Molecular aspects of endotoxic reactions

Potentiation of the T-lymphocyte response to mitogens. II. The cellular source of potentiating mediator(s)

Effective supernatants (SUP), which potentiate mouse T-cell responses to phytohemagglutin (PHA), are obtained from cells of several species (human, rabbit, rat, mouse) and indeed from syngeneic spleen, thymus, or bone marrow cells. Unstimulated cells release some SUP activity but more is produced after stimulation. Lipopolysaccharide (LPS) produced very active SUP in all cultures tested. PHA was similarly active on human leukocytes only, whereas concanavalin A (Con A) gave highly efficient SUP only with mouse spleen cells. SUP production is not correlated with a mitotic response of the donor cells and is observed in cultures unable to respond mitotically to the stimulant. Adherent mouse spleen cell populations, consisting largely or entirely of macrophages, produce active SUP, while nonadherent cells do not. Similarly, purification of human peripheral leukocytes on nylon columns, with removal of macrophages and other adherent cells, destroys their ability to produce SUP. The importance of indirect effects in stimulating mitotic responses of T cells is emphasized by the fact that the mitotic response of mouse thymocytes to LPS and its ability to potentiate the response of these cells to PHA disappears with removal of adherent cells from the thymocyte population. Conversely the production of SUP from spleen cells stimulated by Con A requires the presence of T cells.

Localization and biological and physicochemical properties of the cell wall lipopolysaccharide of Rhodopseudomonas capsulata

Electron micrographs of phenol-water-extracted lipopolysaccharide (LPS) of Rhodopseudomonas capsulata show filamentous and netlike aggregates. Treatment of the LPS with sodium deoxycholate resulted in a reversible splitting into subunits. The LPS represents a cell wall constituent with O-antigenic specificity. In passive hemagglutination tests, high titers were obtained when erythrocytes sensitized with untreated or heat-treated LPS were incubated with antisera obtained by immunization of rabbits with whole cells of R. capsulata. The alkali-treated LPS was not active in this test. Mouse lethality tests have shown that the LPS of R. capsulata is less toxic than LPS of Escherichia coli. Also, the X-ray protection efficacy and the phagocytic activity stimulation of LPS from R. capsulata in mice are small, as compared with LPS of E. coli. Incubation of living bacteria in saline (37 C) resulted in a solubilization of an LPS-protein-lipid complex from the outer layer of the cell wall. The isolated complex contained the components which were found in the LPS. In addition, 20% amino acids and a large amount of palmitic and stearic acids, which are typical phospholipid components, were present.

Studies on the serological and immunological response of chickens to endotoxin and endotoxoid

Chicks two, three and four weeks of age respond well serologically to endotoxin given intravenously, with the older chicks giving a better response. The induced immunity against live organism challenge produced by homologous endotoxin from Escherichia coli or Salmonella typhimurium is specific between these two organisms, however, cross-immunity occurs between E. coli 045 and E. coli 0109 and between Salmonella enteritidis and S. typhimcrium and further, endotoxins from different organisms may be combined to provide immunity against the homologous organisms. Endotoxoid administered to chicks rendered them more susceptible to live organism challenge for five days, following which some immunity developed.

Purification of Pseudomonas aeruginosa endotoxin by membrane partition chromatography

A procedure is described for obtaining large quantities of purified endotoxin of Pseudomonas aeruginosa by using Diaflo ultrafiltration. This method allowed us to isolate from the protein-lipopolysaccharide complex two low-molecular-weight substances which do not play any antigenic role. It provides a useful tool for immunological purposes.

Enzyme activities of the livers of mice infected with Salmonella typhimurium

The activities of the mouse liver enzymes tryptophan oxygenase, tyrosine aminotransferase, and pyruvate kinase were measured after infection with three dose levels of Salmonella typhimurium strain SR-11. Infection occurred in all groups as evidenced by an increase in bacterial numbers and by death of the animals. The activities of the enzymes increased in all groups during the course of the infection. The results obtained during infection are compared with those obtained after endotoxin injection.

Outer cell envelope glycoprotein from two strains of Serratia marcescens

Cell envelope glycoproteins were extracted with sodium dodecyl sulfate from isolated cell walls of two strains of Serratia marcescens and purified by gel filtration column chromatography on Sepharose 4B. There was no significant difference in the chemical composition. Both fractions contained approximately 50% proteins and 10% carbohydrates. Glucosamine and glucose were identified as the only sugar components in the carbohydrate moiety. Immunochemically they shared at least one common antigenic component with each other and possibly with their corresponding lipopolysaccharide fractions.

Endotoxin: stimulation of bone resorption in tissue culture

Bacterial endotoxins can stimulate the release of previously incorporated calcium-45 and tritiated proline from fetal rat bone in tissue culture. Endotoxin from Bacteroides melaninogenicus, an organism regularly found in the gingival crevice of man, produces a response similar to parathyroid hormone and is effective at doses as low as 0.1 microgram per milliliter. This response is inhibited by serum and dependent upon the presence of albumin. Endotoxins may play a role in the bone loss characteristic of human periodontal disease.

Enhancement of the lethal effects of endotoxins by interferon inducers

Prior treatment of mice with poly I:C or NDV enhanced the lethal effect of E. coli or B. dermatitidis endotoxins.