bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental cecitis in gnotoxenic chickens monoassociated with Clostridium butyricum strains isolated from patients with neonatal necrotizing enterocolitis
Authors: Popoff M R , Szylit O , Ravisse P , Dabard J , Ohayon H
Published: January 2020

An animal model for Clostridium butyricum necrotizing cecitis has been developed in axenic chickens inoculated orally between 2 and 50 days of life. Cecitis was obtained with two C. butyricum strains isolated from neonatal necrotizing enterocolitis and not with a Clostridium beijerinckii strain from dairy products; the rate of colonization of the intestinal tract by this strain was lower than that obtained with C. butyricum strains. The clinical findings showed a slow gain in body weight. The cecitis lesions were well developed 3 and 4 weeks after oral inoculation, including enlargement with an increase of the cecum weight-body weight ratio, a marked hyperplasia, congestion, inflammatory infiltrate and pneumatosis of the cecal wall and mesentery, hemorrhage in the lamina propria and submucosa, and ulcerations and necrotic areas in the mucosa. By immunofluorescence and electron microscopy, the bacterial cells were located in the cecal lumen and in necrotic areas of the mucosa. The presence of 4% lactose in the diet seemed to be a prerequisite for the development of cecitis in chickens. A gradual rise of fluorescent antibodies in the sera was observed.
Chlamydial pneumonitis induced in newborn guinea pigs
Authors: Rank R G , Hough A J , Jacobs R F , Cohen C , Barron A L
Published: January 2020

One- to three-day-old guinea pigs were inoculated intranasally with the chlamydial agent of guinea pig inclusion conjunctivitis. Physical signs of infection included a marked increase in respiration rate on days 5 to 10 of infection and radiographic evidence of pneumonia on day 6. When animals were killed at various times after infection and lung tissue was examined by histopathology, evidence of pneumonia was found beginning on day 4 and lasting as long as day 12, with maximal pathological changes on days 6 to 8. The pneumonia was generally unilateral and consisted of an acute inflammatory component in the bronchioles with granulocytes in both the lumen and the wall of the bronchioles and an interstitial and intra-alveolar mononuclear infiltrate in the parenchyma of the lung. Chlamydial antigen was detected in the bronchial epithelial cells by immunoperoxidase staining, and the guinea pig inclusion conjunctivitis organism was isolated from lung tissue on days 6 to 9. No other significant bacteria were isolated from lung tissue or seen on gram stains of lung sections. Both immunoglobulin M and immunoglobulin G serum antibodies to the guinea pig inclusion conjunctivitis agent were detected as early as day 8 and reached peak levels on day 12. The infection was apparently self-limiting. This model presents the opportunity to investigate pathophysiological and immunological aspects of chlamydial respiratory infections in a neonatal animal.
Serum opsonic activity after immunization of adults with Haemophilus influenzae type b-diphtheria toxoid conjugate vaccine
Authors: Cates K L , Marsh K H , Granoff D M
Published: January 2020

We measured the uptake of radiolabeled Haemophilus influenzae type b by human polymorphonuclear leukocytes. Haemophilus influenzae type b strains were preopsonized in individual sera from six adults immunized with type b polysaccharide vaccine (PRP) or six adults immunized with PRP covalently coupled to diphtheria toxoid (PRP-D vaccine). Serum was heat inactivated before use, and exogenous human complement was added. Of the 12 subjects, 3 had high levels of opsonic activity (greater than 40% of immune control) in their preimmunization serum. This activity did not correlate with the concentrations of anti-PRP antibody and was unaffected by absorption of anti-PRP antibody. At 1 month after vaccination, the serum of PRP-D subjects had higher opsonic activity than that from subjects who received PRP (5% serum, mean PRP-D = 86%, mean PRP = 53%, P = 0.001). After 12 months, both groups had higher serum opsonic activity than before immunization (P less than 0.02), but there was no difference between the two groups (mean PRP-D = 48%, mean PRP = 51%). In postimmunization serum, opsonic activity induced by PRP-D or PRP vaccines correlated directly with anti-PRP antibody concentrations as measured by a radioantigen binding assay. We conclude that both vaccines induce opsonic activity, opsonic activity induced by immunization of adults correlates well with the concentration of anti-PRP antibody achieved, and in preimmune sera with low concentrations of anti-PRP antibody, factors other than anti-PRP antibody contribute to opsonic activity.
Environmental silica in badger lungs: a possible association with susceptibility to Mycobacterium bovis infection
Authors: Higgins D A , Kung I T , Or R S
Published: January 2020

Badger lungs contain dark granular foci (0.2 to 2.0 mm) comprising aggregates of enlarged macrophages containing birefringent crystalline particles. Particles were examined from the lungs of three badgers; many were silicates and a significant number were pure silica (SiO2). The particles and the accompanying pathology resembled mixed dust fibrosis and silicosis in humans, diseases associated with increased susceptibility to tuberculosis.
Tracheobronchial mucin receptor for Pseudomonas aeruginosa: predominance of amino sugars in binding sites
Authors: Vishwanath S , Ramphal R
Published: January 2020

Pseudomonas aeruginosa, a common respiratory tract colonizer and pathogen, adheres to injured tracheal cells and to tracheobronchial mucin. These phenomena suggest that there are specific receptors for this organism in the respiratory tract. The receptor on injured tracheal cells contains n-acetylneuraminic acid as the principal sugar, but the structure of the receptor in mucin has not been described. Using a microtiter plate assay to study bacterial adherence to mucin, we have partially characterized the mucin receptor for P. aeruginosa. The receptor for both nonmucoid and mucoid strains is sensitive to periodate oxidation, suggesting that it is carbohydrate in nature, and the amino sugars n-acetylglucosamine and n-acetylneuraminic acid inhibited the adherence of both types of strains. Nonmucoid strains were more sensitive to inhibition by n-acetylneuraminic acid than to inhibition by n-acetylglucosamine, but the mucoid strains varied in their sensitivities to inhibition by each amino sugar. Preincubation of mucin with heat-inactivated influenza A virus (which binds to neuraminic acid) significantly reduced the adherence of P. aeruginosa. Treatment of mucin with Clostridium perfringens neuraminidase also reduced bacterial adherence significantly. Treatment of mucin with pronase did not affect adherence. Our results suggest that n-acetylglucosamine and n-acetylneuraminic acid are important constituents of the binding sites for P. aeruginosa on human tracheobronchial mucin.
Neutrophil chemotactic responses induced by fresh and swollen Rhizopus oryzae spores and Aspergillus fumigatus conidia
Authors: Waldorf A R , Diamond R D
Published: January 2020

With the induction of germination, Rhizopus oryzae spores and Aspergillus fumigatus conidia activate the complement system and induce neutrophil chemotaxis. In contrast, freshly isolated R. oryzae spores did not induce neutrophil migration into lung tissue of mice after intranasal inoculation. Moreover, in microchemotaxis assays neither fresh R. oryzae spores nor A. fumigatus conidia activated sera to stimulate human neutrophil chemotaxis above control migration until at least 10(7) or 10(8) spores or conidia per ml of sera were used. The increased generation of chemotactic factors by swollen spores and conidia was not due to an increased surface area, as there was decreased neutrophil chemotactic response to Rhizopus or Aspergillus hyphae when compared with swollen spores or conidia.
Protective effect of Lactobacillus casei on Pseudomonas aeruginosa infection in mice
Authors: Miake S , Nomoto K , Yokokura T , Yoshikai Y , Mutai M , Nomoto K
Published: January 2020

The protective effect of heat-killed Lactobacillus casei YIT9018 (LC 9018) against Pseudomonas aeruginosa infection in mice was compared with that of Corynebacterium parvum. Survival of mice after intraperitoneal (i.p.) infection with P. aeruginosa was augmented in mice that had been pretreated i.p. with LC 9018 5 days previously. Similar treatment of mice with C. parvum, however, was not effective at all. Moreover, mice became more susceptible to infection with P. aeruginosa after such treatment. Growth of P. aeruginosa in the peritoneal cavity and spleen was markedly inhibited in LC 9018-pretreated mice, whereas such inhibition of bacterial growth was not observed in C. parvum-treated mice. The protective effect of LC 9018 was observed in mice subjected to 800 rads of whole body irradiation but was abrogated when mice were treated with carrageenan. These results suggest that augmentation of the resistance of mice to P. aeruginosa was caused by the induction of activated macrophages. The number of macrophages detectable in the peritoneal cavity was almost the same in LC 9018- and C. parvum-treated mice. Growth of Listeria monocytogenes was inhibited by pretreatment with LC 9018. Inhibition of L. monocytogenes was also observed after the same pretreatment with C. parvum. It was suggested that macrophages activated with LC 9018 were involved in the protective immunity to P. aeruginosa.
Identification and characterization of the protein antigens of Leptospira interrogans serovar hardjo
Authors: Nunes-Edwards P L , Thiermann A B , Bassford P J , Stamm L V
Published: January 2020

We radiolabeled Leptospira proteins with [35S]methionine. Solubilized extracts of radiolabeled L. interrogans serovar hardjo strain hardjoprajitno were analyzed by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. We compared the protein profile obtained in this manner to the protein profiles of various [35S]methionine-labeled Leptospira spp. The profiles of the pathogenic L. interrogans strains were very similar but not identical and exhibited no obvious relationship to those of the two nonpathogenic species. We used solubilized, radiolabeled hardjoprajitno extracts and a sensitive radioimmunoprecipitation procedure to identify protein antigens recognized by immunoglobulin G antibodies present in various rabbit anti-hardjo sera. Homologous hyperimmune rabbit serum efficiently precipitated a large subset of proteins, the majority of which were between 30,000 and 66,500 daltons. Radioimmunoprecipitations with sera prepared against each of four recent hardjo isolates cultured from infected cattle produced similar results. Immunoprecipitations done with various radiolabeled Leptospira extracts and anti-hardjoprajitno serum demonstrated that the pathogenic leptospires possessed a number of cross-reactive major and minor protein antigens. By cell fractionation procedures, we found that most of the major protein antigens were present in the outer envelope. These proteins were exposed on the leptospiral cell surface because intact radiolabeled leptospires bound antibodies directed against them.
Antigenic properties of Chlamydia trachomatis lipopolysaccharide
Authors: Brade L , Nurminen M , Mäkelä P H , Brade H
Published: January 2020

The antigenic properties of the lipopolysaccharide (LPS) of Chlamydia trachomatis L2 were investigated. By means of passive hemolysis, passive hemolysis inhibition, and absorption experiments, it was shown that antiserum raised against chlamydial elementary bodies contained at least two different antibody specificities which reacted with different antigenic determinants of chlamydial LPS. One of these antibodies cross-reacted with enterobacterial Re LPS, recognizing a structure which is shared by both LPSs, whereas the reactivity of the second antibody was restricted to chlamydial LPS. The former antibody could be absorbed with Salmonella minnesota Re LPS, whereas the latter was not affected by this absorption. Therefore, chlamydial LPS possesses two distinct antigenic determinants, one of which is C. trachomatis specific, the other of which is responsible for the cross-reactivity with enterobacterial Re-type LPS. Both antigenic determinants were destroyed during mild acid-catalyzed hydrolysis. It was further shown that free chlamydial lipid A exhibits antigenicity that cross-reacts with free enterobacterial lipid A. This antigenicity, however, as in enterobacterial LPS, is present in a cryptic form, i.e., it is unmasked only after acid hydrolysis of LPS.
Binding activity of a murine anti-lipid A monoclonal antibody
Authors: Elkins K , Metcalf E S
Published: January 2020

In this report we briefly describe an immunoglobulin G3 monoclonal antibody, 2G6/1H11, which binds purified lipid A from Salmonella minnesota and a lipid A precursor molecule derived from Salmonella typhimurium. 2G6/1H11 does not bind well to purified whole S. typhimurium lipopolysaccharide (LPS), S. minnesota LPS, LPS preparations from a series of S. minnesota rough mutants, or intact S. typhimurium bacteria. Thus, there are antigenic determinants in purified lipid A which are not exposed when lipid A is presented as part of the whole LPS molecule or intact bacteria.
Cloned gtfA gene of Streptococcus mutans LM7 alters glucan synthesis in Streptococcus sanguis
Authors: Pucci M J , Macrina F L
Published: January 2020

Streptococcus mutans LM7 (Bratthall serotype e) chromosomal DNA was partially digested with EcoRI and ligated into the positive-selection plasmid vector pOP203(A2+). The ligation mixture was transformed into Escherichia coli, and transformants were selected for tetracycline resistance. Recombinant-bearing clones were screened for their ability to ferment raffinose, using the procedure of Robeson et al. (J. Bacteriol. 153:211-221, 1983). One raffinose-fermenting clone was isolated and found to contain a plasmid with an insert consisting of four EcoRI fragments totalling approximately 10.3 kilobases (kb). This strain was capable of growth on defined medium plus raffinose or sucrose and generated reducing sugars from a sucrose substrate. Southern hybridization analysis of the four EcoRI fragments revealed homology not only to S. mutans LM7 chromosomal DNA but also to S. mutans serotypes b, c, and f. Subcloning of this fragment array into a streptococcal E. coli shuttle vector indicated that a 2.4-kb EcoRI fragment was essential for sucrase activity. E. coli minicell experiments revealed a gene product of 55 kilodaltons. These data along with restriction endonuclease analysis and Southern hybridizations suggested that the cloned S. mutans LM7 gene was closely related to the gtfA gene cloned by Robeson et al. from S. mutans PS13 (Bratthall serotype c). The shuttle plasmid containing the 2.4-kb fragment was transformed into Streptococcus sanguis, which subsequently displayed increased sucrase activity in both intracellular and extracellular fractions. Elevated levels of synthesis of alcohol-insoluble and water-insoluble glucans were observed with crude extracellular fractions of the S. sanguis strain bearing the 2.4-kb fragment. An isolate cured of the shuttle plasmid plus the 2.4-kb fragment displayed wild-type S. sanguis glucan synthesis. In S. sanguis, this gtfA allele may play a role in glucan synthesis by interacting with extant high-molecular-weight glucosyltransferases.
Bactericidal activity of human lysozyme, muramidase-inactive lysozyme, and cationic polypeptides against Streptococcus sanguis and Streptococcus faecalis: inhibition by chitin oligosaccharides
Authors: Laible N J , Germaine G R
Published: January 2020

The basis of the bactericidal activity of human lysozyme against Streptococcus sanguis was studied. Experiments were designed to evaluate the role of lysozyme muramidase activity in its bactericidal potency. Inactivation of the muramidase activity of lysozyme was achieved by reduction of essential disulfides with dithiothreitol (DTT) or by incubation with the chitin oligosaccharides chitotriose and chitobiose. Muramidase-inactive lysozyme, prepared by reduction with DTT, was equal in bactericidal potency to native lysozyme. Solutions of native chicken egg white lysozyme and human lysozyme exhibited equal bactericidal potency yet differed ca. fourfold with respect to lytic (muramidase) activity. The above results suggested that the bactericidal activity of lysozyme is not dependent upon muramidase activity. Chitotriose and chitobiose were found to inhibit both lytic and bactericidal activities of lysozyme. The bactericidal activity of muramidase-inactive lysozyme (reduction with DTT) was also inhibited by chitotriose and chitobiose. Further investigations demonstrated that chitotriose and chitobiose were also potent inhibitors of the bactericidal activity of the cationic homopolypeptides poly-L-arginine and poly-D-lysine. These latter results suggested that the essential bactericidal property of lysozyme was its extreme cationic nature and that some bacterial endogenous activities, inhibitable by chitotriose and chitobiose, were essential for expression of the bactericidal activity of either native or muramidase-inactive lysozyme or of the cationic homopolypeptides. Experiments with Streptococcus faecalis whole cells, cell walls, and crude autolysin preparations implicated endogenous autolytic muramidases as the bacterial targets of chitotriose and chitobiose. The essentially identical responses of S. sanguis and S. faecalis to chitotriose in bactericidal assays with muramidase-inactive lysozyme and polylysine suggested that muramidase-like enzymes exist in S. sanguis and, furthermore, play an essential role in cationic protein-induced loss of viability of the oral microbe.
Studies of biochemical markers in cerebrospinal fluid in patients with meningoencephalitis
Authors: Ronquist G , Callerud T , Niklasson F , Friman G
Published: January 2020

Several biochemical markers in the cerebrospinal fluid (CSF) of 120 patients with serous meningoencephalitis (SM) of viral origin were compared with those of 74 patients with viral or bacterial infections accompanied by neck stiffness but no CSF abnormality (i.e., meningism). CSF adenylate kinase was higher (P less than 0.025) in SM and correlated with lactate concentration (r = 0.37; P less than 0.01). CSF hypoxanthine was lower (P less than 0.001) in SM, whereas CSF xanthine was similar in the two conditions. The xanthine/hypoxathine ratio correlated with the CSF leukocyte count (r = 0.32; P less than 0.01), and especially with the mononuclear cell count (r = 0.45; P less than 0.001). CSF adenylate kinase correlated with fever in SM (r = 0.28; P less than 0.01). CSF urate and protein displayed a mutual correlation in both conditions (r = 0.26 and P less than 0.05 for SM; r = 0.55 and P less than 0.001 for meningism). These results support the hypothesis of impaired brain cell metabolism, probably of ischemic nature, in viral meningoencephalitis, causing leakage of adenylate kinase into the CSF, where hypoxanthine may be reutilized by mononuclear leukocytes.
A completely synthetic toxoid vaccine containing Escherichia coli heat-stable toxin and antigenic determinants of the heat-labile toxin B subunit
Authors: Houghten R A , Engert R F , Ostresh J M , Hoffman S R , Klipstein F A
Published: January 2020

The immunodeterminant regions of the Escherichia coli heat-labile toxin B subunit were identified by determining the antigenicity, by using enzyme-linked immunosorbent assays, of synthetically produced peptides corresponding to various segments of its 124-amino-acid sequence. The addition of the 18-amino-acid sequence of heat-stable toxin (ST) to some of these peptides enhanced their B subunit antigenicity. Peptide residues containing the 26 amino acids of B subunit sequence 58 to 83 joined to the 18-amino-acid sequence of ST yielded a 44-amino-acid peptide whose antigenicity was 50% that of both native B subunit and ST. This peptide was completely nontoxic when tested in Chinese hamster ovary tissue culture, suckling mouse, and rat ligated ileal loop assays. Peroral immunization of rats with the polymeric form of this peptide yielded a dose-dependent response of intestinal immunoglobulin A antitoxin titers to both the ST and B subunit components and provided strong protection against challenge with viable ST- and heat-labile toxin-producing E. coli strains. The immunogenicity of the synthetic peptide in rats was the same as that of ST and about 50% that of native B subunit. The completely synthetic peptide vaccine has the following advantages over previously described toxoid vaccines that consist of synthetic ST chemically cross-linked to native B subunit derived from bacterial cultures: it is produced by a single synthetic process, it is completely nontoxic, and it is immunogenic for both ST and B subunit.
Corynebacterium parvum augments antibody production in splenectomized mice and mice with sham operations
Authors: Hebert J C , Ershler W B , Gamelli R L
Published: January 2020

The antibody response to a variety of antigens, including pneumococcal polysaccharides, is diminished in splenectomized (splx) mice. We investigated the capacity for the biological response modifier Corynebacterium parvum to augment antibody production in splx and sham-splx mice inoculated with pneumococcal polysaccharides and tetanus toxoid. As expected, antibody response to tetanus toxoid was similar in both splx mice and sham-splx mice. C. parvum augmented anti-tetanus toxoid antibody in both sham-splx (P less than 0.05) and splx mice (P less than 0.05). Antibody against pneumococcal type 3 polysaccharides was decreased in splx mice compared with sham-splx mice (P less than 0.05). Both groups treated coincidently with C. parvum and pneumococcal type 3 polysaccharides demonstrated a biphasic antibody response which was greater than that observed in saline-treated controls (sham-splx, P less than 0.001; splx, P less than 0.05). Whereas the secondary peak response to pneumococcal type 3 polysaccharides after treatments with C. parvum appears to be due to persistent elevations of immunoglobulin G and immunoglobulin M in sham-splx mice, it is primarily due to antibody of the immunoglobulin G class alone in the splx mice.
Role of lipopolysaccharide in opsonization and phagocytosis of Pseudomonas aeruginosa
Authors: Engels W , Endert J , Kamps M A , van Boven C P
Published: January 2020

When the opsonization of various Pseudomonas aeruginosa strains--PAC 1, its O-chain-deficient mutant PAC 605, and an intermediate strain, P14--was measured either directly by determination of the amount of C3b attached to the bacterial surface or indirectly by assessing phagocytosis by human polymorphonuclear leukocytes and the responses of chemiluminescence, it was demonstrated that PAC 1 was opsonized and phagocytized to a lower extent than P14 and PAC 605. In contrast to PAC 605, PAC 1 showed an increased consumption of complement in the fluid phase and a rapid release of lipopolysaccharide antibodies bound to the bacterial surface due to the alternative pathway of the complement system. Furthermore, it was shown that with respect to PAC 1 and PAC 605, the lack of an O-chain resulted in increased sensitivity to serum and decreased virulence. From both in vivo and in vitro experiments, we concluded that the structure of the O-antigen polysaccharide chain of lipopolysaccharide is an important virulence factor of P. aeruginosa against the defense mechanisms of the host.
Effect of bacterial competition on the opsonization, phagocytosis, and intracellular killing of microorganisms by granulocytes
Authors: Dijkmans B A , Leijh P C , Braat A G , van Furth R
Published: January 2020

The ingestion of Escherichia coli by human granulocytes in vitro was reduced in the presence of Bacteroides fragilis or Staphylococcus aureus. This reduction of ingestion proved to be mainly attributable to the absence of opsonization of E. coli, which was due to complement consumption by B. fragilis and S. aureus. The intracellular killing of E. coli was decreased in the presence of B. fragilis and S. aureus because of consumption of complement components required for extracellular stimulation of granulocytes to kill intracellular bacteria. Decreased intracellular killing of E. coli by granulocytes containing either B. fragilis or S. aureus is due to the limited killing capacity of granulocytes. These interactions between E. coli and B. fragilis or S. aureus found for phagocytosis and intracellular killing were also observed in in vivo studies: in an experimental thigh lesion infection in mice, E. coli showed stronger proliferation after coinoculation with B. fragilis or with S. aureus than after injection of E. coli alone. These in vitro and in vivo findings indicate that bacterial interactions, not only between aerobic and anaerobic bacteria but also between two species of aerobic microorganisms, compete for host defense mechanisms (i.e., opsonization, phagocytosis, and intracellular killing).
Effect of chemotactins released by Staphylococcus aureus and Pseudomonas aeruginosa on the murine respiratory tract
Authors: Sordelli D O , Cerquetti M C , Morris Hooke A , Bellanti J A
Published: January 2020

Staphylococcus aureus, the Pseudomonas aeruginosa temperature-sensitive (ts) mutant A/10/25, and the P. aeruginosa parental wild type were aerosolized to C5-deficient mice, and the total number of polymorphonuclear leukocytes (PMN) recovered by lung lavage was determined 4 h after aerosol exposure. S. aureus induced a slight but significant recruitment of PMN, as compared with the effect of a saline aerosol. Both wild-type P. aeruginosa and the ts mutant induced a significant PMN recruitment of a magnitude ca. 180 times higher than that produced by S. aureus. Gentamicin-killed ts P. aeruginosa induced a PMN recruitment of a magnitude similar to that produced by live ts P. aeruginosa. Thorough washing of the bacteria, however, removed ca. 90% of the chemotactic activity. Exposure of the animals to a ts P. aeruginosa culture supernatant aerosol induced significant PMN recruitment into the lower airways. The same culture supernatants were chemotactic for mouse PMN in a dose-dependent fashion when tested in vitro in the absence of serum. Culture supernatants of S. aureus exhibited weak chemotactic activity in vitro and did not induce PMN recruitment in the lungs when aerosolized to DBA/2J mice. The results suggest that chemotactins released by P. aeruginosa may be an important virulence factor and play a significant role in lung tissue damage.
Opsonophagocytic killing activity of rabbit antibody to Pseudomonas aeruginosa mucoid exopolysaccharide
Authors: Ames P , DesJardins D , Pier G B
Published: January 2020

We used an in vitro opsonophagocytic killing assay to measure the functional activity of antibody directed at the mucoid exopolysaccharide (MEP) antigen expressed by Pseudomonas aeruginosa strains isolated from cystic fibrosis patients. Rabbit antibodies raised to purified MEP were able to mediate phagocytic killing in the presence of human peripheral blood leukocytes and a low level (final concentration, 0.3%) of fresh normal human serum as a complement source. No bacterial killing was observed when peripheral blood leukocytes, antiserum, or complement was omitted. Specificity of the antibody for the MEP antigen was shown by adsorption and inhibition assays. Affinity-purified antibody to MEP also mediate phagocytic killing. These data indicate that antiphagocytic properties attributable to MEP can be overcome by specific antibody.
Demonstration of a capsule plasmid in Bacillus anthracis
Authors: Green B D , Battisti L , Koehler T M , Thorne C B , Ivins B E
Published: January 2020

Virulent and certain avirulent strains of Bacillus anthracis harbor a plasmid, designated pXO2, which is involved in the synthesis of capsules. Two classes of rough, noncapsulated (Cap-) variants were isolated from the capsule-producing (Cap+) Pasteur vaccine strains ATCC 6602 and ATCC 4229. One class was cured of pXO2, and the other class still carried it. Reversion to Cap+ was demonstrable only in rough variants which had retained pXO2. Proof that pXO2 is involved in capsule synthesis came from experiments in which the plasmid was transferred by CP-51-mediated transduction and by a mating system in which plasmid transfer is mediated by a Bacillus thuringiensis fertility plasmid, pXO12. Cells of Bacillus cereus and a previously noncapsulated (pXO2-) strain of B. anthracis produced capsules after the acquisition of pXO2.
Effect of Listeria monocytogenes infection on serum levels of colony-stimulating factor and number of progenitor cells in immune and nonimmune mice
Authors: Wing E J , Barczynski L C , Waheed A , Shadduck R K
Published: January 2020

Studies were performed to determine changes in serum macrophage colony-stimulating factor (M-CSF) levels and the number of macrophage progenitor cells in bone marrow and spleens of nonimmune and immune mice infected with Listeria monocytogenes. Immunity in mice was established by infecting mice 6 weeks before use with a sublethal dose of L. monocytogenes. When challenged with 10(4) L. monocytogenes organisms, immune mice had an early (12 h) peak in M-CSF serum concentrations. Levels remained elevated for 24 h but fell towards normal by 48 h. By contrast, M-CSF levels in nonimmune mice did not rise until 24 h after challenge, remained elevated for 7 days, and returned to normal by 14 days. The number of macrophage progenitor cells in the bone marrow of immune mice rose slightly during infection, whereas the number in nonimmune mice fell significantly by days 4 and 7. Progenitor cells in spleens of immune mice more than doubled during infection; in nonimmune mice, a sixfold increase was noted. These results indicate that important parameters of monocyte production differ in immune and nonimmune mice during listeria infection and suggest a possible mechanism for differences in resistance to infection.
Kinetics of assembly and decay of complement components on Escherichia coli O111:B4 preparation of stable intermediates
Authors: Rottini G , Tedesco F , Basaglia M , Roncelli L , Patriarca P
Published: January 2020

The preparation of bacterial intermediates bearing complement components at various steps of the complement sequence was investigated by suspending immunoglobulin M-opsonized Escherichia coli O111:B4 cells in complement-deficient sera at different temperatures and ionic strengths. The optimal conditions for the formation of the intermediates at Tmax were found to be an ionic strength of 0.091 mu and a temperature of 37 degrees C, except for BAC142, which could be formed equally well at room temperature. In contrast to all the other intermediates, which, once formed at Tmax, were stable in the presence of the whole serum, BAC142 decayed with a half-life of 10 min due to the lability of bound C2. Washing with a buffer of either 0.091 or 0.046 mu did not affect the bacterial intermediates, with the exception of BAC1-3 formed either in the presence of C5-deficient serum or with purified C3 added to BAC142. All the intermediates were found to be stable after incubation in 0.091-mu buffer for 30 min at 37 degrees C.
Immunoglobulin A subclass distribution of naturally occurring salivary antibodies to microbial antigens
Authors: Brown T A , Mestecky J
Published: January 2020

The distribution of immunoglobulin A1 (IgA1) and IgA2 antibodies to various microbial antigens was determined in human parotid saliva by using monoclonal antibodies to the IgA subclasses in a solid-phase radioimmunoassay. In 12 subjects examined, antibodies to Streptococcus mutans glucosyl transferase, protein antigen I/II, and cell wall carbohydrate, as well as dextrans B1355 fraction S and B512 and phosphorylcholine, occurred predominantly in the IgA1 subclass. In contrast, antibodies to lipoteichoic acid from Streptococcus pyogenes and whole lipopolysaccharides from Bacteroides gingivalis, Bacteroides fragilis, and Escherichia coli were predominantly of the IgA2 subclass. The data indicate that in most individuals naturally occurring antibodies to a given antigen are predominantly associated with one of the two subclasses of IgA.
Detection of the thermostable direct hemolysin gene and related DNA sequences in Vibrio parahaemolyticus and other vibrio species by the DNA colony hybridization test
Authors: Nishibuchi M , Ishibashi M , Takeda Y , Kaper J B
Published: January 2020

A specific gene probe for the Vibrio parahaemolyticus thermostable direct hemolysin gene was constructed and used to examine the presence or absence of the thermostable direct hemolysin gene or related DNA sequences in V. parahaemolyticus and other vibrios by the DNA colony hybridization method. The gene probe consisted of a 406-base-pair, completely internal fragment covering 71% of the structural gene with PstI linkers added to the ends. Six copies of this 415-base-pair PstI fragment were cloned into plasmid pBR322, which yielded large amounts of the probe DNA. One hundred forty-one V. parahaemolyticus strains were tested with the gene probe, and the results were compared with those of phenotypic assays for the thermostable direct hemolysin. All Kanagawa phenomenon-positive strains were gene positive. However, 86% of the strains that exhibited weak Kanagawa phenomenon and 16% of Kanagawa phenomenon-negative strains also reacted with the gene probe. Immunological methods for the detection of the thermostable direct hemolysin (modified Elek test, enzyme-linked immunosorbent assay) showed better correlation with gene probe results. All gene-positive strains produced hemolysin detectable in the enzyme-linked immunosorbent assay, although occasional strains showed weak reaction. The modified Elek test was slightly less sensitive than the enzyme-linked immunosorbent assay. All gene-negative strains were also negative in these immunological assays. One hundred twenty-one strains of Vibrio spp. other than V. parahaemolyticus were tested with the gene probe; only Vibrio hollisae strains reacted with the probe under stringent conditions.
Ultrastructural study of ehrlichial organisms in the large colons of ponies infected with Potomac horse fever
Authors: Rikihisa Y , Perry B D , Cordes D O
Published: January 2020

Potomac horse fever is characterized by fever, anorexia, leukopenia, profuse watery diarrhea, dehydration, and high mortality. An ultrastructural investigation was made to search for any unusual microorganisms in the digestive system, lymphatic organs, and blood cells of ponies that had developed clinical signs after transfusion with whole blood from horses naturally infected with Potomac horse fever. A consistent finding was the presence of rickettsial organisms in the wall of the intestinal tract of these ponies. The organisms were found mostly in the wall of the large colon, but fewer organisms were found in the small colon, jejunum, and cecum. The organisms were also detected in cultured blood monocytes. In the intestinal wall, many microorganisms were intracytoplasmic in deep glandular epithelial cells and mast cells. Microorganisms were also found in macrophages migrating between glandular epithelial cells in the lamina propria and submucosa. The microorganisms were round, very pleomorphic, and surrounded by a host membrane. They contained fine strands of DNA and ribosomes and were surrounded by double bileaflet membranes. Their ultrastructure was very similar to that of the genus Ehrlichia, a member of the family Rickettsiaceae. The high frequency of detection of the organism in the wall of the intestinal tract, especially in the large colon, indicates the presence of organotrophism in this organism. Infected blood monocytes may be the vehicle for transmission between organs and between animals. The characteristic severe diarrhea may be induced by the organism directly by impairing epithelial cell functions or indirectly by perturbing infected macrophages and mast cells in the intestinal wall or by both.
C1q, a subunit of the first component of complement, enhances binding of plasma fibronectin to bacteria
Authors: Sorvillo J M , Pearlstein E
Published: January 2020

The interaction of plasma fibronectin with C1q of the complement system has been demonstrated in the past several years. In addition, the antibody-independent binding of C1q to bacteria, as well as the binding of plasma fibronectin to bacteria, is well documented. This study examines whether the binding of C1q to bacteria enhances the interaction of C1q and bacteria with plasma fibronectin. Highly purified 125I-C1q bound to several species of bacteria in the absence of antibody. The binding of 125I-C1q to bacteria was saturable and specific since the addition of unlabeled C1q inhibited binding while the presence of bovine serum albumin did not. Bacteria which had been pretreated with either buffer or unlabeled C1q were tested for their ability to bind 125I-fibronectin. When bacteria were preincubated with buffer, Staphylococcus aureus bound fivefold more 125I-fibronectin than did Escherichia coli. However, preincubation of E. coli with C1q increased the binding of 125I-fibronectin by up to 20-fold, whereas pretreatment of S. aureus with C1q increased fibronectin binding by only twofold. These results were confirmed by immunoblotting studies which demonstrated the presence of C1q, as well as an increase in fibronectin antigens on the C1q-treated bacteria as compared with the level of fibronectin on buffer-treated bacteria. In addition, preincubation of 3H-labeled bacteria with C1q enhanced their attachment to fibronectin-coated surfaces but not to albumin-coated surfaces. The biological consequences of these observations are discussed.
Pyruvate dehydrogenase activity in Streptococcus mutans
Authors: Carlsson J , Kujala U , Edlund M B
Published: January 2020

Streptococcus mutans NCTC 10449 and Escherichia coli K-12 strain 37 were grown under aerobic and anaerobic conditions. In cell extracts of both strains, pyruvate dehydrogenase activity dependent on thiamine pyrophosphate, coenzyme A, and NAD was shown. The enzyme was induced by pyruvate in the growth medium, and there was higher activity in aerobically grown cells than in anaerobically grown cells. Acetyl phosphate was a potent inhibitor of the activity. This inhibition was partly overcome by inorganic phosphate.
Growth inhibition of Streptococcus mutans by cellular extracts of human intestinal lactic acid bacteria
Authors: Ishihara K , Miyakawa H , Hasegawa A , Takazoe I , Kawai Y
Published: January 2020

The in vitro growth of Streptococcus mutans was completely inhibited by water-soluble extracts from cells of various intestinal lactic acid bacteria identified as Streptococcus faecium, Streptococcus equinus, Lactobacillus fermentum, and Lactobacillus salivarius. The growth inhibition was dependent on the concentrations of the extracts. In contrast, the extracts did not inhibit the growth of the major indigenous intestinal lactic acid bacteria isolated from humans. These lactic acid bacteria were not acutely toxic in mice.
Plasmid-mediated susceptibility to intestinal microbial antagonisms in Escherichia coli
Authors: Andremont A , Gerbaud G , Tancrède C , Courvalin P
Published: January 2020

Self-transferable plasmid pIP1100 confers to Escherichia coli an unusually high level of resistance (1 to 2 mg/ml) to erythromycin by production of an erythromycin esterase. The effect of pIP1100 on the destiny of E. coli strains in the intestines of gnotobiotic mice was studied. In germfree mice, pIP1100 was efficiently transferred to a plasmid-free E. coli recipient. Intestinal counts of the donor, the recipient, and the transconjugants were greater than 8.5 log CFU/g of feces. When erythromycin was added to the diet of the mice, counts of the plasmid-bearing strains were only slightly lowered and partial inactivation of erythromycin was observed in the feces. Transfer of pIP1100 also occurred in human-flora-associated mice. In this model all the E. coli strains were subject to microbial antagonisms caused by the anaerobic components of the flora. However, strains harboring pIP1100 were strongly inhibited (less than 2.5 log CFU/g of feces), whereas their plasmid-free counterparts persisted at much higher population levels (greater than 5.2 log CFU/g of feces). The ecological disadvantage conferred by pIP1100 to E. coli when a complex human flora was concomitantly present in the intestine of the mice persisted during erythromycin administration. These results provide an explanation for the low incidence of isolation of highly erythromycin-resistant E. coli strains despite the extensive use of the antibiotic.
Role of caseinase from Aeromonas salmonicida in activation of hemolysin
Authors: Titball R W , Bell A , Munn C B
Published: January 2020

Mutants of the bacterial fish pathogen Aeromonas salmonicida selected for inability to digest casein concomitantly lost hemolytic activity against horse erythrocytes under certain conditions. Mixtures of wild-type with mutant culture supernatants indicated that mutants produce an inactive precursor of a hemolysin which was activated by autogenous caseinase and, with less efficiency, by other serine proteases. Selective inhibition or repression of caseinase production in the wild-type strain also resulted in the production of an inactive precursor of a hemolysin. The precursor of hemolysin was also activated by a serum factor which appeared to exert its maximum effect at the bacterial surface or after entry into the bacterial cell. These results could affect the interpretation of studies evaluating the role of individual extracellular products in the pathogenesis of A. salmonicida infections.
Effect of Exogenous Interferon on L Cells Persistently Infected with Newcastle Disease Virus
Authors: Hallum Jules V. , Thacore Harshad R. , Youngner Julius S.
Published: January 2020

Prolonged treatment with relatively high concentrations of interferon was required to “cure” L cells persistently infected with Newcastle disease virus.
Experimental Venezuelan Equine Encephalomyelitis Virus Infection of the Bovine
Authors: Walton Thomas E. , Johnson Karl M.
Published: January 2020

Two groups of four dairy cows (
Bos taurus
) were infected subcutaneously with the epizootic Venezuelan equine encephalomyelitis virus (VEE) strains MF-8 and San Pelayo, respectively. Animals experienced no clinical illness, but all developed significant neutropenia. Virus was recovered once each from the blood of three animals but did not exceed 10
2.2
SMICLD
50
(Suckling mouse intracerebral lethal dose
50
)/ml. Specific neutralizing antibodies appeared in the serum of all animals, but there were no significant differences in titers against different naturally occurring VEE subtypes. Dairy cattle thus appear to play no role in virus transmission during VEE epizootics but may serve as retrospective immunological sentinels of virus activity.
Enteric Immunization with Live Adenovirus Type 21 Vaccine I. Tests for Safety, Infectivity, Immunogenicity, and Potency in Volunteers
Authors: Dudding Burton A. , Bartelloni Peter J. , Scott Robert M. , Top Franklin H. , Russell Philip K. , Buescher Edward L.
Published: January 2020

Studies were undertaken in volunteers to determine whether living adenovirus type 21 (ADV-21) vaccine could be safely administered orally to susceptible young adults. In the first study, ten volunteers were fed 10
6.4
tissue culture infectious dose
50
(TCID
50
) of ADV-21 vaccine virus, and five received placebo tablets. Nine of ten infected volunteers shed ADV-21 in stools (mean duration, 10.1 days; range, 4 to 17 days). No pharyngeal excretion of ADV-21 was observed in any of these volunteers. Each of the nine developed type-specific neutralizing (N) antibodies to ADV-21. No evidence for person-to-person transmission of vaccine was observed. In a second study, volunteers were immunized with ADV-21 vaccines containing 10
6.8
, 10
4.6
, and 10
2.4
TCID
50
. ADV-21 N antibody responses were detected in nine of eleven who received the highest dose, six of twelve who received the middle dose, and two of twelve who were fed the lowest dose. None of twelve susceptible volunteers receiving the placebo capsule developed ADV-21 N antibodies postimmunization. This study established that the human infectious dose
50
for these lots of ADV-21 vaccine was approximately 10
4.6
TCID
50
and that the dose response to ADV-21 vaccine was lower than those previously reported for live ADV-4 and ADV-7 enteric vaccines.
In Vivo Release of Previously Cleared Interferon by Cycloheximide
Authors: Chester Thomas J. , De Clercq Erik , Nuwer Marc R. , Merigan Thomas C.
Published: January 2020

The release of previously cleared interferon by cycloheximide was studied in the mouse. When cycloheximide was administered after either endogenous interferon stimulation or administration of exogenous interferon, the clearance of interferon from the blood stream was interrupted and a sharp rise in interferon titer occurred approximately 6 hr after cycloheximide administration followed by a rapid decline to low levels. This effect was observed with either interferon stimulated endogenously (by polyriboinosinic·polyribocytidylic acid), or homologous (mouse) or heterologous (rabbit) interferon administered exogenously. Serum protein concentrations also exhibited this rise and fall phenomenon after cycloheximide administration although the magnitude of the change in protein concentrations was less pronounced than that observed with interferon. Hematocrits, although elevated in mice receiving cycloheximide, did not exhibit this rise and fall phenomenon. Hence, cycloheximide administration leads to the release into the circulation of previously cleared interferon as well as other proteins.
Immunological Distinction of Mycobacterial Beta-Lactamases
Authors: Thompson John S. , Severson Charles D. , Stearns Nancy A. , Kasik John E.
Published: January 2020

Beta-lactamase-containing fractions have been isolated from
Myobacterium tuberculosis
strain R
1
R
v
and
M. smegmatis
strains NCTC 8158 and T-64. Antisera raised in rabbits to these fractions demonstrated no cross-reactivity with a commercial
Bacillus cereus
beta-lactamase. Antiserum to either strain of
M. smegmatis
revealed no cross-reactivity with
M. tuberculosis
R
1
R
v
, one specificity in common with the other
M. smegmatis
strain, and two specificities unique to the immunizing fractions. Further characterization of the common specificity was not possible, but beta-lactamase activity was related to the strain-specific precipitin lines in each case. These studies demonstrate the feasibility of isolating beta-lactamase enzyme fractions that may prove useful in the classification and diagnosis of mycobacteria.
Isolation by Electrofocusing of Two Lymphocyte Mitogens Produced by
Staphylococcus aureus
Authors: Kreger Arnold S. , Cuppari Girolamo , Taranta Angelo
Published: January 2020

Staphylococcus aureus
strain DA352, grown in a diffusate of Todd-Hewitt broth, produced two extracellular nondialyzable lymphocyte mitogens having isoelectric points of 5.5 to 5.7 and 8.6 to 9.0. The mitogens were separable from one another by isoelectric focusing and could be isolated free of detectable amounts of other staphylococcal products by ethanol precipitation followed by isoelectric focusing. Dose-response curves with both mitogens showed a maximum per cent transformation in the range (90%+) obtained with phytohemagglutinin (PHA), a decrease of transformation with excess mitogen, and, with decreasing concentrations, a slope somewhat less steep than that obtained with PHA. Incubation with undigested or pepsin-digested pooled human gamma globulin enhanced the activity of the basic mitogen.