bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Salivary Components and Extracellular Polysaccharide Synthesis from Sucrose on the Attachment of
Streptococcus mutans
6715 to Hydroxyapatite Surfaces
Authors: Clark W. B. , Gibbons R. J.
Published: January 2020

The adsorption of
3
H-labeled
Streptococcus mutans
6715 cells to disks of hydroxyapatite (HA) was studied. The number of streptococci that adsorbed was logarithmically related to the concentration of cells available up to at least 2 × 10
8
per ml; equilibrium occurred within 45 min. Assay reliability was verified by direct scanning electron microscopic counts. Untreated HA disks exposed to buffered saline (PBS)-suspended streptococci at a concentration of 1.1 × 10
8
per ml absorbed 3.2 × 10
6
cells per cm
2
; approximately 3% of the surface area was, therefore, occupied by adsorbed organisms. The presence of adsorbed salivary components on HA reduced the number of attaching
S. mutans
cells by half. When
S. mutans
cells were suspended in saliva to mimic conditions existing in the mouth, the number of streptococci adsorbing to saliva-treated HA was reduced more than 30-fold compared to untreated HA. Approximately one-half of the streptococci adsorbed to untreated or to saliva-treated HA disks could be desorbed over a 4-h period with 0.067 M phosphate buffer.
S. mutans
cells exposed to sucrose to permit extracellular polysaccharide synthesis before or during adsorption attached in fewer numbers to both saliva-treated and untreated HA than PBS-treated organisms. When
S. mutans
cells adsorbed on untreated HA were exposed to sucrose, fewer organisms could be desorbed; thus, in situ polysaccharide synthesis promoted their more firm attachment to untreated HA. However, when saliva-suspended streptococci were adsorbed to saliva-treated HA surfaces, exposure to sucrose before or subsequent to adsorption did not promote more firm attachment. Evidently, the powerful adherence-inhibiting and desorptive effects of salivary components overshadowed any promoting effects attributable to glucan synthesis from sucrose. Similarly, no differences were noted in the desorption of
S. mutans
cells from human teeth after exposure to sucrose, glucose, or PBS relative to a strain of
Streptococcus mitis
(
S. mitior
). Thus, no evidence was obtained to support the hypothesis that glucan synthesis from sucrose was essential for, or promoted, the attachment of
S. mutans
cells to HA surfaces exposed to saliva or to the smooth surfaces of human teeth.
Granuloma formation in lungs of mice after intravenous administration of emulsified trehalose-6,6'-dimycolate (cord factor): reaction intensity depends on size distribution of the oil droplets
Authors: Yarkoni E , Rapp H J
Published: January 2020

The intensity of the granulomatous reaction evoked in lungs of mice by trehalose-6,6'-dimycolate administered intravenously in oil-water emulsion depended on the size distribution of the oil droplets. Emulsions containing the greatest number of the largest oil droplets were the most granulomagenic.
Changes in the Microflora and Physiology of the Anterior Intestinal Tract of Pigs Weaned at 2 Days, with Special Reference to the Pathogenesis of Diarrhea
Authors: Barrow P. A. , Fuller R. , Newport M. J.
Published: January 2020

The gastrointestinal microflora and gastric physiology of piglets weaned at 2 days was compared with that of piglets allowed to continue sucking the sow. Although there was a significantly higher count of
Escherichia coli
in the stomach, duodenum, and jejunum of the early-weaned compared with sow-reared pigs, these differences were not detectable in samples from the ileum. There were no quantitative differences in lactobacilli and in streptococci between the two treatments.
Lactobacillus fermentum, L. acidophilus, Streptococcus salivarius, S. bovis
, and related biotypes were isolated from both groups of pigs.
L. fermentum
and
S. salivarius
were isolated more frequently from sow-reared piglets. The weight of digesta in the stomach was greater in weaned than in sucking pigs and was even greater in scouring weaned pigs, suggesting that in scouring pigs there may be gastric stasis. The gastric pH was higher in the weaned pigs at 4 days of age, but gradually decreased up to 10 days, during which time the lactic acid concentration rose. In weaned pigs there was a highly significant negative correlation between pH and lactic acid concentration in the stomach digesta, and also a positive correlation between pH and number of
E. coli.
These correlations suggest that lactic acid, from bacterial fermentation, is the major component in the regulation of gastric pH in weaned pigs. Three of twenty sucking pigs, but none of the weaned pigs, were secreting HCl (chloride concentration > 3 mg/g, pH < 3.5). In sucking pigs there was an inverse relationship between the chloride and lactic acid concentrations in the digesta. In weaned scouring pigs there was a nonsignificant increase in pepsin concentration in the stomach tissue. There was a threefold increase in the total proteolytic activity of the stomach tissue.
Passive protection by antitoxin in experimental Pseudomonas aeruginosa burn infections
Authors: Pavlovskis O R , Pollack M , Callahan L T , Iglewski B H
Published: January 2020

The protective effect of intravenously administered rabbit antitoxin serum was studied in lethal Pseudomonas aeruginosa burn infections in mice. Survival after infection with 2 median lethal doses of a toxigenic, low-protease-producing strain (PA103) was enhanced in antitoxin-treated mice, as compared with controls that had received anti-bovine serum albumin serum (P = 0.0004). Survival time was prolonged in other antitoxin-treated mice infected with toxigenic, high-protease-producing strains (PA86 and PA220, P = 0.0003 and P = 0.01, respectively). In contrast, antitoxin had no protective effect in mice challenged with a nontoxigenic strain (WR 5, P = 0.57). There were fewer viable bacteria in blood and liver of antitoxin-treated mice than in those of anti-bovine serum albumin-treated controls after infection with toxigenic organisms, whereas there were no significant differences between the two groups after challenge with the nontoxigenic strain. These data suggest that P. aeruginosa exotoxin A contributes to lethality in this burn infection model, and this effect is diminished by passive immunization with antitoxin.
Effect of serum from various animal species on erythrocyte attachment of endotoxins and other bacterial antigens
Authors: Praino M , Neter E
Published: January 2020

Lipopolysaccharide O antigens (endotoxins) and other bacterial antigens readily attach to erythrocytes in vitro. This attachment is prevented by certain mammalian and avian sera. In this study, the inhibitory capacity of sera from lower animals was compared with that of higher animals for a total of 30 species. Antigens and the corresponding antisera included both crude O antigens and purified lipopolysaccharide preparations, the common enterobacterial antigen from Escherichia coli O14, the Vi antigen from Citrobacter ballerup, the polyribose-phosphate antigen from Haemophilus influenzae type b, and the crude teichoic acid antigen from Staphylococcus aureus. Antigen and serum mixtures were incubated at 37 degrees C for 30 min and used for erythrocyte modification; failure of hemagglutination by homologous bacterial antiserum provided evidence of inhibitory capacity. Sera from the classes Mammalia and Aves were very strong inhibitors; those of Reptilia and Osteichthyes were moderate in activity, displaying variation within the classes; those of Amphibia and Chondrichthyes were minimal inhibitors; and those of Merostomata, Crustacea, and Lamellibranchiata displayed questionable or no inhibitory capacity. Inhibitory sera were active with all antigens tested. The findings suggest evolution of inhibitory factors consistent with the theory of two diverging lines of animal phylogeny based on embryological criteria and closely parallel the observations of an endotoxin-altering capacity in vertebrate sera that is not found in invertebrate sera or hemolymph.
Autoantibodies detected in rabbits hyperimmunized with group A, C, and G streptococcal vaccines
Authors: Onică D , Mihalcu F , Lenkei R , Gherman M , Tudor M
Published: January 2020

Rabbits hyperimmunized with group A, C, and G streptococcal vaccines developed autoantibodies with affinities for different tissues (smooth muscle, cytoplasmic, and myocardial antibodies) and for autologous proteins (anti-albumin and anti-immunoglobulin antibodies). The presence of anti-albumin and smooth muscle antibodies, associated with a high level of immunoglobulin, suggests the development of hepatic disorders in the hyperimmunized rabbits.
Anomalous high native resistance to athymic mice to bacterial pathogens
Authors: Nickol A D , Bonventre P F
Published: January 2020

Congenitally athymic (nude) mice exhibited an anomalous high resistance against infections with the facultative intracellular parasite Listeria monocytogenes and other bacterial pathogens. Protection against lethal infection was demonstrated to result from the presence of naturally occurring activated macrophages in the reticuloendothelial organs of the nude mice. This was exemplified after intravenous challenge by enhanced bacterial clearance from the blood and augmented bacterial killing in the spleens and livers of nude mice as compared with immunologically competent control mice. Resident peritoneal macrophages of nude mice were not activated in terms of phagocytic, bactericidal, or tumoricidal potential. The development of activated fixed tissue macrophages appears to arise as a result of the T-lymphocyte deficiency since thymus implantation abrogated the enhanced resistance of nude mice. Antibiotic elimination of intestinal bacteria also modified resistance to bacterial infection, indicating a role of environmental factors on macrophage activation. Several possible mechanisms leading to macrophage activation and heightened resistance to infection in nude mice are offered.
Species specificity of attachment and damage to oviduct mucosa by Neisseria gonorrhoeae
Authors: Johnson A P , Taylor-Robinson D , McGee Z A
Published: January 2020

Neisseria gonorrhoeae colony type 1 were inoculated into organ cultures of oviducts obtained from various animal species. Gonococci rapidly attached to extensive areas of the mucosa of human oviducts (fallopian tubes), entered the mucous-secreting cells, and caused histological damage to the tissues. In addition, 2 to 4 days after infection there was complete loss of ciliary activity. In contrast, gonococci attached very scantily or not at all to the mucosa of rabbit, porcine, or bovine oviducts. However, the organisms multiplied in the medium of these organ cultures and were located sometimes in the base of mucosal cells and in large numbers in the submucosa. Despit this, there was no histological evidence of damage, and at least 7 days after infection ciliary activity was maintained equally as well as it was in uninfected control cultures. The host specificity of N. gonorrhoeae appears to be determined, at least in part, by a markedly diminished ability of the organisms to attach to and damage the genital mucosa of nonhuman species.
Failure of Endotoxin to Protect C3H/HeJ Mice Against Lethal X-Irradiation
Authors: Urbaschek Renate , Mergenhagen Stephan E. , Urbaschek Bernhard
Published: January 2020

C3H/HeJ mice are more sensitive to lethal X-irradiation and cannot be protected by pretreatment with endotoxin, compared to the C3HeB/FeJ strain. Lack of a granulopoietic response in C3H/HeJ mice is evident.
Elicitation of endotoxemic effects in C3H/HeJ mice with glucocorticoid antagonizing factor and partial characterization of the factor
Authors: Moore R N , Goodrum K J , Couch R E , Berry L J
Published: January 2020

C3H/HeJ mice were used to study the origin and nature of endotoxin-induced glucocorticoid antagonizing factor (GAF). In conventional mice GAF is believed to be responsible for a variety of effects that occur as a result of an injection of endotoxin, including the inhibition of hormonal induction of hepatic phosphoenolpyruvate carboxykinase and of glyconeogenesis. Responses in such animals are seen whether the endotoxin is extracted with phenol-water or with trichloroacetic acid. C3H/HeJ mice do not respond (or produce GAF?) after an intravenous injection of phenol-water lipopolysaccharide, but they react normally (produce GAF?) when given a trichloroacetic acid preparation. They also behave the same as conventional animals when injected with serum from poisoned normal mice, especially when the reticuloendothelial system of the donors has been activated by prior injections of Zymosan or heat-killed tubercle bacilli. The C3H/HeJ mice have been used, therefore, as assay animals to establish that peak levels of GAF appear in donor serum about 2 h after an injection of lipopolysaccharide, and it is produced intraperitoneally in C3H/HeJ mice given a mixture of endotoxin and peritoneal exudate cells derived from responder mice. GAF elutes from Sephadex G-200 along with markers of known molecular weight in the region of 100,000 to 200,000. It is inactivated by trypsin and by heating at 75 degrees C for 1 h.
Local (Immunoglobulin A) Immune Response by the Intestine to Cholera Toxin and Its Partial Suppression with Combined Systemic and Intra-Intestinal Immunization
Authors: Yardley John H. , Keren David F. , Hamilton Stanley R. , Brown Gertrude D.
Published: January 2020

Chronically isolated Thiry-Vella (T-V) ileal loops in rabbits were used to study the local and systemic immune response to purified cholera toxin (CT). Immunization consisted of intraloop (i.l.), subcutaneous (s.c.), or combined i.l. and s.c. inoculation of CT. Fluid from the loops and sera were tested for neutralization of CT by the blueing test and for relative content of isotype-specific (immunoglobulins A [IgA] and G [IgG]) anti-CT. To demonstrate protection against CT, fluid production by the chronic T-V loops was measured after challenge with CT; an “acute” loop prepared from adjacent intestine at the time of challenge was also tested in some animals. The highest neutralizing titers in loop fluids were found in animals receiving i.l. or i.l. and s.c. inoculations, whereas titers in sera were highest in rabbits receiving s.c. or i.l. and s.c. inoculations. IgA anti-CT in fluids became greatest after i.l. inoculation alone and was lowest in s.c. animals. Combined s.c. and i.l. immunization was accompanied by reduced content of IgA anti-CT in fluids as compared with that obtained with i.l. inoculation alone. This finding strongly suggested a suppressive effect on local immunization by s.c. inoculation. While this suppression may have been due to a direct (toxigenic) effect of CT on lymphocytes, an immunogenic mechanism, probably mediated through suppressor T cells, is favored. Little IgG anti-CT was detected in any loop fluids, but high levels were found in sera after two s.c. inoculations or four i.l. inoculations. Neutralization titers for the fluid specimens showed much better correlation with IgA anti-CT values than with IgG anti-CT values. The chronic and acute T-V loops showed protection against fluid production after exposure to CT in systemically and locally immunized animals. However, IgG anti-CT usually appeared in both loops; leakage of serum antibodies because of surgical manipulation was felt, therefore, to invalidate these protection results as a demonstration of local immunity. In challenge studies in undisturbed chronic loops, only local immunization alone was found to result in definite protection.
Parasite-specified phagocytosis of Chlamydia psittaci and Chlamydia trachomatis by L and HeLa cells
Authors: Byrne G I , Moulder J W
Published: January 2020

Phagocytosis of the 6BC strain of Chlamydia psittaci and the lymphogranuloma venereum 440L strain of Chlamydia trachomatis by L cells and HeLa 229 cells occurred at rates and to extents that were 10 to 100 times greater than those observed for the phagocytosis of Escherichia coli and polystyrene latex spheres. Both species of Chlamydia were efficiently taken up by host cells of a type they had not previously encountered. Phagocytosis of chlamydiae was brought about by the interaction of parasite surface ligands with elements of the host cell surface. The chlamydial ligands were readily denatured by heat, were masked by antibody, and were resistant to proteases and detergents. The host cell components were reversibly removed by proteases. Chlamydial phagocytosis was inhibited when host cells were incubated for many hours with cycloheximide. It was suggested that the presence on the chlamydial cell surface of ligands with high affinity for normal, ubiquitously occurring structures on the surface of host cells is an evolutionary adaptation to intracellular existence. The term parasite-specified phagocytosis was used to describe the efficient phagocytosis of chlamydiae by nonprofessional phagocytes and to distinguish it from the host-specified immunological and non-immunological phagocytosis carried out by professional phagocytes.
Effect of Complement Fixation on the Release of Lysosomal Enzymes from Rabbit Alveolar Macrophages
Authors: Sorber William A.
Published: January 2020

Macrophage lysosomal enzymes that have specificities for substrates found in mammalian tissue may contribute to the tissue damage observed in chronic inflammatory diseases. Although a variety of agents that stimulate the release of hydrolases from peritoneal macrophages have been identified, little work has been done to establish the conditions and specific stimuli responsible for enzyme release by alveolar macrophages (AM). To assess the effect of phagocytosis by AM on the release phenomenon, hydrolytic enzymes normally sequestered in AM lysosomes were quantified in the supernatant fluids of phagocytosing and non-phagocytosing AM monolayers in both the presence and absence of serum. Maximum release occurred under conditions known to favor complement fixation by the classical or alternative pathways. Thermal destruction or immune fixation of serum complement before use in culture reduced the magnitude of release to that observed in cultures incubated in the complete absence of serum. Phagocytosis was not essential for release, since cells exposed to particles but treated with a known inhibitor of phagocytosis (cytochalasin B) still showed maximal release in the presence of fresh serum. These data are interpreted to indicate that a heat-labile component of serum, probably a by-product of complement fixation, was primarily responsible for the hydrolase release by AM. On the basis of these findings, individuals suffering from chronic pulmonary disease may suffer acute episodes of lung destruction from endogenous AM enzymes upon the inhalation of materials capable of fixing complement.
Loss of Inorganic Ions from Host Cells Infected with
Chlamydia psittaci
Authors: Chang George T. , Moulder James W.
Published: January 2020

Mouse fibroblasts (L cells) infected with the 6BC strain of
Chlamydia psittaci
released potassium ion (K
+
) into the extracellular milieu in a way that depended on size of inoculum and time after infection. When the multiplicity of infection was 500 to 1,000 50% infectious units (ID
50
) per L cell, loss of intracellular K
+
was first apparent 4 to 10 h after infection and was nearly complete at 6 to 20 h. Magnesium ion and inorganic phosphate (P
i
) were also released. Similar multiplicities of ultraviolet-inactivated
C. psittaci
also caused release of K
+
. Leakage of inorganic ions probably resulted from immediate damage to the host-cell plasma membrane during ingestion of large numbers of chlamydiae. With multiplicities of 1 to 50 ID
50
per L cell, ingestion of
C. psittaci
was not by itself enough to cause release of K
+
and P
i
from infected L cells. There was a delay of 36 to 72 h between infection and massive leakage of intracellular ions during which time the chlamydiae multiplied extensively. Fifty ID
50
of ultraviolet-inactivated
C. psittaci
per L cell did not bring about significant leakage of K
+
, even after 72 h. The mechanism whereby these multiplicities of infection destroy the ability of host cells to retain intracellular molecules is not known. HeLa 229 cells also released K
+
and P
i
after infection, but these losses occurred more slowly than in comparably infected L cells, possibly because
C. psittaci
did not multiply as extensively in HeLa cells as it did in L cells. The significance of the inability of chlamydiae-infected cells to regulate the flow of molecules through their plasma membranes is discussed.
Chlorphenesin: an Antigen-Associated Immunosuppressant
Authors: Whang H. Y. , Neter E.
Published: January 2020

Chlorphenesin (3-
p
-chlorophenoxy-1,2-propanediol), when injected intravenously together with either of two common bacterial antigens, inhibits the antibody response of the rabbit. The antigens studied are those common to
Enterobacteriaceae
and to gram-positive bacteria. The immunosuppression is contingent upon incubation of chlorphenesin and antigen in vitro prior to administration, since separate injection of antigen and inhibitor or of mixtures without prior incubation yields undiminished antibody response. Chlorphenesin, as shown by hemagglutination-inhibition tests, does not alter the antigenic determinants, because antibody neutralization occurs in the presence or absence of the drug. The immunosuppressive effect is reversible, since precipitation of chlorphenesin at 4 C substantially restores immunogenicity. Animals immunized with antigen-drug mixtures, which fail to respond with significant antibody production, nonetheless are immunologically primed. It is concluded that chlorphenesin represents another example of antigen-associated immunosuppressants.
Potentiating Effect of Freund's Adjuvant on Interferon Production by Endotoxin or Poly rI•Poly rC
Authors: De Clercq Erik , Nuwer Marc R. , Merigan Thomas C.
Published: January 2020

Intraperitoneal injection of mice with mineral oil, incomplete (IFA) or complete Freund's adjuvant (CFA) increased the interferon response to endotoxin or (poly rI)•(poly rC) administered intravenously 2 days later. After endotoxin administration, circulating interferon titers were increased at several different times of sampling and with a variety of endotoxin dosages. When injection of endotoxin was delayed until 6 to 8 days after the administration of IFA or CFA, interferon production was markedly decreased. Mice treated with CFA and injected with endotoxin 2 days later became more resistant to intranasal vesicular stomatitis virus challenge than mice injected with endotoxin alone. Hyporeactivity to the interferon-inducing capacity of a second injection of endotoxin 2 days after the first injection could not be overcome by administering CFA simultaneously with the first dose. CFA treatment not only raised the serum interferon titers produced by endotoxin, but also increased the number of interferon-forming cells in the spleen after administration of endotoxin in vivo. In addition, CFA enhanced the intravascular clearance of (poly rI)•(poly rC). The possibility that Freund's adjuvant increased the interferon response to endotoxin and (poly rI)•(poly rC) by stimulating the uptake and processing of the interferon inducer by lymphoreticular cells is discussed.
Effect of Exogenous Interferon on Rubella Virus Production in Carrier Cultures of Cells Defective in Interferon Production
Authors: Mifune Kumato , Desmyter Jan , Rawls William E.
Published: January 2020

An established cell line (Vero) defective in interferon production was used to evaluate the role of interferon in chronic rubella virus infections of cell cultures. Inoculation of Vero cells with a low multiplicity of virus resulted in the development of carrier cultures which had the characteristics of a regulated infection. Although added interferon did not alter rubella virus production in carrier cultures of cells capable of producing interferon, such added interferon caused a dramatic reduction of virus production in the carrier cultures of Vero cells. There was a reduction of the fraction of cells producing virus in Vero carrier cultures, but not in carrier cultures of other cells upon incubation in the continual presence of rubella virus antibodies. In addition, the fraction of infected cells fluctuated in carrier cultures in Vero cells. The data indicate that interferon is not necessary for maintaining a chronic rubella virus infection in vitro and suggest an instability of the virus genome in Vero cells.
Nature and Heterogeneity of the Antigens of
Neisseria gonorrhoeae
Involved in the Serum Bactericidal Reaction
Authors: Glynn A. A. , Ward M. E.
Published: January 2020

Sixty strains of
Neisseria gonorrhoeae
have been classified into four main groups according to their resistance to killing by human complement together with either normal human or immune rabbit antibodies. The rabbit antisera had been raised against 10 of the strains tested. The normal human antibodies had probably been formed against cross-reacting organisms since they could be removed by absorption with
N. pharyngis sicca, N. pharyngis flavus, N. catarrhalis
, or
Escherichia coli.
Bactericidal antibodies could be absorbed from both normal and immune sera by
N. gonorrhoeae
which had been autoclaved or trypsinized, and by red cells coated with gonococcal lipopolysaccharides. The results suggest that the antigens involved in the bactericidal reaction are lipopolysaccharides of several distinct specificities. Since individual sera always reacted more widely in hemagglutination than in bactericidal tests, it is postulated that surface-blocking antigens may restrict access to the lipopolysaccharides in the intact organisms.
Bdellovibrio bacteriovorus
Parasitism in
Shigella
Species
Authors: Gillis J. R. , Nakamura M.
Published: January 2020

Bdellovibrio bacteriovorus
was capable of parasitizing
Shigella boydii, S. flexneri
, and
S. sonnei
. The bdellovibrio was able to produce plaques on lawns consisting of heat-killed or ultraviolet-irradiated
S. boydii
.
Virulence of Nocardia asteroides during its growth cycle
Authors: Beaman B L , Maslan S
Published: January 2020

Cells of Nocardia asteroides undergo structural and chemical changes, especially in the cell wall, during growth in brain heart infusion broth. Experiments were devised to determine whether these changes affected the virulence of Nocardia for mice. It took, on the average, 1,380 times the number of colony-forming units at the stationary phase to achieve the same mortality induced by the log-phase cells. Cells in either the lag phase or early stationary phase of growth were intermediate in the numbers of colony forming units required to kill mice. Dry-weight determinations at different stages of growth demonstrated that the log-phase organisms were approximately 10 times heavier than stationary-phase cells. Thus, on the basis of dry-weight (micrograms) values, the average colony-forming unit of log phase is approximately 130 times more virulent than in stationary-phase cultures. Therefore, the stage of growth affects greatly the virulence of N. asteroides.
Antigenic relationship of human foamy virus to the simian foamy viruses
Authors: Nemo G J , Brown P W , Gibbs C J , Gajdusek D C
Published: January 2020

A foamy virus isolated by Achong et al. from a human nasopharyngeal carcinoma was studied to determine its antigenic relationship to the eight known simiam foamy viruses (SFV). Using reciprocal cross-immunofluorescent and cross-neutralization techniques, we found the human isolate to be closely related to SFV type 6. In a seroepidemiological survey, neutralizing antibody to the human foamy virus was not detected in the sera of animal caretakers or laboratory personnel who routinely handled a wide variety of nonhuman primates. We conclude that the human isolate most probably represents a variant strain of SFV type 6.
Inverse relationship between the susceptibility of lipopolysaccharide (lipid A)-pretreated mice to the hypothermic and lethal effect of lipopolysaccharide
Authors: Greer G G , Rietschel E T
Published: January 2020

Mice pretreated (day 0) by a single injection of lipopolysaccharide (LPS) responded with hypothermic tolerance to (LPS) challenge on day 1 and with hypothermic hyperreactivity to LPS challenge on day 4. Reciprocally, mice pretreated similarly but with a higher challenge dose were hyperreactive with respect to LPS lethality on day 1, but highly tolerant to lethality when challenged on day 4. Hyperreactivity to LPS lethality (day 1) was evident from an accelerated onset of death as well as from a reduced 50% lethal dose in pretreated mice, the level of hyperreactivity being more pronounced with higher LPS pretreatment doses. Lethal hyperreactivity, however, was only seen after challenge with a 50% lethal dose of soluble LPS. In contrast, protection to lethality occurred after challenge with a 50% lethal dose of insoluble LPS (day 1). Tolerance to LPS lethality in mice was observed on day 4 after pretreatment with one (day 0) or four daily injections of LPS. Since reciprocal hyperreactivity (day 1) and cross-tolerance to lethality (day 4) could be achieved by treatment with Salmonella smooth- or rough-form LPS as well as with free lipid A, it was concluded that lipid A represents the active principle of LPS in inducing both hyperreactivity and tolerance to the lethal effect of LPS.
Cell envelope of Neisseria gonorrhoeae: phospholipase activity and its relationship to autolysis
Authors: Cacciapuoti A F , Wegener W S , Morse S A
Published: January 2020

The relationship between conditions which permit or inhibit cell lysis and those which promote phospholipid hydrolysis in Neisseria gonorrhoeae was investigated. Suspension of exponential-phase gonococci in buffer in the absence of divalent cations resulted in autolysis but not in phosphlipid hydrolysis. The addition of Ca2+ or Mg2+ to the buffer inhibited autolysis and markedly stimulated the hydrolysis of phosphatidylethanolamine. Incubation of cells in buffer at pH 6 inhibited both autolysis and phospholipid hydrolysis.
Heterogeneity of group A streptococcal pyrogenic exotoxin type B
Authors: Barsumian E L , Cunningham C M , Schlievert P M , Watson D W
Published: January 2020

Streptococcal pyrogenic exotoxin type B purified from culture filtrates of either the NY-5 or T-19 strain of group A streptococcus was found to be heterogeneous in charge. Three protein fractions with isoelectric points of 8.0, 8.4, and 9.0 were isolated by differential solubility in ethanol and acetate-buffered saline followed by isoelectric focusing and shown to be antigenically identical to streptococcal pyrogenic exotoxin type B. The molecular weights of all three fractions were approximately 17,500, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with aggregates forming in the presence of hyaluronic acid. Only the pI 8.4 fraction showed the characteristic activities of streptococcal pyrogenic exotoxin in rabbits: pyrogenicity and ability to enhance susceptibility to lethal endotoxin shock. The pI 8.0 and pI 9.0 fractions were not pyrogenic, but could be used to immunize against pyrogenicity. These two fractions failed either to enhance lethal endotoxin shock or to immunize against enhancement activity. When the isolated fractions were electrofocused again they appeared heterogeneous, suggesting an instability of the B toxin molecular forms.
Effect of sucrose in culture media on the location of glucosyltransferase of Streptococcus mutans and cell adherence to glass surfaces
Authors: Hamada S , Torii M
Published: January 2020

Streptococcus mutans strain B13 (serotype D) almost exclusively produced free glucosyltransferase (GTase) in the culture supernatant when grown in sucrose-free TTY broth medium, which was composed of Trypticase (Baltimore Biological Laboratory [BBL] Cockeysville, Md.), tryptose (Difco Laboratories, Detroit, Mich.), yeast extract (BBL), salts, and 1% glucose. Organisms grown in sucrose-free TTY broth retained very weak cell-associated GTase activity and did not adhere significantly to glass surfaces in the presence of exogenous sucrose. If sucrose was added to TTY broth, however, GTase was found on the cell surface where cell-bound, water-insoluble glucans were synthesized. Most commercially available products of Todd-Hewitt broth were found to contain trace amounts of sucrose, as did Trypticase soy broth (BBL), whereas brain heart infusion broth (Difco and BBL) was found to be essentially free of sucrose. Almost all detectable GTase activity was cell associated when S. mutans B13 was grown in Todd-Hewitt or trypticase soy broth. Heat-treated B13 cells grown in Todd-Hewitt broth and cell-free, water-insoluble glucans bound free GTase and produced marked adherence in the presence of sucrose. Experiments strongly suggest that the binding sites for free GTase are the surface glucans, and cell-associated and extracellular GTases are most likely alternate states of the same enzyme protein.
Effect of cytochalasin D on Toxoplasma gondii cell entry
Authors: Ryning F W , Remington J S
Published: January 2020

Cytochalasin D did not prevent attachment but did prevent entry of Toxoplasma gondii into peritoneal macrophages and bladder tumor 4934 cells. Inhibition of entry of T. gondii into peritoneal macrophages by cytochalasin D was dose related and comparable to inhibition of phagocytosis. Prevention of entry of T. gondii into bladder tumor 4934 cells by cytochalasin D followed a dose response identical to that observed with peritoneal macrophages. After removal of the medium containing cytochalasin D, its effect was completely reversible, and the kinetics of the loss of inhibition followed a similar time course for both phagocytic and "nonphagocytic" cell types. The studies support the concept that the host cells actively participate in the process by which T. gondii gains entry into cells.
Immuno-stimulation by a ribosomal vaccine associated with a bacterial cell wall adjuvant in humans
Authors: Michel F B , Dussourd D'Hinterland L , Bousquet J , Pinel A M , Normier G
Published: January 2020

We have studied a new vaccine of ribosomal nature associated with glycoprotein cell walls from Klebsiella pneumoniae which served as an immunoadjuvant. Thus vaccine was administered by the aerosol route to working men free of any important disease, especially of respiratory disease. A total of 104 men working for the Commissariat à l'Energie Atomique, all volunteers, were randomly placed into two groups. During the first period, 51 patients (group I) were vaccinated three times a week during 5 weeks, and the second group was used as control. During the second period, which started on day 225, the control group received the vaccine, and the first group was revaccinated. Results of this experience show a significant difference in the immunity of the two groups. The specific antibodies increased with vaccination as illustrated by chi-square test (Yates correction), which corresponds to an independent probability equal to 0 (P = 0.5 X 10-4).
Acquired cellular resistance, delayed hypersensitivity, and altered macrophage migration in Listeria monocytogenes-infected guinea pigs
Authors: Dustoor M M , Blazkovec A A
Published: January 2020

A Listeria monocytogenes infection in guinea pigs was used to study the interrelationship between antigen-induced macrophage migration inhibition, delayed-type hypersensitivity, and acquired cellular resistance. Early after infection (at 2 and 7 days), very significant enhancement of macrophage migration was observed. Migration inhibition was detected beginning on day 14 and was uniformly observed only on day 21 of the infection, after which a shift again to enhancement was seen. The early detection (by day 2) of migration enhancement suggested that this assay may be more sensitive than assessment of delayed type hypersensitivity in vivo, which in this system was first detectable only on day 4. Acquired cellular resistance, as measured by enhanced survival following a high dose challenge with Listeria, was present from day 7 after infection until at least day 60. By splenic clearance studies, however, acquired cellular resistance was present only until day 14 after infection, suggesting that in this system splenic clearance was not a very reliable criterion for measuring acquired cellular resistance.
Pulmonary Infection of Mice with
Staphylococcus aureus
Authors: DeMaria Thomas F. , Kapral Frank A.
Published: January 2020

The survival of
Staphylococcus aureus
in the lungs of mice was studied under various conditions. Doses of 10
7
to 10
9
washed staphylococci were quantitatively introduced into the lungs after intratracheal inoculation in mice under either ether or sodium pentobarbital anesthesia. Mice were sacrificed at intervals, the lungs were excised and homogenized, and the cocci were enumerated by plate count. The 50% lethal dose was 6 × 10
8
cocci per mouse, and mice died within 24 h but without proliferation of the inoculum. Mice given 10
8
cocci intratracheally under pentobarbital anesthesia regularly survived and eliminated the organisms over a 48-h period. The use of ether anesthesia resulted in persistence of the inoculum for up to 48 h, but the organisms were then eliminated. Inability to proliferate did not appear to result from a lack of iron because pretreatment of the mice with ferric ammonium citrate or Imferon did not alter inoculum survival. Staphylococci inoculated intratracheally in mice infected with influenza virus 3 to 21 days previously showed no enhanced persistence or multiplication. Cocci preclumped with fibrinogen, inocula mixed with 10 times the number of Formalin-killed staphylococci, or inocula of the encapsulated Smith strain did not survive any better than conventional inocula, suggesting that phagocytosis might not be the sole mechanism for elimination. However, a sedimentable fraction from normal or infected lung homogenates proved either inhibitory or cidal for staphylococci in vitro.
Interstitial pneumonia and subclinical infection after intranasal inoculation of murine cytomegalovirus
Authors: Jordan M C
Published: January 2020

Although cytomegalovirus (CMV) infections are common throughout the world, little is known about the means of person-to-person transmission. To determine whether infection could be established by a respiratory route, studies were conducted in a murine CMV (MCMV) model by using intranasal inoculation. The infectious dose which resulted in pulmonary and systemic infection of half the mice was 100 plaque-forming units of MCMV. Here, infection was subclinical, but virus replicated in the lungs and subsequently disseminated via the blood to other organs within 7 days. The serum immunofluorescence antibody titer peaked by day 21. None of these mice died, although focal peribronchial interstitial pneumonitis was found in infected animals. In mice given greater than or equal to 10(4) plaque-forming units of MCMV intranasally, severe diffuse interstitial pneumonitis resulted uniformly, closely resembling that seen in immunocompromised patients and in newborn infants, and 20% of the animals died. Normal pulmonary architecture was obliterated by sheets of histiocytes, many containing MCMV intranuclear inclusions, and by accumulation of proteinaceous fluid in the interstitial and alveolar spaces. Of relevance to human disease, these experiments show that MCMV as a sole pathogen can cause severe interstitial pneumonitis in normal mice and that subclinical systemic infection results from respiratory inoculation of small amounts of virus.
Immunofluorescence and electron microscopy of the attachment of Mycoplasma synoviae to chicken embryo fibroblasts
Authors: Aldridge K E , Cole B C
Published: January 2020

The techniques of immunofluorescence and of transmission and scanning electron microscopy were used to demonstrate the attachment of Mycoplasma synoviae to chicken embryo fibroblasts. Although the organisms colonized the surface of many of the cells, there was marked variation in the number of organisms associated with individual cells.
Inhibition of mycoplasma-induced lymphocyte activation by sodium aurothiomalate
Authors: Naot Y , Merchav S
Published: January 2020

Sodium aurothiomalate, at concentrations of 10 to 150 microgram/ml of culture, inhibited rat lymphocyte stimulation by Mycoplasma pulmonis mitogen in a dose-dependent manner.
Encephalitozoon cuniculi antibodies in a specific-pathogen-free rabbit unit
Authors: Bywater J E , Kellett B S
Published: January 2020

We describe our discovery of Encephalitozoon cuniculi antibodies in a specific-pathogen-free rabbit colony. Small-sized samples had failed to reveal the presence of infection with a prevalence of about 5%. Using an India ink immunoreaction test by which we were able to visualize both negative and positive reactions, we were able to undertake a 100% screen of the colony of more than 700 rabbits and to repeat this 4 weeks later when we had culled the positive reactors. By collating the results of those tests with the results of tests on previously collected samples, we have been able to discuss and observe age and sex susceptibilities and the mode of transmission of the naturally occurring disease.
Adherence of
Mycoplasma gallisepticum
to Human Erythrocytes
Authors: Banai M. , Kahane I. , Razin S. , Bredt W.
Published: January 2020

Pathogenic mycoplasmas adhere to and colonize the epithelial lining of the respiratory and genital tracts of infected animals. An experimental system suitable for the quantitative study of mycoplasma adherence has been developed by us. The system consists of human erythrocytes (RBC) and the avian pathogen
Mycoplasma gallisepticum
, in which membrane lipids were labeled. The amount of mycoplasma cells attached to the RBC, which was determined according to radioactivity measurements, decreased on increasing the pH or ionic strength of the attachment mixture. Attachment followed first-order kinetics and depended on temperature. The mycoplasma cell population remaining in the supernatant fluid after exposure to RBC showed a much poorer ability to attach to RBC during a second attachment test, indicating an unequal distribution of binding sites among cells within a given population. The gradual removal of sialic acid residues from the RBC by neuraminidase was accompanied by a decrease in mycoplasma attachment. Isolated glycophorin, the RBC membrane glycoprotein carrying almost all the sialic acid moieties of the RBC, inhibited
M. gallisepticum
attachment, whereas asialoglycophorin and sialic acid itself were very poor inhibitors of attachment. Only part of the
125
I-labeled glycophorin bound to mycoplasmas could be removed by neuraminidase or by exchange with unlabeled glycophorin. It is suggested that glycophorin, representing the isolated major RBC receptor for
M. gallisepticum
, binds to the mycoplasmas both specifically, through its sialic acid moieties, and nonspecifically, through its exposed hydrophobic polypeptide moiety.
Cell-Mediated Immunity in Diabetes Mellitus
Authors: Plouffe Joseph F. , Silva Joseph , Fekety Robert , Allen Jamie L.
Published: January 2020

Cell-mediated immunity was evaluated in patients with diabetes mellitus by delayed hypersensitivity skin tests and in vitro lymphocyte transformations. Only 44% of diabetic patients had skin test reactivity to
Candida
antigen, compared with 88% of normal controls (
P
< 0.001). Insulin-dependent diabetic (IDD) patients had abnormally low lymphocyte transformation responses to phytohemagglutinin, concanavalin A, and streptokinase-streptodornase (
P
< 0.05). This defect was not corrected by culturing the cells in nondiabetic plasma. IDD patients with persistent hyperglycemia (fasting serum glucose level, >200 mg/dl) had lower levels of transformation than did IDD patients with fasting serum glucose levels less than 150 mg/dl. Lymphocytes from two IDD patients with poor lymphocyte transformation responses had marked improvement in response to phytohemagglutinin when the lymphocytes were cultured after a preincubation period designed to deplete cultures of suppressor activity. Seven IDD patients were studied serially over 12 months. Lymphocyte transformation responses in four of these patients improved coincidentally with a change in the level of fasting hyperglycemia from >200 to <150 mg/dl. The other three IDD patients with consistent fasting serum glucose levels of >200 mg/dl had poor lymphocyte transformation responses. Diabetic patients have demonstrable defects in lymphocyte function which improved in a small number of patients with reduction in the level of fasting hyperglycemia.
Rapid method for identification and enumeration of oral Actinomyces
Authors: Marucha P T , Keyes P H , Wittenberger C L , London J
Published: January 2020

Serotype-specific antisera prepared against whole cells of Actinomyces viscosus, A. naeslundii, and A. israeli were labeled with fluorescein dye and used to detect and quantitate antigenically related microorganisms in human dental plaque. By relating the DNA content of the dental plaque microflora to the number of Actinomyces present in the plaque samples, a reproducible method was developed for specifically enumerating five serotypic representatives of this genus found in human plaque.
Effects of Local Immunization with Glucosyltransferase Fractions from
Streptococcus mutans
on Dental Caries in Hamsters Caused by Homologous and Heterologous Serotypes of
Streptococcus mutans
Authors: Smith Daniel J. , Taubman Martin A. , Ebersole Jeffrey L.
Published: January 2020

Seven serotypes of
Streptococcus mutans
have been identified. The biochemical, genetic, and serological characteristics of these serotypes have indicated that certain serotypes are quite similar, whereas others are quite distinct. The effect of local immunization with glucosyltransferase (GTF) enzymes from serotypes
a, c
, or
g
on infection and disease caused by homologous or heterologous cariogenic
S. mutans
is reported. Organisms with either similar (
a
and
g
) or different (
c
and
g
) biochemical and serological characteristics were selected for heterologous challenge. NIH white hamsters were injected four times at weekly intervals with GTF prepared by 6 M guanidine-hydrochloride elution from water-insoluble glucan of serotypes
a, c
, or
g
, which resulted in enzyme (homologous) inhibitory activity in sera and salivas. After infection of GTF-immunized and sham-immunized groups of hamsters with cariogenic
S. mutans
of the same serotype as the injected antigen (homologous infection) or with
S. mutans
of a different serotype from the injected antigen (heterologous infection), the numbers of streptomycin-labeled
S. mutans
, caries, and lesions were determined. Immunization with GTF preparations from each of the three serotypes resulted in statistically significant reductions in the extent of infection and disease and number of lesions caused by infections with homologous cariogenic
S. mutans
. Statistically significant reductions in these three parameters were also observed in groups immunized with enzyme from serotype
a
(strain E49) and challenged with cariogenic serotype
g
(strain 6715) organisms; or immunized with enzyme from serotype
c
(strain Ingbritt) and challenged with cariogenic serotype
g
(strain 6715) organisms; or immunized with enzyme from serotype
g
(strain 6715) and challenged with cariogenic serotype
c
(strain Ingbritt) organisms. These studies suggest that soluble antigen preparations containing GTF from one serotype may elicit a protective immune response against infection with cariogenic
S. mutans
from many or possibly all serotypes.