bluuebunny/crossref_metadata_2025 huggingface dataset:
Antigen-Mediated Fusion of Specifically Sensitized Rabbit Alveolar Macrophages
Authors: Galindo B.
Published: January 2020

Rabbits sensitized intravenously with heat-killed
Mycobacterium tuberculosis
(strain H37Ra) suspended in mineral oil developed a strong pulmonary granulomatous response which reached its peak about 3 to 4 weeks after injection. Alveolar cells (4 × 10
6
cells/ml of tissue culture medium 199) procured 6 weeks after sensitization showed extensive development of multinucleated giant cells after 12 hr of incubation in tissue culture flasks containing heat-killed H37Ra (5 μg/ml). Giant cells measured 80 μm to 2.5 mm in length and contained between 30 and 700 nuclei. In contrast, no giant cells were observed when similar samples of the same cell populations were incubated in flasks containing: (i) no mycobacteria; (ii) heat-killed
Escherichia coli
; (iii) heat-killed
Bacillus subtilis
; (iv) latex particles; (v) ovalbumin; or (vi) phytohemagglutinin. The addition of immune (anti-H37Ra) sera potentiated the phenomenon of giant cell formation. In addition, supernatant fluids obtained from sensitive alveolar cells incubated with H37Ra were capable of inducing giant cell formation when incubated with nonsensitized alveolar cells. The results suggest that fusion of alveolar macrophages is mediated by an immunological mechanism.
Two apparently nonrepeated epitopes on gametes of Plasmodium falciparum are targets of transmission-blocking antibodies
Authors: Carter R , Bushell G , Saul A , Graves P M , Kidson C
Published: January 2020

One-site and two-site immunoradiometric assays have been developed against an antigen on gametocytes of Plasmodium falciparum, using monoclonal antibodies (Mabs) which block transmission of the parasites to mosquitoes. Three such Mabs have been studied, each of which immunoprecipitates a complex of three gamete surface proteins of apparent Mr 260,000, 59,000, and 53,000 from Triton X-100 extracts of the parasites. The assays showed that the Mabs recognized one or the other of two distinct, nonrepeated epitopes on the target antigen(s). In the one-site assay certain combinations of two Mabs interacted at appropriate concentrations to enhance binding of the Mabs to the antigen. The same combinations of Mabs synergize to suppress infectivity of gametocytes to mosquitoes.
Kinetic and chemical analyses of the biologic significance of lipoteichoic acids in mediating adherence of serotype III group B streptococci
Authors: Nealon T J , Mattingly S J
Published: January 2020

The mechanism(s) involved in the binding of lipoteichoic acid (LTA), isolated from virulent, asymptomatic, or avirulent serotype III strains of group B streptococci, to human embryonic epithelial cells (HEC), human fetal epithelial cells (HFC), and human adult buccal epithelial cells was investigated. It was determined that the binding of purified [3H]LTA to human adult buccal epithelial cells differed from the binding to HEC and HFC. LTA from all group B streptococcus strains bound to human adult buccal epithelial cells in a similar manner and was enhanced by the lipid portion of the polymer; in contrast, [3H]LTA binding to HEC and HFC was mediated by hydrophobic as well as specific interactions due to the glycerolphosphate backbone of LTA. Binding avidity of the LTAs to HEC and HFC varied depending on the bacterial strain. Polymers from asymptomatic and avirulent strains were easily dissociated from cell surfaces with unlabeled virulent LTA through competitive interactions; however, 10-fold greater levels of the same material were required to displace virulent [3H]LTA from HEC and HFC surfaces. These observed differences in binding avidity were shown to be due to longer LTA chains (30 to 35 glycerolphosphate units) in virulent strains when compared with LTA chains (10 to 12 glycerolphosphate units) of asymptomatic and avirulent strains. Thus, LTA appears to enhance the ability of virulent group B streptococci to bind to HEC and HFC with stronger avidity by virtue of the increased length of the cell-associated polymers synthesized by these strains. Mild enzymatic treatment of HEC and HFC with trypsin or periodate abolished LTA binding, which suggests the presence of a certain glycoprotein receptor(s) for LTA which does not appear to be present on human adult buccal epithelial cells. These data may therefore partially explain the increased susceptibility of newborn infants to group B streptococcal infections.
Stimulation of human leukocytes by protein II+ gonococci is mediated by lectin-like gonococcal components
Authors: Rest R F , Lee N , Bowden C
Published: January 2020

We investigated the ability of carbohydrates, glycosidases, and concanavalin A to inhibit the stimulation of the human leukocyte oxidative burst by gonococci in the absence of serum. The gonococci used in this study contained protein II (P.II) outer membrane proteins, and neutrophil oxidative burst was measured by luminol-enhanced chemiluminescence (CL). The following carbohydrates inhibited CL induced by nonpiliated P.II+ gonococci: beta-D-glucosamine greater than N-acetylneuraminic acid (sialic acid) greater than mannose greater than alpha-methylmannoside greater than N-acetyl-beta-D-glucosamine greater than or equal to glucose greater than or equal to lactose. Fucose, galactose, or beta-D-galactosamine (all 100 mM) did not inhibit or slightly increased CL, indicating a specificity for the observed effects. Mannose and alpha-methylmannoside also inhibited induction of monocyte CL by P.II+ gonococci. Incubation of neutrophils with concanavalin A inhibited subsequent gonococcus-induced CL but not phorbol myristate acetate-induced CL. Treatment of neutrophils with alpha-mannosidase reduced subsequent gonococcus-induced CL greater than 99%, whereas such treatment of gonococci had no effect on their ability to induce neutrophil CL. Incubation of a P.IIb-containing variant of Neisseria gonorrhoeae FA1090 with anti-P.IIb monoclonal antibody inhibited subsequent stimulation of neutrophil CL in a dose-responsive manner, indicating a specific role for P.IIb in the stimulatory process. The data suggest that one or more lectin-like components on the surface of P.II+ gonococci mediate their ability to stimulate the oxidative burst of human phagocytes.
Changes in intestinal fluid and mucosal immune responses to cholera toxin in Giardia muris infection and binding of cholera toxin to Giardia muris trophozoites
Authors: Ljungström I , Holmgren J , Svennerholm A M , Ferrante A
Published: January 2020

The effect of Giardia muris infection on the diarrheal response and gut mucosal antibody response to cholera toxin was examined in mice. The results obtained showed that the fluid accumulation in intestinal loops exposed to cholera toxin was increased in mice infected with a low number (5 X 10(4) ) of G. muris cysts compared with the response in noninfected mice. This effect was associated with a marked reduction in absorption of oral rehydration fluid from the intestine. In contrast, mice infected with a high dose (2 X 10(5) ) of cysts showed a marked decrease in fluid accumulation in response to the toxin. This decrease might be related to the finding that both G. muris and Giardia lamblia trophozoites can bind significant amounts of cholera toxin. Evidence is presented which suggests that the gut mucosal antibody response, mainly immunoglobulin A but also immunoglobulin G, to an immunization course with perorally administered cholera toxin was depressed in mice infected with G. muris. The reduction in antibody levels was particularly evident when the primary immunization was made very early after infection. The serum antitoxin antibodies to the oral immunization with cholera toxin were, however, not affected. Likewise, the delayed-type hypersensitivity response against sheep erythrocytes in animals primed subcutaneously with sheep erythrocytes was not modified during the course of G. muris infection.
Induction of natural killer cell activity by inactivated Candida albicans in mice
Authors: Marconi P , Scaringi L , Tissi L , Boccanera M , Bistoni F , Bonmassar E , Cassone A
Published: January 2020

Injection of merthiolate-inactivated yeast form cells of Candida albicans into the peritoneal cavities of mice induced the appearance of a cytolytic effector population against YAC-1 tumor cell lines. This induction was maximally manifested in 5- to 8-week-old animals 3 to 4 days after injection of 2 X 10(7)C. albicans cells, and the peritoneal lytic population exerted its optimum cytotoxic effect after 4 h of incubation. No significant natural cytotoxic activity was generated by C. albicans in the bone marrow or thymus, whereas there was a slight, transient, but significant depression of natural splenic cytotoxicity. Experiments performed to characterize the natural cytotoxic population elicited by the inactivated yeast showed that the effectors were nonadherent, nonphagocytic cells. Moreover, the anti-YAC-1 lytic activity was partially sensitive to anti-Thy1.2 serum and was completely abrogated by treatment of peritoneal nonadherent cells with monoclonal anti-asialo GM1 antibodies. Finally, the peritoneal population of cytotoxic cells induced by C. albicans was fully susceptible to Ly5.1 plus anti-immunoglobulin G2a and complement lysis. Although different cell populations could be induced by inactivated C. albicans, all of our data support the view that the anti-YAC-1 activity was entirely attributable to natural killer lymphocytes.
Expression of the cloned toxic shock syndrome toxin 1 gene (tst) in vivo with a rabbit uterine model
Authors: de Azavedo J C , Foster T J , Hartigan P J , Arbuthnott J P , O'Reilly M , Kreiswirth B N , Novick R P
Published: January 2020

Toxic shock syndrome (TSS) toxin 1 (TSST1) is produced by strains of Staphylococcus aureus associated with TSS. Purified TSST1 induces in rabbits a shock-like illness with many features similar to TSS in humans. These symptoms were also induced by TSST1-producing bacteria in diffusion chambers implanted in the rabbit uterus. Naturally occurring TSST1+ strains and a TSST1- strain harboring a pE194-derived plasmid carrying the cloned TSST1 determinant tst gave the same symptoms. TSST1- strains and a TSST1- strain carrying a pE194-tst plasmid with a deletion of the tst gene had no effect in rabbits. The results with the plasmid-carrying TSST1+ and TSST1- strains, which were isogenic apart from tst, show that the toxin is responsible for the illness in rabbits and suggest that it is a major factor in the pathogenesis of TSS.
Complementation analyses of recombinant plasmids encoding type 1 fimbriae of members of the family Enterobacteriaceae
Authors: Clegg S , Pruckler J , Purcell B K
Published: January 2020

Insertion mutants of recombinant plasmids encoding type 1 fimbriae of four genera of enteric bacteria were used to detect genetic complementation. After transformation by pairs of plasmids, double transformants were screened for their ability to express type 1 fimbriae. Complementation was observed between genes derived from the same genus but was absent with chimeric molecules carrying genetic information from two different genera. The results indicate that diffusible gene products of the fim cluster are necessary for phenotypic expression of type 1 fimbriae.
Pathogenic properties of Campylobacter jejuni: assay and correlation with clinical manifestations
Authors: Klipstein F A , Engert R F , Short H , Schenk E A
Published: January 2020

The pathogenic properties of 20 strains of Campylobacter jejuni isolated from persons with clearly defined clinical manifestations were determined. Cell-free broth filtrates were examined for (i) enterotoxin production by Chinese hamster tissue culture assay and an enzyme-linked immunosorbent assay (ELISA) employing GM1 ganglioside and affinity-purified antiserum to Escherichia coli heat-labile toxin, (ii) cytotoxin production by Vero and HeLa cell tissue culture lines, and (iii) their ability to cause fluid secretion in rat ligated ileal loops. Viable bacteria were examined for invasive properties by an ELISA with the immunoglobulin fraction of antiserum to Formalin-killed bacteria of an invasive strain, and by their effect on fluid secretion and morphology in rat ligated ileal loops. None of the eight isolates obtained from asymptomatic carriers had any detectable pathogenic properties. All six strains isolated from persons with bloody invasive-type diarrhea elaborated a cytotoxin; their viable bacteria had high titers in the ELISA for invasive properties and caused fluid secretion in ligated ileal loops, although consistent morphologic abnormalities and evidence of mucosal invasion, examined by immunofluorescence techniques, were not detected. All six strains isolated from persons with watery secretory-type diarrhea produced an enterotoxin, one elaborated a cytotoxin, and broth filtrates of all strains caused fluid secretion in ligated ileal loops; viable bacteria had low titers in the ELISA for invasive properties and evoked fluid secretion in ligated loops by means of enterotoxin production. These observations show (i) that a correlation exists between the pathogenic properties of the infective C. jejuni strain and gastrointestinal manifestations in the infected host, and (ii) that these pathogenic properties can be identified by in vitro assays, including ELISAs.
In vitro binding of natural killer cells to Cryptococcus neoformans targets
Authors: Nabavi N , Murphy J W
Published: January 2020

Nylon wool-nonadherent splenic cells from 7- to 8-week-old CBA mice were further fractionated on discontinuous Percoll gradients. Enrichment of natural killer (NK) cells in Percoll fractions 1 and 2 was confirmed by morphological examination, by immunofluorescent staining, and by assessing the cytolytic activity of each Percoll cell fraction against YAC-1 targets in the 4-h51Cr release assay. Cells isolated from each Percoll fraction were tested for growth-inhibitory activity against Cryptococcus neoformans, a pathogenic yeastlike organism, by using an in vitro 18-h growth inhibition assay. The results showed that NK cell enrichment was concomitant with enrichment of anti-Cryptococcus activity in Percoll fractions 1 and 2. Cells from NK cell-rich fractions formed conjugates with the mycotic targets similar to the conjugates reported in NK cell-tumor systems. In addition, the percentage of effector cell-Cryptococcus conjugates was directly proportional to the level of the C. neoformans growth-inhibitory activity of the effector cells used. Scanning electron microscopy of the effector cell-Cryptococcus conjugates showed direct contact between the effector cells and the cryptococcal targets. An immunolabeling method combined with scanning electron microscopy was used to demonstrate that the effector cells attached to C. neoformans were asialo GM1 positive and, therefore, had NK cell characteristics.
Acquired resistance and expression of a protective humoral immune response in guinea pigs infected with Treponema pallidum Nichols
Authors: Pavia C S , Niederbuhl C J
Published: January 2020

Resistance to cutaneous syphilitic reinfection in strain 2 and strain 13 guinea pigs developed gradually 3 to 7 months after primary infection and reached maximum levels at 6 to 7 months after the induction of primary cutaneous disease. Associated with this acquired resistance was the occurrence of Arthus reactions and anamnestic-type antibody responses. Passive transfer of immune serum containing high-titered treponemal antibody into normal strain 2 guinea pigs significantly delayed the appearance and markedly diminished the severity and duration of skin lesions that developed after these recipients were challenged with treponemes but did not prevent the dissemination of organisms to the draining lymph nodes. These findings provide direct evidence that syphilitic infection elicits the formation of serum factors that are, at least, partially protective against symptomatic disease.
Antigenic heterogeneity of lipid A of Haemophilus influenzae
Authors: Apicella M A , Dudas K C , Campagnari A , Rice P , Mylotte J M , Murphy T F
Published: January 2020

The chemical structure and biologic function of the lipid A portion of lipopolysaccharide are not identical among gram-negative bacteria. This study indicates that antigenically heterogeneous lipid A exists among strains of Haemophilus influenzae. An immunoglobulin G3 murine monoclonal antibody, 3D2, produced against a nontypable H. influenzae strain 3524 has specificity for a site on the lipid A portion of the H. influenzae lipopolysaccharide. With the Western blot and immunodot assay, 3D2 recognized this lipid A determinant on 14 of 24 (58%) of strains of nontypable H. influenzae and in 51 of 95 (54%) strains of H. influenzae type b. This lipid A epitope has a high degree of specificity for H. influenzae, since it is not present on the lipid A of 39 gram-negative strains from 14 non-Haemophilus species. In addition, studies of 36 strains of six Haemophilus species other than H. influenzae and 8 strains of 4 species of Actinobacillus did not contain the 3D2 epitope. Enzyme-linked immunosorbent assay analysis with a kinetic assay and enzyme-linked immunosorbent assay inhibition confirmed the antigenic heterogeneity of H. influenzae lipid A. Thin-layer chromatography demonstrated that the 3D2 epitope is associated with a chloroform-soluble lipid moiety in the lipid A. Fluorescent antibody analysis of H. influenzae indicated that the epitope is on the cell surface. The monoclonal antibody was not bactericidal for strain 3524, and it did not inhibit the bactericidal action of normal human serum against the same strain. These studies demonstrate that the lipid As of H. influenzae are antigenically heterogeneous.
Periodontal bone loss and immune characteristics of congenitally athymic and thymus cell-reconstituted athymic rats
Authors: Yoshie H , Taubman M A , Ebersole J L , Smith D J , Olson C L
Published: January 2020

We investigated the ability to reconstitute the T-cell deficiency in congenitally athymic (nude; rnu/rnu) Rowett rats by intravenous injection of 10(7) heterozygous normal (rnu/+) rat thymus cells. The thymus cell-reconstituted animals showed essentially normal lymphocyte proliferation to phytohemagglutinin P and concanavalin A, normal spleen and lymph node T-lymphocyte distribution, and normal serum immunoglobulin G levels. These rats were used to study the effect of T-cell deficiency on periodontal disease. Animals with minimal oral flora were divided into three groups: nude, thymus cell-reconstituted nude, and normal rats. Immune response, gingival inflammation, and periodontal bone loss were examined in these animals. Less than 40% of the T cells recovered from the normal rat gingiva could be recovered from the nude rat gingiva. In contrast to the situation in normal or thymus cell-reconstituted rat gingiva, B cells were vastly predominant in the nude rat gingiva, with approximately four B cells for each T cell. There was increased periodontal bone loss in the nude rats compared with that in the normal rats. Thymus cell reconstitution of the nude rats was associated with decreased bone destruction. It is suggested that T cells have a regulatory function in relation to the potentially excessive B-cell response to abundant antigen and polyclonal activators in the oral cavity.
Myelopoiesis in experimentally contaminated specific-pathogen-free and germfree mice during oral administration of polymyxin
Authors: Goris H , de Boer F , van der Waaij D
Published: January 2020

Oral administration of polymyxin to specific-pathogen-free C3H/Law mice which with previously contaminated with gram-negative bacteria resulted in complete suppression of cecal gram-negative bacteria. Suppression of cecal gram-negative bacteria was accompanied by reduction of the cecal endotoxin concentration from 10 to 1 microgram/g of cecal content as measured with a microtechnique for the Limulus amebocyte lysate assay. Endotoxin determination by this assay appeared to be unaffected by the amount of polymyxin present in cecal preparations after oral administration of this antibiotic. In experimentally contaminated specific-pathogen-free mice, the femoral concentration of progenitor cells forming granulocyte-macrophage colonies in vitro (CFU-GM) decreased significantly (P less than 0.001) to 66% of the initial control after 4 days of polymyxin treatment. However, the femoral CFU-GM concentration in germfree mice and splenic CFU-GM concentration in experimentally contaminated specific-pathogen-free and germfree mice was not affected by polymyxin treatment. The kinetic behavior of femoral and splenic CFU-GM in experimentally contaminated specific-pathogen-free and germfree mice was expressed as the in vivo sensitivity to the S-phase-specific cytostatic drug hydroxyurea, i.e., the hydroxyurea kill. Administration of polymyxin to experimentally contaminated specific-pathogen-free mice significantly diminished the hydroxyurea kill of femoral CFU-GM from 29 to 13% (P less than 0.02) and of splenic CFU-GM from 53 to 27% (P less than 0.005). The hydroxyurea kill of femoral CFU-GM in germfree mice was not significantly affected by polymyxin treatment. On basis of these results we conclude that the effect of polymyxin treatment on myelopoiesis is most likely due to elimination of intestinal gram-negative bacteria and may indicate a significant role of intestinal gram-negative bacteria in the regulation of myelopoiesis.
Endotoxin-induced selective dysfunction of rabbit polymorphonuclear leukocytes in response to endogenous chemotactic factors
Authors: Hartiala K T , Langlois L , Goldstein I M , Rosenbaum J T
Published: January 2020

To assess the mechanism and specificity of polymorphonuclear leukocyte (PMN) dysfunction induced by endotoxin, rabbits were injected intravenously with 100 micrograms of Escherichia coli endotoxin, and PMN function was studied 18 to 24 h later. Compared to PMN from normal rabbits, peripheral blood PMN from rabbits injected with endotoxin showed diminished chemotactic responsiveness to two endogenous peptides, C5a (complement) and platelet-derived growth factor, and to two endogenous lipids, leukotriene B4 and platelet-activating factor. The chemotactic response to the synthetic chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine (FMLP), was unimpaired. In contrast to migration, endotoxin injection resulted in inhibition of the secretory response to the two endogenous peptides but not to the lipids or to FMLP. At a 1:4 (vol/vol) dilution, the plasma either 1 or 24 h after the endotoxin injection inhibited normal PMN chemotactic responses to C5a but not to FMLP. Similarly, at a 1:10 dilution, this plasma inhibited normal PMN chemotactic responses to leukotriene B4. The factor responsible for inhibiting responses to leukotriene B4 was anionic, specific for leukotriene B4 responses, and greater than 12,000 daltons. These data may be relevant to understanding PMN dysfunction during gram-negative sepsis.
Effect of streptococcal lipoteichoic acid on prolyl hydroxylase activity as related to collagen formation in mouse fibroblast monolayers
Authors: Leon O , Panos C
Published: January 2020

Dried and wet mouse fibroblast monolayers with labeled collagenous substrate were used to study the effects of lipoteichoic acid (LTA) on cellular prolyl hydroxylase activity. LTA is a scavenger of cations, and Fe2+ is essential for prolyl hydroxylase activity. Surprisingly, addition of LTA to dried monolayers resulted in increased prolyl hydroxylase activity, whereas preincubation of Fe2+ with LTA only negated this increase. However, significant inhibition of enzyme activity by wet monolayers occurred whether LTA was added directly to the test system or whether it was used after preincubation with Fe2+. These data suggest that LTA causes membrane perturbations. Also, that the binding of LTA to the membrane of dried and wet monolayers appears to be decidedly different when based on the subsequent availability of Fe2+ for cellular prolyl hydroxylase activity. The ability of LTA to act as a cationic exchanger and the presence of intracellular Fe2+ inaccessible to LTA probably accounted for the lack of complete inhibition of prolyl hydroxylase activity by this amphiphile in the wet cell system. Considerably less iron was needed to negate the partial inhibition of prolyl hydroxylase activity by LTA in viable cells than was needed to restore the increased enzyme activity by this amphiphile in equivalent dried preparations. These and other results showed that, although LTA does not affect collagen polypeptide chain formation in wet monolayers, its involvement at the molecular level does result in a marked decrease in the hydroxylation of collagenous peptidyl prolyl residues through LTA interaction with Fe2+. This reduction in prolyl hydroxylase activity equaled the reduction in hydroxylation of collagenous protein in fibroblast monolayers caused by LTA reported earlier (O. Leon and C. Panos, Infect. Immun. 40:785-794, 1983). Therefore, these data suggest that partial inhibition of prolyl hydroxylase activity is directly related to the synthesis of defective collagen by wet fibroblast monolayers exposed to minute amounts of group A, type 12 streptococcal LTA. Use of LTA also showed that complete inhibition of hydroxyproline formation is not required for the continued formation and accumulation of defective collagenous protein by these monolayers.
Antigenic diversity of Chlamydia psittaci of mammalian origin determined by microimmunofluorescence
Authors: Perez-Martinez J A , Storz J
Published: January 2020

A group of twenty-five isolates of Chlamydia psittaci representing at least seven different biotypes of bovine, ovine, caprine, equine, feline, porcine, and guinea pig origin were immunotyped by an indirect microimmunofluorescence test. Different groups of chlamydia-free BALB/c mice received two weekly intravenous inoculations with chicken embryo-propagated, partially purified elementary bodies of each strain. Antisera for immunotyping were collected 4 days after the first inoculation and 3 to 4 days after the second inoculation and tested for antichlamydial immunoglobulin M and immunoglobulin G antibodies by the indirect microimmunofluorescence test with cell culture-propagated, partially purified homologous and heterologous antigens. Nine immunotypes of C. psittaci were distinguished. The correlation between immunotypes and biotypes was close, and a pattern of either disease or host specificity could be associated with each immunotype. Most immunotypes identified induced cross-reacting antibodies against each other, but no significant cross-reactions were observed with elementary bodies of the mouse pneumonitis strain of C. trachomatis. Findings from this study should provide the necessary background for the rational selection of prototype strains of C. psittaci for further antigenic analysis at the molecular level.
Enteroadhesion fimbriae and enterotoxin of Escherichia coli: genetic transfer to a streptomycin-resistant mutant of the galE oral-route live-vaccine Salmonella typhi Ty21a
Authors: Yamamoto T , Tamura Y , Yokota T
Published: January 2020

An enterotoxigenic Escherichia coli plasmid encoding colonization factor antigen (CFA) I fimbriae and heat-stable toxin was transferred into a streptomycin-resistant mutant of the Salmonella typhi galE strain Ty21a (a live attenuated oral typhoid vaccine). The virulence plasmid-carrying transconjugants produced CFA I fimbriae and heat-stable toxin. The marked production of CFA I fimbriae was observed even in a vaccine medium for Ty21a. The data lead to a new type of potential live oral vaccine, S. typhi Ty21a producing enteroadhesion fimbriae.
Binding, ingestion, and multiplication of Chlamydia trachomatis (L2 serovar) in human leukocyte cell lines
Authors: Bard J A , Levitt D
Published: January 2020

We examined the ability of lymphoblastoid-myeloid cell lines to bind, ingest, and permit multiplication of Chlamydia trachomatis (L2 serovar). Four types of chlamydia-cell line interactions were observed: minimal bacterial binding; bacterial binding, followed by ingestion and high-level multiplication; bacterial binding, followed by ingestion but minimal multiplication; and bacterial binding, but minimal ingestion or replication. Our data demonstrate that at 37 degrees C in vitro the L2 serovar can both bind avidly to a cell without entering it and enter nonphagocytic cells but not grow.
Association of alginate from Pseudomonas aeruginosa with two forms of heparin-binding lectin isolated from rat lung
Authors: Ceri H , McArthur H A , Whitfield C
Published: January 2020

An endogenous heparin-binding lectin activity isolated from rat lung was separated into two distinct isolectin forms which showed subtle changes in carbohydrate specificity. The two lectin forms displayed different specificities toward alginic acid-purified cystic fibrosis isolates of Pseudomonas aeruginosa when assayed by inhibition of both hemagglutination and [3H]heparin binding. This ability of isolectin forms to show higher affinity toward alginic acid from certain P. aeruginosa strains may suggest that there is a selective mechanism in the colonization of patients with cystic fibrosis.
Effect of Tamm-Horsfall urinary glycoprotein on phagocytosis and killing of type I-fimbriated Escherichia coli
Authors: Kuriyama S M , Silverblatt F J
Published: January 2020

Human polymorphonuclear leukocytes (PMN) ingest type I (mannose sensitive) fimbriated Escherichia coli even in the absence of antibody, complement, or other serum opsonins. Our studies suggest that the Tamm-Horsfall urinary glycoprotein (THP) interferes with serum-independent ingestion. Electron micrographs showed that dissolved THP adhered to type I fimbriae and formed a pseudocapsule around bacteria bearing type I fimbriae. Phase-variant bacteria grown on blood agar neither expressed fimbriae nor bound THP. Affinity column chromatography demonstrated mannose-sensitive binding between purified type I fimbriae and purified THP. The ability of human PMN to bind and ingest type I-fimbriated E. coli was diminished if the bacteria had been coated by exposure to THP at physiologic concentrations. At 1 h, PMN were associated with an average of 2.62 uncoated bacteria, but with only 0.18 coated bacteria (P less than 0.001). alpha-Methyl mannoside blocked the observed effect of THP on binding and phagocytosis in a dose-dependent fashion: increased mannoside led to increased blocking. PMN preincubated with THP were able to bind and phagocytose normally. There did not appear to be any significant clumping of bacteria in suspension to account for these effects. Bactericidal assays with leukocytes in suspension demonstrated protection of THP-coated bacteria. At 1 h, PMN killed 42% of noncoated E. coli (a decrease of 0.24 log), but the number of THP-coated bacteria increased by 75% (an increase of 0.24 log). These observations may partially explain the virulence of E. coli in the bladder and kidney, where serum activity is low and THP is abundant.
Susceptibility of Entamoeba histolytica to oxidants
Authors: Ghadirian E , Somerfield S D , Kongshavn P A
Published: January 2020

The effect of hydrogen peroxide and hypochlorite on culture forms of Entamoeba histolytica trophozoites was examined by using two strains of E. histolytica, virulent (IP:0682:1) and nonvirulent (DKB). The amoebae were incubated with various concentrations of hydrogen peroxide and hypochlorite, and their viability was determined at different times after incubation. When the viability of the virulent and nonvirulent strains was compared to different oxidant strengths, it became apparent that the virulent strain was less susceptible than the nonvirulent one to the cytotoxic effect of hydrogen peroxide and hypochlorite. Our studies further showed that the toxic effect was both time and dose dependent. To confirm that the killing of amoebae in this system was associated with the presence of hydrogen peroxide, amoebae were incubated with hydrogen peroxide and catalase. Catalase reduced the killing effect of hydrogen peroxide to the control level. These data confirmed previous observations of the susceptibility of amoebic trophozoites to hydrogen peroxide and also demonstrated susceptibility to hypochlorite.
Involvement of birds in the epidemiology of the Lyme disease agent Borrelia burgdorferi
Authors: Anderson J F , Johnson R C , Magnarelli L A , Hyde F W
Published: January 2020

Borrelia burgdorferi, the causative agent of Lyme disease, was isolated from the liver of a passerine bird, Catharus fuscescens (veery), and from larval Ixodes dammini (tick) feeding on Pheucticus ludovicianus (rose-breasted grosbeak) and Geothlypis trichas (common yellowthroat). In indirect immunofluorescence antibody tests, isolates reacted with polyclonal and monoclonal (H5332) antibodies. Studies on the DNA composition of the veery liver isolate and the strain cultured from an I. dammini larva indicated that both were B. burgdorferi and not Borrelia anserina or Borrelia hermsii. The veery liver isolate infected hamsters and a chick. In contrast, B. anserina infected chicks but not hamsters. B. burgdorferi is unique among Borrelia spp. in being infectious to both mammals and birds. We suggest that the cosmopolitan distribution of B. burgdorferi may be caused by long-distance dispersal of infected birds that serve as hosts for ticks.
Isolation and characterization of a 60-kilodalton salivary glycoprotein with agglutinating activity against strains of Streptococcus mutans
Authors: Babu J P , Beachey E H , Hasty D L , Simpson W A
Published: January 2020

A bacterial agglutinin specific for strains of Streptococcus mutans was isolated from human saliva. Physiochemical analyses showed the agglutinin to be a glycoprotein with a molecular weight of 60,000. The agglutinin aggregated four of the eight strains of Streptococcus mutans tested but did not aggregate the strains of Streptococcus salivarius, Streptococcus sanguis, and Streptococcus mitis tested. Chemical modification of carbohydrate moieties of the agglutinin with sodium metaperiodate had no effect on aggregation, whereas modification of the polypeptide portion with trypsin abolished aggregating activity. A set of five murine hybridoma antibodies was employed to further analyze the agglutinin. Two carbohydrate-specific antibodies, directed against D-mannose and N-acetylgalactosamine moieties, respectively, failed to block agglutinin- or whole saliva-mediated aggregation of S. mutans cells. In contrast, two antibodies directed against pronase-sensitive antigenic sites blocked both agglutinin- and saliva-mediated aggregation of S. mutans cells. Western blot analysis with the agglutinin-specific hybridoma antibodies demonstrated the agglutinin in whole saliva and in artificial tooth pellicles formed on hydroxyapatite beads incubated with saliva. These results suggest that a 60-kilodalton glycoprotein of human saliva is a bacterial agglutinin with specificity for certain strains of S. mutans. They further suggest that aggregation is mediated by polypeptide rather than carbohydrate determinants of the glycoprotein.
Multiplication of Shigella flexneri within HeLa cells: lysis of the phagocytic vacuole and plasmid-mediated contact hemolysis
Authors: Sansonetti P J , Ryter A , Clerc P , Maurelli A T , Mounier J
Published: January 2020

Virulent strains of Shigella flexneri invade HeLa cells with high efficiency. This crucial step in the pathogenic process is encoded by a 140-megadalton plasmid which induces phagocytosis of the bacteria by host cells. In this report we used pWR100, the virulence plasmid of S. flexneri serotype 5, and pHS4108, a 32-megadalton subclone of pWR100, to demonstrate that the plasmid is also responsible for rapid intracellular growth of the bacteria. The ability to replicate intracellularly was not correlated with induction of Shiga toxin. However, plasmid-mediated intracellular multiplication was strongly correlated with the ability of the bacteria to rapidly and efficiently lyse the phagocytic vacuole and replicate freely in the cytoplasm. Temperature-regulated plasmid-mediated contact hemolytic activity strongly correlated with both phagosomal membrane lysis and efficient intracellular multiplication. We propose this virulence plasmid-associated hemolysin to be an important factor in the invasion and proliferation of Shigella spp. in mammalian cells.
Molecular alteration of the 140-megadalton plasmid associated with loss of virulence and Congo red binding activity in Shigella flexneri
Authors: Sasakawa C , Kamata K , Sakai T , Murayama S Y , Makino S , Yoshikawa M
Published: January 2020

A plasmid of about 140 megadaltons has been associated with the invasiveness of Shigella flexneri. Upon subculturing in liquid media of fully virulent isolates of Shigella flexneri 2a YSH6000, which contains only a 230-kilobase-pair (kbp) plasmid in addition to 3.3- and 4.2-kbp cryptic plasmids characteristic to all S. flexneri strains, loss of invasiveness, loss of Congo red binding activity (Pcr), and complete loss of, or a deletion, or even a single-site IS insertion in the plasmid occurred simultaneously. This was ascribed to the fact that, once a noninvasive Pcr- cell has emerged, it overgrows the wild type as a consequence of its selective advantage in artificial media. A deletion map of the 230-kbp plasmid was made by analyzing SalI digests of 39 deletion derivatives plus 1 formed by insertion of an IS1-like element in independently isolated, noninvasive Pcr- mutants. Of 39 deletion derivatives, 16 belonged to a single type, and 6 belonged to another, suggesting deletion hot spots. The deletion map was confirmed and extended by analyzing 359 SalI-generated partial digests of the wild-type plasmid cloned into pBR322. Three copies of IS1-like elements were found on three different SalI fragments by Southern hybridization. Segments required for the Pcr+ phenotype seemed to occur at several different locations in the plasmid. Each of 28 representative Pcr- mutants were negative by the Sereny test. Hence, many, or possibly all, Pcr determinants were required for full virulence.
Molecular cloning of a genetic determinant for Congo red binding ability which is essential for the virulence of Shigella flexneri
Authors: Sakai T , Sasakawa C , Makino S , Kamata K , Yoshikawa M
Published: January 2020

A DNA sequence of about 1.0 kilobase (kb) derived from a 230-kb (140-megadalton) plasmid in a fully virulent Shigella flexneri 2a strain, YSH6000, was cloned into Escherichia coli K-12 by selecting for the ability to bind Congo red (Pcr+ phenotype). It was mapped and localized within the SalI restriction fragment F on the plasmid. This clone converted an S. flexneri strain which is avirulent as a result of a small deletion in the plasmid to full virulence but did not convert those without the 230-kb plasmid or with a plasmid bearing a more extensive deletion. This indicates that there are more than two virulence determinants on the plasmid. Thus, this sequence contains a genetic determinant which is essential but not sufficient for full virulence and expression of the Pcr+ phenotype in S. flexneri but is essential and sufficient for expression of the Pcr+ phenotype in E. coli K-12. We noted that there exist some other regions on the 230-kb plasmid which express the Pcr+ phenotype in E. coli K-12. Although these regions express the Pcr+ phenotype less markedly than the region cloned in the present study, they do hybridize with it.
Conditioned medium from stimulated mononuclear leukocytes augments human neutrophil-mediated killing of a virulent Acanthamoeba sp
Authors: Ferrante A , Abell T J
Published: January 2020

Human neutrophils in the presence of serum containing anti-amoeba antibody either lacked amoebicidal activity or were poorly amoebicidal for Acanthamoeba culbertsoni. In contrast, neutrophils preexposed for 1 h to supernatants from human peripheral blood mononuclear leukocytes (MNLs) stimulated with phytohemagglutinin demonstrated significant amoeba killing in the presence of serum containing anti-acanthamoeba antibodies. Supernatant from MNL cultured in the absence of phytohemagglutinin were not effective in stimulating significant activity in the neutrophils. Serum containing antibody promoted the adherence of many neutrophils to one amoeba. There was no significant difference between the ability of neutrophils treated with supernatants from stimulated MNLs (stimulated conditioned medium [sCM]) and supernatants from nonstimulated MNLs (nonstimulated conditioned medium [nsCM]) in their binding to acanthamoeba. The effects of sCM on neutrophils was a general phenomenon. For example, the sCM but not the nsCM enhanced the antibody-dependent neutrophil-mediated cytotoxicity against three tumor targets (K562 erythroid myeloid leukemia cell line, B16 melanoma, and P815 (DBA/2 mastocytoma). Furthermore, the sCM but not the nsCM increased the bactericidal (against Staphylococcus aureus and Streptococcus pneumoniae) and fungicidal (against Torulopsis glabrata) activity of the neutrophil. The sCM but not the nsCM contained activities which inhibited neutrophil migration and stimulated a respiratory burst in these leukocytes. These results suggest that the neutrophil antimicrobial power can be increased by exposing the leukocytes to MNL mediators.
Effects of dexamethasone on human natural killer cell cytotoxicity, interferon production, and interleukin-2 receptor expression induced by microbial antigens
Authors: Piccolella E , Lombardi G , Vismara D , Del Gallo F , Colizzi V , Dolei A , Dianzani F
Published: January 2020

Dexamethasone inhibits the expression of the interleukin-2 receptor, the synthesis of immune interferon, and the development of natural killer cells when added to peripheral blood mononuclear cells cultured with soluble microbial antigens (purified protein derivative and a polysaccharide extract from Candida albicans [MPPS]) or human recombinant interleukin-2.
Immunoadsorption of Cryptococcus-specific suppressor T-cell factors
Authors: Mosley R L , Murphy J W , Cox R A
Published: January 2020

In the murine cryptococcal suppressor cell circuit, two different T-cell suppressor factors, TsF1 and TsF2, have been identified which specifically suppress the delayed-type hypersensitivity (DTH) response to cryptococcal culture filtrate antigen (CneF). TsF1 is produced by a first-order T suppressor (Ts1) cell population and suppresses the afferent limb of the DTH response, whereas TsF2 is produced by a second-order T suppressor (Ts2) cell population and suppresses the efferent limb of the cryptococcal DTH response. The objective of this study was to ascertain whether TsF1 or TsF2 could bind to cryptococcal antigen. To assess this, adsorption of TsF1 and TsF2 was performed with heat-killed Cryptococcus neoformans cells and by solid-phase immunoadsorption (SPIA) on columns containing cryptococcal antigens, i.e., CneF covalently bound to Sepharose 4B. The suppressive effect of TsF1 was removed by adsorption with intact heat-killed cryptococci and by SPIA on CneF-Sepharose 4B. The binding of cryptococcal TsF1 to the cryptococcal SPIA column was shown to be specific since Sepharose 4B columns either coupled with Saccharomyces cerevisiae mannan or blocked with glycine did not adsorb the suppressor activity. In contrast, the suppressive component of TsF2 did not bind to heat-killed cryptococci, CneF-Sepharose 4B, S. cerevisiae mannan-Sepharose 4B, or glycine-Sepharose 4B columns. These results, together with the finding that cryptococcal antigen, anticryptococcal antibody, and C1q-binding immune complexes were not demonstrated in either TsF1 or TsF2, establish that TsF1 and TsF2 can be differentiated on the basis of their affinity for cryptococcal antigen.
Serological characterization of black-pigmented Bacteroides endodontalis
Authors: van Winkelhoff A J , Kippuw N , de Graaff J
Published: January 2020

Serological studies on the black-pigmented Bacteroides species B. endodontalis revealed three serotypes based on capsular determinants. A common antigen (O-antigen) could be demonstrated after decapsulation. Weak cross-reactivity was found with B. asaccharolyticus, but not with B. gingivalis. Similarity between the serology of Enterobacteriaceae and black-pigmented Bacteroides spp. is discussed.
Activation of the complement system by Cryptococcus neoformans leads to binding of iC3b to the yeast
Authors: Kozel T R , Pfrommer G S
Published: January 2020

The complement system plays a key role in resistance to cryptococcosis. In the present study, we examined several factors that influence the binding of C3 cleavage fragments to Cryptococcus neoformans. Binding of C3 was determined by using normal human serum supplemented with 125I-labeled C3. Incubation of encapsulated cryptococci in 20% serum led to the binding of approximately 3.2 X 10(6) molecules of C3 to each cell. The binding of C3 was markedly inhibited by heating the serum at 56 degrees C for 30 min or by chelation of the serum with EDTA. Chelation of the serum with EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] reduced binding of C3 by 37%. These results indicated that activation of C3 cleavage fragments and their binding to C. neoformans was primarily dependent upon the alternative pathway. Bound C3 could be removed by incubation with 1.0 M hydroxylamine (pH 10) but not by incubation with 3.5 M NaSCN or with phosphate-buffered saline containing 0.1% sodium dodecyl sulfate. These results suggested that C3 fragments were bound to C. neoformans by ester bonds. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of C3 fragments eluted from the yeast showed the presence of protein bands consistent with the presence of iC3b. C3b was not detected on the yeast after incubation with serum for time intervals as short as 2.5 min, indicating a rapid conversion of cell-bound C3b to iC3b. These results indicate that iC3b is the ligand which most likely interacts with the phagocyte C3 receptors involved in the phagocytosis of C. neoformans.
In vivo repackaging of recombinant cosmid molecules for analyses of Salmonella typhimurium, Streptococcus mutans, and mycobacterial genomic libraries
Authors: Jacobs W R , Barrett J F , Clark-Curtiss J E , Curtiss R
Published: January 2020

Strains of Escherichia coli K-12 were constructed that permitted the amplification of in vitro-packaged recombinant cosmid-transducing particles by in vivo repackaging of recombinant cosmid molecules. Thermal induction of these thermoinducible, excision-defective lysogens containing recombinant cosmid molecules yielded high titers of packaged recombinant cosmids and low levels of PFU. These strains were used to amplify packaged recombinant cosmid libraries of Mycobacterium leprae, Mycobacterium vaccae, Salmonella typhimurium, and Streptococcus mutans DNA. Contiguous and noncontiguous libraries were compared for the successful identification of cloned genes. Construction of noncontiguous libraries allowed the dissociation of desired genes from genes that were deleterious to the survival of a cosmid recombinant and permitted selection for unlinked traits that resulted in a selected phenotype. In vivo repackaging of recombinant cosmids permitted amplification of the original in vitro-packaged collection of transducing particles, storage of cosmid libraries as phage lysates, facilitation of complementation screening, expression analysis of repackaged recombinant cosmids after UV-irradiated cells were infected, in situ enzyme or immunological screening, and facilitation of recovery of recombinant cosmid molecules containing transposon inserts.