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At least 19 recordsLinked to original sources

PubMed1979

Interferon and cytotoxic factor (cytotoxin) released in the blood of mice infected with Mycobacterium bovis BCG. I. Enhanced production of interferon and appearance of cytotoxin stimulated by capsular polysaccharide of Klebsiella pneumoniae or bacterial lipopolysaccharide.

Interferon production stimulated by the active substance (neutral fraction) of the capsular polysaccharide of Klebsiella pneumoniae (neutral CPS-K) in BCG-infected mice was compared with that by bacterial lipopolysaccharide (LPS). Prior infection with BCG increased the responsiveness of mice to the lethal effect of neutral CPS-K as well as to that of LPS. Associated with this, BCG-infected mice showed a markedly enhanced ability to produce interferon after stimulation not only by LPS but also by neutral CPS-K. In addition, a cytotoxic factor (cytotoxin) was found to be released in the serum of BCG-infected mice after injection of these inducers. The kinetics of production of interferon and cytotoxin stimulated by neutral CPS-K were very similar to those stimulated by LPS. The time pattern of cytotoxin production was not in parallel with that of interferon production. Interferon reached a peak 2 hr and cytotoxin 3 hr after injection with these inducers. Interferon and cytotoxin produced by neutral CPS-K showed essentially the same stabilities to heating at 56 C and to treatment at pH 2 respectively as those produced by LPS. Interferon was inactivated by heating at 56 C more rapidly than cytotoxin. Cytotoxin was inactivated by treatment at pH 2 for 24 hr, whereas interferon activity was well preserved after this treatment. These results suggest that both activities are the result of different substances.

Animals↗

PubMed1979

Interferon and cytotoxic factor (cytotoxin) released in the blood of mice infected with Mycobacterium bovis BCG. II. Influence of time after BCG inoculation on production of interferon and cytotoxin by capsular polysaccharide of Klebsiella pneumoniae or by bacterial lipopolysaccharide and on hyperreactivity to their lethal effects.

The time course of the occurrence of hyperreactivity in interferon and cytotoxin responses to the active substance (neutral fraction) of the capsular polysaccharide of Klebsiella pneumoniae (neutral CPS-K) and bacterial lipopolysaccharide (LPS) and of the hyperreactivity to their lethal effects was followed after infection with BCG in SMA and ICR strains of mice. The duration of these hyperreactivities of BCG-infected mice depended on the inoculum doses of BCG. The time patterns of the hyperreactivity to the lethal effects of neutral CPS-K and LPS were similar in both strains of mice, although the maximum toxicity of LPS by the intraperitoneal route in BCG-infected mice on a weight basis was stronger than that of neutral CPS-K. Irrespective of inducer and mouse strain, the time pattern of the hyperreactivity to produce cytotoxin was similar to that of the hyperreactivity to produce interferon. The patterns for these phenomena when neutral CPS-K was used as an inducer were also similar to those when LPS was used. In ICR mice the hyperreactivity in interferon and cytotoxin responses to either neutral CPS-K or LPS decayed significantly earlier than the hyperreactivity to their lethal effects, whereas in SMA mice the occurrence of both types of hyperreactivities seemed to be associated. Therefore, it is suggested that the mechanism for the hyperreactivity in interferon and cytotoxin responses to neutral CPS-K or LPS in BCG-infected mice is not necessarily the same as that for the hyperreactivity to their lethal effects.

Animals↗

PubMedDate not supplied

Partial purification and characterization of a cytotoxin from Clostridium difficile.

A trypsin-sensitive, heat-labile cytotoxin was purified from the supernatant of a culture of Clostridium difficile by a procedure that included ultrafiltration, precipitation with (NH4)2SO4, gel filtration, and ion-exchange chromatography. The procedure resulted in recovery of 20% of the cytotoxin and an estimated 1,500-fold increase in cytotoxic activity. The minimal amount of protein required to give an actinomorphic response in WI-38 cell cultures was 1.4 ng/ml. The estimated molecular weight of the cytotoxin is 240,000. A cytotoxin having similar properties was purified from the stool of a patient with antibiotic-associated pseudomembranous colitis by (NH4)2SO4 precipitation and gel filtration chromatography. This procedure resulted in a recovery of 26% of the cytotoxin, a 50-fold increase in cytotoxic activity, and a cytotoxic response with a minimum of 12.1 ng of protein/ml.

Anti-Bacterial Agents↗

PubMed1977

Cytotoxins against a granulocyte antigen system: detection by a new method employing cytochalasin-B-treated cells.

A method for demonstrating granulocyte cytotoxins using a modified microdroplet dye exclusion technique and cytochalasin-B-treated cells is described. Cytochalasin-B-treated granulocytes were reacted against 223 sera from multitransfused pregnant and renal transplant patients. Incidence of granulocyte cytotoxins was 11.2%. Analysis (2 X 2 contingency tables) of the reactivity of GCT+ sera showed highly significant (p less than 0.001) positive associations among 5 sera and a significant (p less than 0.001) negative association with another serum. The data are consistent with the hypothesis that a granulocyte antigen system is detected by cytotoxins and that granulocyte antigens 'Grl' and 'Gr2' may be products of allelic genes.

Alleles↗

PubMed1979

Cultures for Clostridium difficile in stools containing a cytotoxin neutralized by Clostridium sordellii antitoxin.

Stools from patients with antibiotic-associated diarrhea or colitis were cultured to detect the presence of Clostridium difficile. All specimens contained a cytotoxin which was neutralized by Clostridium sordellii antitoxin. Initial testing employed several methods with comparative merits in recovering this organism. These included the use of nonselective media, antibiotic-incorporated media, alcohol shock, and paracresol-containing broth. Optimal results were achieved with primary plating of serial dilutions onto a selective agar containing cycloserine and cefoxitin. This technique was then employed in a large number of specimens. The overall results showed that C. difficile was recovered in specimens from 71 of 73 patients. All isolates of C. difficile produced a cytotoxin which was neutralized by C. sordellii antitoxin in vitro. These results verify the utility of this medium and support the concept that C. difficile accounts for the cytotoxin found in stools in nearly all cases.

Antitoxins↗

PubMed1979

Isolation of a cytotoxin-enterotoxin from Entamoeba histolytica.

A heat-labile material with cytotoxic and enterotoxic activities was isolated from axenically cultivated Entamoeba histolytica. The cytotoxin-enterotoxin was partially purified from the particulate-free supernatant of sonicated trophozoites by ammonium sulfate precipitation and gel filtration. Cytotoxic activity, assayed on monolayers of HeLa or BHK-21 cells, was restricted to proteins that eluted in the molecular weight range of 25,000--35,000 daltons. Cytotoxicity was demonstrated at protein concentrations as low as 2--4 microgram/ml, was heat-labile (75 C, 30 min), and was inhibited by specific immune IgG and by an undetermined factor in nonimmune serum. Enterotoxic activity of the partially purified toxin was demonstrated by induction of fluid secretion in ligated rabbit ileal loops. The cytotoxin-enterotoxin of E. histolytica may play an important role in the production of diarrhea and mucosal injury in amoebic colitis.

Animals↗

PubMed1979

Non-HLA lymphocyte cytotoxins in various diseases.

Cold non-HLA lymphocyte cytotoxins were found to be principally reactive against B lymphocytes. These antibodies were studied in 1335 patients with a wide range of diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), scleroderma, Hashimoto's disease, asthma, diabetes, lymphoma, psoriasis, leukemia, multiple sclerosis, and also in healthy donors. Antibodies reactive to B lymphocytes in the cold or warm test conditions were not directed against HLA specificities. Since B lymphocytes differ from T lymphocytes principally in that they have surface immunoglobulin, it is postulated that at least one target antigen of cold lymphocyte cytotoxins is not a virus, infectious agent, or a genetically determined structural antigen, but, rather, simply immunoglobulin.

B-Lymphocytes↗

PubMedDate not supplied

Occurrence of granulocyte cytotoxins and agglutinins.

Granulocyte cytotoxic activity in sera from over 257 patients was shown to be distinct from HL-A lymphocytoxic activity. Granulocyte cytotoxins occur in approximately 25 per cent of sera from patients having leukemia, 45 per cent with aplastic anemia, 22 per cent with kidney disease on hemodialysis, and 19 per cent of pregnant women. By testing sera on the same panel of cells, the granulocyte cytotoxic activity was shown not to be associated with granulocyte agglutination activity or lymphocytotoxic acitivty. It is likely that granulocyte cytotoxins and granulocyte agglutinins will be useful in transfusion and bone marrow transplantation as a separate tool from the more widely used lymphocyte cytotoxicity reaction.

Agglutination Tests↗

PubMedDate not supplied

Nature and properties of C3Hf natural antitumor cytotoxins directed against murine lymphosarcoma cells.

The nature and some biological properties of the natural antitumor cytotoxins previously found in normal C3Hf serum, have been investigated. By immunoelectronmicroscopy study, employing rabbit hybrid antibodies with specificity for mouse Ig and ferritin, the C3Hf cytotoxins were shown to belong to immunoglobulins. By gel filtration, by inhibition experiments of the cytotoxic serum activity with monospecific anti-IgG and anti-IgM sera, and by 2-mercaptoethanol treatment of the C3Hf serum, the cytotoxic immunoglobulins were demonstrated to belong to the IgM class. They were not inactivated by heating until 60 degrees C and were able to activate guinea pig, rabbit, and human complement. The highest cytotoxic activity of the normal C3Hf serum was found when cells and serum were incubated at the low temperature, suggesting a low binding affinity of the cytotoxic IgM.

Animals↗

PubMed1975

[Humoral antitumor cytotoxins in patients with melanoma of the skin].

The level of humoral antitumor cytotoxins in sera of malignant melanoma patients has been studied by means of a cytotoxic test in vitro. The authors have shown a cytotoxic effect of sera of most patients on autochthonous tumor cells of melanoma. Hela cells were used as a control cell line. There was no cytotoxic effect of sera (of both melanoma patients and healthy donors) on Hela cells. The patients' sera cross-reacted in allogenic combinations of melanoma target cells and sera. Humoral cytotoxins against melanoma tumor cells have also been found tin sera of healthy donors.

Antibiotics, Antineoplastic↗

PubMed1979

Further studies on a vaccinia virus cytotoxin present in infected cell extracts: identification as surface tubule monomer and possible mode of action.

A vaccinia virus-specific cytotoxic protein (3--10 X 10(4) daltons) had previously been detected in extracts of infected HeLa cells. In this study the protein has been shown to be a late gene product and a virion component--almost certainly the monomer of the surface tubules of the vaccinia virion. The relationship of this cytotoxin to a number of early vaccinia-induced cytopathic effects was examined: it was not the mediator of vaccinia-induced early cell rounding, did not inhibit protein or RNA synthesis in cell-free systems or intact cells (after uptake-induction by hypertonic MgSO4), or cause the release of beta-glucuronidase from a crude preparation of HeLa cell lysosomes. Its possible role in vaccinia-induced cell degeneration, late in infection, is discussed.

Cell-Free System↗

PubMed1977

Vero response to a cytotoxin of Escherichia coli.

A cytotoxin was found in culture filtrates of a number of Escherichia coli strains that differed from the known heat-stable and heat-labile enterotoxins of E. coli. It was cytotoxic for Vero but not for Y-1 or CHO cells, and its effect on Vero was distinctly different from that of heat-labile enterotoxin. It was labile to heat and antigenically different from heat-labile enterotoxin, and membrane filtration indicated a molecular weight of 10,000 to 30,000.

Antigens, Bacterial↗

PubMed1978

Properties of an Escherichia coli cytotoxin.

Isoelectric focusing of a heat-labile cytotoxin of Escherichia coli H30 revealed the presence of two molecular variants, pI 7.2 and a comparatively small quantity of pI 6.8. Predominant component pI 7.2 had a molecular weight of 28,000, induced some fluid accumulation in rabbit ileal loops, and showed no morphological response in Y-1 cells but a strong cytotoxic effect on Vero cells.

Animals↗

PubMed1978

[Effect of the cytotoxin of Central Asia cobra venom on the functional state of rat liver mitochondria].

A study was made of the action of various concentrations of cytotoxin (C), free of phospholipase A admixtures, on the respiration, oxidative phosphorylation of the rat liver mitochondria and their "ghosts", and also on the permeability of their internal membranes for various ions. Low C concentrations (10--25 micrometer) failed to influence the functional parameters of the intact mitochondria, but sharply increased the permeability of the internal membranes for monovalent ions. Apparently the uncoupling action of C on the mitochondrial "ghosts" was caused by the formation in the membrane of nonspecific conductivity "canals" with poor selectivity to the ion size and charge.

Animals↗

PubMed1977

Vaccinia virus cytotoxin.

Extracts of vaccinia-infected HeLa cells were rendered free from infectious virus by centrifugation followed by membrane filtration and were shown to be toxic to uninfected HeLa cells in the presence of hypertonic MgSO4, used as a macromolecular uptake inducer, under conditions which did not kill control cells. Extracts from uninfected cells were nontoxic. This biological test was adapted to a semi-quantitative assay which was used to monitor the purification of the cytotoxic factor by DEAE-cellulose and Sephadex G-100 chromatography. The cytotoxic factor was purified 100-fold, shown to be of molecular weight 30 -- 100,000 daltons, acidic and completely inactivated by soluble trypsin but not by ribonuclease under conditions believed to degrade both single- and double-stranded RNA species. It was demonstrated to be virus specific by approrpiate immunosorbent chromatography. Extracts were also prepared from vaccinia-infected HEp-2, RK and W-K cells respectively. A virus-specific factor, toxic to uninfected HeLa cells, with similar chromatographic properties to that isolated from infected HeLa cells, was isolated from these three additional cell lines. The concept of virus induced cytotoxins, substances which exert their toxic effect in the host cells in which they are made, is discussed.

Antigens, Viral↗

PubMed1975

The cytotoxins of cobra venoms. Isolation and partial characterization.

Eight basic proteins which lyse virus-transformed mouse fibroblasts in culture have been isolated from the venoms of six Asian Naja naja subspecies. These cytotoxins appear to represent an homologous series of proteins, all within the molecular weight range of 7000-8000. They have been divided into three arbitrary types on the basis of amino acid composition, electrophoretic mobilities and elution order upon ion-exchange chromatography. The rate at which the toxins effect cell lysis: (1) appears to be a function of the basicity of each toxin; (2) is dependent upon toxin concentration; (3) is temperature dependent; and (4) is inhibited by heparin sulfate. In view of the physical changes, which the cell undergoes during lysis and of the various factors which affect the action of these proteins, it is proposed that interaction of membrane receptors with the toxin, leading to alteration of cell membrane structure, is the principal event which ultimately leads to the disruption of the cell.

Amino Acids↗

PubMed1978

Enhancement of human kidney allografts by cold B-lymphocyte cytotoxins.

The sera of 233 kidney transplant patients before transplantation were tested by cytotoxicity against a panel of B and T lymphocytes at 5 degrees C and 37 degrees C. The results divided the patients into four groups: those whose sera reacted with B lymphocytes at 5 degrees C; those reacting with B lymphocytes at 5 degrees C and 37 degrees C; those reacting with T lymphocytes at 37 degrees C; and those with no antibodies. The patients with pre-transplant antibodies reactive with B lymphocytes at 5 degrees C had a significantly higher kidney-transplant survival rate at 6 months (70%) and 1 year (65%) than patients who had no antibodies (47% and 46%, respectively). Patients with antibodies reactive at 37 degrees C had a 6-month survival-rate of 38% when reactive against B cells and 43% when reactive against T lymphocytes. The cold cytotoxins were IgM.

B-Lymphocytes↗

PubMed1975

The pathogenesis of Shigella diarrhea. V. Relationship of shiga enterotoxin, neurotoxin, and cytotoxin.

The biological activity of the enterotoxin of Shigella dysenteriae 1 was compared with that of a well-studied 20-year-old partially purified preparation of neurotoxin from the same organism. Enterotoxicity, neurotoxicity, and cytotoxicity were present to an equivalent extent in both preparations. Human convalescent antisera and experimental rabbit antisera had equal toxin-neutralizing antibody to the cytotoxic activity in these toxin preparations. Multiple protein bands were present in each toxin studied. Two separate HeLa cell fractions could be obtained by Sephadex gel filtration chromatography, isoelectric focusing in a sucrose gradient, and polyacrylamide gel electrophoresis. Only one of these fractions (isoelectric at pH 7.2) was associated with enterotoxicity and neurotoxicity. The second smaller-molecular-weight fraction, which was isoelectric at pH 6.1, possessed only cytotoxic activity. These data suggest that Shiga enterotoxin and neurotoxin are closely related proteins and, indeed, may be identical. The nature of the cytotoxin with pH 6.1 is not clear, although it may be a subunit of the larger toxin that is capable of acting directly on the HeLa cell.

Diarrhea↗