PubMed Health⌕ Search

Biomedical subjects

Z Sír

Publications and source records attributed to Z Sír.

8 recordsLinked to original sources
PubMed1991

The role played the lipid fractions of Mycobacterium bovis BCG in the development of antituberculosis immunity in an animal experiment.

The authors investigated the antituberculosis and antitumour immunogenicity as well as tuberculin allergenicity of the lipid fractions from Mycobacterium bovis BCG strains of Danish, French, Japanese origin and of Czechoslovak 725. The fractions explored included phospholipids, Cord factor, ethanol-extractable lipids, waxes A, B, C + D and fats. The fractions were divided into three groups according to their effectiveness. 1. The Cord factor and phospholipids from all the studied strains were effective in the antituberculosis and antitumour models with the only exception of strain 725 phospholipids. Phospholipids from all strains were capable of inducing tuberculin allergy. 2. In the second group (waxes A, C + D and lipids extractable by ethanol) a variance was observed in the antigenic properties of identical fractions from different strains suggesting differing metabolism in the strains producing these fractions. A mixture of waxes C + D from the French and Danish strains showed a degree of suppression in its antituberculosis effectiveness. 3. Waxes B and fats were entirely ineffective in the antitumour model and, with the exception of waxes B from strain 725 and fats from the Japanese strain, in the antituberculosis model. The antituberculosis and antitumour effectiveness directly depended on the content of a mycolic acid complex in fractions. Tuberculin allergenicity was associated with the intensity of phospholipid production by mycobacteria.

Animals↗
PubMed1982

Comparison of bcg strains for delayed hypersensitivity induction tested in vivo in guinea pigs and in vitro.

Previous studies performed on guinea pigs demonstrated a direct dependence of tuberculin reaction size (in vivo hypersensitivity) on immunogenicity in a number of BCG strains. The present work used an in vitro method, MIF detection, for assessing hypersensitivity and compared the results obtained with tuberculin hypersensitivity tests, correlating the data with the immunogenicity of the individual BCG strains employed. The following strains were used: the Czechoslovak BCG strain No. 725, Japanese BCG strain Tokyo, Danish BCG strain Copenhagen and Soviet BCG strain Moscow. The results obtained by the two hypersensitivity testing methods, in vivo and in vitro were in a direct correlation; a direct relationship was also demonstrated between hypersensitivity tested by the in vitro method and immunogenicity. The in vitro method of MIF detection is reproducible and comparable with the other two methods employed and may be used as an alternative approach to BCG vaccine efficacy testing. It might probably also be applicable to estimation of the status of cell-mediated immunity against intracellularly parasitizing bacteria in general.

Animals↗
PubMed1981

Resistance to Mycobacterium tuberculosis H37Rv infection induced by Listeria and mycobacterial lipids.

The avirulent strain Listeria monocytogenes (Welshimer) induced upon a single injection 4 weeks prior to challenge with Mycobacterium tuberculosis H37Rv resistance in guinea-pigs, which was manifested by a significant decrease of spleen weight and Feldman's index in immunized animals. The degree of resistance was dependent on the immunizing dose and time of administration. Repeated high doses of Listeria yielded only a low or no effect. Further increase of resistance was obtained using the BCG lipids; however, stimulation of resistance with listeria lipids was not successful and, finally, Freund's incomplete adjuvant was significantly effective in the Feldman index only. The BCG lipids, extracted with ethanol, which contained nitrogen and water-soluble substances, induced a significant resistance against M. tuberculosis infection. The chloroform-methanol BCG lipids were also effective, however, significantly less than the ethanol-extracted material. The listeria factor Ei itself or together with Freund's incomplete adjuvant possessed only low effectiveness against mycobacterial infection. However, if injected together with ethanol-extracted BCG lipids, it produced a significant degree of resistance which was higher than that induced by lipids only. The degree of resistance was comparable with the effect of living BCG strain which served as a source of isolated lipids.

Animals↗
PubMed1978

Effect of M.bovis BCG and M.microti on sarcoma 180 growth in mice.

The antitumorous efficacy of the Czechoslovak BCG 725, Czechoslovak BCG 901, the Danish SAS maintained, the Japanese SAS and SH maintained BCG strain and the Czechoslovak OV 247 (M.microti) strain was studied. (SAS--original Sauton's medium with asparagine, SH--Sauton's medium with the asparagine replaced by enzymatic casein hydrolysate.) Ascitic Sa 180 cells were used as the experimental tumor and 800 mice as experimental animals. All the strains employed displayed an anticarcinogenic effect in a protective assay (immunization 8 weeks before inoculation of Sa 180 cells). In a therapeutic test (vaccine administered 24 hr after inoculation of Sa 180 cells and then at weekly intervals), Czechoslovak BCG 725 and Czechoslovak OV 247 were used and proved effective.

Animals↗