bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation of enterochelin from the peritoneal washings of guinea pigs lethally infected with Escherichia coli
Authors: Griffiths E , Humphreys J
Published: January 2020

Escherichia coli secretes enterochelin while infecting normal guinea pigs. Since production of enterochelin is a well-characterized response to an iron-restricted environment, this work establishes that host iron-binding proteins do indeed influence the metabolism of the invading organism.
Hepatitis A virus in the liver and intestine of marmosets after oral inoculation
Authors: Mathiesen L R , Møller A M , Purcell R H , London W T , Feinstone S M
Published: January 2020

A total of 12 seronegative marmosets (Saguinus mystax) were inoculated orally with hepatitis A virus (HAV) and sacrificed at 3- to 4-day intervals. Tissues from the livers, intestines, mesenteric lymph nodes, and spleens were obtained for immunofluorescence studies, and bile and intestinal contents were obtained for enzyme-linked immunosorbent assay studies. Two marmosets sacrificed on days 34 and 41 after inoculation developed antibody to HAV and demonstrated HAV in their livers but not in any part of their intestinal tissues. None of the remaining marmosets sacrificed from days -3 to 31 survived long enough to develop antibody to HAV, but an additional two marmosets, which were sacrificed on days 21 and 31, demonstrated HAV in their livers and also in bile but not in the intestinal tissues or their contents. The mesenteric lymph nodes and spleens were negative for HAV by immunofluorescence in all the marmosets. No evidence of HAV replication was demonstrated in any part of the intestine at any time during the incubation period or during acute illness in the marmosets inoculated orally with HAV. The shedding of HAV in stools in the late incubation period can be explained by excretion of HAV from the livers with the bile.
Inhibitory effect of Pseudomonas aeruginosa on phagocytosis and killing of rabbit polymorphonuclear leukocytes
Authors: Kamimura T , Mine Y , Nonoyama S , Nishida M , Goto S , Kuwahara S
Published: January 2020

Polymorphonuclear leukocyte (PMN)-resistant strains of Pseudomonas aeruginosa had the ability to interfere with phagocytosis of Escherichia coli, whereas PMN-sensitive strains of P. aeruginosa did not. When mice were infected with an ordinarily nonpathogenic strain of E. coli, addition of a PMN-resistant strain of P. aeruginosa gave a mortality considerably higher than that obtained with P. aeruginosa alone, whereas addition of a PMN-sensitive strain of P. aeruginosa gave a mortality not different from that observed with P. aeruginosa alone. This increased mortality in mixed infection with E. coli and PMN-resistant P. aeruginosa was obtained by facilitation of tissue invasion by both bacteria from the inoculum site.
Characterization of Pneumococcal Purpura-Producing Principle
Authors: Chetty Chamroen , Kreger Arnold
Published: January 2020

Purpura was grossly observable in albino mice 6 to 8 h after the intraperitoneal injection of sterile, deoxyribonuclease-treated, cell-free extracts prepared by sodium deoxycholate-induced lysis, sonic disruption, Parr bomb treatment, autolysis without sodium deoxycholate, or alternate freezing and thawing of washed suspensions of
Streptococcus pneumoniae
type I. Cell-free extracts obtained from sonically disrupted, heat-killed cells (100°C for 20 min) did not contain purpurogenic activity. The reaction was maximal at approximately 24 h postinjection, started to fade slowly after 24 to 48 h, and usually was not grossly observable by 4 to 6 days postinjection. The purpura-producing principle (PPP) in the cell-free extract was purified by sequential ammonium sulfate precipitation, protamine sulfate precipitation, Sepharose 6B gel filtration, wheat germ lectin-Sepharose 6MB affinity chromatography, ribonuclease and trypsin treatment, and a second Sepharose 6B gel filtration step. The final preparation (i) contained glucosamine (5.6%), muramic acid (8.0%), neutral carbohydrate (12.8%), phosphate (8.0%), orcinol-reactive material (6.0%), and Lowry-reactive material (1.6%), and (ii) was free of detectable amounts of deoxyribonucleic acid, capsular polysaccharide, neuraminidase, cytolysin, and hyaluronidase. The isoelectric point and molecular size of the PPP were approximately pI 3.0 and several million daltons, respectively, and the activity remained in the supernatant fluid after centrifugation for 1 day at 105,000 ×
g.
PPP activity was destroyed by incubation with egg white lysozyme and sodium metaperiodate but was resistant to trypsin, pronase, α-amylase, deoxyribonuclease, ribonuclease, alkaline phosphatase, pancreatic lipase, 7% trichloroacetic acid, 6 M urea, autoclaving (121°C) for 30 min, and mild acid and alkali exposure. Our observations indicate that the PPP requires intact β-1,4-glucosidic linkages for activity and support the working hypothesis that activity is associated with pneumococcal peptidoglycan solubilized by the bacterium's autolysin.
Lectin Activity in
Entamoeba histolytica
trophozoites
Authors: Kobiler David , Mirelman David
Published: January 2020

A lectin (carbohydrate-binding protein) has been found in extracts of a number of axenically grown trophozoites of
Entamoeba histolytica
strains. The strains grown in TYI-S-33 medium (Diamond et al., Trans. R. Soc. Trop. Med. Hyg.
72:
431-432, 1978) were HK-9, 200:NIH, and HM-1:IMSS. Strain HU-1:MUSC (HSC) was grown monoxenically in the same medium. The amoebic lectin agglutinated glutaraldehyde-fixed erythrocytes. This activity was pH dependent and heat and oxidation sensitive, and was destroyed by proteolysis upon autoincubation. The relative agglutinating potency of the different strains of amoebae was investigated. Strain HSC had the highest specific activity (210 U/mg of protein), and strain HM-1 had the lowest (14 U/mg). One unit of hemagglutinating activity is defined as the amount of lectin present in 1 ml of extract which will agglutinate 1 ml of 4% erythrocytes. Upon subcellular fractionation of the lectin present in extracts of strain HK-9, two-thirds of the activity was detected in the soluble, nonsedimentable (100,000 ×
g
, 60 min) fraction. Partial hydrolysate of chitin was found to inhibit the hemagglutinating activity. Among the oligosaccharides of
N
-acetylglucosamine, the trimer and tetramer were the most potent inhibitors. The lectin was purified approximately 300-fold by a one-step affinity chromatography on a chitin column. The loading and elution from the column were based on the pH dependence of the lectin activity.
Interaction of Nocardia asteroides with rabbit alveolar macrophages: effect of growth phase and viability on phagosome-lysosome fusion
Authors: Davis-Scibienski C , Beaman B L
Published: January 2020

Rabbit alveolar macrophages were infected in vitro with cells of Nocardia asteroides GUH-2 in either logarithmic or early or late stationary phases of growth. Previous studies have established that during the growth cycle dramatic changes occur both in cell wall composition and structure and in the virulence of this organism. This study establishes the correlation between the relative virulence of the phase of growth of the infecting organisms and the degree of inhibition of macrophage phagosome-lysosome fusion. The occurrence of phagosome-lysosome fusion in infected macrophages was determined by both fluorescent and electron microscopy. It was found that relatively few phagosomes containing the highly virulent log-phase organisms had any evidence of lysosomal fusion; more of the phagosomes containing early stationary-phase cells had evidence of fusion. The greatest amount of phagosome-lysosome fusion was observed with the least virulent late stationary-phase cells. Electron microscopic evaluation of infected macrophages indicated that this increase in fusion was not associated with an increase in cell damage. Comparison of macrophages infected with either viable or nonviable organisms indicated that loss of viability did not decrease inhibition of fusion by early or late stationary-phase cells. In contrast, loss of viability did decrease inhibition of fusion by log-phase cells.
Inhibition of protein synthesis in intact HeLa cells by Shigella dysenteriae 1 toxin
Authors: Brown J E , Rothman S W , Doctor B P
Published: January 2020

Shiga toxin purified to near homogeneity from cell lysates of Shigella dysenteriae 1 inhibited protein and deoxyribonucle acid syntheses in intact HeLa cells. Inhibition was dependent on toxin concentration and time of incubation. A minimal latent period of 30 min was observed with saturating doses of toxin. Ribonucleic acid synthesis, uptake of alpha-aminoisobutyric acid, and maintenance of intracellular K+ concentrations were not affected until well after maximal inhibition of protein and deoxyribonucleic acid syntheses. The inhibitory effect of toxin was sensitive to heat inactivation and was prevented by antibody neutralization. Several cytotoxic components were separated by polyacrylamide gel electrophoresis of the purified toxin preparations; all inhibited protein and deoxyribonucleic acid syntheses equally.
Rabbit tumor necrosis factor: mechanism of action
Authors: Ruff M R , Gifford G E
Published: January 2020

Rabbit tumor necrosis factor (TNF) was examined for effects on normal and transformed cells in culture. Several assays for killing of L-929 cell targets were developed, and their sensitivities were compared. Normal cells were not killed by TNF, and the discrimination between normal and transformed cells was shown not to be due to a cell cycle-dependent mechanism. TNF killing of L-929 cells was delayed for 10 to 12 h and thereafter showed concentration and time-dependent increases in cytolysis. Actinomycin D or cycloheximide treatment of L-929 cells resulted in an enhancement of the rate of cell killing as well as a shortening of the preceding lag period. TNF killing of L-929 cells was temperature dependent; cells were considerably more resistant to lysis at 25 degrees C and showed enhanced killing at 39 degrees C as compared to 37 degrees C controls. The slope of the dose curve showed less than single-hit kinetics. A model for cell killing whose general features incorporate both the specificity and catalytic properties of an enzymatic reaction is proposed for TNF action.
In vivo evidence that an intact lytic complement pathway is not essential for successful removal of circulating Borrelia turicatae from mouse blood
Authors: Newman K , Johnson R C
Published: January 2020

Complement component C5-deficient mice were found to be able to eliminate blood-borne Borrelia turicatae as effectively as normocomplementemic control animals. The absence of C5 and the resultant loss of hemolytic complement activity were confirmed for the deficient mouse strains used. Immunofluorescent staining of complement component C3 on blood-derived borreliae could be readily accomplished as early as 2 days before spirochetal elimination from all mice tested. These observations would suggest that C3 deposition was occurring, even though the terminal lytic steps were blocked in the complement-deficient mice. We propose that spirochetolysis is not requisite for successful removal of borreliae from the circulation of mice.
Effect of Human Saliva on Glucose Uptake by
Streptococcus mutans
and Other Oral Microorganisms
Authors: Germaine Greg R. , Tellefson Lois M.
Published: January 2020

We examined the effects of human whole salivary supernatant and parotid fluid on glucose uptake by
Streptococcus mutans, Streptococcus sanguis, Streptococcus mitis, Actinomyces viscosus, Staphylococcus aureus
, and
Escherichia coli.
The following three effects of saliva were observed: (i) inhibition of glucose uptake (
S. mutans, S. sanguis
), (ii) promotion of a transient, rapid (0 to 30 s) burst of glucose uptake (
S. mutans, S. sanguis
), and (iii) enhancement of glucose uptake (
S. mitis, A. viscosus, S. aureus, E. coli
). We observed no differences between the effects of whole salivary supernatant and the effects of parotid fluid. Heat treatment (80°C, 10 min) of saliva or the addition of dithiothreitol abolished inhibition of glucose uptake. Supplementation of saliva with H
2
O
2
potentiated inhibition of glucose uptake.
S. mitis
and
A. viscosus
, which were stimulated by saliva alone, were inhibited by H
2
O
2
-supplemented saliva; 50% inhibition of glucose uptake by
S. mutans
and
S. mitis
required ca. 10 μM H
2
O
2
in 50% (vol/vol) saliva. Loss of the inhibitory action of saliva occurred at about 5% (vol/vol) saliva. Supplementation of saliva dilutions with SCN
−
and H
2
O
2
extended the inhibitory activity to solutions containing ca. 0.2% (vol/vol) saliva. We suggest that the salivary lactoperoxidase-SCN
−
-H
2
O
2
system is responsible for the inhibitory activity of saliva reported here. Furthermore, we concluded that lactoperoxidase and SCN
−
are present in saliva specimens in concentrations that exceed minimal inhibitory levels by factors of ca. 500 and 10 to 20, respectively. The resistance of
A. viscosus, S. aureus
, and
E. coli
to the inhibitory potential of saliva alone was probably due to the production of catalase by these organisms. The resistance of
S. mitis
may have been due to special effects of saliva on H
2
O
2
accumulation by this organism compared with
S. mutans
and
S. sanguis.
The basis of saliva-dependent enhancement of glucose uptake and the basis of promotion of a transient, rapid burst of glucose uptake are unknown. The role of the salivary lactoperoxidase-SCN
−
-H
2
O
2
system in the oral microbial ecosystem is discussed.
Mitomycin C-treated Trypanosoma cruzi in vaccination of mice: induction of immunosuppression but not protection
Authors: Tarleton R L , Kuhn R E , Cunningham D S
Published: January 2020

Attempts to immunize susceptible hosts against infection with Trypanosoma cruzi have generally not met with a high degree of success. In the present study, we used the antimetabolite mitomycin C to produce nonreplicating, attenuated culture forms of T. cruzi. Attempts to immunize highly susceptible C3H(He) mice with single or multiple inoculi of mitomycin C-treated trypanosomes 2 weeks before injection of infective blood-form trypomastigotes did not, however, lead to greater longevity in immunized mice over nonimmunized, control mice. It was determined that a single injection of 10(7) attenuated parasites induced a transient suppression of the immune response to sheep erythrocytes which was maximum on day 7, less on day 14, and undetectable by the 21st day after immunization. This immunosuppression to a heterologous antigen did not, however, appear to be the cause of the failure of the vaccination procedure to elicit protective immunity since mice immunized once with 10(7) mitomycin C-treated trypanosomes and challenged 30, 60, or 90 days later exhibited no greater longevity than control mice.
Loss of lectin-like activity in aberrant type 1 fimbriae of Escherichia coli
Authors: Eisenstein B I , Ofek I , Beachey E H
Published: January 2020

Growth of a streptomycin-resistant strain of Escherichia coli (VL-2) in the presence of 30 microgram of streptomycin per ml resulted in the production by these bacteria of structurally altered, nonfunctional type 1 fimbriae. This strain, when grown in this subinhibitory concentration of streptomycin, became incapable of producing mannose-sensitive hemagglutination (<1% of that of the control). Adhering ability to epithelial cells and human leukocytes was also diminished (42 and 7% of that of the control, respectively). Although these streptomycin-treated bacteria were as heavily fimbriated as untreated bacteria, their fimbriae were significantly longer. Furthermore, in contrast to the fimbriae of the untreated bacteria, those isolated from the drug-treated bacteria were found to lack mannose binding activity as measured by hemagglutination. It appears, therefore, that streptomycin can cause even resistant bacteria to produce an aberrant fimbrial protein, possibly by causing misreading of messenger RNA. These studies indicate that the use of sublethal doses of certain antibiotics whose mode of action is well known may shed light on the genetic and chemical modulation of bacterial factors involved in mucosal colonization.
Effect of bile acid derivatives on taurine biosynthesis and extracellular slime production in encapsulated Staphylococcus aureus S-7
Authors: Ohtomo T , Yoshida K , San Clemente C L
Published: January 2020

Various bile acids were added to cultures of encapsulated strains of Staphylococcus aureus growing in serum-soft agar medium of brain heart infusion broth. We examined effects of these compounds on cellular characteristics such as growth type, cell volume index, clumping factor reaction, slime yield, taurine content, and L-(--)-cysteic acid decarboxylase activity. Upon addition to the medium of either taurochenodeoxycholic acid, taurocholic acid (25 to 50 microgram/ml), or cholic acid (10 to 25 microgram/ml), the colonial morphology of taurine-positive cells (strain S-7) was altered from the diffuse to the compact type in serum-soft agar. Also, the titer of the clumping factor reaction increased, while the cell volume index and slime yield were markedly decreased. Tauro-bile acids, including taurocholic acid, taurochenodeoxycholic acid, taurodehydrocholic acid, and taurodeoxycholic acid (50 microgram/ml) inhibited the synthesis of taurine and resulted in decreased L-(--)-cysteic acid decarboxylase activity. Among all of the derivatives cholic acid itself was found to inhibit slime production and L-(--)-cysteic acid decarboxylase activity to the greatest extent. Glyco-bile acid derivatives and taurolicholic acid (50 to 100 microgram/ml) had no effect on L-(--)-cysteic acid decarboxylase activity. Compounds such as glycodeoxycholic acid (50 to 100 microgram/ml) had no effect upon any of the cellular characteristics tested. No effect was observed upon addition of any of these compounds to cultures of the taurine-negative strain (T-26-B). We did find a correlation between the inhibition of taurine biosynthesis and decreased slime production. Electron micrographs indicated that this encapsulated strain was converted to an unencapsulated state in the presence of bile acids.
Ultrastructural localization and protective activity of a high-molecular-weight antigen isolated from Legionella pneumophila
Authors: Elliott J A , Johnson W , Helms C M
Published: January 2020

Immunoperoxidase labeling showed that the F-1 antigen of Legionella pneumophila is located on the bacterial cell surface. Protection against lethal intraperitoneal challenge with serogroup 1 L. pneumophila was induced in guinea pigs by heat-killed cells and F-1 antigen from serogroup 1, but not by heat-killed cells or F-1 antigens from serogroup 2, 3, or 4.
Serological diagnosis in children infected prenatally with lymphocytic choriomeningitis virus
Authors: Sheinbergas M M , Lewis V J , Thacker W L , Verikiene V V
Published: January 2020

Lymphocytic choriomeningitis virus antibody was detected by immunofluorescence in sera collected 2 to 8 years after birth from six children probably infected prenatally. A neutralization test failed to detect antibodies in two of these children.
Host defenses in experimental scrub typhus: inflammatory response of congenic C3H mice differing at the Ric gene
Authors: Jerrells T R , Osterman J V
Published: January 2020

Two strains of C3H mice differed in their susceptibility to lethal infection with Rickettsia tsutsugamushi strain Gilliam. Adult C3H/RV mice were markedly more resistant to lethal infection than C3H/HeDub mice, and both were histocompatible as assessed by mixed-lymphocyte cultures and graft-versus-host responses. The inflammatory response of susceptible C3H/HeDub mice to intraperitoneal infection was evident approximately 5 days postinfection, and the magnitude of the cellular influx increased until death of the animal. The inflammation consisted of an early polymorphonuclear leukocyte response, followed by a mononuclear cell influx which persisted until death of the animal. The C3H/RV mice evidenced similar kinetics of cell influx, but the inflammatory response was significantly reduced in magnitude, and the response of C3H/RV animals to Gilliam was predominantly mononuclear in nature, with little influx of polymorphonuclear leukocytes into the peritoneal cavity. C3H/RV mice were rendered susceptible to Gilliam infection by induction of a nonspecific inflammation with thioglycolate if given 3 days after infection. Conversely, treatment of C3H/HeDub mice with indomethacin, an anti-inflammatory agent, prolonged survival after infection with Gilliam. The results of this study indicate that genetic resistance to Gilliam is not due simply to a greater host response to infection or, conversely, that susceptibility is due to a host response quantitatively lacking in a cellular component necessary for antirickettsial immunity.
Distribution of glucose incorporated into macromolecular material by treponema pallidum
Authors: Barbieri J T , Austin F E , Cox C D
Published: January 2020

Treponema pallidum was observed to incorporate glucose carbons into lipids, ribonucleic acid, deoxyribonucleic acid, and protein. Only the glycerol portions of phosphatidylcholine and phosphatidylglycerol contained glucose-derived carbons. Incorporation of exogenous choline into phosphatidylcholine was detected. Glucose was incorporated into only the pentoses of nucleic acids. About 50% of the glucose incorporated into protein was present in only one amino acid, aspartate. Evidence suggests that aspartate synthesis could follow the conversion of phosphoenolpyruvate to oxalacetic acid by a guanosine 5'-diphosphate-dependent phosphoenolpyruvate carboxykinase.
Natural killer cell activity in chickens: target cell analysis and effect of antithymocyte serum on effector cells
Authors: Sharma J M , Okazaki W
Published: January 2020

A battery of lymphoid and nonlymphoid cells was examined for susceptibility to lysis by natural killer cells of chickens. Several susceptible targets were recognized, and most susceptible among these were cells of line LSCC-RP9, derived from a lymphoid tumor induced by Rous-associated virus 2. The natural killer reactivity against LSCC-RP9 target cells did not appear to be directed against an antigen(s) induced by Rous-associated virus 2 because other lymphoid and nonlymphoid cells infected with this were resistant to lysis in vitro by natural killer cells. The effector cells of natural killer reactivity in chickens were refractory to treatment with potent anti-T-cell and anti-B-cell sera. Inoculation of Marek's disease virus in line 15 X 7 chickens resulted in enhanced natural killer cell activity, and the effector cells of this enhanced activity, and the effector cells of this enhanced activity were also resistant to anti-T-cell serum.
Effect of mouse phagocytes on Candida albicans in in vivo chambers
Authors: Cutler J E , Poor A H
Published: January 2020

Mouse phagocytic cells in in vivo diffusion chambers had either candidacidal or candidastatic activity depending on the kind of phagocyte studied, the type of mouse whence the phagocytes came, and whether the chamber inoculum of Candida albicans consisted primarily of yeasts or hyphae. Killing of C. albicans occurred when yeasts were placed into chambers with membranes with 3.0-micrometer pores and implanted intraperitoneally into normal mice or thymus-deficient (nude) mice. Although C. albicans remains in chambers with 3.0-micrometer pores, host phagocytic cells can migrate into the chambers. Killing also occurred when yeasts were combined with normal or nude mouse neutrophils in chambers made with membranes with 0.45-micrometer pores, which restrict migration of host cells, but not diffusion of soluble factors. Populations of cells rich in macrophages were candidastatic for yeasts when the phagocytes came from normal mice but candidacidal when obtained from nude mice. Results of gradient fractionations of peritoneal exudates indicated that more than one cell type may be responsible for candidacidal activity by nude mouse macrophage-rich cells. Hyphal-phase cells of C. albicans appear to be more resistant than yeast-phase cells to killing by normal and nude mouse phagocytic cells.
Isolation of plasmids in Legionella pneumophila and Legionella-like organisms
Authors: Mikesell P , Ezzell J W , Knudson G B
Published: January 2020

Agarose gel electrophoresis was employed to screen nine strains of Legionella-like bacteria and one strain of Legionella pneumophila for the presence of extrachromosomal deoxyribonucleic acid. Cryptic plasmids with molecular weights ranging from 46.6 x 10(6) to 59.8 x 10(6) were found in three of the isolates examined.
Development of immunity to porcine rotavirus in piglets protected from disease by bovine colostrum
Authors: Bridger J C , Brown J F
Published: January 2020

Bovine colostrum with rotavirus-neutralizing activity was fed for 10 days to two groups of piglets, one of which was inoculated intranasally with a rotavirus of porcine origin. A third group, which did not receive colostrum, was also inoculated with the virus, and these piglets developed diarrhea, excreted rotavirus in the feces, and died 6 days after infection. In contrast, the infected piglets fed with bovine colostrum remained healthy, although they developed antibody to rotavirus. Twenty-seven days after the primary inoculation, piglets in the colostrum-fed groups were inoculated intranasally with virus. Those in the previously unexposed group became clinically ill and excreted rotavirus, whereas those which had experienced a previous subclinical infection (the colostrum-fed, virus-inoculated group) remained healthy. It was concluded that bovine colostrum protected piglets from the clinical effects of a porcine rotavirus and that these animals developed an immunity which prevented subsequent disease.
Specific and nonspecific immune factors in dental plaque fluid and saliva from young and old populations
Authors: Cole M F , Hsu S D , Baum B J , Bowen W H , Sierra L I , Aquirre M , Gillespie G
Published: January 2020

Separate samples of supragingival dental plaque overtly free of blood were centrifuged to obtain the free fluid phase (plaque fluid). Bound protein was eluted from the plaque bacteria and matrix by washing the plaque with a low-pH buffer. The plaque fluid, low pH eluate, and whole saliva were assayed for immunoglobulins A, G, and M, the third component of complement, lysozyme, lactoferrin, and lactoperoxidase. Concentrations of total protein and albumin were also determined. Antibody reactive with specific plaque bacteria was detected by indirect immunofluorescent microscopy. Specific and nonspecific immune proteins were present in plaque fluid from adult subjects at significantly greater concentrations than in their saliva, which suggests that these proteins are concentrated in dental plaque. The results indicate that both saliva and gingival exudate contribute to the immunological proteins found in the free fluid phase of dental plaque. The observation that immunoglobulin A antibody reactive with plaque bacteria could be detected in plaque fluid suggests that a wide variety of immunological reactions may occur in the dental plaque. These potential interactions between host, plaque bacteria, and their products could serve to influence the plaque flora and its ability to induce disease.
Gonococcal infection in endotoxin-resistant and endotoxin-susceptible mice
Authors: Streeter P R , Corbeil L B
Published: January 2020

The role of endotoxin responsiveness in defense against gonococcal infection was studied in endotoxin-resistant (C3H/HeJ) and endotoxin-susceptible (C3H/HeN) mice by using a model of disseminated gonococcal infection (DGI) and a model of gonococcal survival in the female genital tract to determine the ability of the mice to eliminate gonococci. The 50% lethal dose in the DGI model was 10(9.6) for C3H/HeJ mice and 10(5.2) for C3H/HeN mice. Levels of bacteremia during infection indicated the C3H/HeJ mice cleared large numbers of gonococci from their peripheral blood by 24 h post-inoculation but that C3H/HeN mice did not. Additionally, the peritoneal leukocyte response after intraperitoneal inoculation of gonococci was greater in C3H/HeJ mice than in C3H/HeN mice, which suggested that the ability to mount an inflammatory response to endotoxin may be important in defense against DGI. Besides being different in susceptibility to DGI, C3H/HeJ mice were found to be more resistant then C3H/HeN mice to genital colonization by gonococci. The resistance of C3H/HeJ mice to genital colonization by gonococci appeared to be due to both the high numbers of polymorphonuclear leukocytes in the genital secretion and the predominance of inhibitory gram-negative genital flora in that mouse strain.
Replication of vesicular stomatitis virus in murine spleen cells: enrichment of the virus-replicating lymphocytes and analysis of replication restriction
Authors: Webb D R , Munshi S , Banerjee A K
Published: January 2020

Vesicular stomatitis virus (Indiana strain) will only grow in T lymphocytes which have been stimulated to undergo cell division. Evidence is presented that a considerable enrichment of the vesicular stomatitis virus-replicating T cells may be accomplished in the mouse spleen by passing the spleen cells over glass wool columns. By using this procedure experiments were performed to study the nature of the block in vesicular stomatitis virus replication in unstimulated (nonpermissive) versus mitogen-stimulated (permissive) splenic T cells. The results show that, as is the case in permissive T-cell lines, stimulated normal T cells allow the synthesis of the 42S virion ribonucleic acid.
Black-pigmented Bacteroides spp. in the human oral cavity
Authors: Zambon J J , Reynolds H S , Slots J
Published: January 2020

Five healthy children under 6 years of age, five healthy adults, and 10 adult periodontitis patients were examined for the prevalence and distribution of black-pigmented Bacteroides in the oral cavity. A total of 13 samples was obtained from each individual, including four supragingival and four subgingival dental plaques, dental occlusal surface, buccal mucosa, dorsal tongue, tonsil, and whole saliva. Black-pigmented Bacteroides were recovered from nine adult periodontitis patients. Healthy adults harbored the organisms in low incidence and proportions, whereas the children exhibited no cultivable black-pigmented Bacteroides. The organisms were isolated in highest proportions from dental plaque, especially subgingival plaque, and from the tonsil area, indicating that these sites constitute the organisms' primary ecological niche in the oral cavity. The predominant isolate was Bacteroides melaninogenicus subsp. intermedius followed by Bacteroides gingivalis and B. melaninogenicus subsp. melaninogenicus. B. melaninogenicus subsp. levii constituted low proportions of supragingival microflora of one adult periodontitis patient. A positive correlation was demonstrated between the proportion of black-pigmented Bacteroides (mainly B. melaninogenicus subsp. intermedius) and both the severity of gingival inflammation and the periodontal pocket depth, suggesting that these organisms may contribute to the pathogenesis of certain forms of periodontal disease.
Heparin inhibits phagocytosis by polymorphonuclear leukocytes
Authors: Victor M , Weiss J , Elsbach P
Published: January 2020

Phagocytosis of unopsonized Salmonella typhimurium 395, MR-10, opsonized Salmonella typhimurium 395 MS, and Staphylococcus epidermidis by rabbit polymorphonuclear leukocytes was inhibited by heparin at concentrations as low as 0.5 U/ml. Inhibition was dose dependent and nearly complete at 20 U/ml. Provided that heparin concentrations did not exceed 100 U/ml, inhibition could be largely reversed by washing. Heparin also reversibly inhibited the adherence of polymorphonuclear leukocytes to glass. In contrast, hexose monophosphate shunt activity of polymorphonuclear leukocytes stimulated by noningested S. typhimurium MR-10 or Streptococcus pyogenes B14 was not inhibited by heparin at concentrations as high as 100 U/ml.
Adhesion of Streptococcus pneumoniae to human pharyngeal epithelial cells in vitro: differences in adhesive capacity among strains isolated from subjects with otitis media, septicemia, or meningitis or from healthy carriers
Authors: Andersson B , Eriksson B , Falsen E , Fogh A , Hanson L A , Nylén O , Peterson H , Svanborg Edén C
Published: January 2020

A method was developed to study the adhesion of Streptococcus pneumoniae to human pharyngeal epithelial cells. Epithelial cells from healthy persons, pneumococcal strains from patients with otitis media, meningitis, or septicemia, and pneumococcal cells from the nasopharynx of healthy carriers were used. Adhesion was found to be influenced by changes in the bacterial incubation medium and growth phase, the concentration of bacteria and epithelial cells, the epithelial cell donor, the incubation time and temperature, and the pH and osmolarity of the incubation medium. Pretreatment of bacteria with heat, Formalin, or trypsin decreased adhesion. The highest adhesion was obtained when 10(9) bacteria cultivated for 18 h in streptococcus cultivation broth were added to 10(4) pharyngeal cells and incubated at 37 degrees C for 30 min. S. pneumoniae strains from patients with frequent episodes of otitis media and strains from healthy carriers had the highest adhesion values; septicemia and meningitis strains had the lowest. The capsular polysaccharide type did not determine the adhesive capacity of the strains, but otitis strains belonging to the capsular types often associated with otitis media adhered in high numbers. Adhesion may be important for pneumococci colonizing the nasopharynx or inducing otitis media.
Differences in Response Among Inbred Mouse Strains to Infection with Small Doses of
Mycobacterium bovis
BCG
Authors: Forget Adrien , Skamene Emil , Gros Philippe , Miailhe Annie-Claude , Turcotte Raymond
Published: January 2020

Intravenous infection of six inbred mouse strains with small doses of dispersed cells of
Mycobacterium bovis
BCG (15.5 × 10
3
or 15.5 × 10
4
colony-forming units) separated them into resistant (C3H/HeCr, A/J, and DBA/2) and sensitive (B10.A, C57BL/6, and BALB/c) strains as assessed by the magnitude of bacterial multiplication in the spleens at 28 days. The two groups were more sharply separated after infection with the lower dose of BCG (15.5 × 10
3
colony-forming units), which allowed for true multiplication of the bacteria in the spleens of permissive hosts, expressed as the ratio of the number of BCG recovered from the spleens to the number of BCG injected. This coefficient of increase was less than 1 in resistant strains, whereas it was higher than 2.5 in sensitive strains. Significant splenomegaly developed only in mice of the sensitive strains infected with BCG when compared with uninfected controls. There was no correlation between the magnitude of the delayed-type hypersensitivity (DTH) to BCG and susceptibility to infection: DTH was absent in both the sensitive and the resistant strains when the smaller dose of BCG was used for infection. Moreover, significant DTH was detected in animals of the most sensitive (BALB/c) as well as of the most resistant (C3H/HeCr) strain when the higher dose of BCG (15.5 × 10
4
) was used for immunization. These results document significant genetic differences in the ability of inbred mice to inhibit bacterial multiplication after infection with small dispersed doses of BCG. Resistance to BCG multiplication, in this model, does not appear to be related to the establishment of DTH.
Influence of (+)-cyanidanol-3 on the leukocyte migration inhibition test carried out in the presence of purified protein derivative and hepatitis B surface antigen
Authors: Vallotton J J , Frei P C
Published: January 2020

It has been shown that (+)-cyanidanol-3, therapeutically administered during the course of acute hepatitis B, is able to favor the elimination of hepatitis B surface antigen (HBsAg) from the blood. This observation suggests that (+)-cyanidanol-3 might stimulate the cell-mediated immune response, since it is known that this type of response is responsible for elimination of the virus. In the present study, the possible action of (+)-cyanidanol-3 on this type of immunity was investigated by adding the substance in vitro to leukocyte migration inhibition tests, performed with the antigens purified protein derivative (PPD) and HBsAg and with leukocytes from individuals sensitized to these antigens. In normal individuals sensitized to PPD, the addition of (+)-cyanidanol-3 amplified the inhibition of migration by 7.0% (P less than 0.05). In patients previously infected by hepatitis B virus and sensitized to HBsAg, the addition of (+)-cyanidanol-3 amplified the migration inhibition by 10.5% (P less than 0.05). A trend to a dose-response relation was observed with the antigen PPD. (+)-Cyanidanol-3 did not modify leukocyte migration in the absence of an antigen. (+)-Cyanidanol-3 therefore seems capable of amplifying the cell-mediated immune response as measured by the leukocyte migration inhibition test. It is thus possible that it favors the elimination of HBsAg in patients by this mechanism.
Evidence for two mechanisms of dengue virus infection of adherent human monocytes: trypsin-sensitive virus receptors and trypsin-resistant immune complex receptors
Authors: Daughaday C C , Brandt W E , McCown J M , Russell P K
Published: January 2020

Trypsin treatment of adherent human monocytes greatly reduced or eliminated the ability of these cells to support dengue virus replication. However, addition of dilute (nonneutralizing) antibody to the inoculum and the culture medium resulted in viral yields similar to those from monocytes not treated with trypsin. These results suggested that viral entry was facilitated by phagocytosis of immune complexes via Fc receptors on the monocytes. This concept was tested by (i) pretreating monocytes with aggregated gamma globulin, which resulted in a 40-fold reduction of viral yields after infection with dilute antibody-virus complexes and (ii) forming an immune complex with virus, antivirus F(ab')2 fragments, and rabbit anti-human Fab. Whereas F(ab')2 fragments alone would not enhance virus replication in trypsin-treated monocytes, the immune complex containing a rabbit Fc piece did increase the yield of dengue virus. These results suggest that dengue virus can infect a cultured monocyte in two ways: (i) through a viral receptor that is trypsin sensitive or (ii) through an Fc receptor that is not trypsin sensitive.
Artificial Salmonella vaccines: Salmonella typhimurium O-antigen-specific oligosaccharide-protein conjugates elicit opsonizing antibodies that enhance phagocytosis
Authors: Jörbeck H J , Svenson S B , Lindberg A A
Published: January 2020

Outbred NMRI mice and rabbits were vaccinated with different artificial Salmonella typhimurium immunogens and the specificity and activity of elicited antibodies were studied in in vivo and in vitro phagocytosis assays. The Salmonella immunogens used were: (i) the synthetic disaccharide, abequose (formula see text) D-mannose, representative of Salmonella O antigen 4, covalently linked to bovine serum albumin (BSA); (ii) the octa- and dodecasaccharides, (formula see text) covalently linked to BSA; and (iii) whole heat-killed Salmonella. Rabbit antibodies passively administered to mice significantly enhanced the clearance of intravenously injected S. typhimurium challenge bacteria from the bloodstream. The clearance rate and the titer of anti-O-antigen-specific antibodies correlated. The clearance rate of an S. thompson (O6,7) strain, which has a different O antigen, was the same irrespective of the rabbit serum given. NMRI mice actively immunized with the various oligosaccharide-BSA conjugates had a significantly increased clearance rate of S. typhimurium only. In the in vitro assay, mouse antioligosaccharide-BSA sera promoted phagocytosis of S. typhimurium, but not S. thompson, when incubated with complement and mouse peritoneal exudate cells activated with Freund complete adjuvant.
Adherence of Streptococcus mutans and Streptococcus sanguis to salivary components bound to glass
Authors: Stinson M W , Jinks D C , Merrick J M
Published: January 2020

Adherence of radiolabeled Streptococcus mutans and Streptococcus sanguis to saliva-treated glass surfaces was studied under conditions which minimized bacteria-glass interactions. Treatment of glass with an alkylsilane solution decreased nonspecific bacterial adherence and enhanced adsorption of radiolabeled salivary components to these surfaces. Addition of Triton X-100 to the bacterial suspensions also reduced nonspecific adherence to siliconized glass, but did not affect adherence to salivary components attached to siliconized glass. Calcium stimulated S. mutans adherence to saliva-free glass, but inhibited adherence to saliva-treated glass. S. sanguis adherence to either saliva-free or saliva-treated glass was inhibited slightly at high calcium ion concentrations. Adherence of streptococci to saliva-treated glass exhibited saturation kinetics, and the numbers of binding sites on the experimental salivary pellicle and the affinity constants for bacteria-saliva attachment were determined. Preincubation of the streptococci with whole saliva decreased their capacity to adhere to saliva-treated glass, but not to saliva-free glass. Bacteria adherent to saliva-treated glass surfaces were readily desorbed by washing with saliva. The addition of homologous antisera, ammonium sulfate-precipitated immunoglobulins, or Fab fragments to the bacterial suspensions inhibited cell adherence to saliva-treated glass.
Surface expression of a nonstructural antigen on influenza A virus-infected cells
Authors: Shaw M W , Lamon E W , Compans R W
Published: January 2020

Rabbit antiserum to the influenza A virus nonstructural protein, NS1, was used for indirect immunofluorescence studies of infected cells. Nonstructural antigens were detected on surfaces of P815 cells as early as 4 h after infection with A/WSN/40 virus. Adsorption of the serum with virion structural proteins did not affect the observed fluorescence, and a progressive increase in surface fluorescence at later times postinfection indicated that the surface antigen was newly synthesized during the replication cycle.
Antibodies against measles virus polypeptides in different disease conditions
Authors: Norrby E , Orvell C , Vandvik B , Cherry J D
Published: January 2020

The occurrence of antibodies to the nucleoprotein and matrix (M) antigens of measles virus was determined in early and late measles convalescent sera and in sera from patients with multiple sclerosis, subacute sclerosing panencephalitis, chronic active hepatitis, and atypical measles. Antibodies to the two components were identified separately in serially diluted samples both by radioimmune precipitation assays and by complement fixation tests employing purified nucleoprotein and M components as antigens. The antibody response to M antigen in connection with acute infections was weak, and with time titers of antibodies to M antigen were reduced below detectable levels in most cases. A different situation was seen in patients with atypical measles. A pronounced antibody response to M antigen was shown to be a part of the generally accentuated immune response in these patients. Confirming results of others, it was shown that in spite of the increased antibody titers against most measles components in sera from patients with subacute sclerosing panencephalitis, no or only low titers of antibodies to M antigen were present. However, a similar representation of antibodies to measles virus components was also seen in sera from patients with active chronic hepatitis. The significance of this finding for the interpretation of a weak antibody response to M antigen in the presence of a pronounced antibody response to other components is discussed.
Surface-exposed protein antigens of the gonococcal outer membrane
Authors: Swanson J
Published: January 2020

Whole, 125I-labeled gonococci (GC) were incubated with rabbit sera against whole GC. After washing, the [125I]GC were lysed in detergent, and radioiodinated antigen-antibody complexes were immunoprecipitated by protein A-Sepharose. Several GC outer membrane proteins, including proteins I, II, and III, could be identified in immunoprecipitates obtained with these antisera. In many immunoprecipitates, a 44K protein was present. Reactivity of antisera toward protein II could be demonstrated, and some rabbit sera contained very prominent apparent antibody activity toward this protein. Proteins I and III were found in similar ratios in immunoprecipitates, suggesting that they form heteropolymers in GC outer membranes. Qualitative and quantitative difference in antibody reactivity and specificity could be demonstrated with serially obtained sera from rabbits immunized with whole GC. The use of viable or Formalin-fixed heat-killed staphylococci yielded "non-immunological" precipitation of 125I-labeled GC constituents; this occurred with staphylococci regardless of whether they contained protein A.
Inhibition of formylmethionyl-leucyl-phenylalanine-stimulated neutrophil chemiluminescence by human immunoglobulin A paraproteins
Authors: Van Epps D E , Brown S L
Published: January 2020

Immunoglobulin A (IgA) paraproteins from patients with myeloma have been shown to inhibit human neutrophil chemotaxis to C5a, casein, and chemotactic factors produced by Escherichia coli. This study demonstrates that these paraproteins also inhibit neutrophil chemotaxis in response to the synthetic peptide formylmethionyl-leucyl-phenylalanine (f-MLP). Furthermore, the neutrophil chemiluminescence response stimulated by f-MLP was markedly suppressed by the presence of IgA paraprotein. Maximal inhibition of chemiluminescence was observed when the paraprotein was present during the chemiluminescence response. The inhibitory activity was substantially reduced by removal of the Fc region of IgA or by conversion of polymeric IgA to monomeric IgA by limited reduction and alkylation. Additional experiments showed that these IgA paraproteins inhibited C5a but not phorbol myristate acetate-stimulated chemiluminescence. These observations are constant with the hypothesis that polymeric forms of IgA bind to human neutrophils and interfere with the binding of chemotactic factor to its receptor or the consequent receptor-mediated oxidative burst or both.
Effect of human saliva on the fluoride sensitivity of glucose uptake by Streptococcus mutans
Authors: Germaine G R , Tellefson L M
Published: January 2020

The fluoride (F) sensitivity of glucose uptake by whole cell suspensions of streptococcus mutans in the presence and absence of human whole salivary supernatant was studied. It was observed that dithiothreitol (DTT) and other thiols markedly reduced the F sensitivity of cells when saliva (50%, vol/vol) was present during glucose uptake. In the absence of saliva, cells were sensitive to 2 to 2.5 mM F regardless of the presence of thiols. Supplementation of cells in phosphate or tris(hydroxymethyl)aminomethane-hydrochloride buffers with physiological concentrations of calcium or phosphate had no effect on the F sensitivity of the organism. Experiments with permeabilized cells suggested that thiols themselves had no direct effect on the F sensitivity of enolase (a principal F target). Cells pretreated with DDT subsequently exhibited decreased F sensitivity when examined in the presence of saliva but not in the absence of saliva. Cells pretreated with whole salivary supernatant were found to be subsequently less sensitive to F in the absence of saliva during glucose uptake. Furthermore, in cases where cells were pretreated with saliva, subsequent additions of DDT were unnecessary to obtain maximal reduction in the F sensitivity of glucose uptake. It was concluded that the saliva-dependent reduction in F sensitivity of glucose uptake was not due to sequestration of available F by salivary constituents. The data suggest that a salivary component(s) interacts directly with the microorganism in some manner which results in reduced F sensitivity of the process under study. Possible mechanisms of saliva action are discussed.