CHARACTERIZATION OF A CR51-LABELED ENDOTOXIN AND ITS IDENTIFICATION IN PLASMA AND URINE AFTER PARENTERAL ADMINISTRATION

Abstract

Radioisotopes such as 1 ~, Na2C#tO,, and Cr61C18 have been utilised for marking endotoxin in efforts to determine in ~ivo uptake and distribution of the latter material (3, 7-9, 11, 12, 14). These reports are in fair agreement conceming the quantitative distribution of the endotoxin as based on subsequent cotmting of plasma and organ samples. Until recently, evidence for the presence of endotoxin itself in tissues and fluids has been presumed on the basis of the following two observations; (a) differences in in ~/ro distribution of the free label as contrasted to that of the label bound to endotoxin and (b) the increased rate of plasma clearance of radioactivity in animals rendered tolerant to endotoxins. Current studies have shown that a correlation exists between the toxicity and the radioactivity present in plasma samples collected at various times after administration of a chromate-labded endotoxin (6). Furthermore, the presence of endotoxin in such plasma samples was demonstrated immunologically by means of ring test precipitation (5). However, evidence has been lacking that the endotoxin moiety per se bears the radioactive label either before injection or after recovery from the tissues and fluids of recipient animals. It is the purpose of this report to show that the labeling of endotoxin with hexavalent Cr 51 results in a specifically tagged product, a part of which retains both label and toxicity in circulating plasma for several hours after administration. Furthermore, it will be shown that endotoxin is demonstrable in urine but in a non-toxic and non-labeled state. Materials and MethodsEndo~o~n.--The source of endotoxin was the Danysz strain of Salmonella entedtldls prepared by the method of Boivin (1). The product was labeled by incubating 100 mg with 1.5 me of Na¢C#IO4 (specific activity --73 mc/mg), during 48 hours according to a method of Brande, e~ al. (2). After labeling, the specific activity of the endotoxin was 1.5 #c/rag which

Relationship between Particle Size and Biological Activity of E. coli Boivin Endotoxin*

“…Oroszlan and Mora (18) (6,7,19). The binding of chromate may thus provide an important clue to the mechanism of toxicity.…”

“…These data were also processed in the computer with a parallel line assay program. 6 Antibody titration by the hemagglutination procedure. The ability of the test materials to stimulate antibody formation was determined in the rabbits that were used for the pyrogen assay.…”

Production of an Extracellular Toxic Complex by Various Strains of Pseudomonas Cepacia

“…The LPS was purified from this cell pellet by the procedure of Staub (1967) and further purified by ultracentrifugation (Chedid et al, 1963). Endotoxic activity of the LPS was measured by the LAL assay (Sullivan et al, 1976).…”

Interaction of Lipopolysaccharides With Plasma High Density Lipoprotein in Rats

“…The time for which endotoxin circulates in the blood may depend on several factors, some of which may concern the type (smooth [S] or rough [R]) (8,25) and dose of lipopolysaccharide (LPS) used (7) and the method of extraction, as well as the state of the animals used (7,11,12). Studies on the distribution of LPS in the blood showed that the circulating LPS was present mainly in the plasma (4,7,10); LPS was not detectable in erythrocytes (4,24), but some authors have detected LPS in platelets and in polymorphonuclear cells (4,15,24,33). The very early targets of endotoxin may therefore be constituents of the plasma.…”