bluuebunny/crossref_metadata_2025 huggingface dataset:
Transfer of a CFA/I-ST plasmid promoted by a conjugative plasmid in a strain of Escherichia coli of serotype O128ac:H12
Authors: Reis M H , Heloiza M , Affonso T , Trabulsi L R , Mazaitis A J , Maas R , Maas W K
Published: January 2020

Escherichia coli strains belonging to serotype O128ac:H12 and producing heat-stable enterotoxin (ST) and colonization factor CFA/I were found in Sao Paulo in children with diarrhea, but not in normal children. Segregants occurred in such strains with a frequency of about 10%, which have lost the ability to produce ST and CFA/I at the same time. From one strain, both properties were transformed jointly in matings to an E. coli K-12 strain. All such ST+ CFA/I+ progeny had received two plasmids of length 97 and 64 kilobases in the matings. Insertion of a transposon, Tn5, carrying a gene for kanamycin resistance, into the two plasmids enabled us to select for kanamycin-resistant progeny in further matings. Analysis of such progeny strains in terms of plasmid content and production of ST and CFA/I revealed that the larger plasmid carries the genes for St and CFA/I and is not self-transmissible, whereas the smaller plasmid does not carry any recognizable phenotypic traits, but is conjugative and promotes cotransfer of the larger plasmid with a frequency of about 30%.
Requirement for two discrete stimuli for induction of the intestinal rapid expulsion response against Trichinella spiralis in rats
Authors: Bell R G , McGregor D D
Published: January 2020

Rats subjected to a 7-day abbreviated enteral infection with Trichinella spiralis subsequently reject more than 90% of a challenge infection within 24 h. This process is known as rapid expulsion. In these experiments parabiotic rats were used to examine the factors that establish rapid expulsion in the intestine. Induction with low to moderate doses of worms required exposure to two separate stimuli. These initiated different responses; one was readily transferred between parabiotic rats, whereas the second response was sessile and restricted to the intestine. These two responses interacted synergistically to produce strong rapid expulsion. Stage-specific exposure of parabiotic rats to preadult or adult trichinae (or the unrelated parasite Heligmosomoides polygyrus) showed that only preadult worms induced the transferable factor. Exposure to adult worms or to H. polygyrus induced a strictly local intestinal effect that was nonspecific. It is suggested that preadult worms initiated an immune response specific for preadults. This was transferable between parabionts but was unable to produce rapid expulsion unless the intestine had been non-specifically stimulated. Intestinal stimulation is accomplished by exposure to adult worms in natural infections or artificial regimes. These results suggest novel techniques for the development of enteral antihelminth vaccines.
Genetic and physical evidence for plasmid control of Shigella sonnei form I cell surface antigen
Authors: Kopecko D J , Washington O , Formal S B
Published: January 2020

Virulent Shigella sonnei synthesize a surface antigen (form I) which appears to be one of several requirements needed for this host to invade epithelial cells. Upon restreaking on agar media, form I cells readily and irreversibly generate form II cells that lack the form I antigen. All form II cells are avirulent. Plasmid deoxyribonucleic acid of form I and II cells of four different S. sonnei isolates, obtained from different areas of the world, was analyzed by agarose gel electrophoresis. A large plasmid (approximately 120 megadaltons in three of the strains) that is present in form I cells was always absent from form II derivatives. Attempts to transfer conjugally only this large plasmid from form I to genetically marked form II cells were unsuccessful. However, a composite molecule, apparently formed by recombination between the large form I plasmid and a self-transmissible plasmid, was found to transfer the form I trait. Transconjugant S. sonnei strains acquiring the form I antigen could retransfer this trait to S. sonnei, Shigella flexneri, or Salmonella typhi. These preliminary findings demonstrate that S. sonnei form I antigen synthesis is mediated by a large plasmid which is lost spontaneously at a relatively high frequency from S. sonnei strains.
Immunosuppression and alterations of T-lymphocyte subpopulations after rubella vaccination
Authors: Arneborn P , Biberfeld G , Wasserman J
Published: January 2020

Lymphocyte stimulation tests and determinations of T-lymphocyte subpopulations were undertaken in 11 subjects before and after rubella vaccination and in 11 controls. The lymphocyte stimulation response to phytohemagglutinin was suppressed 7 to 10 days after vaccination. The proportion of T lymphocytes with receptors for the Fc part of immunoglobulin G increased after vaccination, whereas there was no significant change in the proportion of T lymphocytes with immunoglobulin M-Fc receptors.
Complement activation induced by rabbit rheumatoid factor
Authors: Meyer R R , Brown J C
Published: January 2020

Rabbit rheumatoid factor produced in animals by hyperimmunized with group C streptococcal vaccine activated guinea pig complement. Anti-streptococcal serum was fractionated by Sephacryl S-200 chromatography into excluded (19S) and included (7S) material and examined for hemolytic activity in a sensitive homologous hemolytic assay system. In the presence of complement, both 19S and 7S antistreptococcal serum fractions induced lysis of bovine (ox) erythrocytes coated with mildly reduced and carboxymethylated rabbit anti-erythrocyte immunoglobulin G. That rabbit rheumatoid factor was responsible for the observed hemolytic activity was substantiated by hemolytic inhibition assays. Significant inhibition of hemolysis was effected when antistreptococcal serum fractions were incubated in the presence of human immunoglobulin G, rabbit immunoglobulin G, and Fc, whereas, no inhibition was detected when the same fractions were tested in the presence of rabbit Fab or F(ab')2 fragments. Deaggregation of inhibitor preparations revealed a preferential reactivity of rheumatoid factor for rabbit immunoglobulin G. In addition to the rheumatoid factor-dependent hemolytic activity observed in humoral preparations, immunoglobulin G-specific antibody-forming cells in spleen and peripheral blood lymphocyte isolates were enumerated by plaque-forming cell assay.
Role of complement in chemotaxis: study of a localized infection
Authors: Wilson D M , Ormrod D J , Miller T E
Published: January 2020

A model of Escherichia coli-induced pyelonephritis was used to study the effect of complement depletion in an organ-specific, nonimmunological inflammatory lesion in rats. In this model of a local infection, which can be considered to be nonspecific inflammatory stimulus, the depletion of complement by the administration of a purified cobra venom factor did not alter the course of the disease. There were minor differences when the results from complement-depleted and normocomplementemic animals were compared, but the composition of the inflammatory infiltrate was not greatly altered. Therefore, the presence of C3 and a functional complement system are relatively unimportant factors in determining the characteristics of the inflammatory response in a localized infection-induced lesion.
Dimethyl sulfoxide inhibits killing of Staphylococcus aureus by polymorphonuclear leukocytes
Authors: Repine J E , Fox R B , Berger E M
Published: January 2020

Increasing concentrations of the highly permeable, hydroxyl radical scavenger dimethyl sulfoxide progressively decreased killing of Staphylococcus aureus 502A by human polymorphonuclear leukocytes; methane, a product of the reaction of the hydroxyl radical with dimethyl sulfoxide, was generated in the process.
Adhesion, hemagglutination, and virulence of Escherichia coli causing urinary tract infections
Authors: Hagberg L , Jodal U , Korhonen T K , Lidin-Janson G , Lindberg U , Svanborg Edén C
Published: January 2020

The capacity of 453 Escherichia coli strains to agglutinate erythrocytes and yeast cells and to attach to human urinary tract epithelial cells was tested. The strains were isolated from the urine of patients with acute pyelonephritis, acute cystitis, or asymptomatic bacteriuria and from the stools of healthy school children. Three main patterns of hemagglutination were found: (i) mannose-resistant agglutination of human erythrocytes alone or simultaneously with mannose-sensitive agglutination of guinea pig erythrocytes; (ii) only mannose-sensitive agglutination of guinea pig and other erythrocytes; and (iii) no agglutination. Strains with mannose-resistant agglutination of human erythrocytes alone or in combination with mannose-sensitive hemagglutination attached in high numbers to human urinary tract epithelial cells. Bacteria inducing only mannose-sensitive hemagglutination attached in low numbers, and non-agglutinating strains did not bind to the urinary tract epithelial cells. The bacterial surface antigen(s) mediating mannose-resistant hemagglutination of human erythrocytes and attachment to human urinary tract epithelial cells may be one factor selecting for E. coli from among the fecal flora which infect the urinary tract. The highest proportion of strains with this property was found among acute pyelonephritis isolates (77%), and the lowest proportion of strains with this property was found among normal fecal E. coli (16%).
Effect of splenectomy on the size of amoebic liver abscesses and metastatic foci in hamsters
Authors: Ghadirian E , Meerovitch E
Published: January 2020

The role of the spleen in hepatic amoebiasis in hamsters was studied. In hamsters receiving an intrahepatic inoculation of 10(5) trophozoites of axenic Entamoeba histolytica at 7 or 14 days postsplenectomy, the mean weight of metastatic foci increased significantly when compared with sham-splenectomized or intact controls. In contrast, when both splenectomy and intrahepatic inoculation with amoebae were carried out at the same time, there was not only a significant increase in the mean weight of metastatic foci but also in the liver abscess. It is suggested that the spleen is important for host defense against E. histolytica infection, especially in the reduction in the degree of metastatic spread from the primary site.
Immune response to herpes simplex virus infections: virus-specific antibodies in sera from patients with recurrent facial infections
Authors: Zweerink H J , Stanton L W
Published: January 2020

Radioimmunoprecipitation assays were used to identify antibodies against a number of herpes simplex virus type 1-specific antigens in serum samples from individuals with recurrent facial herpes virus infections and from seropositive individuals without recurrent infections. Individuals with recurrent infections contributed three sequential serum samples each: immediately after the appearance of lesions, 3 weeks later, and 3 months later. Antibodies against at least 18 viral polypeptides were present in all positive sera: these included antibodies against the major nucleocapsid polypeptide (approximate molecular weight, 150,000) and against two glycopolypeptides with molecular weights of 115,000 to 130,000. No significant differences were observed between the serum samples in regard to their virus-specific antibody composition. The high-molecular-weight glycopolypeptides were partially purified and used in quantitative titration experiments. All sera tested were equally reactive with this material. It was concluded that under the experimental conditions an individual's susceptibility to recurrent herpetic infections could not be correlated with quantitative or qualitative changes in the levels of virus-specific antibodies.
Role of antibody in Coxiella burnetii infection
Authors: Humphres R C , Hinrichs D J
Published: January 2020

BALB/c mice infected with Coxiella burnetii phase I developed a state of acquired resistance which could be detected during week 2 postinfection. Immune serum, administered to normal mice 24 h before challenge with C. burnetii, appeared to accelerate the development of resistance. An increased clearance rate could be measured in these serum recipients 1 week postinfection. Simultaneous administration of immune serum and C. burnetii did not affect the normal clearance rate of rickettsiae from the spleens of infected mice during week 1, but enhanced clearance of the organism by 14 days postchallenge. Passive transfer of immune serum 24 h after challenge of normal mice with viable C. burnetii had no effect on rickettsial growth within the spleens of animals treated in this fashion. Treatment of athymic mice with immune serum 24 h before challenge with C. burnetii had no effect on rickettsial multiplication within the spleens of these T-cell-deficient animals.
General Transduction in Vibrio cholerae
Authors: Ogg J E , Timme T L , Alemohammad M M
Published: January 2020

Evidence was obtained for general transduction in Vibrio cholerae. Transduction of three amino acid markers and three antibiotic resistance characters was demonstrated using strains of biotype eltor and biotype cholerae. Some of the genetic characters were transduced from a biotype eltor donor (and its mutant derivatives) to biotype cholerae and eltor recipients. For the genetic traits examined, the frequencies of transduction ranged between 10(-5) and 10(-8). Maximal frequencies were obtained with transducing phage lysates that were irradiated with ultraviolet light. The development of a system of general transduction will now aid in fine structure analysis and detailed mapping of the chromosome of V. cholerae.
Binding of bacteria from the genus Brucella to human B lymphocytes
Authors: Bratescu A , Mayer E P , Teodorescu M
Published: January 2020

In previous studies, we have shown that various lymphocyte subpopulations bind different strains of bacteria of different genera and species. Among these bacteria was a strain of Brucella melitensis which bound to all human B lymphocytes. To determine whether the binding of B. melitensis to human B lymphocytes was strain, species, or genus characteristic, we tested the binding of B. melitensis, Brucella abortus, Brucella ovis, Brucella suis, Brucella canis and Brucella neotomae to human normal and leukemic B lymphocytes. The binding of different Brucella species to B lymphocytes was determined by single- and double-labeling experiments in which a strain of Escherichia coli, coated with anti-light chain antibodies, was used as a marker for B cells. As in previous experiments, we found that B. melitensis and antibody-coated E. coli bound to the same cells. Also, we found that all the other species of bacteria tested bound to the B lymphocytes, normal or leukemic. B. ovis and B. neotomae, which are not human pathogens, bound to fewer B lymphocytes than did the human pathogens B. abortus, B. melitensis, B. suis, and B. canis. Furthermore, we found that the quality of rosettes formed by the nonpathogenic bacteria with the lymphocytes, i.e., the number of bacteria per lymphocytes, was lower than that of pathogenic Brucella species. We conclude that all of the Brucella species tested have the ability to bind to human B lymphocytes, but that only those which are human pathogens bind firmly to all B lymphocytes and may be used as reliable markers for these cells. We also suggest that the binding of Brucella species to B lymphocytes may have some bearing on the pathogenesis of brucellosis in humans.
Macrophage antimicrobial activity: evidence for participation by lysosomes in the killing of Saccharomyces cerevisiae by normal resident macrophages
Authors: Hart P D
Published: January 2020

Ammonium chloride added to normal resident mouse peritoneal macrophages reduced the rate of killing of ingested Saccharomyces cerevisiae. It is suggested that this is attributable to the inhibition by ammonia of phagosome-lysosome fusion or of lysosomal protein degradation and that, consequently, lysosomal mechanisms contribute to the normal killing of these yeasts.
Specific skin-reactive protein from culture filtrate of Mycobacterium bovis BCG
Authors: Nagai S , Matsumoto J , Nagasuga T
Published: January 2020

A highly purified protein, named MPB70, was isolated from the culture filtrate of Mycobacterium bovis BCG. This protein accounted for more than 10% of the proteins secreted into the culture medium. MPB70 was purified by precipitation with ammonium sulfate, followed by treatment with diethylaminoethyl ion exchanger, with or without 3 M urea, and by gel filtration. The final MPB70 preparation was homogenous as judged by several analyses. The molecular weight was estimated to be 18,000 by electrophoresis or molecular sieve and 15,100 by sedimentation equilibrium. The preparation did not contain sugars. The amino acid composition did not include cysteine or tryptophan. In skin reaction, MPB70 was a strictly BCG-specific antigen and, among the guinea pigs sensitized with the heat-killed cells of the various species of mycobacteria--Mycobacterium tuberculosis strains H37Rv and Aoyama B, Mycobacterium kansasii, Mycobacterium intracellulare, Mycobacterium phlei, and BCG, it elicited a delayed cutaneous reaction only in the guinea pigs sensitized with BCG. The potency of MPB70 in the skin reaction was about one-twentieth of the standard purified protein derivative.
In vitro responses of guinea pig peritoneal macrophages to Legionella pneumophila
Authors: Kishimoto R A , White J D , Shirey F G , McGann V G , Berendt R F , Larson E W , Hedlund K W
Published: January 2020

Transmission and scanning electron microscopy were used to study the phagocytosis of virulent and avirulent strains of Legionella pneumophila. The interaction between L. pneumophila and peritoneal macrophages from normal guinea pigs or from animals that had survived infection was studied. The virulent strains survived and proliferated within the phagocyte after ingestion by either type of macrophage, whereas the avirulent strain of bacteria was killed by normal macrophages. Although the addition of immune serum enhanced phagocytosis, the outcome was the same as with normal serum.
Enhancement of plaque formation and cell fusion of an enteropathogenic coronavirus by trypsin treatment
Authors: Storz J , Rott R , Kaluza G
Published: January 2020

Plaque formation, replication, and related cytopathic functions of the enteropathogenic bovine coronavirus strain L9 in bovine fetal thyroid (BFTy) and bovine fetal brain (BFB) cells were investigated in the presence and absence of trypsin. Plaque formation was enhanced in both cell types. Plaques reached a size with an average diameter of 5 mm within 4 days with trypsin in the overlay, whereas their diameter remained less than 1 mm at this time after plating without trypsin in the overlay. Fusion of both cell types was observed 12 to 18 h after infection when trypsin was present in the medium. Fusion was not observed in infected BFB cell cultures and was rarely observed 48 h after infection of BFTy cells maintained with the trypsin-free medium. The largest polycaryons formed had 15 to 22 nuclei. They then lysed and detached. Cell fusion depended on de novo synthesis of hemagglutinin and infectivity. Fusion from without was not observed. Virus produced under trypsin-enhancing conditions accompanied by cell fusion did not lyse mouse erythrocytes that reacted with L9 coronavirus hemagglutinin. Trypsin-treated, infected BFTy cultures produced coronaviral particles that excluded stain from the envelope confinement. These virions had uniformly shorter surface projections than did the viral forms generated by trypsin-free cell cultures.
Hamster (Mesocricetus auratus) enteritis caused by epithelial cell-invasive Escherichia coli
Authors: Frisk C S , Wagner J E , Owens D R
Published: January 2020

When inoculated orally, Escherichia coli strain 1056 caused acute enteritis in 7 of 22 weanling hamsters. E. coli strain 1056 was isolated from the ileum of a hamster with proliferative ileitis. It was lactose negative, nonmotile, and anaerogenic. By electron microscopy and indirect fluorescent-antibody techniques, E. coli strain 1056 was detected in absorptive epithelial cells, resembling invasive E. coli and shigella infections of other species. Ileitis did not progress to epithelial cell hyperplasia, which is characteristic of proliferative ileitis of hamsters. A control group of 10 hamsters, inoculated with nonenteropathogenic E. coli isolated from a normal hamster, did not develop signs or lesions.
Interference of secretory immunoglobulin A with sorption of oral bacteria to hydroxyapatite
Authors: Kilian M , Roland K , Mestecky J
Published: January 2020

The potential of secretory immunoglobulin A (S-IgA) to interfere with the initial phase of dental plaque formation was studied by using an in vitro method which permits the quantitative determination of the sorption of radiolabeled oral bacterial cells to hydroxyapatite (HA) beads. The importance of specific S-IgA antibodies was evaluated by a comparison of the effect of pure preparations of colostral S-IgA, polymeric myeloma IgA, or preabsorbed S-IgA. Specific antibody molecules bound at the HA surface significantly enhanced the sorption of two Streptococcus sanguis strains. In contrast, HA-bound S-IgA antibodies inhibited the sorption of Streptococcus mitior and Streptococcus salivarius. The same was true for Streptococcus mutans cells, but only when they were propagated in the absence of sucrose. Suspended in saliva, cells of all streptococcal species adhered in significantly lower numbers to HA. Comparative experiments with bacteria suspended in solutions of various preparations of IgA or immunoglobulin-deficient salivas with S-IgA or myeloma IgA added indicated that the adherence inhibition seen with S. Sanguis, S. mitior, S. salivarius, and glucose-grown S. mutans was partly attributable to functions of S-IgA antibodies. Under the in vitro conditions of the study, S-IgA antibodies had no effect on the sorption of sucrose-grown S. mutans, Actinomyces viscosus, and Actinomyces naeslundii to HA. The results indicated that S-IgA can interfere with the sorption of some oral bacteria to HA by several different functions.
Antibacterial and Antitoxin Responses in the Serum and Milk of Cholera Patients
Authors: Majumdar Anis S. , Dutta Phalguni , Dutta Dharitri , Ghose Asoke C.
Published: January 2020

Antibacterial and antitoxin responses in the acute and convalescent (7 to 10 days) sera of 14 cholera patients were determined by various serological techniques. Similar studies were also carried out with corresponding milk samples of six of these patients who were lactating women. A significant rise in antibacterial titers was observed in all convalescent serum and milk samples. A similar rise in antitoxin titers was observable in all serum and four milk samples. Specificity of the antibacterial titers was further evaluated by the indirect hemagglutination test using lipopolysaccharide antigen, and close correlations were noted between these titers and vibrio agglutination (
P
<0.001) and vibriocidal (
P
<0.001) titers of sera. Serum and milk convalescent cholera patients could effectively neutralize cholera toxin action in vivo, although the neutralizing activity of serum was higher than that of milk. Determination of antibody titers by the enzyme-linked immunosorbent assay demonstrated that anti-lipopolysaccharide activity in sera belonged predominantly to immunoglobulin M (IgM) and, to a lesser extent, to IgG and IgA, whereas such activity in milk was mostly contributed by secretory IgA, although some IgM antibodies also could be detected. On the other hand, antitoxic activity in convalescent sera primarily belonged to IgG, whereas such activity in milk was almost exclusively contributed by secretory IgA. These results demonstrate that an antibody response in the mammary gland was stimulated due to the antigen exposure in the gut and are consistent with the idea of a common homing pattern of immunocytes within the secretory immune system. Moreover, some differences in the antibody production mechanism between the systemic and secretory immune systems are indicated.
Shigella sonnei phase I and phase II: susceptibility to direct serum lysis and opsonic requirements necessary for stimulation of leukocyte redox metabolism and killing
Authors: Madonna G S , Allen R C
Published: January 2020

The synthesis of the lipopolysaccharide O-specific repeat polymer by Shigella sonnei phase I is a clearly defined bacterial virulence factor necessary for penetrating epithelial cells; S. sonnei phase II does not synthesize this antigen and is uniformly avirulent. The serum opsonic requirements, relative to differences in gross lipopolysaccharide structure, were investigated by quantification and comparison of polymorphonuclear leukocyte (PMNL) metabolism and PMNL-mediated microbicidal action to phase I and phase II organisms, using normal and immune serum. The stimulation of PMNL O2-redox metabolism, as required for oxidative killing, was quantified by a chemiluminescent technique, using luminol as a chemilumigenic substrate. Susceptibility to direct serum or serum PMNL-mediated killing was evaluated by serum and serum-phagocytic killing assays. Stimulation of PMNL metabolism and phagocytic killing of S. sonnei phase I required opsonification by specific phase I antibody plus the classical pathway of complement. S. sonnei phase II was susceptible to direct complement-mediated serum killing. Likewise, opsonification of the phase II microbe, as measured by PMNL-associated chemiluminescence, was effected by complement in the absence of immune antibody. These data demonstrate the importance of the O-specific repeat polymer in protecting the microbe from the microbicidal action of PMNL and the bacteriolytic action of serum.
Adherence of bacteria to vaginal epithelial cells at various times in the menstrual cycle
Authors: Sobel J D , Schneider J , Kaye D , Levison M E
Published: January 2020

Adherence of vaginal isolates of Escherichia coli, Lactobacillus species, group B streptococci, Gardnerella vaginalis and Neisseria gonorrhoeae to exfoliated vaginal epithelial cells was studied in 10 healthy, sexually active medical students. Studies were done pre- and postmenstrually and at midcycle for two consecutive menstrual cycles. The mean number of adherent bacteria per vaginal epithelial cell (range) was 3.4 (0 to 14) for E. coli, 60.5 (12 to 152) for Lactobacillus species, 54.8 (21 to 76) for group B streptococci, 67.4 (15 to 161) for G. vaginalis, and 58.9 (15 to 186) diplococci for N. gonorrhoeae. Adherence of G. vaginalis increased with increasing acidity of the test medium (pH 4 to 8). There were no significant differences in adherence to vaginal epithelial cells obtained at the various times in the menstrual cycle for any of the organisms (p greater than 0.05). The pattern and extent of adherence among the women was similar for each organism. In this in vitro model, adherence characteristics did not vary with the menstrual cycle.
Factors Affecting Complement Activation by
Staphylococcus aureus
Cell Walls, Their Components, and Mutants Altered in Teichoic Acid
Authors: Wilkinson Brian J. , Kim Youngki , Peterson Phillip K.
Published: January 2020

In a previous study,
Staphylococcus aureus
purified cell walls (PCW), consisting of peptidoglycan (PG) plus covalently linked teichoic acid (TA), were found to be more active in complement consumption than isolated PG. Isolated TA has now been shown to be capable of activating complement. Mild sonication markedly increased the ability of PG to activate complement but had essentially no effect on the activities of PCW and TA. Optimal sonication of PG did not yield activities equal to those of PCW in dose-response and kinetic studies, which may imply that TA plays some role in complement consumption. Sonication did not lead to solubilization of PCW or PG but may have enhanced the activity of PG in complement consumption by better dispersing PG particles, thereby exposing more surface area. Lysostaphin solubilization of PCW and PG markedly decreased their activities in complement consumption. The PCW of an
S. aureus
TA-deficient mutant, which were mostly PG, caused similar amounts of complement consumption as the parent strain PCW. Of the treatments of PCW commonly used to isolate PG, formamide and periodate extractions in particular led to PG preparations with lower activities in complement consumption than the PCW from which they were prepared, although these activities were stimulated by sonication. When whole organisms were studied by using a TA-deficient mutant, a mutant with an additional cell surface polymer, and the TA-containing parent strains and complement consumption by these strains was compared, no difference was found in either the rate or the degree of complement activation. This led to experiments demonstrating that both material released extracellularly from staphylococci and the cytoplasmic fraction of
S. aureus
were active in complement consumption. The results of these experiments indicate that both physical and chemical factors must be considered in studies of complement activation by isolated bacterial cell wall components. Under certain conditions, staphylococcal TA may enhance complement activation, but studies with whole organisms clearly show that this cell wall constituent does not play an essential role in this process. In addition, studies of complement consumption with intact organisms have demonstrated that there may be contributions both from cell surface components and from material released by the cells.
Mouse-protecting and histamine-sensitizing activities of pertussigen and fimbrial hemagglutinin from Bordetella pertussis
Authors: Munoz J J , Arai H , Cole R L
Published: January 2020

We compared the protective activities of fimbrial hemagglutinin (FHA) and pertussigen and their respective antibodies in mice infected intracerebrally with Bordetella pertussis. We found that mice were protected by a 1.7-microgram/mouse dose of pertussigen which was free of detectable FHA and was detoxified by treatment with glutaraldehyde. A pertussigen preparation made from cells grown in shake cultures that did not contain demonstrable FHA protected mice at a dose of 1.4 microgram/mouse. FHA at a dose of 10 microgram/mouse protected mice from intracerebral infection, but it also sensitized mice to histamine at a dose of 2 micrograms/mouse, which indicated that it was contaminated with pertussigen. When FHA was obtained free of demonstrable pertussigen, it failed to sensitize mice to histamine at a dose of 30 micrograms/mouse and to protect mice from infection at a dose of 12 micrograms/mouse (largest doses tested). Passive protection tests with antisera known to contain antibodies to pertussigen protected mice from intracerebral infection, whereas sera lacking anti-pertussigen antibodies but containing high concentrations of anti-FHA antibodies did not protect mice. The most important antigen for the immunization of mice against intracerebral infection with B. pertussis appears to be pertussigen.
Influence of Mucoid Coating on Clearance of
Pseudomonas aeruginosa
from Lungs
Authors: Blackwood Linda L. , Pennington James E.
Published: January 2020

Pulmonary infection with mucoid strains of
Pseudomonas aeruginosa
in present in the majority of cystic fibrosis patients with chronic lung disease. It has been postulated that this mucoid coating may act to decrease lung clearance of
Pseudomonas
by limiting access of phagocytes, antibodies, and antibiotics to the bacteria. To determine whether mucoid coating of
Pseudomonas
might decrease intrapulmonary killing, groups of guinea pigs were infected with intrabronchial instillations of equivalent numbers of mucoid and nonmucoid
Pseudomonas.
For this study, mucoid strains of
Pseudomonas
were obtained from cystic fibrosis sputa and passaged on blood agar plates to obtain their nonmucoid revertants. Animals were then sacrificed at timed intervals after infection, and quantitative cultures were performed on lung homogenates. In all cases, mucoid challenge strains retained their mucoid morphology after passage in guinea pig lungs. No difference in killing of mucoid and nonmucoid
Pseudomonas
could be detected at 6, 24, or 48 h after lung infection. Further challenge studies used guinea pigs that were either prevaccinated with lipopolysaccharide
P. aeruginosa
vaccine or else treated with tobramycin sulfate after infection. Nonvaccinated or untreated controls had reduced intrapulmonary killing of
Pseudomonas
compared with vaccinees or treated groups (
P
< 0.02 and
P
< 0.01, respectively). However, there were no differences in pulmonary killing of mucoid and nonmucoid
Pseudomonas
in the presence of either specific antibodies or antibiotic. We conclude from these studies that mucoid coating of
Pseudomonas
does not selectively impede mechanisms of intrapulmonary killing in guinea pig lungs.
Artificial
Salmonella
Vaccines:
Salmonella typhimurium
O-Antigen-Specific Oligosaccharide-Protein Conjugates Elicit Protective Antibodies in Rabbits and Mice
Authors: Svenson Stefan B. , Lindberg Alf A.
Published: January 2020

Several saccharides representative of the O-antigenic polysaccharide chain of
Salmonella typhimurium
(O antigens 4 and 12) were used as haptenic groups covalently linked to bovine serum albumin. The disaccharide abequose 1 → 3 D-mannose was synthesized, and the [Formula: see text] tetra-, octa- and dodecasaccharides were isolated after cleavage of isolated
S. typhimurium
O-polysaccharide chains by using bacteriophage
endo
-glycosidases. Rabbits immunized with the saccharide-protein conjugates suspended in Freund complete adjuvant readily responded with O4 antibody titers as high, or almost as high, as those elicited by heat-killed bacteria. The octa- and dodecasaccharide conjugates also gave rise to O12 antibody titers. The antibody response in mice differed in two ways from that seen in rabbits: mice did not respond with measurable antibody production against the disaccharide haptens, and the highest
S. typhimurium
lipopolysaccharide antibody response elicited by the saccharide haptens was still approximately 50-fold lower than that elicited by heat-killed bacteria. The latter difference may be a consequence of the fact that the mouse preferentially produces antibodies against the galactose residue which is terminal in the hapten but not in the native O-antigenic polysaccharide chain. Antibodies elicited in rabbits against all saccharide-protein conjugates protected passively transferred mice against intraperitoneal challenge with 100 times the 50% lethal dose of
S. typhimurium
SH 2201 (O4, 12) but not against challenge with
S. enteritidis
SH 2204 (O9, 12). The antibodies elicited by the saccharide-protein conjugates protected as well as antibodies elicited by heat-killed bacteria.
Comparative virulence of Haemophilus influenzae with a type b or type d capsule
Authors: Roberts M , Stull T L , Smith A L
Published: January 2020

To determine the importance of specific capsule type in the pathogenesis of invasive Haemophilus influenzae disease, we compared the virulence of type b and type d strains isolated from different children with the virulence of transformation-derived type b and type d organisms. In addition, the unencapsulated derivative of these strains was also examined. Virulence was assessed by determining the ability of the strains to produce bacteremia with intranasal or subcutaneous inoculation. Unencapsulated derivatives were unable to cause bacteremia by any route; all type b strains (whether natural or derived by transformation), a natural type d, and a type d derived by transformation were able to produce bacteremia with similar frequency (42 to 62%) when 10(7) colony-forming units was given intranasally. Subcutaneous inoculation of 10(3) colony-forming units of strains with the type b capsule produced bacteremia at a greater frequency than did the strains with the type d capsule (P less than 0.002). The type d isolate was more virulent than a mutagenized derivative of the strain. We conclude that the type b strains are more virulent than type d when inoculated subcutaneously.
Kinetics of adenosinediphosphoribosylation of elongation factor 2 in cells exposed to diphtheria toxin
Authors: Moynihan M R , Pappenheimer A M
Published: January 2020

When susceptible cells are exposed to diphtheria toxin (Mr, 62,000) the N-terminal 21,150-dalton A fragment of toxin reaches the cytoplasm, where it catalyzes the transfer of adenosinediphosphoribose from nicotinamide adenine dinucleotide to elongation factor 2 (EF2). Adenosinediphosphoribose-EF2 is inactive, so that protein synthesis is blocked. Using a simple, rapid assay for the amount of adenosinediphosphoribosylatable EF2 in unfractionated lysates of cultured cells we have followed the kinetics of inactivation of EF2 in CV-1 and BHK cells exposed to diphtheria toxin. With both cell lines a lag was observed between the addition of toxin to the cells and the adenosinediphosphoribosylation of EF2. The lag decreased with increasing toxin concentration until a limiting value of about 12 min was reached. The rate of adenosinediphosphoribosylation of EF2 after the lag was 10 to 20 times more rapid in CV-1 cells than in BHK cells exposed to the same toxin concentration. The concentration of fragment A active in the cytoplasm of toxin-treated cells was estimated from the rate of adenosinediphosphoribosylation observed. Comparison of these estimates with data from studies of binding of 125I-toxin to cells suggests that the fragment A of only a minor fraction of toxin molecules bound to cell surface receptors reaches the cytoplasm and participates in the inactivation of EF2. A model summarizing our current views on the process by which fragment A enters cells is presented.
Sucrose-induced ecological response of experimental dental plaques from caries-free and caries-susceptible Human volunteers
Authors: Minah G E , Lovekin G B , Finney J P
Published: January 2020

Microbial succession, experimental cariogenicity, and sucrose metabolism were examined in dental plaques which developed on sterile bovine enamel inserts in acrylic palatal appliances. The appliances were worn for a period of 14 days by 10 caries-free and 10 caries-susceptible human volunteers. Three of six enamel inserts on each appliance were exposed extraorally to 10% sucrose in 0.85% saline six times a day, and three were exposed simultaneously to 0.85% saline as a control environment. The responses of the plaques to the high-sucrose environment in both caries status populations were compared. In all plaques, exposure to 10% sucrose stimulated the succession of Veillonella spp., Lactobacillus spp., Streptococcus salivarius, and, to a lesser extent, Streptococcus mutans and a decline in levels of Streptococcus sanguis, Neisseria spp., and gram-negative anaerobic rods. Plaques from caries-free mouths, in contrast to those from caries-susceptible mouths, harbored higher levels of Veillonella spp., gram-negative anaerobic rods, and Neisseria spp. and lower levels of Lactobacillus spp. Sucrose-exposed plaques from caries-free mouths also induced less enamel microhardness changes and formed less lactic acid from [14C]sucrose during a 60-min incubation at 37 degrees C than did comparable plaques from caries-susceptible mouths. The experiments revealed consistent differences in the ecological response to a cariogenic substrate environment in plaques from the two populations, with plaques from caries-free subjects exhibiting less cariogenic potential than those from caries-susceptible subjects.
Protective effect of muramyl dipeptide analogs against infections of Pseudomonas aeruginosa or Candida albicans in mice
Authors: Fraser-Smith E B , Matthews T R
Published: January 2020

Two analogs of N-acetylmuramyl-L-alanyl-D-isoglutamine (muramyl dipeptide) were found to give better protection than muramyl dipeptide against intraperitoneal Pseudomonas aeruginosa infection or intravenous Candida albicans infection in mice. The analogs tested were N-acetyl-nor-muramyl-L-alanyl-D-isoglutamine and N-acetylmuramyl-L-alpha-amino-butyryl-D-isoglutamine. The optimum treatment was 80 mg/kg per day given once daily for 4 consecutive days before infection by the intraperitoneal, intravenous, or subcutaneous route. Dose response was limited. The compounds were not orally active. Synergism was seen between N-acetyl-nor-muramyl-L-alanyl-D-isoglutamine and gentamicin. No postinfection protection was observed. A nonspecific stimulation of macrophage cells by muramyl dipeptide analogs may contribute to the protection because antiinfective activity against Listeria monocytogenes given intraperitoneally was achieved with CBA mice.
Pathogenesis of Experimental Skin Infections Induced by Drug-Resistant Herpes Simplex Virus Mutants
Authors: Klein Richard J. , Friedman-Kien Alvin E. , DeStefano Eugene
Published: January 2020

The comparative analysis of the pathogenicity of a parental herpes simplex virus type 1 strain and its phosphonoacetic acid (PAA)-resistant and acyclovir (ACV)-resistant mutants showed marked differences among them. After orofacial skin inoculation of hairless mice the parental and PAA-resistant viruses were detected during the first 4 days after infection at high and increasing titers in the trigeminal ganglia; the ACV-resistant mutant was present at low and decreasing titers in the ganglia. Severe and slow-healing skin lesions were produced by the parental and PAA-resistant viruses; mild and rapidly healing lesions were produced by the ACV-resistant mutant. Virus titers in ganglia and the intensity of skin lesions were related to the virus dose used in the primary infection. Latent infections became established in trigeminal ganglia of mice inoculated with 10
6.0
plaque-forming units of the parental or PAA-resistant virus; no latent infections were detected in ganglia of mice inoculated with 10
7.0
plaque-forming units of the ACV-resistant mutant. Serum antibody titers attained similar values 4 weeks after primary infection with both mutants and the parental virus. Mice infected with the ACV-resistant mutant were reinfected with the parental and PAA-resistant viruses; the degree of protection against development of skin lesions, mortality, and latency was related to the dose of ACV-resistant virus used in the primary infection. Mortality was prevented by a dose of 10
6.0
plaque-forming units, skin lesions were prevented by a dose of 10
6.5
plaque-forming units, and latency was prevented by a dose of 10
7.0
plaque-forming units of the ACV-resistant mutant. Protection against reinfection with the PAA-resistant mutant was achieved with lower doses than protection against the parental virus. Serum antibody titers showed a 4- to 15-fold increase after reinfection. The results suggest that the ACV-resistant, latency-negative mutant has many attributes of a live attenuated herpes simplex virus vaccine.
Respiratory tularemia: comparison of selected routes of vaccination in Fischer 344 rats
Authors: Jemski J V
Published: January 2020

Fischer 344 rats were given the attenuated live vaccine strain of Francisella tularensis by small-particle aerosol, intranasal instillation, or intraperitoneal, intramuscular, or subcutaneous injection. All of the vaccinated rats developed subclinical infection by 3 days after exposure, which cleared by day 28. Temporal patterns and concentrations of the live vaccine strain organism within the hosts were dependent on the route of vaccination. Pathological alterations were limited to minimal lung lesions in aerosol-vaccinated rats and mild splenitis in intraperitoneally vaccinated rats. Agglutinins to live vaccine strain were detected in the serum of each vaccinated animal and in the bronchoalveolar wash fluids of 66% of the aerosol-vaccinated rats. Agglutinin activity of the vaccinated rats was associated predominantly with the immunoglobulin M class. Regardless of the route of vaccine administration, all vaccinated rats survived an aerosol challenge of 5.3 log10 cells of virulent F. tularensis, whereas all nonvaccinated rats died. Systemic infection did not occur in the vaccinated rats. Pulmonary infection was not prevented in the vaccinated rats after aerosol challenge, but proliferation of the virulent F. tularensis organisms in the lungs was significantly lower (analysis of variance, P less or equal to 0.01) than that which occurred in the control animals. These studies demonstrate the utility of the inbred Fischer 344 rat as a model host for further investigations of F. tularensis infection and its associated immune response.
Platelet interactions with Candida albicans
Authors: Skerl K G , Calderone R A , Sreevalsan T
Published: January 2020

The interaction of human platelets and Candida albicans was studied. Platelet-rich plasma was obtained from freshly drawn blood or outdated platelet concentrates. From the platelet-rich plasma, a platelet extract was derived which stimulated germ tube formation by C. albicans when incubated with yeast cells at 37 degrees C. The active component(s) was heat stable, trypsin sensitive, and ribonuclease and deoxyribonuclease insensitive, and possessed cationic properties since it readily attached to carboxymethyl-Sephadex. The active component(s) seemed to bind to heparin also, since germ tube-promoting activity was eluted from a heparin-cyanogen bromide-activated Sepharose 4B column. In addition, platelet-derived growth factor (Collaborative Research, Inc.) stimulated germination when incubated with low amounts (0.4% final concentration) of bovine calf serum. The aggregation of platelets, prepared as platelet-rich plasma by C. albicans cell wall or alkali-extracted cell wall fractions, was also studied. Aggregation of platelets was observed when cell wall or cell wall fractions were incubated with platelet-poor plasma at 37 degrees C for 20 min and then added to platelet-rich plasma. The component of platelet-poor plasma which promoted aggregation of platelets by C. albicans cell wall or alkali-extracted fractions was inactivated at 56 degrees C (30 min) and by cobra venom factor, indicating a role for the alternate complement pathway in the aggregation response.
Detection of an immediate early herpes simplex virus type 1 polypeptide in trigeminal ganglia from latently infected animals
Authors: Green M T , Courtney R J , Dunkel E C
Published: January 2020

In this study, trigeminal sensory ganglia from animals with acute herpes simplex virus, type 1 (HSV-1) infection were compared to those with a latent infection for the expression of HSV-specific antigens. By the indirect immunofluorescence assay, antisera to an immediate early polypeptide of molecular weight 175,000, designated VP175 or ICP4, and a hyperimmune antiserum to HSV-1 were used to determine whether early viral polypeptides were being expressed in neurons during the latent stage of infection. All 17 ganglia from animals with acute infection (sacrificed 3 to 12 days postinfection) exhibited positive staining when treated either with anti-HSV-1 or with anti-VP175. Forty of 42 ganglia from animals sacrificed during the latent stage of infection (22 to 200 days postinfection) exhibited immunofluorescent staining when treated with anti-VP175. The staining appeared to be similar to that observed in ganglia from acutely infected animals stained with anti-VP175, except that the number and distribution of stained cells were markedly reduced. No immunofluorescence was observed in ganglia from noninfected control animals when stained with anti-VP175 or anti-HSV-1, or when ganglia from latently infected animals were stained with anti-HSV-1 or preimmune serum.