bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzymatic activities of cell-free extracts of Rickettsia typhi
Authors: Coolbaugh J C , Progar J J , Weiss E
Published: January 2020

Cell-free extracts of Rickettsia typhi were tested for activities of enzymes of the tricarboxylic acid cycle, of glutamate catabolism, and of glycolysis. The organisms were grown in the yolk sacs of chicken embryos, harvested shortly before the time of embryo death, purified by Renografin density gradient centrifugation, and ruptured in a French pressure cell. The following enzymatic activities were demonstrated: high levels of malate dehydrogenase (MDH), moderate levels of glutamate-oxaloacetate transaminase, glutamate, succinate, and isocitrate dehydrogenases, and citrate synthase, and low levels of glutamate-pyruvate transaminase. The specific activities of some of these enzymes were higher when the rickettsiae were harvested at a time of active proliferation, 3 to 4 days prior to embryo death. Rickettsial MDH was differentiated from host MDH by its migration pattern on polyacrylamide gel electrophoresis. The activities of MDH and two other dehydrogenases, demonstrable after the cells had been disrupted, were absent from purified, intact rickettsial preparations. No activity was detected for glucose-6-phosphate, 6-phosphogluconate, glyceraldehyde-3-phosphate, lactate dehydrogenases, phosphoglucose isomerase, fructoaldolase, or pyruvate kinase. Our results suggest that extracts of R. typhi that contain demonstrable enzymes involved in the catabolism of glutamate and tricarboxylic acid cycle intermediates, unlike Coxiella burnetti, lack detectable glycolytic activity.
Depression of lymphocyte response to concanavalin A in rabbits infected with Treponema pallidum (Nichols strain)
Authors: Pavia C S , Folds J D , Baseman J B
Published: January 2020

Peripheral blood lymphocytes isolated from rabbits in the early stages of Treponema pallidum infection responded poorly when exposed to concanavalin A in vitro. Maximal depression of blastogenesis occurred when lymphocytes were cultured in the presence of autologous serum in comparison with fetal calf or normal homologous rabbit serum.
Experimental Candida albicans infection in conventional mice and germfree rats
Authors: Rogers T , Balish E
Published: January 2020

Swiss-Webster white mice were intravenously infected with various doses of Candida albicans, and the viable units in their spleens, livers, lungs, and kidneys were determined at various intervals after challenge. The results showed that C. albicans multiplied to a greater extent in the kidneys of mice than in their spleens, lungs, or livers. The infection in mice was chronic; increasing numbers of C. albicans were observed in their kidneys until about 17 to 24 days postchallenge. Clearance of C. albicans from infected kidneys was not symmetrical, since the number of viable C. albicans in one kidney did not coincide with the viable counts observed in the opposite kidney of that same animal. Male and female mice did not differ in their overall susceptibility (50% lethal dose test) or in the number of viable C. albicans in the kidneys at various time intervals after infection. C. albicans also multiplied in the kidneys of germfree rats; however, the peak of the C. albicans infection in their kidneys occurred earlier than in those of conventional mice.
Suckling mouse model for detection of heat-stable Escherichia coli enterotoxin: characteristics of the model
Authors: Giannella R A
Published: January 2020

Although the suckling mouse assay is widely used for the detection of heat-stable Escherichia coli enterotoxin (ST), few data have been published concerning the reproducibility, optimal growth, and test conditions of this assay. Four strains of toxigenic E. coli known to elaborate both heat-labile enterotoxin and ST or ST alone were used to study these parameters. ST activity after heat treatment and the effect of purified choleragen were also examined. ST production was optimal in Casamino Acids-yeast extract media, but both Trypticase soy and brain heart infusion broths resulted in several false negative reactions. Growing cultures in roller tubes was the most reliable method of ST production. Shaking-flask cultures and stationary-grown cultures resulted in suboptimal ST production in several strains. Optimal mouse incubation time was 3 h, and fluid secretion did not rise thereafter. Adequate toxin production occurred after 16 to 24 h of incubation. The coefficient of variation of various toxins tested on many occasions varied between 10.5 and 15.7%. Toxin activity was stable for 6 months when frozen at - 20 C. There was no decrease in ST activity when heated at 65 C for 15 min, but a small decrease was observed in two of four strains after heating at 100 C for 30 min. Choleragen, tested at various doses and at multiple times, gave uniformly negative results. These studies indicate that when done under the proper conditions, the suckling mouse assay is a simple, rapid, and reproducible assay for E. coli ST.
Depression of the immune response to sheep erythrocytes in mice infected with Taenia crassiceps larvae
Authors: Good A H , Miller K L
Published: January 2020

Intraperitoneal infection of mice with larvae of the cestode parasite Taenia crassiceps results in depression of both primary and secondary antibody responses to sheep erythrocytes in vivo. The depression is not associated with a shift in kinetics of the response. Both immunoglobulin M (IgM) and IgG responses are depressed, but IgG is depressed more than IgM in the secondary response. Secondary in vitro sheep erythrocyte responses are consistently depressed in both spleen and mesenteric lymph node cell preparations from infected mice, whereas primary in vitro sheep erythrocyte responses are consistently depressed in mesenteric lymph node cell preparations but not always in spleen cell preparations. These results are consistent with antigenic competition. The cell type or types involved in mediation of the immunological defect in the infected animals remain to be identified.
Analysis of the intradermal response against a soluble cercarial antigenic preparation from Schistosoma mansoni
Authors: Katz S P , Colley D G
Published: January 2020

Intradermal testing was performed with a soluble cercarial antigenic preparation (CAP) from Schistosoma mansoni cercariae in CBA/J mice multiply infected with S. mansoni or sensitized with CAP. Both an early (5-h) response and a late (24- to 48-h) reaction to CAP, as measured by increase in dermal thickness, was elicited after injection of antigen into the ears of either multiply infected (3X-75) or CAP-sensitized (CAP/complete Freund adjuvant [CFA]) mice. Histopathological examination showed that the early response was primarily vascular in nature and involved a polymorphonuclear cell infiltrate in and around dilated capillaries. The late reaction to CAP consisted of a perivascular cellular infiltrate of polymorphonuclear and mononuclear cell types. Passive transfer of 3X-75-infected or CAP/CFA-sensitized serum (0.4 ml) to normal mice conveyed the ability to mount an early (5-h) response to CAP which was marked histopathologically by a prominent polymorphonuclear cell infiltrate. The majority of the responsiveness in normal mice after administration of lymph node cells (40 X 10(6)) from multiply infected or CAP/CFA-sensitized mice was observed 24 to 48 h after injection of CAP and was mononuclear in nature.
Isolation of a purified skin test antigen from Blastomyces dermatitidis yeast-phase cell wall
Authors: Lancaster M V , Sprouse R F
Published: January 2020

Preparative polyacrylamide gel electrophoresis was used to isolate individual components of an alkaline-soluble-water-soluble fraction of the cell wall of Blastomyces dermatitidis yeast phase. One component isolated demonstrated exceptional specificity and reactivity when tested on guinea pigs infected with B. dermatitidis. This component displayed no cross-reactivity when tested on animals infected with Histoplasma capsulatum. The significance of isolation of a purified, specific antigen is discussed.
Isolation and characterization of two new herpes-like viruses from capuchin monkeys
Authors: Lewis M A , Frye L D , Gibbs C J , Chou S M , Cutchins E C , Gajdusek D C , Ward G
Published: January 2020

Two herpes-like viruses were isolated from capuchin monkey (Cebus apella) brain and (Cebus albifrons) spleen cell cultures, respectively. Both isolates induced similar cytopathic effects consisting of rounded and ballooned cells in the original monkey cell cultures and in a wide range of permissive cell types. Neutralizing antibody to each virus was present in serum from the capuchin monkey from which it was isolated, but the two viruses did not cross-react by neutralization. Fluorescein isothiocyanate conjugates of hyperimmune rabbit serum to one of the isolates showed an antigenic cross relationship between the two isolates. By electron microscopy, herpes-like virus particles were observed in the nucleus and cytoplasm of infected human diploid fibroblast cell cultures. Virus-infected cell cultures stained with acridine orange revealed small deoxyribonucleic acid-containing intranuclear inclusion bodies. Both viruses were inhibited by 5-fluorodeoxyuridine and inactivated by chloroform or exposure to 56 degrees C for 30 min. Antisera prepared against 16 prototype herpesviruses and cytomegaloviruses did not neutralize approximately 100 50% tissue culture infective doses of either capuchin isolate. Neutralizing antibody to the capuchin isolates was detected in sera from 8 of 17 capuchin monkeys but not in sera from 16 humans, 15 chimpanzees, and 10 spider, 6 rhesus, and 5 squirrel monkeys.
Reovirus-like agent associated with fatal diarrhea in neonatal pigs
Authors: Lecce J G , King M W , Mock R
Published: January 2020

Large numbers of a reovirus-like agent were visualized with electron microscopy in bacteria-free gut homogenates obtained from piglets with a fatal diarrhea resembling transmissible gastroenteritis. The syndrome, of vomiting, diarrhea, dehydration, and death, was reproduced in piglets artificially infected with these bacteria-free gut homogenates. Reovirus-like particles persisted in serial piglet passage and none was seen in uninfected, asymptomatic controls. Hyperimmune sera (made in recovered piglets) aggregated the reovirus-like particles, as judged by immunoelectron microscopy, and neutralized the infectious agent. The cytoplasm in enterocytes on infected intestinal epithelium fluoresced when this hyperimmune sera was used in an indirect fluorescent antibody test. Feeding cow colostrum or diets containing porcine gamma globulin protected infected piglets. No cytopathogenic effect was noted in infected tissue cultures, nor did this agent affect neonatal guinea pigs, hamsters, mice, and rats. The agent did not agglutinate human O or A erythrocytes.
H and M antigens of Histoplasma capsulatum: preparation of antisera and location of these antigens in yeast-phase cells
Authors: Green J H , Harrell W K , Gray S B , Johnson J E , Bolin R C , Gross H , Malcolm G B
Published: January 2020

Antiserum has been prepared in rabbits against the H and M antigens of H. capsulatum with immunoelectrophoretic precipitin arcs used as vaccines. The antiserum is specific for H. capsulatum in the immunodiffusion test and can be used as reference serum for identifying antibodies to these antigens in sera from suspected cases histoplasmosis. We found that (1) hand m antigens are not located on the surface of yeast-phase cells and (ii) complement fixation releases the antigens reactive in the complement fixation test from yeast-phase cells.
Mechanisms of immunity in typhus infections. V. Demonstration of Rickettsia mooseri-specific antibodies in convalescent mouse and human serum cytophilic for mouse peritoneal macrophages
Authors: Beaman L , Wisseman C L
Published: January 2020

Antibodies in both mouse and human Rickettsia mooseri (Rickettsia typhi) convalescent serum that were cytophilic for mouse macrophages were demonstrated by the rosette technique. Mouse peritoneal macrophages, passively sensitized with early and late serum from mice with a sublethal infection of R. mooseri, were washed and exposed to rickettsiae. Rosettes of rickettsiae were found around macrophages, maintained at 4 degrees C, which had been sensitized with immune serum (direct sensitization of macrophages), but no rosettes were found around macrophages sensitized with serum from normal mice. When the macrophages were maintained at 34 degrees C after addition of the rickettsiae, phagocytosis of rickettsiae occurred, indicating one probable role for cytophilic antibodies in typhus infections. If the rickettsiae were mixed with serum from infected mice, washed, and then added to macrophages (indirect sensitization of macrophages), more rosettes were found around the macrophages than around directly sensitized macrophages. The presence of mouse immunoglobulin G on the macrophage surface was also shown by staining living sensitized macrophages with rabbit fluroescein-conjugated anti-mouse immunoglobulin G.
Large-scale purification and characterization of the exotoxin of Pseudomonas aeruginosa
Authors: Leppla S H
Published: January 2020

The exotoxin (PE) of Pseudomonas aeruginosa was purified from 50-liter cultures by a simple three-step procedure, yielding 135 mg of essentially homogeneous protein. In Ouchterlony gel diffusion, PE produces a single line which does not interact with a diphtheria toxin-antitoxin precipitin line. The protein has a molecular weight of 66,000, an isoelectric point of 5.1, N-terminal arginine, and four disulfide bridges. The amino acid composition shows no apparent similarity to that of diphtheria toxin. The median lethal dose of this PE preparation in mice weighing 20 g is 0.1 mug. The median lethal dose in 350-g rats is 20 mug. The cytotoxicity of PE for mouse L929 fibroblasts is completely neutralized by small amounts of specific pony antitoxin. The exotoxin possesses adenosine diphosphate-ribosylation activity. Both cytotoxic and adenosine diphosphate-ribosylation activities are shown to be properties of the intact 66,000-dalton protein.
Extrachromosomal elements in a variety of strains representing the Bacteroides fragilis group of organisms
Authors: Tinnell W H , Macrina F L
Published: January 2020

Previous nucleic acid association studies have identified at least nine deoxyribonucleic acid (DNA) homology classes of the Bacteroides fragilis group of organisms. Using these classes as a taxonomic framework, we have screened representative strains of the B. fragilis group for the presence of extrachromosomal (plasmid) DNA. [3H]thymidine-labeled cell lysates were subjected to sodium dodecyl sulfate-salt precipitation, and supernatant fractions from such preparations were analyzed using cesium chloride-ethidium bromide equilibrium centrifugation. One strain from each group was examined in this fashion. Five of the strains were judged to contain no detectable plasmid DNA; however, four strains were observed to yield satellite bands corresponding to covalently closed circular plasmid DNA. Plasmid DNA from such gradients was subjected to velocity sedimentation through both neutral and alkaline sucrose gradients to determine molecular size. A 23 X 10(6)-molecular-weight plasmid was found in a B. fragilis strain representing one DNA homology group of this species, whereas a 3 X 10(6)-molecular-weight plasmid was found in a B. fragilis strain representing a second homology group. Similarly, a 31 X 10(6)-molecular-weight plasmid was found in a Bacteroides thetaiotaomicron strain representing one DNA homology group of this species, whereas a 3 X 10(6)-molecular-weight plasmid was found in a B. thetaiotaomicron strain representing a second homology group. In all instances, the small-molecular weight plasmids were present to the extent of about 15 copies per chromosomal equivalent, whereas the large plasmids were present to the extent of approximately 1 copy per chromosomal equivalent. The biological function of these plasmids is unknown.
Bacterial decontamination and antileukemic therapy of AKR mice
Authors: Srivastava K K , Pollard M , Wagner M
Published: January 2020

Four nonabsorbable antibiotics (streptomycin, neomycin, bacitracin, and amphotericin B) and a germicidal dip solution (Zephiran chloride/water) were used to eliminate all the detectable bacteria from conventional AKR mice. Control mice were not decontaminated and were used as such. When antibiotic-decontaminated and control mice developed clinical manifestations of spontaneous lymphatic leukemia, each was treated for the disease with an antitumor drug (cyclophosphamide [CP]) at weekly intervals. With the decontamination procedure, mice of each of the two groups became bacteria-free after 16 weeks of continuous oral administration of the antibiotics and two separate germicidal dippings. All decontaminated mice remained free of bacteria throughout the experiment. The bacterial flora of the control mice remained unaltered. With CP therapy, the mean survival time of the female decontaminated mice was 65 days, whereas that of male mice was 218 days. The average survival time of the CP-treated control leukemic mice was 51 days. Untreated decontaminated or control mice usually died of leukemia within 7 days after the onset of symptoms of leukemia. Although CP therapy was not curative, it did prolong the life expectancy of the decontaminated mice significantly.
Herpes simplex virus infections in guinea pigs deficient in the fourth component of complement
Authors: Strunk R C , John T J , Sieber O F
Published: January 2020

Separate groups of normal and C4-deficient guinea pigs were inoculated with herpes simplex virus by intradermal (i.d.) and intraperitoneal (i.p.) routes. Virus infection, confirmed by clinical, virological, and serological criteria, did not last longer and was not more severe in C4-deficient guinea pigs than in normal guinea pigs. Serum C component levels were measured before, during, and after herpes simplex virus infection. In normal gruinea pigs there was no evidence for C4 utilization after either i.d. or i.p. inoculation. In both normal and C4-deficient guinea pigs, C1 and C3-9 levels remained unchanged in spite of i.d. or i.p. infection. These data suggested that C4 and the classical C pathway were not important for virus clearance.
Relationship between antigenic stimulation and increased splenic peroxidase levels during the immune response
Authors: Strauss R R , Friedman H , Mills L , Zayon G
Published: January 2020

Immunization of mice with either soluble or particulate antigens induced a marked increase in peroxidase activity of spleen cell homogenates. Animals immunized with sheep erythrocytes showed maximum splenic peroxidase activity at 2 days. By the 4th day after immunization, when the hemolytic antibody plaque-forming cell response was maximal, peroxidase activity returned to normal levels. Increased splenic peroxidase activity also occurred in mice immunized with rabbit erythrocytes, as well as with rabbit serum or bovine serum albumin. No change in splenic peroxidase activity occurred in mice injected with syngeneic mouse erythrocytes or serum. Both glass-adherent spleen cell populations, morphologically consisting of 90 to 95% macrophages, as well as nonadherent cells, consisting of more than 90% lymphocytes by the same criteria, showed peroxidase activity. Immunization of mice with sheep erythrocytes resulted in an intracellular redistribution of the peroxidase activity among several distinct subcellular fractions prepared by differential centrifugation. Maximum redistribution occurred with granule-associated enzyme activity. A possible relationship between peroxidase activity with functional activity of lymphocytes and macrophages during humor immune responses seemed likely.
Solid-phase radioimmunoassay as a method for evaluating antigenic differences in type A influenza viruses
Authors: Schieble J H , Cottam D
Published: January 2020

An indirect solid-phase radioimmunoassay (RIA) procedure was developed to determine its usefulness in assessing antigenic variation in the surface antigens of type A influenza virus strains. The importance of several test variables was examined, and those having a significant effect on the binding ratios were identified. The reproducibility of the RIA procedure was investigated. Maximum variation of the mean binding ratios encountered in repetitive tests was found to be approximately 20%. The antigenic characteristics of the A/Aichi/68 virus strain were compared with several different type A virus strains. Utilizing anti-A/Aichi/68 immune serum together with specific anti-hemagglutinin and antineuraminidase immune sera, the RIA method was shown to quantitatively differentiate the surface antigens of the A/Aichi/68 virus strain from the surface antigens of the type A strains that preceded, as well as from those that succeeded, the introduction of the Aichi virus strain in 1968. Using antigen-specific serum, both the hemagglutinin and neuraminidase antigens can be independently characterized in one test system. This advantage, together with the ease and greater sensitivity of the RIA, should make it a useful serological test for evaluating antigenic variation of type A influenza viruses.
Effect of Trichinella spiralis infection on passive cutaneous anaphylaxis in mice
Authors: Munoz J J , Cole R L
Published: January 2020

Infection of CFW mice with Trichinella spiralis induced a state of relative unresponsiveness to passive cutaneous anaphylaxis (PCA) induced with hen egg albumin and its corresponding antibodies. The unresponsiveness was to PCA produced either with immunoglobulin G1 (IgG1) or IgE type of antibodies, but was more pronounced with the latter. As few as 25 larvae given by stomach tube 20 days before induced this resistance, although 400 larvae induced a greater resistance. When 400 to 600 larvae were fed to mice, the refractoriness of these mice to PCA was noticed 15 days later. The sera of infected mice had the ability to inhibit mainly PCA induced by IgE. This inhibitory property of sera from infected mice was more pronounced 35 days after infection than 10 months later, when only weak inhibitory activity was detected. Purified rat IgE inhibited the PCA reactions induced in both mice and rats with mouse IgE-type antibody. At high concentrations, evidence of inhibition of the IgG1-induced PCA in mice was also obtained. We believe that the relative unresponsiveness of infected mice is due to an increase in production of IgE which competitively blocks the mast cell sites for other IgE molecules.
Evaluation of experimentally induced Fusobacterium necrophorum infections in mice
Authors: Conlon P J , Hepper K P , Teresa G W
Published: January 2020

Two strains of mice, Swiss Webster and DBA/2Cr, were injected intraperitoneally or intravenously with varying dosages of Fusobacterium necrophorum. The ability to eliminate the infection was assessed by quantitative enumeration of the organisms present in the blood, liver, and spleen, Three- to 4-week-old DBA/2Cr mice were highly resistant to both routes of injection. The intraperitoneal injection of older mice failed to demonstrate a dose-effect relationship whereas an intravenous injection of as few as 10(4) cells of F. necrophorum produced progressively necrotic leg abscesses, apparently involving the lymphonodus ischiadicus which filters the site of injection. Mortality was increased with sensitization by a previous sublethal injection. Also, an ethanol-killed cell vaccine delayed the onset of lethal infection, whereas repeated sublethal live cell injections provided nonspecific protection since mice vaccinated with the growth medium were equally protected. The development of leg abscesses after intravenous injection visibly demonstrated the pathogenicity of F. necrophorum and may provide a suitable model for the evaluation of vaccines and the effectiveness of antibiotics.
Levan and levansucrase of Actinomyces viscosus
Authors: Pabst M J
Published: January 2020

A levansucrase was demonstrated in the growth medium and in association with the cell surface of Actinomyces viscosus. The amount of enzyme produced relative to cell density is not significantly affected by the growth conditions. Sugar alcohols inhibit growth of the cells. The levansucrase hydrolyzes sucrose to produce free glucose and levan; some free fructose is also formed. There is no requirement for cofactors. The Km for sucrose is 12 mM. A variety of heavy metal ions and two disaccharides, lactose and cellobiose, inhibit the enzyme. The levansucrase was purified to homogeneity and has a specific activity of 90 micronmol of glucose release per min per mg. The enzyme has a molecular weight of 220,000 and is composed of subunits of molecular weight 80,000. The levan product contains both beta(2 leads to 1) and beta(2 leads to 6) linkages. The enzyme remains tightly bound to the levan product, resulting in the formation of high-molecular-weight polymer on the order of 10(8) daltons. The possible role of the levan and levansucrase of A. viscosus in the pathogenesis of periodontal disease is discussed.
Production of a capsule of Neisseria gonorrhoeae
Authors: Richardson W P , Sadoff J C
Published: January 2020

Neisseria gonorrhoeae can be induced to form a large capsule that can be visualized with India ink. Encapsulated gonococci appeared to be resistant to non-antibody-mediated phagocytosis compared with unencapsulated gonococci of the same strain and colony type.
In vitro lymphocyte responses of coccidioidin skin test-positive and -negative persons to coccidioidin, spherulin, and a coccidioides cell wall antigen
Authors: Cox R A , Brummer E , Lecara G
Published: January 2020

The biological activity of C-ASWS, an alkali-soluble, water-soluble cell wall antigen isolated from mycelial-phase cells of Coccidioides immitis, was compared with that of a commercial coccidioidin (CDN; Cutter Laboratories); CDN-TS, a toluene-induced lysate of mycelial-phase cells; and spherulin, a spherule-derived extract of C. immitis. Lymphocytes obtained from healthy CDN skin test-positive donors (group I), healthy skin test-negative donors (group II), and patients with active coccidioidomycosis (group III) were assayed for lymphocyte transformation and production of macrophage inhibitory factor in response to the Coccidioides antigens. C-ASWS, CDN CDN-TS, and spherulin were each effective in eliciting blastogenic responses in lymphocytes of group I subjects. However, only C-ASWS and CDN-TS were effective in eliciting macrophage inhibitory factor production. The responses of group III subjects (patients) were depressed and, in most instances, were indistinguishable from those obtained in lymphocytes of group II subjects.
Evaluation of serum opsonic capacity by quantitating the initial chemiluminescent response from phagocytizing polymorphonuclear leukocytes
Authors: Allen R C
Published: January 2020

Phagocytically activated polymorphonuclear leukocytes produced a chemiluminescence that could be correlated metabolically with the stimulated oxidation of glucose via the hexose monophosphate shunt, The chemiluminescence observed was considered to originate from the relaxation of electronically excited carbonyl groups produced during singlet molecular oxygen-mediated microbicidal oxidation of the ingested microbe. With adequate adjustment of leukocyte and bacterial concentrations, the rate of chemiluminescence increase was nearly constant for the first minutes after initiation of phagocytosis. This rate was dependent on the quantity of bacteria phagocytized by the leukocytes. If both leukocytes and bacterial concentrations were held constant, this initial rate of chemiluminescence reflected the opsonic capacity of the sera used for opsonization. The prior absorption of opsonins from serum resulted in a decresed rate of chemiluminescence related to the quantity of bacteria used for absorption. Heating of sera to 56 degrees C for 30 min resulted in a great decrease in the chemiluminescent responses and may reflect the role of complement in the opsonization process.
Contrasting effects of immunosuppression on Theiler's virus infection in mice
Authors: Lipton H L , Canto C D
Published: January 2020

In the present study, cyclophosphamide and rabbit anti-mouse thymocyte serum were used to immunosuppress SJL/J mice infected with Theiler's mouse encephalomyelitis virus (TMEV) in order to delineate the potential mechanism(s) of virus-induced cellular injury in this infection. Whereas both immunosuppressive agents produced a significant increase in mortality, this treatment had differing effects on the pathological involvement of gray and white-matter structures in the central nervous system. The central nervous system of immunosuppressed TMEV-infected mice had increased microglial cell proliferation and neuronal necrosis, longer maintenance of high virus levels and spread of virus antigen to involve the neocortex and hippocampal complex. These observations indicate that TMEV causes a cytolotic infection of neurons and possibly other cells in gray matter. In contrast, immunosuppression produced a dramatic reduction in mononuclear inflammatory cells in the leptomeninges and spinal cord white matter of infected mice and prevented demyelination. Further, virus antigen was not detected in the leptomeninges and white matter of immunosuppressed and infected mice. These findings suggest that demyelination of TMEV infection is immune mediated.
Bacteriological and histopathological evaluation of guinea pigs after infection with Listeria monocytogenes
Authors: Dustoor M , Croft W , Fulton A , Blazkovec A
Published: January 2020

Randomly bred guinea pigs were infected with Listeria monocytogenes using the intracardial, intravenous and intraperitoneal routes of infection. Doses of Listeria ranged from 5 to 1,000 x the 50% lethal dose based on the 50% lethal dose for intracardially injected Listeria. A complete necropsy was performed on all animals that died after infection. Gross and microscopic examination of tissues revealed major pathological features which include myocarditis, edema and congestion with interstitial pneumonitis present in the lungs, and fatty hepatic changes with focal necrosis. For all or a majority of the animals, large numbers of Listeria were likewise recovered from these organs and from lymph nodes, spleen, kidneys, and adrenal gland tissue. Of the three routes of infection used, guinea pigs were most susceptible to Listeria injected via the intracardial route. The relatively high lethal dose of listeric for the quinea pig, however, suggests that the organism is a low-grade pathogen for this species.
Bacteriophage deoxyribonucleic acid-induced mutation of Streptococcus mutans
Authors: Higuchi M , Rhee G H , Araya S , Higuchi M
Published: January 2020

A cariogenic strain, Streptococcus mutans PK 1, has been demonstrated to have prophage by observation of phage particles with an electron microscope and by induction with mitomycin C. The phage particles could not be detected in a mutant strain which lost the characteristic adhesive nature on glass surfaces and exhibited diminished ability to synthesize insoluble polysaccharide. By infecting the mutant cells with the phages or with free phage deoxyribonucleic acid isolated from the parent strain of S. mutans PK1, the mutant cells were transformed to the cariogenic strain with adhesive nature. The transformants retained the general characteristics of S. mutans PK 1, but in addition all transformants showed a new character; namely, the transformant cell could produce ammonia from arginine, whereas neither the parent nor mutant strains of S. mutans PK 1 had such a property;
Ureaplasmal epithelial lesions related to ammonia
Authors: Stalheim O H , Gallagher J E
Published: January 2020

The pathological effects of ureaplasmas on oviductal epithelium (ciliostasis and deciliation) were duplicated by adding ammonia to the medium as ammonium sulfate or by adding jack bean urease, which hydrolyzed the urea in the medium.
Effectiveness of parenteral and oral typhoid vaccination in mice challenged with a Salmonella typhi-Salmonella typhimurium hybrid
Authors: Diena B B , Ryan A , Wallace R , Johnson E M , Baron L S , Ashton F E
Published: January 2020

Live Salmonella typhi administered intraperitoneally, acetone-killed S. typhi administered intraperitoneally, and live S. typhi given orally, with their effectiveness decreasing in that order, protected Swiss white mice against death from challenge with a virulent Salmonella typhimurium hybrid expressing S. typhi antigens.
Peripheral blood lymphocyte response to acute infections in humans
Authors: Thorley J D , Smith J W , Luby J P , Sanford J P
Published: January 2020

The response of subpopulations of peripheral venous blood lymphocytes to systemic bacterial or viral infections was studied. B-lymphocytes were defined by the presence of surface binding sites for mu chains, which were determined by immunofluorescent staining. T-lymphocytes were defined by the ability to form active sheep cell rosettes. Virus-infectible lymphocytes, which may represent activated T-lymphocytes, were defined by the ability to support virus replication. Patients with bacterial infections had an increase in the B-lymphocytes of peripheral venous blood, whereas patients with viral infections had an increase in T-lymphocytes as compared to controls. The number of virus-infectible lymphocytes was increased in patients with bacterial infections but not in patients with viral infections. These studies suggest that subpopulations of human peripheral blood lymphocytes vary in response to different types of infectious agents.
Incidence of exotoxin production by Pseudomonas species
Authors: Bjorn M J , Vasil M L , Sadoff J C , Iglewski B H
Published: January 2020

Pseudomonas aeruginosa exotoxin A has been shown to catalyze the transfer of the adenosine 5'-diphosphate (ADP)-ribose moiety of nicotinamide adenine dinucleotide onto elongation factor 2, resulting in the inhibition of mammalian protein synthesis. The enzymatic activity (ADP-ribosyl [ADPR]-transferase) is thought to account for the toxicity of exotoxin A. The distribution of the expression of exotoxin A within Pseudomonas species was examined. Laboratory strains as well as clinical isolates of Pseudomonas aeruginosa were tested. The production of exotoxin A was determined by assaying for ADPR-transferase activity in dialyzed frozen (-20 degrees C) and thawed cell-free supernatants from 22-h cultures or in 10-fold-concentrated supernatants. In addition, toxin production was detected immunologically using a modified Elek test. Exotoxin A production was detected in approximately 90% of the 111 isolates of P. aeruginosa. In contrast, none of the other species of Pseudomonas examined produced exotoxin A detectable by either ADPR-transferase activity or immunological reactivity.
Immunoprophylaxis of experimental Mycoplasma pneumoniae disease: effect of route of administration on the immunogenicity and protective effect of inactivated M. pneumoniae vaccine
Authors: Greenberg H , Helms C M , Grizzard M B , James W D , Horswood R L , Chanock R M
Published: January 2020

Formalin-inactivated Mycoplasma pneumoniae vaccine was administered subcutaneously or intranasally to hamsters to examine the effect of route of administration on immunogenicity and protective effect. Parenterally administered vaccine in the doses employed induced serum complement-fixing antibody formation, but did not significantly decrease the frequency of pneumonia following challenge with virulent M. pneumoniae. Intranasally instilled vaccine was ineffective in stimulating serum antibody, but did diminish the frequency of experimentally induced pneumonia due to M. pneumoniae. However, a greater degree of resistance was induced by intranasal infection with either wild-type organisms or the ts 640 attenuated mutant of M. pneumoniae.
Protective Effect of Vaccines on
Mycoplasma pulmonis
-Induced Respiratory Disease of Mice
Authors: Taylor Geraldine , Howard C. J. , Gourlay R. N.
Published: January 2020

Mice inoculated intranasally with either a virulent or an avirulent strain of live
Mycoplasma pulmonis
were resistant to respiratory disease induced by a subsequent intranasal challenge with virulent organisms. Similarly, mice inoculated intravenously with the virulent strain were resistant to intranasal challenge with the same strain. In contrast, mice inoculated intravenously with avirulent
M. pulmonis
were not resistant to intranasal challenge with the virulent mycoplasma strain. Studies on mice inoculated intravenously with the two strains of
M. pulmonis
indicated that persistance of mycoplasmas in the respiratory tract may be important in inducing resistance to intranasal challenge with
M. pulmonis.
These observations, together with the lack of correlation between the level of serum antibodies and resistance to
M. pulmonis
-induced respiratory disease, suggested that local immune mechanisms were important in resistance. It is proposed that an effective vaccination schedule to protect mice against
M. pulmonis
-induced respiratory disease may be one that stimulates both systemic and local immune defenses. This suggestion is supported by the observation that systemic followed by local administration of inactivated
M. pulmonis
was more effective in inducing resistance in mice to intranasal challenge with live organisms than was systemic administration alone. In addition, mice inoculated solely by the intranasal route with inactivated mycoplasmas were resistant to
M. pulmonis
-induced respiratory disease. These studies indicate the importance of local defense mechanisms in the induction of resistance to
M. pulmonis
-induced respiratory disease in mice.
Appearance of cellular and humoral immunity in guinea pigs after infection with Coxiella burnetii administered in small-particle aerosols
Authors: Kishimoto R A , Burger G T
Published: January 2020

The development of humoral and cell-mediated immune responses was studied in guinea pigs infected with Coxiella burnetti administered in small-particle aerosols. Direct macrophage migration inhibition was observed in cultured peritoneal exudate cells as early as 3 days after exposure. Maximum inhibition of macrophages cultured with phase I or II antigen occurred 14 to 21 days postexposure and persisted through 35 days. This inhibitory action was no longer detectable at 42 days. Serum antibody to the phase II antigen of C. burnetii was detected at 14 days, and serum antibody to phase I antigen was detected at 21 days, 18 days after the cell-mediated immune response.
Local Immunity Against Newcastle Disease Virus in the Newly Hatched Chicken's Respiratory Tract
Authors: Malkinson Mertyn , Small Parker A.
Published: January 2020

Inoculation of 200 mean egg infectious doses (EID
50
) of lentogenic Newcastle disease virus strain B1 (NDV-B1) into the air sac of 4-day-old specific-pathogen-free chicks provided significant protection against challenge of the air sac with 100 chicken mean lethal doses (LD
50
) of velogenic NDV-H but no protection against reinfection when the challenge was by the eye. Conversely, inoculation of the eye with 200 EID
50
of NDV-B1 provided significant protection against challenge of the eye but not of the air sac with 100 chicken LD
50
of NDV-H. Birds that received both antiserum and intraocular immunization were subsequently protected against both eye and air-sac challenge. On the other hand, birds that received antiserum and air-sac immunization were protected only against air-sac challenge but not against ocular challenge. Low levels of passively administered antibody did not prevent infection of the eye or air sac but greatly reduced the mortality rate after inoculation of either the vaccine or the challenge viruses. Passively administered antibody also suppressed hemagglutination-inhibiting and virus-neutralizing antibody formation stimulated by air-sac infection but not antibody formation stimulated by ocular infection. These data are consistent with the hypothesis that local immunity is responsible for prevention of infection, since birds were immune to reinfection at one site and simultaneously susceptible at the other site of infection.
Mycoplasma-induced hydrocephalus in rats and hamsters
Authors: Kohn D F , Kirk B E , Chou S M
Published: January 2020

Mycoplasma pulmonis, a pathogen of the respiratory tract in rats, was inoculated intracerebrally into neonate rats and hamsters to determine if it would induce lesions in the ependyma. Hydrocephalus was induced in 116 of 120 rats and in 23 of 28 hamsters. The severity of hydrocephalus was greater in the rats than in the hamsters. Hydrocephalus induction occurred only subsequent to inoculation of viable M. pulmonis. At 2 weeks of age, rats became refractory to induction of hydrocephalus. Light microscopy indicated that the hydrocephalus was communicating without an inflammatory response in the ventricles and meninges. Preliminary electron microscopy revealed that amorphous material covered portions of the ependymal surface and that cilia were sometimes matted together. It was suggested that the hydrocephalus was due to ciliary dysfunction or to an imbalance of cerebrospinal fluid secretion and absorption. This M. pulmonis-induced hydrocephalus may be a useful model for elucidating the pathogenesis of certain types of congenital hydrocephalus in humans.
Antigenic, Chemical, and Structural Properties of Cell Walls of
Histoplasma capsulatum
Yeast-Form Chemotypes 1 and 2 After Serial Enzymatic Hydrolysis
Authors: Reiss E. , Miller Sara E. , Kaplan W. , Kaufman L.
Published: January 2020

Cell walls of
Histoplasma capsulatum
yeast-form chemotypes 1 (
chem 1
) and 2 (
chem 2
) treated sequentially with several polysaccharolytic enzymes and Pronase yielded soluble, nondialyzable polysaccharides at each step, which were analyzed for monosaccharides, protein composition, and serological activity. Polysaccharide recovered after digestion of
chem 1
walls with β(1→3)-glucanase contained glucose > mannose > glucosamine > galactose. This fraction (
chem 1
βG
1
) was analyzed by polyacrylamide gel electrophoresis and contained a component having an apparent molecular weight of 120,000. The
chem 1
βG
1
fraction was reactive in immunodiffusion (ID), producing an immune precipitate not identical to the H and M factors of histoplasmin. In a side-by-side ID comparison with extracts of
chem 2
, the
chem 1
βG
1
antigen contained an additional determinant not found in
chem 2
extracts when tested with goat antiserum to
H. capsulatum.
Therefore, the
chem 1
antigen gave preliminary ID evidence of antigenic group specificity. A chemical difference observed was the absence of glucosamine from
chem 2
polysaccharide. In complement fixation (CF) tests, 9 of 17 sera from human histoplasmosis patients reacted with
chem 1
βG
1
, but some cross-reactivity with sera of patients with other systemic mycoses occurred. The immunoelectrophoretic patterns of
chem 1
wall-derived polysaccharides showed a marked shift in mobility after Pronase digestion, implying the presence of covalent peptides. The ultrastructural appearance and serological activity of intact walls and enzyme-resistant mural cores were also studied. The surface of the mural cores of both chemotypes was perforated and frayed. In shadow-cast preparations both fibrillar and globular areas persisted in the mural cores. The CF end point serum dilutions showed an increase after α- and β-glucanase extractions of
chem 2
walls and fourfold reduction after Pronase digestion. The mural cores of both chemotypes were still reactive in CF tests and retained some ability to bind fluorescent antibody. The
chem 1
mural core reacted with specific fluorescein-labeled
H. capsulatum
antiglobulins produced by adsorption with
Blastomyces dermatitidis
, thus indicating at least partial retention of
H. capsulatum
-specific factors. The presence of galactose, mannose, and glucose was detected in the mural cores as well as enriched levels of amino sugar, despite exposure to chitinase.
Affinity of Sendai virus for the inner ear of mice
Authors: Shimokata K , NISHIYAMA Y , Ito V , Kimura Y , Nagata I
Published: January 2020

The direct immunofluorescent antibody method revealed that Sendai virus, which was thought to be most prevalent in respiratory diseases in mice, infected the inner ear of mice when the virus was injected intracerebrally. Specific immunofluorescence that indicated the presence of antigens of Sendai virus was observed in both perilymphatic and endolymphatic structures. The routes of virus spread are discussed. This experimental study, using newborn mice and Sendai virus, may be useful for the investigation of the pathogenesis of viral labyrinthitis not only because of the high frequency of inner ear infection, but also because of long-time survivors which facilitate prolonged observation.
Effect of streptolysin S on human and mouse T and B lymphocytes
Authors: Hryniewicz W , Pryjma J
Published: January 2020

The effect of streptolysin S on T and B human and mouse lymphocytes was studied. The dose-dependent inhibition of T cell rosette formation was observed, and this was accompanied by a dose-dependent cytotoxicity. The existence of a difference in the degree of susceptibility of T and B cells to the cytotoxic effect of streptolysin S is shown.
Immune response and dental caries incidence in Streptococcus faecalis-monoassociated Harvard caries-resistant and caries-susceptible rats
Authors: Peri B A , Wagner M
Published: January 2020

Harvard caries-resistant rats (CR) monoassociated with cariogenic Streptococcus faecalis (SF) for 150 days developed early high levels of specific SF serum agglutinins, moderate levels of salivary antibody, and little or no caries activity. Harvard caries-susceptible (CS) SF-monoassociated rats developed serum antibody more slowly and never reached the titers of the CR group. Little or no salivary agglutinin was found, and extensive caries developed. Second-generation monoassociated CR rats (CR-2) born to SF-monoassociated CR parents showed an immune response and caries activity more nearly resembling those of the CS rat than those of their CR parent. The CR rat appeared to be a high responder and the CS rat, a low responder to viable antigen on the mucous surfaces in both serum and salivary antibody production. Immunization by parenteral injection of killed SF cells produced equally high serum titers in both CR and CS strain rats, but failed to increase salivary agglutinin titers in any group or to protect against caries. These data suggest that there may be an immunologic basis for genetic differences in caries susceptibility between CR and CS Harvard rat strains and that this difference has been modified by some factor in the environment of the CR-2 rats.
Purification and characterization of group A streptococcal T-1 antigen
Authors: Johnson R H , Vosti K L
Published: January 2020

A method is described for the recovery of purified T-antigen from crude trypsin extracts of an avirulent strain of M-1 protein deficient, T-type 1 group A Streptococcus. The purified T-antigen was resistant to enzymatic degradation with trypsin and pepsin, formed a single precipitin line with standard T-1 antiserum, failed to react with antisera for teichoic acid, group A carbohydrate, and cross-reactive protein antigens, stimulated only a single precipitin system when rabbits were immunized, contained glycine, aspartic acid, glutamic acid, lysine, and serine as the five most predominant amino acids, and consisted of subunit size isomers.