respiration of M. phlei. The oxidation by the H37Rv strain of lactate, pyruvate, glycerol, and glucose was also inhibited. Cytochrome oxidase activity was suppressed. Mycosuppressin was most stable at pH 6 to 7. It was nondialyzable, stable at 98 C, and not affected by lyophilization or freezing. It was soluble, in alcohol and acetone, insoluble in ether and water. Under appropriate conditions, mycosuppressin combined with, or was adsorbed to, mycobacterial cells, and was inactivated by serum and bovine serum albumin. It did not inhibit but, instead increased markedly, the respiration of Staphylococcus aureus and Escherichia coli.

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