Effect of Microbial Fractions on the Metabolism of Liver and Monocytes from Mice.

The complex biochemical interactions which occur between parasites and their host cells require elucidation for a clear understanding of how an infectious process develops. Whether the reactions between microorganisms and tissues occur directly or are mediated through secondary mechanisms has been the subject of considerable discussion (Sanford, Barnett, and Gott, 1960; Gilbert, 1960; Atkins, 1960). The administration of bacterial products (e.g., endotoxins) generally elicits profound physiological changes in recipient animals, and it seems clear that many of the effects on cell metabolism are related to andrenergic mechanisms. Other studies (Yunis and Harrington, 1960; Vicari, Olitzki, and Olitzki, 1960; Cohn and Morse, 1960; Berk, Nelson, and Pickett, 1960) have shown in vitro in the absence of hormonal factors that some bacterial preparations directly affect certain mammalian enzyme systems. Many of the discrepant findings seem best explained in terms of differences in cell type employed (e.g., rabbit polymorphonuclear leukocytes, human leukemic leukocytes, mouse monocytes) and in kind of bacterial preparation tested. Previous studies in this laboratory indicated that the succinoxidase activity in vitro of mouse monocytes was depressed in the presence of dead Pseudomonas aeruginosa (Berk et al., 1960; Berk and Nelson, 1960a). In addition, other studies demonstrated that trace amounts of a pseudomonad polysaccharide (Piromen) depressed the oxidase activities of liver mitochondria (Berk and Nelson, 1960b). The studies reported here were undertaken to characterize better the nature of the inhibitory substance from pseudomonads, and to compare its action on mouse tissues with lipopolysaccharide endotoxins of other bacteria.