Showing papers by "Hakon Leffler published in 1987"

Receptor-specific agglutination tests for detection of bacteria that bind globoseries glycolipids.

Abstract: Specific binding to the globoseries of glycolipid receptors explains the adherence of uropathogenic Escherichia coli to host cells. The minimal receptor disaccharide Gal alpha 1----4Gal beta [galactose alpha (1----4)galactose beta] is recognized by most attaching clinical isolates. However, wild-type isolates can express adhesins with several different receptor specificities. Bioassays do not permit separate analysis of each receptor specificity, since the target cells contain multiple potentially receptor-active molecules. In this study, bacterial adhesins were analyzed by using receptors immobilized into latex beads in one of two ways. In one way, di- and trisaccharides were covalently linked via a spacer arm to latex beads coupled with bovine serum albumin. In the other way, receptor-active glycolipids were coated onto the bovine serum albumin-latex beads. The latex beads were subsequently used for agglutination by using type strains with known receptor specificity. The composition was optimized regarding receptor structure and size of latex beads. Gal alpha 1----4Gal beta was as active as the trisaccharide derivative Gal alpha 1----4Gal beta 1----3glucose or Gal alpha 1----4Gal beta 1----3glucosamine. Among the natural glycolipids tested, globotetraosylceramide was the most active. Subsequently, the sensitivity and specificity of the Gal alpha 1----4Gal beta-latex and globotetraosylceramide-latex reagents were compared for 733 E. coli urinary isolates. Hemagglutination of human erythrocytes was used as the positive standard. No significant difference in the specificity or sensitivity of the latex reagents was found; the sensitivity ranged from 86%, when isolates agglutinating human erythrocytes of blood groups P1 and p were included, to 93%, when those isolates agglutinating erythrocytes of blood group p were excluded. These reagents provide tools for bacterial identification in patients with urinary tract infection.

Binding to galactose alpha 1----4galactose beta-containing receptors as potential diagnostic tool in urinary tract infection.

Abstract: The diagnosis of urinary tract infection is based largely on quantitative urine cultures. The usefulness of qualitative information about the virulence of the infecting bacteria remains undefined. Ability to attach to human uroepithelial cells is one characteristic of the pyelonephritogenic clones, as well as a virulence factor per se. The identification of host cell receptors for attaching bacteria has permitted the construction of agglutination tests for simple detection of bacterial binding properties. In the present study, the reactivity with Gal alpha 1----4Gal beta-latex [galactose alpha (1----4)galactose beta-latex] and globotetraosylceramide-latex was analyzed for strains from patients with acute pyelonephritis (n = 135), acute cystitis (n = 121), and asymptomatic bacteriuria (n = 119) and from the fecal flora of healthy children (n = 120) and compared with agglutination of human blood group P1 and p, as well as guinea pig, erythrocytes. The reactivity by bioassay and the receptor-specific assays were significantly correlated. The frequency of positive reactions among the pyelonephritis isolates was 78.5% with the globotetraosylceramide-latex reagent, compared with 41% for the cystitis isolates, 25% for the asymptomatic bacteriuria isolates, and 13% for the fecal isolates. The combination of bioassays and receptor-specific assays increased the resolution of adhesins. Thus, adhesins reacting with human p erythrocytes frequently were coexpressed with Gal alpha 1----4Gal beta-specific adhesins. The receptor-specific assays provide a refined reagent to resolve bacterial binding specificities, as well as a potential tool for clinical diagnosis.

Soluble lactose-binding lectins from chicken and rat.

Abstract: Publisher Summary Soluble dimeric lactose-binding lectins with subunit molecular weights in the range of 15,000 have been found in many vertebrate tissues They have been purified from fish, amphibians, reptiles, birds, and mammals Lectins from chicken and rats are referred to as chicken lactose–lectin I (CLL-I) and rat lectin 145 (RL-145) respectively Chicken and rat also contain other lactose-binding lectins—chicken lactose–lectin II (CLL-II) and rat lectins with apparent molecular weights of 18,000 and 29,000 (RL-18, RL-29) All can be purified by affinity chromatography on asialofetuin–Sepharose, using modifications of the method of DeWaard et al The individual lectins can then be resolved either by preparative isoelectric focusing or by ion-exchange chromatography This chapter describes the isolation and some properties of these lectins There is also some discussion on the process of purification of rat lung lectins by affinity chromatography and purification of chicken lactose-binding lectins The cellular localization of CLL-I, CLL-II, and RL-1 45 in certain tissues has been determined by immunohistochemical studies using highly specific antisera These findings suggest that these lectins may function in specific types of extracellular matrix, possibly by interacting with glycoconjugates found there, and that this may be especially significant during development