No abstract

Escherichia coli strains with defined receptor specificity were used as probes to analyze the individual variation in host cell receptors with respect to blood groups. The adhesins were initially characterized as mannose sensitive (MS), mannose resistant (MR), or nonagglutinating (-). The receptor specificity of the strains with MR adhesins was defined by agglutination of synthetic Galkl-4Galp covalently linked via a spacer arm, (CH2)2S(CH2)2CO-H-bovine serum albumin (BSA) to BSA-latex beads as specific for the globoseries glycolipid receptors (MR:GS). Strains with MR adhesins not reacting with Gala1-4Gal0-BSAlatex were designated MR:nonGS. The attachment and hemagglutination of the MR:GS strains was strictly dependent on Galal-*4Galp-containing receptors, as shown by the absence of binding to cells from individuals of blood group P lacking these structures. Previous reports showed differences in the composition of globoseries glycolipids between erythrocytes from individuals of P1 and P2. No significant difference was found, However, in the the mean adhesion to P1 and P2 epithelial cells or in the agglutination titer for P1 and P2 erythrocytes. The MR:GS receptors were equally distributed on squamous and transitional epithelial cells. In contrast, the distribution of MR:nonGS receptors was skewed. Attachment occurred mostly to squamous epithelial cells. The attachment of strains with MR:nonGS adhesins was independent of the P blood group of the cell donor. The binding ability of MR:GS and MR:nonGS adhesins appeared independent and additive. The attachment was not influenced by the ABH blood group. However, increased binding to epithelial cells from nonsecretors occurred regardless of the P blood group, suggesting a shielding of receptors by products controlled by the secretor genes. These results illustrate how individual variation in cell surface components with and without receptor activity determine the interaction of a ligand with a known receptor. Adhesive capacity is a virulence factor for Escherichia coli causing upper urinary tract infection (25). The attachment results from the interaction of host cell receptors with bacterial surface structures known as adhesins (14). Since the exact structures of the adhesins remain to be determined, they are classified according to either target cell specificity or, in some instances, receptor specificity (when the receptor structure has been identified). Wild-type bacteria, e.g., urinary E. coli isolates, can coexpress several adhesins, even on a single bacterial cell (5, 10). Receptors for attaching bacteria can consist of host cell surface carbohydrates, i.e., either glycoproteins or glycolipids (12). Several glycoconjugate specificities have been suggested to mediate adhesion or hemagglutination of uropathogenic E. coli, including mannose (19), N-acetylglucosamine (27), M antigen (28), NeuAca2-3Gal (21), and 919

The aerosol extinction in various weather situations is calculated from Mie theory by use of an aerosol model which starts from dry particles. The particle size distribution and refractive index are adapted to actual air humidity by use of a growth factor, r/r(o), which is derived according to the theory of the relationship between relative humidity and the equilibrium radius of an aqueous solution droplet. It is shown that the particle number concentration in different size ranges has a dominating influence on the relation between the IR aerosol transmission and the meteorological visibility. Variations in air humidity affect the aerosol extinction mainly through modification of the particle size distribution. The effect on extinction due to the humidity influence on refractive index is proved to be of less importance.

Several monoclonal antibodies (MAbs) directed to blood group P1 (Gal alpha 1-4Gal beta 1-4GlcNAc beta-O) and Pk (Gal alpha 1-4Gal beta 1-4Glc beta-O) determinants were produced with high efficiency by using synthetic neoglycoproteins as immunogens. The specificity of IgM and IgG1 MAbs was characterized by binding to defined oligosaccharides and glycoconjugates. Antibodies that bound equally well to P1 and Pk determinants and to Gal alpha 1-4Gal beta 1-O-derivatives were obtained, together with others that showed selective recognition of the entire trisaccharide chain. Selected antibodies were shown to be useful as reagents for detection of the blood group P antigens in glycolipid extracts of erythrocytes and on the surface of erythrocytes of different P phenotypes, demonstrated both by radioimmune assays and hemagglutination. Six IgM MAbs directed to the Pk determinant bound selectively to Burkitt lymphoma cells and 2 of these antibodies (424/3D9 and 424/6A2) could be used as auxiliary reagents in immunofluorescence for diagnosis and classification of B-cell lymphomas and leukemias using flow cytometric analysis. Eight normal individuals and 37 patients with lymphoma or leukemia were studied. Tumor cells of 2/2 patients with "Burkitt-like" lymphoma, 1 patient with centroblastic lymphoma and 2 patients with acute leukemia were strongly stained for the Pk antigen. The staining patterns for differentiation markers classified the tumor cells to a developmental stage closely related to the Burkitt cell type.

Specific binding to the globoseries of glycolipid receptors explains the adherence of uropathogenic Escherichia coli to host cells. The minimal receptor disaccharide Galdl-*4GalpI [galactosea(1-*4)galactosep] 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 onto latex beads in one of two ways. In one way, diand 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. Gala1l-4GalIp was as active as the trisaccharide derivative Galal-4Galll->3glucose or Galal->4GaIfl- ,-3glucosamine. Among the natural glycolipids tested, globotetraosylceramide was the most active. Subsequently, the sensitivity and specificity of the Galkl->4GalIp-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.