Immunization with endotoxin stimulates the production of specific antibody, however it does not provide the high level of specific protection conferred by the exotoxins. In addition to their antigenic activity, endotoxins elicit other characteristic reactions which are extensive and varied. Such effects may influence host resistance more significantly than does the stimulation of specific antibody. A non-specific increase in resistance to infection with various bacterial pathogens and a reduction or elimination of such reactions as fever, Shwartzman phenomena or lethality have been shown to follow injection of endotoxin. This altered host reactivity usually is of short duration and is independent of demonstrable antibody.Although the mechanisms of such resistance have remained obscure for many years, recent studies on the humoral and cellular alterations in the host which follow the administration of endotoxins may provide meaningful information.In this connection, the effect of endotoxin on serum properdin and on the activity of the reticuloendothelial system (RES) are noteworthy. Endotoxin has been shown (2) to increase the resistance of mice to experimental infections; there is a concomitant increase in serum properdin levels (3) and an enhanced ability of the RES to clear injected colloids or bacteria from the blood (4). However, these effects by themselves are not likely to account for the altered state of resistance (5).In studies on the interactions, in vitro and in vivo, between endotoxins and properdin, attention in the past has been focused on the changes produced in properdin and the components of complement. More recent studies (6-9) have been concerned with the resultant change in endotoxin itself as a consequence of its interaction with serum. We have described a heat-labile component of serum, other than complement, properdin, or specific antibody, which altered endotoxic materials so that they no longer could elicit their characteristic host responses (1).
ENDOTOXIN INACTIVATION BY HUMAN SERUM the antibody excess region. It can be seen that the whey contains a component identical with serum albumin and that this component constitutes near 2.5% of the whey proteins The immunochemical reactions with antibody to y2-globulin gave assay values from an initial 2.5% to values near 1%. The data indicate that a cross-reactive protein( s) is present in the milk whey. It is known that y2-globulins show immunological cross-reactions with other proteins in the yl-and pglobulin areas ( 14-1 6) and the present results may indicate the presence of other serum proteins in the milk whey.Suiztnzur~. The results of electrophoretic. ultracentrifugal and immunochemical analyses indicate that serum albumin is present in human milk whey. The inmunochemical assay shows that it comprises 2.5% of this system. Proteins with the physical properties of human -I2-globulin could not be demonstrated although material showing immunological cross-reactions with such proteins is present .--__--1. Schulte. K. E.
Ten polysaccharides, isolated from various animal and plant sources, were selected for comparison with 2 bacterial polysaccharides, typical of Gram-negative endotoxins. The tissue sources were: mouse (kidney, liver, lung, stomach, Sarcoma 37, and Carcinoma 241-6); rabbit skin and chick embryo skin; and tangerine and Bryonia root. The bacterial endotoxins were those of S. typhosa and Serr. marcescens. Their relative potency was determined in inducing the following host effects: fever, tolerance to pyrogenic action, leucocytic changes, the Shwartzman reaction, damage to Sarcoma 37, dermal hemorrhagic-necrosis by epinephrine, enhancement of antibody production, and lethality.
Some of the polysaccharides were consistently active in all the host reactions studied; except for pyrogenic activity at high dosage, the other polysaccharides were consistently negative throughout. The mouse tissue polysaccharides elicited all the effects studied; in some instances their potency approached those of the bacterial polysaccharides.
It is pointed out that elicitation of the above array of biological phenomena, hitherto considered characteristic of bacterial endotoxins, can be obtained with polysaccharides from animal and plant tissues.
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