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Biomedical subjects

A L Sandberg

Publications and source records attributed to A L Sandberg.

At least 19 recordsLinked to original sources
PubMed1991

Immunochemical and functional studies of Actinomyces viscosus T14V type 1 fimbriae with monoclonal and polyclonal antibodies directed against the fimbrial subunit.

Each of five monoclonal antibodies (mAbs) prepared against the type 1 fimbriae of Actinomyces viscosus T14V reacted with a 54 kDa cloned protein previously identified as a fimbrial subunit. This purified protein completely inhibited the reaction of a specific anti-type-1-fimbria rabbit antibody with A. viscosus whole cells. Maximum values for the number of antibody molecules bound per bacterial cell ranged from 7 x 10(3) to 1.2 x 10(4) for the different 125I-labelled mAbs and was approximately 7 x 10(4) for 125I-labelled rabbit IgG or Fab against either type 1 fimbriae or the 54 kDa cloned protein. Although the different mAbs, either individually or as a mixture, failed to inhibit the type-1-fimbria-mediated adherence of A. viscosus T14V to saliva-treated hydroxyapatite, each rabbit antibody gave 50% inhibition of adherence when approximately 5 x 10(4) molecules of IgG were bound per cell. However, binding of each corresponding rabbit Fab had no significant effect on bacterial attachment unless much higher concentrations were used. These findings suggest that antibodies directed solely against the 54 kDa fimbrial subunit do not react with the putative receptor binding sites of A. viscosus T14V type 1 fimbriae. Instead, inhibition of attachment by the polyclonal antibodies may depend on an indirect effect of antibody binding that prevents the fimbria-receptor interaction.

Actinomyces viscosus↗
PubMed1991

Cooperative complement- and bacterial lectin-initiated bactericidal activity of polymorphonuclear leukocytes.

The recognition of glycoconjugate receptors on sialidase-treated polymorphonuclear leukocytes (PMNs) by the Gal/GalNAc-reactive fimbrial lectin of Actinomyces viscosus T14V has previously been shown to initiate lactose-inhibitable phagocytosis and subsequent killing of the bacteria. Although a mutant lacking fimbriae, A. viscosus 147, was not destroyed by this mechanism, the present studies demonstrate that the deposition of C3 fragments on this bacterium by anti-A. viscosus 147 immunoglobulin M (IgM) prior to incubation with either untreated or sialidase-treated PMNs correlated with a reduction in viability of approximately 2 log10. This bactericidal activity was unaffected by lactose. A similar decrease in viability was observed following the addition of untreated PMNs to A. viscosus T14V preincubated with anti-A. viscosus 147 IgM and complement, conditions favorable for C3- but not lectin-mediated bactericidal activity. Neither IgM nor complement alone was opsonic for either strain, and individually they did not alter killing of A. viscosus T14V by sialidase-treated PMNs or inhibition of this bactericidal activity by lactose. The number of viable A. viscosus T14V cells was decreased by approximately 3.5 log10 when the bacteria were incubated with IgM and complement prior to the addition of sialidase-treated PMNs, and lactose only partially inhibited this response. Thus, the PMN-dependent bactericidal activity initiated by the participation of both the actinomyces lectin and complement was significantly greater than that achieved by either ligand alone.

Actinomyces↗
PubMed1990

Complement activation by individual and combinations of monoclonal antibodies to Actinomyces viscosus T14V fimbriae: a probe for epitope distribution on these polymeric proteins.

The spatial requirements for IgG activation of the classical complement pathway has provided a basis for utilizing complement consumption by individual and pairs of monoclonal antibodies (mAbs) to compare the repeating epitope patterns of the type 1 and type 2 fimbriae of Actinomyces viscosus T14V and to examine the co-operative effects of mAbs against these polymeric proteins. Three of five mAbs specific for the type 1 fimbriae consumed complement when assayed individually. Four patterns of complement consumption were detected with pairs of these mAbs: inhibition, addition, enhancement or synergy. Inhibition occurred when both members of a pair reacted with the same epitope but only one consumed complement. A strictly additive effect was observed if both mAbs consumed complement and, in addition, recognized the same epitope. Complement consumption by mAbs against certain epitopes was enhanced by non-complement consuming mAbs that reacted with different epitopes. Synergy was observed with extremely low concentrations of two mAbs each of which reacted with a different epitope and consumed complement. In contrast to the anti-type 1 mAbs, only one of seven mAbs against the type 2 fimbriae consumed more than 20% of the available complement. Pairs of anti-type 2 mAbs exhibited only inhibition or synergy. The latter effect was particularly striking as pairs containing mAbs that reacted with different epitopes and failed to consume complement or were minimally active when assayed individually were extremely efficient. These data indicated that the spatial arrangements of individual mAbs bound to repeating epitopes in the type 1, but not the type 2, fimbriae were appropriate for activation of complement. Thus, the repeating epitope patterns of the two types of fimbriae apparently differ.

Actinomyces↗
PubMed1988

Identification of C3d receptors on Candida albicans.

Pseudohyphal but not yeast forms of Candida albicans possess both iC3b and C3d receptors, as determined by rosetting with erythrocytes carrying iC3b (EAC3bi) or C3d (EAC3d). Rosetting with EAC3d was markedly reduced when pseudohyphae were heat killed or treated with trypsin or pronase but was not inhibited by several saccharides or aminosaccharides, including alpha-methyl-D-mannoside, or by pretreatment of pseudohyphae with concanavalin A. However, mannoproteins obtained by concanavalin A affinity chromatography of whole pseudohyphal extracts inhibited the attachment of EAC3d to C. albicans, whereas soluble (nonmannosylated) proteins were less active. Thus, although the C3d receptors appeared to be glycosylated, the oligosaccharide component of the receptor was apparently not involved in the recognition of C3d. To isolate these receptors, whole-cell extracts were separated by DEAE-Trisacryl chromatography. Fractions that inhibited rosetting were pooled and affinity purified by C3d-Thiol-Sepharose chromatography. The eluate from this affinity column inhibited attachment of C. albicans to EAC3d. Monoclonal antibodies to C. albicans were prepared, and three of these antibodies blocked rosetting. Western blotting (immunoblotting) with these antibodies indicated the presence of 62- and 70-kilodalton receptors for C3d in the extracts purified by C3d affinity chromatography and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Antibodies, Monoclonal↗
PubMed1988

Stimulation of superoxide and lactoferrin release from polymorphonuclear leukocytes by the type 2 fimbrial lectin of Actinomyces viscosus T14V.

Polymorphonuclear leukocyte (PMN)-dependent destruction of Actinomyces viscosus T14V is initiated by the recognition of galactose-containing receptors on sialidase-treated PMNs by the lectin associated with the type 2 fimbriae of these bacteria. A. viscosus T14V also stimulates the respiratory burst in PMNs as well as the release of contents of the secondary granules, as determined by the presence of lactoferrin in the culture supernatants. Under the experimental conditions employed, these bacteria do not induce the release of beta-glucuronidase, a constituent of primary granules. None of the three PMN responses studied occurs in cultures containing a mutant of A. viscosus T14V that lacks fimbriae. Activation of the PMNs is mediated by the lectin associated with the type 2 fimbriae, as demonstrated by the finding that beta-linked galactosides inhibit stimulation of the respiratory burst. Thus, the interaction of the Actinomyces fimbrial lectin with its complementary receptors on PMNs results not only in killing of these bacteria but also in the release of reactive oxygen intermediates and enzymes that may be detrimental to surrounding host tissues.

Actinomyces↗
PubMed1988

Mutants of Actinomyces viscosus T14V lacking type 1, type 2, or both types of fimbriae.

Mutants of Actinomyces viscosus T14V lacking type 1 or type 2 fimbriae or both were selected by their failure to react with rabbit antibodies against either or both fimbrial antigens. Immunospecific double labeling with iron dextran and ferritin-conjugated antibodies showed two types of fimbriae on individual cells of the parent organism, a single type on mutant strains with type 1+2- and type 1-2+ fimbriae and no labeled or unlabeled fimbriae on a type 1-2- fimbria-deficient strain. The mutational loss of one fimbrial antigen did not appear to affect expression of the other, since bacteria with one or two types of fimbriae bound similar amounts of a monoclonal antibody directed against the fimbrial antigen present on both bacterial phenotypes. The strong adsorption of strains with type 1+2+ or 1+2- fimbriae to saliva-treated hydroxyapatite and weak adsorption of those with type 1-2+ or no fimbriae was consistent with the known involvement of type 1 fimbriae in this attachment process. Similarly, the A. viscosus lectin was clearly associated with the expression of type 2 fimbriae, since only the strains with type 1+2+ or 1-2+ fimbriae participated in lactose-sensitive coaggregations with Streptococcus sanguis 34. Further studies using the fimbria-deficient mutant strains showed that aggregation of A. viscosus T14V in the presence of sialidase-treated human saliva involved both types of fimbriae, whereas neither type was required for the lactose-resistant coaggregation of the organism with certain streptococcal strains.

Actinomyces↗
PubMed1987

Binding of Actinomyces naeslundii to glycosphingolipids.

The type 2 fimbrial lectin of Actinomyces naeslundii WVU45 mediated the binding of this bacterium to glycosphingolipids chromatographed on thin-layer silica gel plates. Radioiodinated bacteria attached to GM1, GD1b, and globoside. After chromatograms were treated with sialidase, the bacteria also bound to GD1a and GT1b. The actinomyces lectin apparently recognized the Gal beta 3GalNAc termini of these gangliosides and the GalNAc beta 3Gal terminus of globoside, suggesting that glycolipids containing these sequences may serve as receptors for A. naeslundii on mammalian cells.

Actinomyces↗
PubMed1986

A 160-kilodalton epithelial cell surface glycoprotein recognized by plant lectins that inhibit the adherence of Actinomyces naeslundii.

The adherence of Actinomyces naeslundii to human epithelial (KB) cells is mediated by the interaction of a fimbrial lectin on this oral bacterium with epithelial cell receptors exposed by sialidase. The D-galactose- and N-acetyl-D-galactosamine-reactive plant lectins from peanut and from Bauhinia purpurea inhibit this interaction. This report describes the partial purification and characterization of a 160-kilodalton (kDa) cell surface glycoprotein which is the principal receptor for these lectins. Radioiodinated lectins detected a band of 160 kDa on sialidase-treated Western blots of epithelial cell extracts but did not detect bands on nontreated filters. However, wheat germ agglutinin was reactive with the 160-kDa band on filters that were not treated with sialidase, suggesting that this lectin recognizes the sialic acid residues of this molecule. The 160-kDa component was partially purified from n-octylglucoside extracts of the epithelial cells by wheat germ agglutinin affinity chromatography. This molecule was metabolically labeled with D-[14C]glucosamine and labeled at the cell surface by lactoperoxidase-catalyzed iodination or periodate oxidation followed by sodium borotritide reduction. Incubation of epithelial cells with sialidase before extraction resulted in the loss of the 160-kDa band and the appearance of a band at 200 kDa which was directly reactive with 125I-labeled peanut agglutinin. These results indicate that the 160-kDa glycoprotein on the surface of the epithelial cell serves as a receptor for the agglutinins from the peanut and B. purpurea and presumably the fimbrial lectin of actinomyces.

Actinomyces↗
PubMed1986

Type 2 fimbrial lectin-mediated phagocytosis of oral Actinomyces spp. by polymorphonuclear leukocytes.

Phagocytosis of Actinomyces viscosus T14V and A. naeslundii WVU45 by human polymorphonuclear leukocytes in the absence of antibody or complement was mediated by the lectin associated with the type 2 fimbriae of these bacteria. This effect was markedly enhanced by exogenous sialidase, an enzyme also secreted by these actinomyces. Since sialidase treatment of the bacteria did not result in increased phagocytosis, this enzyme presumably acts by unmasking receptors for the fimbrial lectin on phagocytic cells. The viability of A. viscosus T14V, which possesses type 1 and type 2 fimbriae (1+ 2+), and A. naeslundii WVU45, which possesses only type 2 fimbriae (2+), was decreased by at least 98% following incubation with polymorphonuclear leukocytes in the presence of sialidase. Entirely analogous findings were obtained with a 1- 2+ mutant of A. viscosus T14V. In contrast, the phagocytosis of 1+ 2- and 1- 2- mutants of A. viscosus T14V and a 2- mutant of A. naeslundii WVU45 was minimal or absent. Lactose and beta-methylgalactoside inhibited the destruction of the bacteria, whereas cellobiose and alpha-methylgalactoside were ineffective. Thus, the type 2 fimbriae of the oral actinomyces recognize galactose-containing receptors on polymorphonuclear leukocytes which have been exposed by the removal of sialic acid, an interaction that is followed by internalization and subsequent killing of the bacteria.

Actinomyces↗
PubMed1984

Lectin-dependent attachment of Actinomyces naeslundii to receptors on epithelial cells.

The adherence of Actinomyces naeslundii WVU45 to monolayer cultures of human epithelial cell lines was mediated by the lactose-sensitive fimbriae (type 2) of strain WVU45. The attachment of Actinomyces viscosus T14V, which has both types 1 and 2 fimbriae, was approximately half that of A. naeslundii, and only minimal attachment of A. naeslundii and A. viscosus mutants lacking type 2 fimbriae was detected. The adherence of strain WVU45 was enhanced two- to threefold by neuraminidase treatment of the epithelial cells. The Fab fragments of antibodies which recognize the type 2 fimbriae inhibited the adherence of A. naeslundii WVU45 to the epithelial cells. The bacterial interaction with epithelial cells was inhibited by lactose, methyl-beta-D-galactoside, and N-acetyl-D-galactosamine, but not by methyl-alpha-D-galactoside, cellobiose, N-acetyl-D-glucosamine, L-fucose, or D-mannose. To further characterize the epithelial cell receptors for the bacterial lectin, we utilized several plant and invertebrate lectins as potential inhibitors of bacterial adherence. Lectins from Bauhinia purpurea and Arachis hypogaea which recognize N-acetyl-D-galactosamine, D-galactose, and D-galactose-beta-(1----3)-N-acetyl-D-galactosamine inhibited bacterial attachment, and binding of these lectins to epithelial cells was enhanced by the addition of neuraminidase. Lectins reacting with alpha-linked D-galactose, alpha-linked N-acetyl-D-galactosamine, D-mannose, or sialic acid were not inhibitory. Under similar assay conditions, adherence of a mannose-sensitive strain of Escherichia coli was inhibited by concanavalin A but not by the lectin from Bauhinia purpurea. These results indicate that certain plant lectins have specificities similar to that of the actinomyces fimbrial lectin and are, therefore, useful probes for identifying receptors on epithelial cells for certain bacteria.

Actinomyces↗
PubMed1981

Detection and localization of a lectin on Actinomyces viscosus T14V by monoclonal antibodies.

A cell-associated lectin activity that mediates lactose-inhibitable adherence of Actinomyces viscosus T14V has been localized to a specific population of fimbriae by the use of monoclonal antibodies. Nine monoclonal antibodies were produced that reacted with only 1 of 2 immunoelectrophoretically distinct fimbrial components on T14V. The fibrillar morphology of this component was revealed by the immunoelectronmicroscopic examination of bacteria incubated with the monoclonal antibodies. The lectin activity associated with these structures was detected when isolated fimbriae were cross-linked with monoclonal antibodies to form immune complexes with agglutination activity for neuraminidase-treated human erythrocytes, a reaction that was inhibited by lactose. Although the 9 monoclonal antibodies differed in their fine specificities, they reacted only with strains of A. viscosus and A. naeslundii that exhibited lactose-inhibitable adherence. These findings indicate that the lectin activity common to these bacteria resides on fimbriae that are antigenically related to those of T14V.

Actinomyces↗
PubMed1979

Characterization of mouse allergens.

The major allergens present in mouse skin, serum, and urine have been identified. Skin extracts, serum, and urine were chromatographed, and the activities of the fractions were monitored by histamine release from the leukocytes of individuals sensitive to mice. Fractionation of skin extracts revealed two major allergens. The large allergen has a molecular weight of approximately 67,000 daltons and by biochemical and immunochemical criteria appears to be identical to mouse albumin. The smaller molecular weight allergen is approximately 17,000 daltons. The same two allergens are also found in mouse serum and mouse urine. Histamine release by leukocytes of individuals allergic to mice demonstrated that some individuals react predominantly to the large allergen, some to the small allergen, and one group of patients reacts to both allergens.

Albumins↗
PubMed1979

Defective prostaglandin synthesis by C3H/HeJ mouse macrophages stimulated with endotoxin preparations.

Macrophages obtained from C3H/HeN mice produced significant amounts of prostaglandin E when exposed to phenol-extracted lipopolysaccharides (LPS), whereas macrophages from C3H/HeJ mice were unresponsive. The lipid A fraction from phenol-extracted LPS was an effective inducer or prostaglandin synthesis by macrophages from C3H/HeN mice. The polysaccharide portion of the LPS molecule had no effect. In contrast, the C3H/HeJ macrophages did not produce prostaglandin E in response to the lipid A moiety of phenol-extracted LPS. LPS prepared by butanol extraction stimulated the production of prostaglandin E by macrophages from both C3H/HeN and C3H/HeJ mice. The component of butanol-extracted LPS that stimulated the C3H/HeJ macrophages was shown to be a lipid A-associated protein. Further studies demonstrated a correlation between prostaglandin production by the macrophages of these two strains of mice in response to butanol- and phenol-extracted LPS and the lethal effects of the endotoxin preparations.

Animals↗
PubMed1978

Chemotactic antibody.

Antibody of the immunoglobulin G class to herpes simplex virus and antibody of the immunoglobulin M class to sheep red blood cells were coupled to the synthetic peptide formylmethionylleucylphenylalanine (fMet-Leu-Phe), which is chemotactic for both mononuclear and polymorphonuclear leukocytes. The resulting molecules were chemotactic and retained their antigen-binding activity. When antibodies coupled to fMet-Leu-Phe were incubated with antigen, the resulting immune complexes were also chemotactic. Chemotactic antibody may provide a potent means of enhancing the migration of inflammatory cells to specific sites.

Antibodies↗