bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Polybasic Amines on the Immunogenicity of Mycobacterial Ribonucleic Acid
Authors: Youmans Anne S. , Youmans Guy P.
Published: January 2020

The five polybasic amines, methylated bovine serum albumin (MBSA), protamine sulfate, neomycin sulfate, streptomycin sulfate, and diethylaminoethyl-dextran (DEAE-dextran), were examined to determine their effects on the immunogenic activity of mycobacterial ribonucleic acid (RNA) preparations, and whether they could substitute for Freund incomplete adjuvant (FIA) by protecting the mycobacterial RNA in vivo. These compounds were either emulsified in FIA or not emulsified in FIA. Different results were obtained when these compounds, complexed with mycobacterial RNA, were emulsified in FIA. MBSA, in ratios of mycobacterial RNA-MBSA of 1:0.2 to 1:0.4, had no effect on immunogenic activity. However, when the ratio was increased to 1:1, 1:2, or to 1:4, marked inhibition of the immunogenic activity occurred. Protamine sulfate and neomycin sulfate also inhibited the immunogenic activity of mycobacterial RNA; however, neither streptomycin sulfate nor DEAE-dextran had any effect on immunogenic activity. Without being emulsified in FIA, these five polybasic amines, with the exception of DEAE-dextran, acted only as weak adjuvants for mycobacterial RNA and, therefore, could not be used as substitutes for FIA for the protection of mycobacterial RNA from host nucleases. DEAE-dextran, although not as effective as FIA, afforded some protection for the mycobacterial RNA. DEAE-dextran alone also produced a low degree of nonspecific immunity against tuberculosis. Since MBSA, protamine sulfate, and neomycin sulfate reduce the biological activity of mycobacterial RNA after complexing with it, it is probable that these compounds “mask” the immunogenic sites on the mycobacterial RNA structure.
Role of Complement in Immune Lysis of
Trypanosoma cruzi
Authors: Anziano Dante F. , Dalmasso Agustin P. , Lelchuk Rosalia , Vásquez César
Published: January 2020

Studies were performed on the mechanism of immune lysis of culture forms of
Trypanosoma (Schizotrypanum) cruzi.
Antibody-mediated lysis is caused by complement, which is activated via the classical pathway. The properdin system is not required. The kinetics of the reaction is similar to that followed by immune lysis of sensitized sheep erythrocytes, as is the concentration of divalent cations required for optimal lysis (0.15 m
m
Ca
2+
and 0.5 m
m
Mg
2+
), the occurrence of cell membrane uptake of the complement components C3 and C4, and the development of characteristic ultrastructural modifications on the cell membrane.
Skin Lesions Produced by
Staphylococcus aureus
Exfoliatin in Hairless Mice
Authors: Kapral Frank A. , Miller Margaret M.
Published: January 2020

Exfoliatin caused skin loss in hairless mutant mice only while they lacked hair, but older mice were more resistant to this effect than neonates.
Calcium Requirement and Magnesium Stimulation of
Escherichia coli
L-Form Induction
Authors: Makemson John C. , Darwish Riad Z.
Published: January 2020

Calcium was found to be required for
l
-form penicillin induction of
Escherichia coli
K-12 W1485, and magnesium was found to be stimulatory.
Mouse Liver Fructose-1, 6-Diphosphatase and Glucose-6-Phosphatase Activities After Endotoxin Poisoning
Authors: McCallum R. E. , Berry L. Joe
Published: January 2020

Hepatic fructose-1, 6-diphosphatase and glucose-6-phosphatase were significantly decreased in fasted mice 17 hr after the intraperitioneal injection of a median lethal dose of
Salmonella typhimurium
endotoxin. Liver glycogen levels were essentially depleted at 17 hr.
Electron Microscopy of the Toxin and Hemagglutinin of Type A
Clostridium botulinum
Authors: Boroff Daniel A. , Nyberg Sverker , Höglund Stefan
Published: January 2020

Electron micrographs of the toxin and the hemagglutinin of type A
Clostridium botulinum
showed the toxin to be either round or disclike particles of 4 to 4.5 nm. These particles could also be seen as arranged in long strands or tubules of 9 nm in width. The hemagglutinin appeared as a crystalloid monolayer of stacked particles of 9 nm forming regularly arranged structures of 20 nm. Seen in cross section, these structures appeared as tubules with a lumen of 9 nm. The regularity of the angle of 83° to the long axis of the structure in which the individual particles were arranged suggested that the hemagglutinins formed a helix with sufficient space within its coil to admit the strands of the toxins. A model of the possible arrangement of the toxin and the hemagglutinin in the native state is proposed.
Purification and Characterization of Epizootic Diarrhea of Infant Mice Virus
Authors: Much David H. , Zajac Ihor
Published: January 2020

Epizootic diarrhea of infant mice virus has been purified from the intestines of infected mice using enzymatic digestion, precipitation with polyethylene glycol, extraction with Genesolv-D, and sucrose step-gradient centrifugation. The purified virus was found to be stable at −70 C or when treated with ether, chloroform, or sodium deoxycholate. Biochemical analysis of purified virions has suggested that the nucleic acid type of epizootic diarrhea of infant mice virus was of the ribonucleic acid type. Preparations of purified virions stained with phosphotungstic acid showed a particle with icosahedral symmetry, 54 ± 2 nm in diameter and probably composed of 32 hollow capsomeres.
Effect of Heat (Arrhenius Effect) on Crude Hemolysin of
Vibrio parahaemolyticus
Authors: Miwatani Toshio , Takeda Yoshifumi , Sakurai Jun , Yoshihara Akiko , Taga Sekiko
Published: January 2020

Crude hemolysins prepared from various strains of
Vibrio parahaemolyticus
, which give positive Kanagawa phenomenon, were partly inactivated by heating at 60 C, but not inactivated significantly by heating at 80 to 90 C. The similar phenomenon has been reported as the Arrhenius effect in staphylococcal alpha toxin.
Antibody Responses to Group A Streptococcal Infections in the Hamster
Authors: Dajani Adnan S. , Ferrieri Patricia , Wannamaker Lewis W.
Published: January 2020

The immune response after streptococcal infections of the skin and of the joints was studied in an experimental animal model. Hamsters were challenged intradermally or intra-articularly with different streptococcal serotypes, and antibodies for streptolysin O (ASO), deoxyribonuclease B (anti-deoxyribonuclease B), and group A carbohydrate (anti-group A CHO) were determined. After a single injection at either site, 7 of 48 animals (14%) developed group A-CHO antibodies; however, none of the animals developed detectable levels of ASO or anti-deoxyribonuclease B. After repeated infections of the skin or joint, anti-deoxyribonuclease B antibodies were detectable in 13% (4 of 30) and 30% (5 of 17) of the animals, respectively. Elevations of ASO occurred after repeated joint infections in 4 of 16 animals (25%), whereas none of 30 hamsters repeatedly infected intradermally developed antibodies against streptolysin O. For all three antibodies tested, elevated levels were more frequently noted after repeated joint infections than after repeated skin infections with the same streptococcal serotype. These data, similar to ones previously noted in human impetigo, indicate that ASO responses are feeble after streptococcal skin infections and that the site of infection per se, rather than the infecting strain, appears to be responsible for this poor response.
Role of the K88 Antigen in the Pathogenesis of Neonatal Diarrhea Caused by
Escherichia coli
in Piglets
Authors: Jones G. W. , Rutter J. M.
Published: January 2020

The role of the K88 antigen of
Escherichia coli
in neonatal diarrhea of piglets was studied by comparing a K88-positive strain with three K88-negative strains derived from the K88-positive strain. K88 antigen was produced by the K88-positive strain in the intestinal tract of gnotobiotic piglets, whereas K88-negative strains did not regain the ability to synthesize K88 antigen. Synthesis of the antigen conferred different colonization characteristics on the four strains; K88-positive bacteria adhered to the mucosa of the small intestine, whereas K88-negative bacteria did not attach and were distributed throughout the lumen. Adhesion of K88-positive bacteria to tissue from the small intestine of gnotobiotic piglets was demonstrated in vitro and was inhibited by antisera that contained K88 antibodies. Attachment did not occur with bacteria grown at 18 C. Adhesion of cell-free K88 antigen was also demonstrated. The K88-positive strain and one of the K88-negative strains were equally virulent in gnotobiotic piglets. In contrast, the K88-positive strain killed 50% of conventionally reared piglets, whereas the K88-negative strain killed only 3%. Adhesion of the K88-positive strain, but not of the K88-negative strain, to the mucosa of the small intestine was demonstrated. Our results show that K88 antigen is responsible for attachment of K88-positive bacteria to the wall of the small intestine, and that adhesion is essential for the virulence of K88-positive bacteria in conventionally reared piglets.
Effect of Methylprednisolone on some BCG-Mediated Changes in Rabbit Alveolar Macrophage
Authors: Wang Patsy , Franson Richard C. , DeChatelet Lawrence R. , Waite Moseley , McCall Charles E.
Published: January 2020

The effect of methylprednisolone sodium succinate treatment on Bacillus Calmette-Guérin (BCG) immunization was examined in alveolar macrophages of New Zealand White rabbits. Intravenous BCG injection caused a marked increase in cell number and in the hexosemonophosphate shunt activity. There was also a selective augmentation in the activity of acid phosphatase and β-glucuronidase and an increase in lysosomal density. Activity of the lysosomal phospholipases was decreased. Steroid treatment suppressed the BCG-induced increase in cell number, hexosemonophosphate shunt activity, acid phosphatase, and β-glucuronidase, and prevented the increase in lysosomal density. On the other hand, steroid treatment increased the activity of the phospholipases to levels higher than either control values or those obtained with cells from BCG-treated rabbits.
Siderophore production and membrane alterations by Bordetella pertussis in response to iron starvation
Authors: Agiato L A , Dyer D W
Published: January 2020

Bordetella pertussis was grown in iron (Fe)-free defined medium to limit the growth of the organism. Doubling times of the Fe-starved organism increased by approximately 1 h, and a 40% reduction in the final extent of growth in Fe-depleted medium was observed. Under these conditions, a hydroxamate siderophore named bordetellin was secreted by B. pertussis. Lactoferrin and transferrin supported growth of B. pertussis even when the protein was sequestered inside dialysis tubing. This suggested that binding of lactoferrin and transferrin to B. pertussis was not essential and that bordetellin production plays a major role in Fe uptake. Solid-phase dot blot assays indicated weak binding of lactoferrin to the cell surface, consistent with previous reports of a lactoferrin receptor. Three new proteins of 97, 77, and 63 kDa were synthesized in response to Fe starvation. Fe-inducible proteins of 103, 72, 24, 21, and 18 kDa were also observed. The synthesis of lipopolysaccharide was also altered by Fe availability.
T-cell immune responses in Mycobacterium avium-infected mice
Authors: Hubbard R D , Flory C M , Collins F M
Published: January 2020

Mycobacterium avium infection was substantially more severe in C57BL/6 (Bcgs) than in (C57BL/6 x DBA/2)F1 hybrid (Bcgr) mice both in terms of bacterial growth in the spleens and lungs and in host survival. Prior Mycobacterium bovis BCG vaccination resulted in increased resistance as well as enhanced tuberculin hypersensitivity to both PPD-S (Mycobacterium tuberculosis) and PPD-A (M. avium). Mice heavily infected with M. avium were used as T-cell donors in an adoptive transfer system. Substantial resistance was observed for both recipient hosts regardless of the genotype of the donor strain. Transfer of resistance was ablated by treatment of the immune spleen cells with anti-Thy 1.2 monoclonal antibody and complement or by cyclophosphamide treatment. Spleen cells which were monodepleted of L3T4+ or Lyt-2+ T cells did not lose their ability to transfer resistance against a subsequent challenge. However, when these cells were doubly deleted, all resistance was ablated in both the BCG-susceptible and -resistant mice. The recipient host expressed a detectable adoptive immune response although the donor had been unable to reduce the growth of the primary M. avium infection in vivo.
Complement component 3 binding to Haemophilus influenzae type b in the presence of anticapsular and anti-outer membrane antibodies
Authors: Hetherington S V , Patrick C C
Published: January 2020

Antibodies directed against the capsular polysaccharide (polyribosyl ribitol phosphate [PRP]) or the outer membrane proteins (OMP) of Haemophilus influenzae type b (Hib) promote bactericidal activity, complement 3 (C3) binding, and ingestion by phagocytic cells. To assess the relative contribution of anti-OMP to host defense against Hib, we compared the opsonic activities of anti-PRP and anti-OMP as reflected by the amounts of C3 bound to the bacterial surface. Immunoglobulin G (IgG) fractions containing either anti-PRP or anti-OMP were incubated with Hib in the presence of a C5-deficient complement source. C3, total IgG, and IgG subclasses bound to the bacteria were quantified by enzyme-linked immunosorbent assay. The maximum amount of C3 which could be bound to Hib was greater in the presence of anti-PRP than in the presence of anti-OMP. Also, except at low IgG concentrations, the rate of increase in bound C3 as a function of increasing IgG concentration was greater for anti-PRP than for anti-OMP. Hib-bound anti-OMP consisted primarily of IgG1 and IgG3, whereas bound anti-PRP was primarily IgG1 and IgG2. Thus, the potential for C3 binding to Hib is greater in the presence of anti-PRP than in the presence of anti-OMP, probably because of the larger number of binding sites available to the former. Nonetheless, OMP appear to provide important targets for opsonic antibody and would be logical components of a PRP-conjugate vaccine or may be efficacious as vaccines against nontypeable H. influenzae.
Tissue-type plasminogen activator-mediated activation of plasminogen on the surface of group A, C, and G streptococci
Authors: Kuusela P , Ullberg M , Saksela O , Kronvall G
Published: January 2020

The interaction of Glu-plasminogen with group A, C, and G streptococci and subsequent formation of surface-associated plasminogen by tissue-type plasminogen activator (t-PA) were studied. Binding of 125I-Glu-plasminogen to streptococci greatly facilitated its activation to 125I-Glu-plasmin by exogenous t-PA, whereas activation in the absence of bacteria took place only slowly. Glu-plasmin formed on the streptococcal surface was further converted to the Lys form. Similar activation and modification took place also in the presence of plasminogen-depleted plasma, containing functional t-PA and plasmin inhibitors, indicating that the surface-associated enzymes were protected against these inhibitors. Lys-plasminogen was 10- to 30-fold more potent than Glu-plasminogen or Glu-plasmin in inhibiting the binding of 125I-Glu-plasminogen to streptococci. This indicated a higher affinity of the Lys form towards plasminogen-binding molecule(s) on the streptococcal surface. The surface-associated plasmin was also enzymically active as judged by digestion of chromogenic substrate S-2251. Surface-associated plasmin activity was observed only when the incubations were carried out in the presence of t-PA and Glu-plasminogen or human plasma as the source of plasminogen. Under these conditions, soluble enzymatic activity was also recovered in the supernatant of group A streptococci. This favors the idea that plasmin can be released from the bacterial surface. The findings provide a mechanism for streptococci to adopt proteolytic activity by binding a host-derived enzyme zymogen on their surface, where the subsequent activation then takes place. The results suggest a role for surface-associated plasmin activity in tissue tropism and tissue invasiveness of streptococci.
Roles of protein kinase C and G proteins in activation of murine resting B lymphocytes by endotoxin-associated protein
Authors: Bandekar J R , Castagna R , Sultzer B M
Published: January 2020

Endotoxin-associated protein (EP) from the outer membrane of gram-negative bacteria is a potent immunomodulator. To examine the mechanism of EP stimulation, the protein kinase C inhibitors H7 and staurosporine were used. Both DNA and RNA synthesis of EP-stimulated murine resting B cells were completely inhibited when inhibitors were added at 0 h, whereas 55 to 76% inhibition of DNA synthesis was observed when H7 was added after 12 h of stimulation. In contrast, HA 1004, which blocks protein kinase A and protein kinase G activity, was relatively ineffective even at high concentrations, suggesting that the activity of protein kinase C is a primary mechanism of EP-induced murine B-cell proliferation. To examine the role of G proteins in EP-induced DNA synthesis in B cells, the effects of pertussis toxin (PT), which inactivates certain G proteins, and the B oligomer of PT (PTB), which does not, were also examined. PT was found to inhibit EP-induced DNA synthesis in a dose-dependent manner. However, PTB also caused equivalent inhibition, suggesting that PTB may be responsible for most of the inhibitory effect seen with the holotoxin. These results serve to question whether G proteins are involved in the signal transduction that occurs during EP-induced DNA synthesis in murine B cells.
Glucans synthesized in situ in experimental salivary pellicle function as specific binding sites for Streptococcus mutans
Authors: Schilling K M , Bowen W H
Published: January 2020

Many researchers have suggested that the role of glucan-mediated interactions in the adherence of Streptococcus mutans is restricted to accumulation of this cariogenic bacterium following its sucrose (i.e., glucan)-independent binding to saliva-coated tooth surfaces. However, the presence of enzymatically active glucosyltransferase in salivary pellicle suggests that glucans could also promote the initial adherence of S. mutans to the teeth. In the present study, the commonly used hydroxyapatite adherence assay was modified to include the incorporation of glucosyltransferase and the synthesis of glucans in situ on saliva-coated hydroxyapatite beads. Several laboratory strains and clinical isolates of S. mutans were examined for their ability to adhere to experimental pellicles, either with or without the prior formation of glucans in situ. Results showed that most strains of S. mutans bound stereospecifically to glucans synthesized in pellicle. Inhibition studies with various polysaccharides and fungal dextranase indicated that alpha 1,6-linked glucose residues were of primary importance in the glucan binding observed. Scanning electron microscopic analysis showed direct binding of S. mutans to hydroxyapatite surface-associated polysaccharide and revealed no evidence of trapping or cell-to-cell binding. S. mutans strains also attached to host-derived structures in experimental pellicles, and the data suggest that the bacterial adhesins which recognize salivary binding sites were distinct from glucan-binding adhesins. Furthermore, glucans formed in experimental pellicles appeared to mask the host-derived components. These results support the concept that glucans synthesized in salivary pellicle can promote the selective adherence of the cariogenic streptococci which colonize human teeth.
Identification of a 58-kilodalton cell surface fibrinogen-binding mannoprotein from Candida albicans
Authors: Casanova M , Lopez-Ribot J L , Monteagudo C , Llombart-Bosch A , Sentandreu R , Martinez J P
Published: January 2020

Treatment of both yeast (blastoconidia) and hyphal (blastoconidia with germ tubes) cells of Candida albicans with beta-mercaptoethanol (beta ME) releases a complex array of cell wall-bound proteins and glycoproteins. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western immunoblotting with fibrinogen-anti-fibrinogen antibody allowed the identification of a 58-kDa mannoprotein (mp58) in both extracts which specifically interacts with human fibrinogen. Treatment of intact cells with low concentrations of beta-glucanase (Zymolyase 20T) for short periods or with beta ME abolished or significantly reduced binding of fibrinogen. A rabbit polyclonal antiserum was raised against the purified mp58 species released by beta ME from germinated blastoconidia (PAb anti-mp58). By Western blotting, the antiserum cross-reacted with the homologous 58-kDa fibrinogen-binding mannoprotein present in beta ME extracts from blastoconidia, and by indirect immunofluorescence, the antiserum labelled both yeast cells and hyphae, yet reactivity was found primarily on the cell surface of filamentous forms. Immunostaining of human infected tissue sections with PAb anti-mp58 showed that the mp58 species is also expressed in vivo; in this case, the species is in the forms of both yeast and hyphal elements similarly labelled by the antiserum. Purified immunoglobulin G fraction from the antiserum did not alter the binding of fibrinogen as determined by a modified enzyme-linked immunosorbent assay and Western blotting. The N- and O-glycosidically linked carbohydrates represent 18 to 20% and 3 to 4%, respectively, of the molecular mass of the mp58. O-linked sugar residues may be involved in the interaction of the molecule with fibrinogen.
Early activation of splenic macrophages by tumor necrosis factor alpha is important in determining the outcome of experimental histoplasmosis in mice
Authors: Wu-Hsieh B A , Lee G S , Franco M , Hofman F M
Published: January 2020

Experimental infection of animals with Histoplasma capsulatum caused a massive macrophage infiltration into the spleen and induced the production of tumor necrosis factor alpha (TNF-alpha) locally. The cytokine was also produced in vitro by peritoneal exudate macrophages exposed to a large inoculum of yeast cells. Depletion of the cytokine by injection of polyclonal sheep anti-TNF-alpha antibody was detrimental to sublethally infected mice. Fungous burdens in the spleens of TNF-alpha-depleted mice were higher than they were in the infected control mice at days 2, 7, and 9 after infection, and the antibody-treated animals succumbed to the infection. Histopathological study of spleen sections revealed that splenic macrophages were not able to control proliferation of intracellular yeasts as a result of TNF-alpha depletion. It seems that TNF-alpha plays a role in early activation of splenic macrophages which is important in controlling the outcome of an infection.
Adhesion of glucosyltransferase phase variants to Streptococcus gordonii bacterium-glucan substrata may involve lipoteichoic acid
Authors: Vickerman M M , Jones G W
Published: January 2020

Growing Streptococcus gordonii Spp+ phase variants, which have normal levels of glucosyltransferase (GTF) activity, use sucrose to promote their accumulation on surfaces by forming a cohesive bacterium-insoluble glucan polymer mass (BPM). Spp- phase variants, which have lower levels of GTF activity, do not form BPMs and do not remain in BPMs formed by Spp+ cells when grown in mixed cultures. To test the hypothesis that segregation of attached Spp+ and unattached Spp- cells was due to differences in adhesiveness, adhesion between washed, [3H]thymidine-labeled cells and preformed BPM substrata was measured. Unexpectedly, the results showed that cells of both phenotypes, as well as GTF-negative cells, attached equally well to preformed BPMs, indicating that attachment to BPMs was independent of cell surface GTF activity. Initial characterization of this binding interaction suggested that a protease-sensitive component on the washed cells may be binding to lipoteichoic acids sequestered in the BPM, since exogenous lipoteichoic acid inhibited adhesion. Surprisingly, the adhesion of both Spp+ and Spp- cells was markedly inhibited in the presence of sucrose, which also released lipoteichoic acid from the BPM. These in vitro findings suggest that, in vivo, sucrose and lipoteichoic acid may modify dental plaque development by enhancing or inhibiting the attachment of additional bacteria.
S-layer-mediated association of Aeromonas salmonicida with murine macrophages
Authors: Garduño R A , Lee E J , Kay W W
Published: January 2020

The interaction of Aeromonas salmonicida with the murine macrophage (M phi) cell line P388D1 was used as a convenient model to study the involvement of the bacterial crystalline surface array (or A-layer) in the association with M phi s. A-layer-positive (A+) cells readily associated with M phi s in phosphate-buffered saline, whereas A- mutants were unable to do so, even when the bacterium-M phi interaction was forced by centrifugation. M phi s selectively interacted with A+ cells when challenged with mixtures of A+ and excess A- cells. Electron microscopy indicated that in phosphate-buffered saline only A+ bacteria were readily internalized, although by a nonconventional mechanism, suggesting that efficient phagocytosis in the absence of opsonins was A-layer mediated. Latex beads coated with a partially assembled A-layer were more efficiently taken up than uncoated or A-protein-coated beads, indicating that an organized A-layer was essential for M phi uptake. The reduced ability of M phi s plated on a substratum coated with the A-layer to bind A+ bacteria also suggested that association was both A-layer and receptor mediated. In the presence of tissue culture medium, competent M phi s interacted efficiently with A- bacteria and internalized them through conventional phagocytosis. A+ cells were markedly cytotoxic to M phi s, whereas the A-protein or A-layer was not. A- cells were cytotoxic to a lesser extent, suggesting that cytotoxicity was targeted.
Effects of gamma interferon and indomethacin in preventing Brucella abortus infections in mice
Authors: Stevens M G , Pugh G W , Tabatabai L B
Published: January 2020

Increased resistance to infection with Brucella abortus 2308 resulted when recombinant murine gamma interferon (rMuIFN-gamma) was given to mice both before and during infection but not when given only before infection. Mice given rMuIFN-gamma had enhanced peritoneal and splenic macrophage bactericidal activity against B. abortus. Treatment of mice with rMuIFN-gamma plus indomethacin did not further enhance resistance to infection or macrophage bactericidal activity compared with that after treatment of mice with rMuIFN-gamma alone.
Capacity of Mycobacterium avium isolates to grow well or poorly in murine macrophages resides in their ability to induce secretion of tumor necrosis factor
Authors: Furney S K , Skinner P S , Roberts A D , Appelberg R , Orme I M
Published: January 2020

The results of this study show that clinical isolates of Mycobacterium avium fall into two categories in terms of their capacity to grow within murine bone marrow-derived macrophage cultures: those that grow progressively and those that are incapable of growing within such cells. Members of the first category were invariably of the smooth-transparent colonial type, while most of the second were of the smooth-doomed type. In addition, this paper shows that although all isolates induced tumor necrosis factor (TNF) secretion by host cells to some extent, this production was always delayed in isolates that subsequently grew well in the host cells. This observation, coupled with the demonstration that the growth of the latter isolates was inhibited by the exogenous addition of TNF, leads us to hypothesize that the ability of a given isolate to somehow avoid host macrophage TNF production early during the course of the infection is a key factor in the pathogenesis of the disease.
Visualizations of binding and internalization of two nonlinked protein components of botulinum C2 toxin in tissue culture cells
Authors: Ohishi I , Yanagimoto A
Published: January 2020

Binding and internalization of two nonlinked components of botulinum C2 toxin were visualized in tissue culture cells with components directly labeled with fluorescence. The binding of both untrypsinized and trypsinized component II (UT-II and T-II, respectively) to common specific sites on the cell membrane was evidenced by competitive binding between fluorescence-labeled and unlabeled components. The distribution patterns of fluorescence-labeled T-II and UT-II after binding to cells at 37 degrees C were different; T-II clustered on the cell membrane and entered the cells in endosomes, whereas UT-II entered the cells inefficiently and not in vesicles and was distributed on the nuclear surface. The difference may be due to the multivalent property of T-II, which is not shared with UT-II. Fluorescence-labeled component I, which binds only to cells bound with T-II, entered cells by the same route as T-II did; both colocated on the same clusters on the cell membrane and also in the same vesicles in the cytoplasm. The present results suggest that component I of C2 toxin, which ADP-ribosylates cytoplasmic actin, directly binds to T-II but not to UT-II on the cell membrane and is internalized into cells together with T-II in the same endosomes.
Growth characteristics of recent sputum isolates of Mycobacterium tuberculosis in guinea pigs infected by the respiratory route
Authors: Balasubramanian V , Wiegeshaus E H , Smith D W
Published: January 2020

The consideration of virulence must distinguish between infectivity and the ability to cause progressive disease once the infection is established. Several investigators have reported the presence of naturally occurring isolates which differ in virulence for guinea pigs. Isolates from south India which differed with respect to gross disease and number of bacilli recovered from spleen after an intramuscular infection also differed in their efficiencies to initiate an infection, once inhaled and retained. Also, this difference was correlated with differences in the rate of multiplication at the site of implantation and rate of multiplication at sites of hematogenous seeding, as well as the extent of hematogenous seeding. The number of metastatic foci was identified as a quantitative measure of hematogenous seeding, which was not confounded by the rate of multiplication of bacilli. Even allowing for the fourfold-reduced efficiency of low-virulence tubercle bacilli to produce a lesion, this measure clearly revealed a significantly reduced ability of the low-virulence tubercle bacilli to disseminate via the bloodstream.
Pathogen and host differences in bacterial adherence to human buccal epithelial cells in a northeast Brazilian community
Authors: Walser B L , Newman R D , Lima A A , Guerrant R L
Published: January 2020

The adherence of several strains of Escherichia coli to human buccal epithelial cells was studied, using cells obtained from five groups: healthy adults, healthy children, children with acute diarrhea, children with persistent diarrhea associated with cryptosporidial parasites, and children with noncryptosporidial persistent diarrhea. All groups lived or worked in an urban slum in northeastern Brazil. Samples of buccal epithelial cells from subjects in each of these groups were incubated with wild-type E. coli K-12 (strain C600), the enteroaggregative E. coli strains 17-2 and PDAS 30-5, CFA/II-positive E. coli 1392+ and its plasmid-cured derivative 1392-, and hydrophobic E. coli 132-3. Samples were evaluated microscopically to determine background contamination and the percentage of cells with more than 15% of their surface area obscured by adherent bacteria after incubation and washing. The assay was tested under field conditions and was shown to produce reliable and consistent results. Both enteroaggregative strains of E. coli were shown to adhere to a significantly higher percentage of all groups of human buccal epithelial cells than any of the other tested strains. In addition, buccal epithelial cells from children with nonparasitic persistent diarrhea showed substantially more bacterial adherence in both the native state and with all tested strains of E. coli than did cells from children with persistent cryptosporidial diarrhea or acute diarrhea or from healthy controls. This study provides evidence that enteroaggregative strains of E. coli demonstrate increased adherence to human buccal epithelial cells (as well as to cultured HEp-2 cells) and that buccal epithelial cells from children with noncryptosporidial persistent diarrhea appear to be more susceptible to bacterial adherence and colonization than buccal epithelial cells from control groups. These findings suggest that host differences as well as pathogen differences are important in the pathogenesis of persistent diarrhea and have implications for a potential role for buccal epithelial cell analysis in the diagnosis or risk stratification of children susceptible to noncryptosporidial persistent diarrhea.
Novel adjuvant action of lipopolysaccharides that possess mannose homopolysaccharides as O-specific polysaccharides on immune responses to nonimmunogenic autoantigens in mice
Authors: Yokochi T , Fukada M , Kawai M , Zhang Y H , Jiang G Z , Takahashi K
Published: January 2020

The adjuvant action of various lipopolysaccharides on immune responses to syngeneic tissue extract in mice was examined. Only lipopolysaccharides possessing the linear mannose homopolysaccharides as O-specific polysaccharides exhibited definite adjuvant action on immune responses to the autoantigens. The intensity of this adjuvant activity of lipopolysaccharide from Klebsiella O3 seemed to be the strongest.
Protection against Vibrio cholerae El Tor infection by specific antibodies against mannose-binding hemagglutinin pili
Authors: Osek J , Svennerholm A M , Holmgren J
Published: January 2020

Both specific polyclonal antiserum and monoclonal antibodies against mannose-binding hemagglutinin fimbriae of Vibrio cholerae (mannose-sensitive hemagglutinin [MSHA]) were shown to protect against experimental cholera caused by vibrios of the El Tor biotype in the infant mouse and in the rabbit intestinal loop models. MSHA-specific Fab immunoglobulin fragments were also protective. No protective effect was observed against challenge with V. cholerae O1 of the classical biotype. These results suggest that MSHA pili play an important role in the pathogenesis of cholera caused by the El Tor biotype of V. cholerae and that induction of intestinal anti-MSHA immunity may be a worthwhile additional objective in the development of oral cholera vaccines.
Immunogenicity of conjugate vaccines consisting of pneumococcal capsular polysaccharide types 6B, 14, 19F, and 23F and a meningococcal outer membrane protein complex
Authors: Vella P P , Marburg S , Staub J M , Kniskern P J , Miller W , Hagopian A , Ip C , Tolman R L , Rusk C M , Chupak L S
Published: January 2020

In an effort to prepare pneumococcal (Pn) capsular polysaccharide (Ps) vaccines that would be immunogenic in infants, covalent conjugates were prepared for Pn types 6B, 14, 19F, and 23F. Each Ps type was covalently bound to an outer membrane protein complex from Neisseria meningitidis serogroup B and evaluated for immunogenicity in mice and infant monkeys. The conjugates induced specific anti-Ps antibody responses in mice and in infant rhesus and African green monkeys; a conjugate of 6B and outer membrane protein complex was immunogenic at Ps doses as low as 20 ng. Although low levels of the Pn group-common cell wall polysaccharide were present in all type-specific Ps preparations, anti-cell wall polysaccharide responses induced by covalent conjugates were < 1% of the total anti-Ps response after two doses of vaccine. In contrast, the anti-cell wall polysaccharide response of a noncovalent conjugate represented 41% of the anti-Ps response after two doses. Relative T-cell dependence, a requirement for the human target population of infants less than 18 months old, was demonstrated for all four Pn Ps conjugates in an athymic mouse model. Therefore, these Pn Ps-outer membrane protein complex conjugate vaccines are excellent candidates for evaluation in human infants.
Lack of vessel wall elastolysis in human invasive pulmonary aspergillosis
Authors: Denning D W , Ward P N , Fenelon L E , Benbow E W
Published: January 2020

In experimental studies, the apparent ability of Aspergillus fumigatus isolates to produce elastase in agar plates correlates with their ability to cause invasive pulmonary aspergillosis in mice pretreated with cortisone. Thus, elastase production may govern the pathogenicity of particular isolates. If this is so, then disruption of the elastic layers within blood vessel walls in invasive aspergillosis would be expected. To test this hypothesis, tissue blocks were prepared from nine patients with invasive pulmonary aspergillosis. Separate but immediately adjacent histological sections were stained by the Grocott and periodic acid-Schiff methods for fungal hyphae and by the elastic van Gieson technique for elastic tissue. Comparison of those segments of vessel walls infiltrated by hyphae with those not infiltrated by hyphae showed no overall loss of elastic tissue. Material from five of the cases was also stained with an unconventional combination of histochemical stains, allowing accurate identification of both fungal hyphae and elastic laminae in the same histological sections. The results showed no more disruption of elastic laminae than would be expected from simple physical displacement of elastic laminae. We conclude that if elastolysis contributes at all to invasion of vessel walls by aspergilli, then it seems to be very localized and/or transient.
Characterization of an 18,000-molecular-weight outer membrane protein of Haemophilus ducreyi that contains a conserved surface-exposed epitope
Authors: Spinola S M , Griffiths G E , Bogdan J , Menegus M A
Published: January 2020

Identification of antigenically conserved surface components of Haemophilus ducreyi may facilitate the development of reagents to diagnose and prevent chancroid. A hybridoma derived from a mouse immunized with nontypeable Haemophilus influenzae produced a monoclonal antibody (MAb), designated 3B9, that bound to 35 of 35 H. ducreyi strains isolated from diverse geographic regions. The MAb 3B9 bound to a non-heat-modifiable H. ducreyi outer membrane protein (OMP) whose apparent molecular weight was 18,000 (the 18K OMP), and the 3B9 epitope did not phase vary at a rate of greater than 10(-3) in H. ducreyi. In immunoelectron microscopy, the 3B9 epitope was surface exposed, and there was intrastrain and interstrain variability in the amount of 3B9 labelling of whole cells. The MAb 3B9 cross-reacted with many species of the family Pasteurellaceae and bound to the 16.6K peptidoglycan-associated lipoprotein (P6 or PAL) of H. influenzae. Unlike P6, the 18K OMP did not copurify with peptidoglycan. In Western blots (immunoblots), five of seven serum samples obtained from patients with chancroid and four of five serum samples obtained from patients with other genital ulcer diseases at the time of presentation contained antibodies that bound to the 18K OMP. In a competition enzyme-linked immunosorbent assay, four of these serum samples inhibited the binding of 3B9 to H. ducreyi by more than 50%. We conclude that members of Pasteurellaceae expressed a conserved epitope on OMPs that sometimes had different physical characteristics. Patients with chancroid usually have antibodies to the 18K OMP and the 3B9 epitope that may have resulted from infection with H. ducreyi or previous exposure to other Haemophilus or Actinobacillus sp. strains.
Genetic association of mating types and virulence in Cryptococcus neoformans
Authors: Kwon-Chung K J , Edman J C , Wickes B L
Published: January 2020

A pair of congenic Cryptococcus neoformans var. neoformans strains, B-4476 (a mating type) and B-4500 (alpha mating type), that presumably differ only in mating type was constructed. This pair and their progeny, five alpha type and five a type, were tested for virulence in mice. In the parent strains as well as the progeny, alpha type was clearly more virulent than a type. In addition, death tended to occur earlier among the alpha-strain-infected mice that died than among the mice that died by infection caused by a strains. These data strongly suggest the genetic association of virulence with mating type in this human fungal pathogen.
Comparison of the cytolysin II genetic determinants of Actinobacillus pleuropneumoniae serotypes
Authors: Jansen R , Briaire J , Kamp E M , Smits M A
Published: January 2020

Cytolysins (Cly) I, II, and III are toxins secreted by Actinobacillus pleuropneumoniae. These toxins are thought to play an important role in the pathogenesis of porcine pleuropneumonia. ClyI and ClyII are RTX toxins and in general these toxins are encoded by operons consisting of four genes, C, A, B, and D. Our group recently cloned the C and A genes of the ClyII operon (clyIICA) of serotype 9. We found that this ClyII operon is truncated and lacked intact B and D genes (clyIIBD). B and D genes of the ClyI operon (clyIBD) were present however in serotype 9. In this study we analyzed the ClyII operons of the reference strains of the 12 A. pleuropneumoniae serotypes and compared them with the ClyII operon of serotype 9. We focused on (i) the presence, (ii) the sequence similarity, and (iii) the genomic environment of the clyIICA genes. The presence of the clyIICA sequences was studied by hybridization analysis of genomic DNA. The sequence similarity was studied by restriction fragment analysis on polymerase chain reaction-amplified DNA. The genomic environment was compared by analysis of the sequences that are located 3' of the clyIICA genes. We demonstrated that the clyIICA genes (i) are present in the reference strains of all serotypes, except serotype 10, (ii) have a high degree of sequence similarity, and (iii) are not contiguous with intact clyIIBD genes. We conclude that the organization and nucleotide sequence of the ClyII operons of A. pleuropneumoniae are very similar. We also studied the presence of clyIBD sequences and found them to be present in the reference strains of all serotypes, except serotypes 3 and 6. Thus, in most serotypes the clyIBD genes may complement the absent clyIIBD genes.
Mycoplasma pulmonis possesses a novel chemoattractant for B lymphocytes
Authors: Ross S E , Simecka J W , Gambill G P , Davis J K , Cassell G H
Published: January 2020

Mycoplasma pulmonis causes chronic murine respiratory mycoplasmosis, which is characterized by extensive peribronchial and perivascular infiltration of mononuclear cells, including B lymphocytes. B-lymphocyte recruitment into sites of inflammation is presently poorly understood but must involve directed chemotaxis of these cells in response to some external recruitment stimulus. In these studies, picogram amounts of M. pulmonis membrane protein were found to possess potent chemoattractant activity for resting rat B lymphocytes. This report is the first description of a bacterially derived chemoattractant for B lymphocytes and offers a unique opportunity to study regulation of B-lymphocyte recruitment to a site of chronic pulmonary inflammation. Furthermore, M. pulmonis membrane activation of fresh rat serum was found to produce a potent stimulus for recruitment of peritoneal and alveolar macrophages. M. pulmonis-mediated recruitment of lymphocytes and macrophages may play a significant role in the pathogenesis of murine respiratory mycoplasmosis, a role in which organisms on the bronchiolar epithelial surfaces may release proteins which can directly or indirectly promote chemotaxis of inflammatory cells from the circulation.
Conservation of an Actinomyces viscosus T14V type 1 fimbrial subunit homolog among divergent groups of Actinomyces spp
Authors: Yeung M K
Published: January 2020

The type 1 fimbrial subunit gene of the human Actinomyces viscosus T14V was used as a DNA probe in Southern analyses to detect related DNA sequences in 16 of 30 strains of Actinomyces spp. under conditions of high stringency. The organisms with homology to the DNA probe included two human and six nonhuman A. viscosus, three human and three nonhuman A. naeslundii, and two A. bovis isolates. Homologous DNA sequences were not detected in strains of A. odontolyticus and A. israelii examined in this study. Northern (RNA) blot analysis revealed expression of a transcript from each of the A. viscosus and A. naeslundii strains and from one A. bovis strain that was comparable in size to that detected from A. viscosus T14V. Cell surface fimbriae were observed on a majority of the strains that expressed the transcript. Various degrees of cross-immunoreactivities between these strains and antibodies specific for type 1 fimbriae of A. viscosus T14V were also observed by colony immunoassay. Thus, the data clearly demonstrate the existence in, and expression by, divergent Actinomyces groups of genomic sequences that are closely related to the type 1 fimbriae of A. viscosus T14V.
Chlamydia trachomatis serovar differentiation by direct sequence analysis of the variable segment 4 region of the major outer membrane protein gene
Authors: Poole E , Lamont I
Published: January 2020

The polymerase chain reaction method was used to amplify DNA from the fourth variable segment of the gene encoding the major outer membrane protein of Chlamydia trachomatis. Direct sequencing of the amplified DNA from prototype strains confirmed previously identified nucleotide sequence differences that were specific for each serovar. This analysis revealed differences in the DNA sequences of prototype strains C/UW-1 and G/IOL-238 from those of prototype strains C/TW-3 and G/UW-57, sequenced previously. This method was also used to determine the serovar types of C. trachomatis in 125 urogenital specimens from infected patients. The most common serovars were E (38%), F (17%), and G and D (14% each). Serovar D was found significantly more often in specimens from men than in specimens from women (P = 0.004). Conversely, serovar G was found significantly more often in specimens from women than in specimens from men (P = 0.026). Only two serovar G isolates gave sequences identical to that of the prototype strain G/IOL-238, suggesting that this strain may be a serovar variant. Three isolates (D+, G-, and J') gave sequences which have not been reported previously. One isolate had the same sequence as the D- serovar variant. Sequence analysis of amplified DNA reveals subtle differences between C. trachomatis strains and provides a very sensitive method for molecular epidemiological analysis.
Nucleotide sequence and transcriptional regulation of a positive regulatory gene of Shigella dysenteriae
Authors: Yao R , Palchaudhuri S
Published: January 2020

A 1,937 bp PstI-HindIII fragment containing the ipaR locus was cloned from the large invasion plasmid of Shigella dysenteriae CG097, and its nucleotide sequence was completely determined. The IpaR protein (35 kDa, calculated from the DNA sequence) was synthesized in Escherichia coli chi 1411 minicells containing the 1,937-bp PstI-HindIII fragment. To determine the regulatory role of ipaR for ipa genes, we applied genetic complementation experiments using chloramphenicol acetyltransferase (CAT) as reporter. Analyses of CAT activity of the recombinant plasmids containing the 5' flanking sequences of the 24-kDa-protein gene and the ippI, ipaB, ipaC, and ipaD genes defined strong promoters upstream of the 24-kDa-protein gene and ipaD gene, weak promoters upstream of the ippI and ipaB genes, and the absence of any promoter activity for the ipaC gene. Complementation analyses showed that the CAT activity only under direction of the ippI promoter region increased 1.8-fold in the presence of IpaR protein. On the basis of our data, we suggest that an operon comprising ippI, ipaB, and ipaC is positively regulated by IpaR protein which has a trans effect on a DNA sequence upstream of the ippI promoter.