bluuebunny/crossref_metadata_2025 huggingface dataset:
Response to Mycobacterium bovis BCG vaccination in protein- and zinc-deficient guinea pigs
Authors: McMurray D N , Yetley E A
Published: January 2020

Groups of specific pathogen-free Hartley strain guinea pigs were vaccinated with viable Mycobacterium bovis BCG and maintained on isocaloric purified diets containing either 30 or 10% protein (ovalbumin) combined with either 50 ppm (microgram/g) or no added zinc. Seven weeks later the guinea pigs were skin tested with purified protein derivative and killed. Both protein and zinc deficiencies had a significant negative impact on growth of the guinea pigs. Both groups consuming the 10% protein diet also demonstrated significant reductions in hematocrit, total serum proteins, and serum albumin, as well as diminished spleen weight. Plasma zinc concentrations were reduced in both low-zinc groups to less than half the value observed in control guinea pigs. Protein deficiency, alone or combined with zinc deficiency, resulted in increased tissue levels of viable M. bovis BCG in the inguinal lymph nodes and subcutaneous vaccination nodule. These same groups exhibited significant impairment in the ability to mount a delayed hypersensitivity reaction. Phytohemagglutinin-driven polyclonal T cell blastogenesis in vitro was significantly diminished in the peripheral lymphocytes of both protein- and protein-zinc-deficient animals at low mitogen doses, but only in the protein-zinc-deficient guinea pigs as the dose of phytohemagglutinin was increased. These results suggest that dietary protein and zinc deficiencies, alone or combined, interfere with immunological responses of the host to vaccination with M. bovis BCG.
Diminished bactericidal capacity for group B streptococci of neutrophils from children with chronic granulomatous disease
Authors: Stroobant J , Harris M C , Cody C S , Polin R A , Douglas S D
Published: January 2020

The bactericidal capacity of neutrophils from healthy adults, male children with chronic granulomatous disease, and obligate heterozygote mothers for type Ic group B streptococci was assessed, using a fluorochrome microassay. Neutrophils from patients with chronic granulomatous disease had impaired bactericidal capacity for group B streptococci when compared with adults (P less than 0.01). Carriers demonstrated intermediate killing capacity.
Cysteine toxicity for oral streptococci and effect of branched-chain amino acids
Authors: Cowman R A , Baron S S , Fitzgerald R J
Published: January 2020

Cysteine was bactericidal to strains of Streptococcus mutans and S. salivarius in concentrations that were nontoxic to S. sanguis, S. milleri, or S. mitior when these microorganisms were incubated in a saliva protein-based synthetic medium. Cysteine toxicity for S. mutans also occurred after incubation in synthetic base medium supplemented with amino acids as the nitrogen source for growth. The bactericidal effect of cysteine for S. mutans or S. salivarius in the saliva protein medium was influenced by the cysteine oxidative activity associated with the saliva protein fraction. Valine alone or in combination with leucine or isoleucine was effective in overcoming cysteine toxicity for susceptible strains of S. mutans or S. salivarius. Cysteine toxicity for these oral streptococci may be due to cysteine inhibition of an enzymatic step in the valine-leucine biosynthetic pathway.
Isolation and nucleotide sequence determination of a gene encoding a heat-stable enterotoxin of Escherichia coli
Authors: Moseley S L , Hardy J W , Hug M I , Echeverria P , Falkow S
Published: January 2020

A gene encoding a heat-stable enterotoxin (ST) from an Escherichia coli strain isolated from a human with diarrhea was cloned and characterized by nucleotide sequence analysis. The gene was found to be partially homologous to a previously characterized ST gene from an E. coli strain of bovine origin. Hybridization studies showed that most ST-producing strains of E. coli isolated from humans with diarrhea possess genes highly homologous to either the ST gene from the bovine strain or the ST gene characterized in the present study.
Modulation of Candida albicans attachment to human epithelial cells by bacteria and carbohydrates
Authors: Centeno A , Davis C P , Cohen M S , Warren M M
Published: January 2020

The effects of carbohydrates (mannose and dextrose). Escherichia coli 07KL. and Klebsiella pneumoniae on Candida albicans attachment to epithelial cells was studied. Dextrose had no effect on yeast attachment to epithelial cells. Conversely, mannose significantly decreased both yeast and piliated bacterial attachment (E. coli 07KL, heavily piliated K. pneumoniae) whereas having no effect on nonpiliated K. pneumoniae attachment to epithelial cells. The number of yeasts attaching to epithelial cells was enhanced by preincubation of epithelial cells with piliated strains of bacteria, whereas preincubation with nonpiliated strains of bacteria had no effect on yeast attachment. Scanning electron microscopy showed that piliated bacteria and yeasts were juxtaposed on the epithelial cell surface. These data suggest that certain piliated strains of bacteria can enhance C. albicans attachment to epithelial cells and that type 1 pili of bacteria can be a factor in the enhanced attachment of C. albicans to epithelial cells.
Interactions of lipid a and liposome-associated lipid A with Limulus polyphemus amoebocytes
Authors: Richardson E C , Banerji B , Seid R C , Levin J , Alving C R
Published: January 2020

Lipid A or lipid A fractions and liposomes containing lipid A were tested for the ability to gel Limulus amoebocyte lysates and for effects on intact Limulus amoebocytes. Liposomes having a relatively low concentration of lipid A did not produce coagulation of lysate and were designated as Limulus-negative, but liposomes having a high concentration of lipid A were Limulus-positive. Limulus-negative liposomes had no effect on intact amoebocytes. Limulus-positive liposomes caused a striking transformation in the appearance of amoebocytes in that the cells sent out long filamentous extensions that formed a tangled network of processes between cells. The filamentous projections were similar to those that have been previously observed in the presence of gram-negative bacteria. We conclude that amoebocytes have the ability to recognize Limulus-positive liposomes, but the lack of activation of Limulus lysate or the absence of amoebocyte recognition does not prove the absence of liposomal lipid A. We also found that individual lipid A fractions were heterogeneous in their ability to gel lysate. Of eight fractions tested, one (fraction 1) had no detectable activity above the background, and the seven others had activity that ranged from 10-fold to 10,000-fold above the background. The heterogeneity of lipid A fractions detected in assays with amoebocyte lysate was consistent with the finding of heterogeneity in other functional assays of lipid A fractions.
Differences in cytolytic T cell response of BALB/c mice infected with myocarditic and non-myocarditic strains of coxsackievirus group B, type 3
Authors: Huber S A , Job L P
Published: January 2020

Two strains of coxsackie B-3 virus, indistinguishable by neutralization with acute mouse antiserum to coxsackie B-3 group virus, differ markedly in pathogenicity. One strain induces extensive mononuclear cell infiltration and necrosis in the heart, and 92% of the infected animals die by day 10 after infection. Inflammation, cardiac damage, and mortality are reduced in mice infected with the nonmyocarditic virus. Peak virus replication occurs on day 3 with both viruses. Virus concentrations decrease to undetectable levels after day 12 of infection. Cytolytic T cells could be isolated from the spleens of animals inoculated with either virus. The spleen cells preferentially lysed target cells infected with the immunizing virus strain. These results suggest that the myocarditic and nonmyocarditic viruses induce only minimally noncross-reacting virus-specific antigens on the target cell surface.
Aggregation of human platelets and adhesion of Streptococcus sanguis
Authors: Herzberg M C , Brintzenhofe K L , Clawson C C
Published: January 2020

Platelet vegetations or thrombi are common findings in subacute bacterial endocarditis. We investigated the hypothesis that human platelets selectively bind or adhere strains of Streptococcus sanguis and Streptococcus mutans and aggregate, as a result, into an in vitro thrombus. Earlier ultrastructural studies suggested that aggregation of platelets over time by Staphylococcus aureus was preceded in order by adhesion and platelet activation. We uncoupled the adhesion step from activation and aggregation in our studies by incubating streptococci with platelet ghosts in a simple, quantitative assay. Adhesion was shown to be mediated by protease-sensitive components on the streptococci and platelet ghosts rather than cell surface carbohydrates or dextrans, plasma components, or divalent cations. The same streptococci were also studied by standard aggregometry techniques. Platelet-rich plasma was activated and aggregated by certain isolates of S. sanguis. Platelet ghosts bound the same strains selectively under Ca2+- and plasma-depleted conditions. Fresh platelets could activate after washing, but Ca2+ had to be restored. Aggregation required fresh platelets in Ca2+-restored plasma and was inducible by washed streptococcal cell walls. These reactions in the binding and aggregometry assays were confirmed by transmission electron microscopy. Surface microfibrils on intact S. sanguis were identified. These appendages appeared to bind S. sanguis to platelets. The selectivity of adhesion of the various S. sanguis strains to platelet ghosts or Ca2+- and plasma-depleted fresh washed platelets was similar for all donors. Thus, the platelet binding site was expressed widely in the population and was unlikely to be an artifact of membrane aging or preparation. Since selective adhesion of S. sanguis to platelets was apparently required for aggregation, it is suggested that functionally defined receptors for ligands on certain strains of S. sanguis may be present on human platelets. Some differences in the selectivity and rate of the aggregation response were noted among platelet donors, although the meaning of the variability requires further study. Nonetheless, these interactions may contribute to platelet accretion in the initiation and development of vegetative lesions in the subacute bacterial endocarditis.
Loss of surface fibronectin from human lung fibroblasts exposed to cytotoxin from Clostridium difficile
Authors: Ahlgren T , Florin I , Jarstrand C , Thelestam M
Published: January 2020

Clostridium difficile cytotoxin caused an irreversible dose- and time-dependent loss of fibronectin from the surfaces of human lung fibroblasts, paralleling the appearance of the cytopathic effect. Fibronectin was not required for the intoxication process. The results lend further support to a transmembrane connective link between fibronectin and the microfilaments.
Cross-Protection in Hamsters Immunized with Group A Arbovirus Vaccines
Authors: Cole Francis E. , McKinney Robert W.
Published: January 2020

Cross-protection between Venezuelan, Eastern, and Western equine encephalomyelitis (VEE, EEE, WEE) viruses was studied in the hamster by using challenge responses and neutralizing antibody titers as indexes of protection. Formalin-inactivated vaccines induced only homologous protection regardless of the sequence of vaccination or the combination of vaccines employed. Use of attenuated VEE vaccine, singly, produced absolute homologous protection as well as 37 and 59% protection against WEE and EEE challenges, respectively. Neither deleterious nor enhancing interaction occurred when attenuated VEE and inactivated WEE and EEE vaccines were employed in various sequences of immunization and all possible combinations. The most rapid and simple immunization scheme eliciting excellent homologous protection consisted of a single dose of combined attenuated VEE and inactivated WEE and EEE vaccines. Studies with attenuated strains of VEE, EEE, and WEE viruses showed that all elicited excellent homologous protection when administered singly. However, use of these live strains in many combinations and sequences resulted in a significant (
P
< 0.05 to <0.001) decrease in the protective efficacy of the WEE or EEE strains. These results are discussed in relation to serum neutralization test data obtained on sera drawn pre- and postchallenge.
Rapid Detection and Quantitative Estimation of Type A Botulinum Toxin by Electroimmunodiffusion
Authors: Miller Carol A. , Anderson Arthur W.
Published: January 2020

An experimental system is described for the detection and quantitative estimation of type A botulinum toxin by electroimmunodiffusion. The method is shown to be rapid, specific, and quantitative. As little as 14 mouse LD
50
per 0.1 ml of type A toxin was detected within 2 hr. When applied to experimentally contaminated foods such as canned tuna, pumpkin, spinach, green beans, and sausage, the technique detected botulinum toxin rapidly and identified it as to type and quantity. A specific rabbit type A antitoxin was produced for this in vitro system since the equine antitoxin (Center for Disease Control) tested in this experiment was found to be unsuitable.
Employment of Tuberculostasis in Serum-Agar Medium for the Study of Production and Activity of Mycobactin
Authors: Kochan Ivan , Cahall David L. , Golden Carole A.
Published: January 2020

Mycobactin (M), an iron-chelating product of tubercle bacilli, neutralized serum tuberculostasis by removing growth-essential iron from transferrin (Tr) and supplying the metal to the bacteria. The competition for iron between Tr and M has been demonstrated by the agar-plate diffusion test. This test is suitable not only for the study of Tr-iron-M interplay but also for the evaluation of serum tuberculostasis. Extremely poor solubility of M in water and consequently its association with lipoidal cell wall of tubercle bacillus was overcome by the use of water-dispersible and surface-active Tween 80. The addition of Tween 80 to culture media insured the presence of M in spent media; otherwise M was extracted from bacillary cells with a solution of Tween 80 or a mixture of ethanol and Tween 80. Although M was produced irrespective of the amount of iron present in culture medium, its production in iron-poor medium was more prolific than in iron-rich medium. M extracted from BCG or H
37
Rv cells neutralized serum tuberculostasis as effectively for the homologous as for heterologous strains. However, the extract of virulent bacilli was much more active in the neutralization than similar extract prepared from attenuated cells; whether this difference is of quantitative or qualitative nature remains to be determined.
In Vitro Antifungal Activity of Clotrimazole (Bay b 5097)
Authors: Shadomy Smith
Published: January 2020

The in vitro antifungal activity of clotrimazole (Bay b 5097) was compared with those of amphotericin B, griseofulvin, nystatin, and pyrrolnitrin. The inhibitory activity of clotrimazole against most systemic pathogens was comparable to that of amphotericin B; minimal inhibitory concentrations of the two drugs for
Blastomyces dermatitidis, Histoplasma capsulatum, Sporothrix schenckii, Cryptococcus neoformans
, and
Coccidioides immitis
were in the range of 0.20 to 3.13 and 0.10 to 6.25 μg/ml, respectively. One isolate of
Allescheria boydii
was resistant to 100 μg of amphotericin B per ml but was inhibited by 6.25 μg of clotrimazole per ml. Clotrimazole was less active than amphotericin B against
Candida albicans
and
Aspergillus fumigatus
. The activity of clotrimazole against dermatophytes was comparable to that of pyrrolnitrin; 0.78 μg of either compound per ml was fungicidal for most isolates of
Trichophyton
sp.,
Microsporum
sp. and
Epidermophyton floccosum
. Both griseofulvin and nystatin were less active than clotrimazole. The size of inoculum was shown to have a significant effect on the results of in vitro susceptibility testing with clotrimazole.
Renal Lysozyme Levels in Animals Developing “Sterile Pyelonephritis”
Authors: Eudy W. W. , Burrous S. E. , Sigler F. W.
Published: January 2020

The induction of sterile unilateral pyelonephritis in rats with heat-killed
Proteus mirabilis
cells is described. The lesions were identical to those produced with viable bacteria. Lysozyme levels in both kidneys of rats developing unilateral sterile pyelonephritis underwent biphasic elevations similar to those produced with viable bacteria. In the injected kidney, the first elevation, associated with the trauma of injection, could be produced by injecting sterile saline. The second elevation was associated with the onset of chronicity in the injected kidney. The nonmanipulated, contralateral kidney showed a similar biphasic elevation, of equal duration but of greater magnitude.
Role of Hemopoietic Colony-Forming Cell Responses in the Pathogenesis of Ectromelia
Authors: McNeill T. A. , Killen M.
Published: January 2020

Intraperitoneal injection of complete Freund's adjuvant which caused an extensive cellular response in the reticuloendothelial system greatly increased the severity of infection which resulted from footpad inoculation of ectromelia virus in mice. The mortality was greatest during the proliferative phase of the cellular response, indicated by the colony-forming cell response. Exposure of colony-forming cells to virus in vitro showed that those from normal bone marrow were much less susceptible to virus than those from the bone marrow of adjuvant-treated mice and more particularly those from the spleen of adjuvant-treated mice. Severe bleeding to induce anemia and a consequent erythropoietic response did not increase the mortality from ectromelia. Previous results were interpreted on the basis of these findings and a more general application of them to the pathogenesis of poxvirus infection was discussed.
Neutralizing Antibodies to Cytomegaloviruses in Normal Simian and Human Sera
Authors: Minamishima Yoichi , Graham Bettie J. , Benyesh-Melnick Matilda
Published: January 2020

Simian and human sera were examined for neutralizing antibodies to simian and human cytomegaloviruses (CMV). Neutralizing antibody to simian CMV was found in sera from 12 of 12 African green monkeys, 8 of 10 rhesus monkeys, and 7 of 7 baboons captured in the wild. The antibody did not cross-react with human CMV strain AD169 but cross-reacted with human strain C87, particularly in the presence of complement. Thirty-six baboons and 10 rhesus monkeys born and hand-reared in captivity remained free of neutralizing antibody both to simian and human CMV for as long as 4 years. Fifteen of 24 human sera (63%) revealed only species-specific neutralizing antibody.
Intracerebral Inoculation of Rhesus Monkeys with a Strain of Measles Virus Isolated from a Case of Subacute Sclerosing Panencephalitis
Authors: Schumacher Heinz P. , Albrecht Paul , Clark Ronald G. , Kirschstein Ruth L. , Tauraso Nicola M.
Published: January 2020

Measles virus isolated from the brain of a patient with subacute sclerosing panencephalitis was injected intracerebrally (ic) into 34 rhesus monkeys. Groups of these animals were injected with measles antigen in Freund's complete adjuvant or treated by schedules used for suppression of the general or cell-mediated immune responsiveness. In another group of animals, experimental allergic encephalitis was induced parallel with measles infection. Measles virus was isolated from the brains of monkeys up to 13 days after ic inoculation. No virus was detected in the central nervous system after 3 to 4 weeks, the longest postinoculation period examined. It was concluded that the subacute sclerosing panencephalitis-derived virus either lost its neurotropic properties at the passage level at which it was used or that it submerged into a silent stage and escaped detection. Neither immunosuppression nor concomitant autoimmune encephalitis had an effect on the survival of measles virus in the central nervous system. The histology of the nervous tissue was basically normal except for characteristic lesions of experimental allergic encephalitis in animals receiving the respective treatment.
Inapparent Respiratory Infection of Inbred Swiss Mice with Sulfadiazine-Resistant, Iodine-Negative Chlamydiae
Authors: Ata F. A. , Stephenson E. H. , Storz J.
Published: January 2020

Three chlamydial strains were isolated from the lungs of three different strains of mice that were inbred for over 30 years. These chlamydial strains were resistant to sulfadiazine and did not induce iodine-positive, glycogen-like material in the inclusions of infected L cells which characterizes them as
Chlamydia psittaci
.
Comparison Between the Polymyxins and Gentamicin in Preventing Endotoxin-Induced Intravascular Coagulation and Leukopenia
Authors: Corrigan James J. , Bell Bobbie M.
Published: January 2020

Three antimicrobial agents were evaluated as to their ability to neutralize the toxic effects of endotoxin in rabbits. These consisted of two cyclic polypeptides, polymyxin B sulfate and colymycin M (sodium colistimethate), and an aminoglycoside, gentamicin sulfate. Polymyxin B regularly prevented endotoxin-induced leukopenia, thrombocytopenia, and disseminated intravascular coagulation. Colymycin M had similar activity but was not as effective as polymyxin B. Gentamicin demonstrated no neutralizing ability in this study.
Antiviral Immune Cytolysis at an Early Stage of Paramyxovirus Infection
Authors: Eaton Monroe D. , Scala Anthony R.
Published: January 2020

Antiviral antibody and rabbit complement added as early as 5 min after infection, and with relatively low virus/cell multiplicity, lysed mouse ascites lymphoma cells infected with Sendai or Newcastle disease virus. Inactive Sendai virus at much higher input also sensitized ascites cells and mouse fibroblast monolayers to early antiviral immune cytolysis. At 4 C where adsorption but no penetration occurred, antibody removed virus from the cell membrane and little cytolysis was observed. The ascites cells were sensitive to antibody and complement at all times after the start of penetration and uncoating, indicating that viral envelope antigen is constantly present on the cell membrane. Significant cross-reactions by immune cytolysis between Newcastle disease virus- and Sendai virus-infected cells suggested possible participation of host antigens of the viral envelope. No comparable antiviral immune cytolysis was observed with influenza strains PR8 and WSN. Cell viability was estimated by dye exclusion and the ability to form acid from glucose as indicated by colorimetric
p
H of the medium. The relation of antiviral immune cytolysis to changes in the membrane resulting in cell fusion is considered.
Cell-Mediated Hypersensitivity in Rabbits Infected with
Trypanosoma brucei
and
Trypanosoma rhodesiense
Authors: Tizard I. R. , Soltys M. A.
Published: January 2020

Animals infected with strains of
Trypanosoma brucei
and
T. rhodesiense
exhibited cutaneous hypersensitivity to intradermal administration of antigen. This reactivity was of two types, an Arthus-type, antibody-mediated reaction which reached maximum intensity 4 hr after injection and a delayed-type, cell-mediated reaction which reached maximum intensity 24 hr after injection. This delayed-type hypersensitivity appeared in rabbits not earlier than 3 weeks after onset of infection. It did not occur in animals which received dead organisms. There was a cross-reaction in both types of reactivity between antigens prepared from
T. brucei
and
T. rhodesiense
. The delayed-type hypersensitivity was transferred to normal rabbits by intravenous inoculation of washed living cells from the spleen of a rabbit which showed delayed hypersensitivity. Dead cells failed to transfer hypersensitivity. The histological picture of the indurated area was typical of a delayed-type reaction.
Toxic Membrane Fractions from
Mycoplasma fermentans
Authors: Gabridge Michael G. , Murphy William H.
Published: January 2020

A recent isolate of
Mycoplasma fermentans
(strain K10, from human leukemic bone marrow) induced a lethal toxicity syndrome in mice. High doses of both viable and inactivated cells were toxic when injected intraperitoneally. Whole lysates and membranes from osmotically shocked cells killed mice, but cytoplasm did not. When membranes were dissolved in detergents and reaggregated by dialysis in the presence of Mg
2+
, the lipid-protein complex thus formed was toxic. Lipids extracted from membranes with chloroform-methanol did not kill mice. Protein-rich fractions (obtained by reaggregation plus acetone washes or ammonium sulfate precipitation of dissolved membranes) were also not toxic. No qualitative differences in proteins from three toxic isolates and three nontoxic laboratory strains of
M. fermentans
were detectable by polyacrylamide gel electrophoresis. The toxic factor contained in reaggregated membranes was heat-stable but sensitive to Pronase, trypsin, and lipase.
Cytotoxicity of Rabbit Blood for
Listeria monocytogenes
Authors: Shultz Leonard D. , Wilder M. S.
Published: January 2020

Our studies reveal that normal rabbit blood contains a potent bactericidin active against
Listeria monocytogenes
. The factor is present in greatest amounts in fresh undiluted serum but is absent in platelet extracts. A correlation was observed between the virulence of
Listeria
strains and their relative ability to survive in serum. The bactericidal titers obtained for plasma and plasma serum indicate that clotting must occur for optimum expression of antilisterial activity. The lethal action is not elevated after immunization with viable
Listeria
nor does it appear to depend on heat-labile components of complement. The active factor was removed from serum by filtration through a cellulose asbestos filter pad and further purified by carboxymethyl cellulose chromatography. Iron significantly diminishes serum lethality and completely abolishes the action of the purified component. The listericidal factor resembles β-lysin but may be a distinct part of a multiple system of similar bactericidins.
Reversible acquisition of a host cell surface membrane antigen by Trypanosoma cruzi
Authors: Chess Q , Acosta A M , Sethi J K , Santos-Buch C A
Published: January 2020

The ability of Trypanosoma cruzi, the etiological agent of Chagas' disease to acquire host cell surface antigen was tested. Parasites emerging after intracellular replication in WOS sarcoma monolayers expressed a sarcoma-associated surface antigen. This antigen was deleted from these parasites after replication in the MNS control monolayer, which does not express WOS sarcoma-associated surface antigen, or by replication in cell-free medium. This type of reversible acquisition of host surface antigen has not been previously described in T. cruzi or other intracellular protozoan parasites.
Enhancement of respiratory syncytial virus-induced cytopathology by trypsin, thrombin, and plasmin
Authors: Dubovi E J , Geratz J D , Tidwell R R
Published: January 2020

A series of proteases of diverse substrate specificity were tested for their effect on respiratory syncytial virus-induced cytopathology. Three of the enzymes, thrombin, plasmin, and trypsin, were able to augment significantly the fusion of virus-infected A549 cells. On a concentration basis, thrombin was the most active promoter, followed by plasmin and then trypsin. Hirudin, a specific thrombin inhibitor, blocked the fusion-enhancing property of thrombin, yet had no influence on the basal rate of fusion in the absence of the enzyme. By contrast, the amidine-type inhibitors of trypsin-like proteases, bis(5-amidino-2-benzimidazolyl)-methane (BABIM), blocked not only the thrombin effect, but also the fusion in the thrombin-free controls. The suppressive activity of BABIM was observed at concentrations so low as to exclude any direct inhibitory effect on thrombin itself. These results make it seem very likely that thrombin advances cell fusion by activating a BABIM-sensitive protease. Plasmin and trypsin can be expected to act in a similar manner.
Alterations in the equine herpesvirus 1 genome after in vitro and in vivo virus passage
Authors: Allen G P , Yeargan M R , Bryans J T
Published: January 2020

The effect of in vitro and in vivo serial virus passage on the genetic stability of equine herpesvirus 1 (EHV-1) was investigated by restriction endonuclease analysis of the viral DNA. DNAs of EHV-1 isolates at different passage levels in cultured cells or in Syrian hamsters were compared by electrophoresis of the DNA cleavage fragments produced by restriction endonuclease digestion. No changes were observed in the restriction profile of the DNAs of EHV-1 strains after 100 sequential passages in cultured equine cells. However, serial passage of the virus in hamsters or in cells of non-equine origin quickly gave rise to alterations in the viral DNA. These changes occurring in the restriction endonuclease profiles of EHV-1 DNA during serial virus passage in non-equine cells or animals hosts could be explained by sequence additions or deletions to preexisting restriction fragments resulting in variation in their electrophoretic mobilities.
Streptococcal growth and toxin production in vivo
Authors: Duncan J L
Published: January 2020

Streptococcal growth in vivo was studied with inoculated micropore filter chambers which were implanted into the peritoneal cavities of mice. Eight of nine group A strains and one group B strain grew in vivo, achieving concentrations of 10(7) to 10(9) CFU/ml in the chambers. Experiments with the Richards strain showed that the number of viable organisms remained high at 5 and 8 weeks after infection. The use of specific inhibitors and appropriate toxin-negative strains demonstrated that both cytolytic toxins produced by group A streptococci, streptolysin S and streptolysin O, were present in the culture fluids harvested from the chambers. This finding represents the first evidence that streptolysin S is produced in vivo. The host response to streptococci growing in vivo was examined by following the increase in serum antistreptolysin O levels. The response was first detected 2 weeks after chamber implantation and appeared to be maximal after 5 weeks. In addition, the production of antibody to streptococcal cell surface antigens was demonstrated indirectly with fluorescein-labeled anti-mouse immunoglobulin G.
Monoclonal antibodies to cholera toxin with special reference to cross-reactions with Escherichia coli heat-labile enterotoxin
Authors: Lindholm L , Holmgren J , Wikström M , Karlsson U , Andersson K , Lycke N
Published: January 2020

Seventy monoclonal antibodies to cholera toxin were prepared and characterized. All were of immunoglobulin G (IgG) isotypes (39 IgG1, 29 IgG2, and 2 IgG3). A total of 61 clones produced antibody directed against the B subunit, and 9 clones produced antibodies with specificity for the cholera toxin A subunit. Among both the anti-B and anti-A antibodies, there were representatives which showed full cross-reactivity with the heat-labile enterotoxin of Escherichia coli (14 clones), others which gave partial cross-reactions (12), and still others (44) which did not cross-react. Although 24 of 25 tested anti-B monoclonal antibodies could neutralize cholera toxin, none of the 9 anti-A clones had any detectable neutralizing ability. Among the anti-B antibodies, those which cross-reacted completely with E. coli heat-labile enterotoxin all had strong cholera toxin-neutralizing capacity, whereas those with lesser or no degree of cross-reactivity varied more in their neutralizing potency. The isolation of monoclonal antibodies that distinguish between enterotoxins of different bacterial origin suggests the possibility of developing immunodiagnostic methods allowing species-specific enterotoxin detection in stools of patients with diarrheal disease.
Effective immunity to dental caries: enhancement of salivary anti-Streptococcus mutans antibody responses with oral adjuvants
Authors: Morisaki I , Michalek S M , Harmon C C , Torii M , Hamada S , McGhee J R
Published: January 2020

In the present study, we compared the ability of the soluble adjuvants concanavalin A (ConA), muramyl dipeptide (MDP), and peptidoglycan (PG) to enhance immune responses to orally administered particulate antigens of Streptococcus mutans 6715 in gnotobiotic rats. The isotype and levels of antibody in saliva and in serum from experimental rats were determined by an enzyme-linked immunosorbent assay using S. mutans whole cells (WC) as the coating antigen. The specificities of salivary and serum immunoglobulin A (IgA) antibodies to particulate S. mutans antigens, lipoteichoic acid, S. mutans serotype g carbohydrate, and dextran were also determined. When 50 micrograms of ConA was used as the oral adjuvant with S. mutans 6715 WC immunogen, a slight enhancement of immune responses was obtained. A higher dose of ConA suppressed humoral responses to the immunogen. Enhanced immune responses, especially of the IgA isotype, in both serum and saliva were induced in gnotobiotic rats given MDP and either S. mutans 6715 WC or purified cell walls (CW) by gastric intubation. Elevated IgA antibody levels to CW, lipoteichoic acid, and carbohydrate were observed in rats given S. mutans WC and MDP by gastric intubation, whereas oral immunization with S. mutans CW and MDP resulted in higher antibody levels to CW and carbohydrate and lower levels to lipoteichoic acid when compared with the antibody levels in rats given antigen alone. Rats orally immunized with either S. mutans WC or CW and MDP and challenged with virulent S. mutans 6715 exhibited significantly (P less than or equal to 0.05) lower plaque scores, numbers of viable S. mutans in plaque, and caries scores than did rats immunized with antigen alone or in infected-only controls. In another series of experiments, a PG fraction derived from S. mutans 6715 CW was assessed for adjuvant properties. The oral administration of PG and either S. mutans WC or CW induced good salivary and serum IgA antibody responses. The specificity of the antibodies was similar to that obtained in rats given antigen and MDP. Rats receiving either S. mutans WC or CW and PG and challenged with virulent S. mutans 6715 had lower plaque scores, fewer numbers of viable S. mutans in plaque, and lower caries activity than did infected rats receiving S. mutans WC or CW immunogen alone. These results provide evidence that soluble adjuvants derived from the gram-positive bacterial CW, e.g., MDP and PG, are effective oral adjuvants and augment IgA immune responses to particulate S. mutans antigens which are protective against the mucosally associated disease, dental caries.
Role of the major histocompatibility complex in resistance and granuloma formation in response to Mycobacterium lepraemurium infection
Authors: Adu H O , Curtis J , Turk J L
Published: January 2020

Resistance to a subcutaneous infection with a moderate dose of Mycobacterium lepraemurium was investigated in C57BL/6 mice and in three congenic strains with the BALB background (BALB/c, BALB/B, and BALB/K). Resistance after 10 weeks of infection was found not to be linked to the major histocompatibility complex. The ability to develop a delayed hypersensitivity response to an ultrasonicate of M. lepraemurium was associated with the background genes, and this ability had no influence on resistance to M. lepraemurium. Granuloma formation at the infection site in the early stages appeared to be linked to the H-2b haplotype. The types of cells involved in the granulomas were also investigated.
Steroids inhibit activation of the alternative-amplification pathway of complement
Authors: Packard B D , Weiler J M
Published: January 2020

Previous studies have demonstrated the ability of methylprednisolone sodium succinate to inhibit complement activation. Two other glucocorticosteroids and three different soluble steroids which lacked glucocorticoid activity were found in the present study to have the capacity to inhibit lysis of sheep erythrocytes by the alternative-amplification pathway. These compounds also inhibited fluid-phase consumption of B in a reaction mixture that contained purified C3b, B, and D, indicating that they exert a direct effect on the generation of alternative amplification pathway convertase. These findings suggest that the capacity to inhibit convertase generation by glucocorticosteroids in high concentration is independent of glucocorticoid activity.
Two inhibitors of neutrophil chemotaxis are produced by hyperimmunoglobulin E recurrent infection syndrome mononuclear cells exposed to heat-killed staphylococci
Authors: Donabedian H , Gallin J I
Published: January 2020

Mononuclear cells from normal volunteers and from patients with the hyperimmunoglobulin E recurrent infection syndrome (HIE) were cultured for 18 h with and without opsonized, heat-killed Staphylococcus aureus (OS). The supernatants from normal mononuclear cell cultures without OS revealed no inhibitory activity for neutrophil chemotaxis, whereas those from HIE patients revealed the previously reported 61,000-dalton factor. However, when normal cells were cultured with OS, they produced a proteinaceous, 56 degrees C-stable, 30,000- to 45,000-dalton factor which preferentially inhibited neutrophil versus monocyte chemotaxis. When HIE cells were exposed to OS, they produced the same 30,000- to 45,000-dalton factor as normal cells, as well as the 61,000-dalton factor that they produced spontaneously. Assay of 1,000-fold dilutions of supernatants from cultures of normal mononuclear cells with OS revealed a mean production of 7.8 +/- 5.4% inhibition of chemotaxis, whereas assay of 1,000-fold dilutions of supernatants from cultures of HIE mononuclear cells (spontaneously producing the 61,000-dalton factor) with OS revealed a 26.6 +/- 3.6% inhibition (P less than 0.02). The data indicate that in short-term culture both normal and HIE mononuclear cells produce an inhibitor of neutrophil chemotaxis when exposed to particulate heat-killed staphylococci but that HIE cells produce qualitatively and quantitatively more inhibitory activity.
Binding of Todd-Hewitt broth antigens by Streptococcus mutans
Authors: Stinson M W , Jones C A
Published: January 2020

Streptococcus mutans 10449, grown in chemically defined culture medium, was tested for its ability to bind 3H-labeled Todd-Hewitt broth components (greater than 12,000 Mr). Maximum adsorption of radioactivity occurred within 5 min at room temperature, and cell-bound material was not completely removed by extended washing with buffer. Heat-killed, arsenate-inhibited, and viable bacteria bound similar quantities. Only 0.09% of the radioactivity in the preparation of high Mr Todd-Hewitt broth components was removed by absorption with excess numbers of S. mutans 10449 cells. Binding followed saturation kinetics and was competitively inhibited by unlabeled medium components, both the dialyzable and nondialyzable fractions. Other oral streptococci were also found to bind these complex medium components. Rabbit antiserum elicited to the high-molecular-weight Todd-Hewitt broth components reacted with monkey cardiac muscle and with S. mutans coated with medium components. Absorption of the anti-Todd-Hewitt broth serum with homogenized heart removed antibodies that reacted with Todd-Hewitt broth-coated S. mutans. Therefore, the tissue-specific antigens of this beef heart infusion medium that adsorb to S. mutans can interfere with the detection and characterization of antigens shared by these bacteria and animal tissues.
Synthesis and biological assays of peptides from a tuberculin-active protein
Authors: Savrda J
Published: January 2020

The octapeptide Asp-Gly-Gly-Ser-Glu-Ser-Glu-Gly and the hexadecapeptide Asp-Gly-Gly-Ser-Glu-Ser-Glu-Gly-Lys-Asn-Gly-Ser-Gln-Met-Arg-Leu, part of a tuberculin-active intracellular mycobacterial protein, were synthesized. The synthetic peptides were shown to possess tuberculin activity by their ability to elicit a delayed-type allergic reaction in skin tests on Mycobacterium tuberculosis-sensitized guinea pigs. Purified protein derivative, the complex mixture of proteins of unknown composition which are excreted into the culture medium by M. tuberculosis and which is in wide use as a tuberculin-active preparation, was shown to cross-react weakly in the radioimmunoassays with the synthetic octapeptide when the 125I-labeled octapeptide and an anti-octapeptide antiserum were used.
Coaggregation of human oral Cytophaga species and Actinomyces israelii
Authors: Kolenbrander P E , Celesk R A
Published: January 2020

A total of 19 strains of oral Cytophaga sp. obtained from subgingival plaque deposits were tested for their ability to coaggregate with strains of Actinomyces israelii, A. viscosus, A. naeslundii, Streptococcus sanguis, S. mutans, S. salivarius, and S. mitis. Coaggregation was observed only with A. israelii. Based on their coaggregation patterns with eight A. israelii strains, the Cytophaga strains were distributed among three distinct groups: those that coaggregated with A. israelii PK16 but not with A. israelii W1011 (ATCC 29322), those that coaggregated with A. israelii ATCC 29322 but not with A. israelii PK16, and those that coaggregated with none of the eight A. israelii strains. In each of the coaggregations, prior heat treatment (85 degrees C, 30 min) of the Cytophaga cells prevented coaggregation, whereas identical treatment of the A. israelii cells had no effect. The ability of A. israelii PK16 to form adherent plaque on a tooth surface previously coated with Cytophaga plaque was tested with one of the coaggregating Cytophaga strains. White patches of A. israelii plaque were found covering both the amber-colored Cytophaga plaque on the cementum surface as well as the enamel surface to which Cytophaga strains do not adhere. Electron micrographs of thin-sectioned mixed-plaque material revealed both cell types in close proximity. In addition, electron micrographs of negatively stained coaggregated cells showed interbacterial adherence between surface fimbrae on A. israelii and outer membrane blebs on the gram-negative Cytophaga sp. The kinetics of binding of A. israelii to spheroidal hydroxyapatite and to root powder were indicative of a high-affinity binding system with comparatively large numbers of available binding sites on both substrata. These results indicate the highly specific nature of Cytophaga sp.--A. israelii recognition. The contribution of such recognition toward the mechanisms that are responsible for the indigenous nature of these oral bacteria is discussed.
Cytopathogenicity of Naegleria fowleri for rat neuroblastoma cell cultures: scanning electron microscopy study
Authors: Marciano-Cabral F , John D T
Published: January 2020

Neuroblastoma cells were inoculated with Naegleria fowleri Lee and examined for cytopathology at various periods post-inoculation by scanning electron microscopy. By 18 h post-inoculation, approximately 50% of neuroblastoma cells were nonviable, as evidenced by trypan blue exclusion and light microscopic examination. This cytopathology resulted from piecemeal consumption of target cells mediated by a sucker apparatus extending from the surface of N. fowleri.
Cross-resistance to fecal excretion of Yersinia enterocolitica in mice by oral vaccination of killed cells
Authors: Kaneko K , Hashimoto N
Published: January 2020

Mice vaccinated orally with heat-killed cells of serovar O3 of Yersinia enterocolitica were protected only against fecal excretion of the homologous serovar, whereas Formalin-killed cells provided cross-protection against serovar O9 and vice versa. Serovar IVA of Yersinia pseudotuberculosis, when Formalin-killed, also provided cross-protection against Y. enterocolitica. On the other hand, Serratia liquefaciens and serovar O6 strains did not furnish cross-protection.
A BALB/c congenic strain of mice that carries a genetic locus (Ityr) controlling resistance to intracellular parasites
Authors: Potter M , O'Brien A D , Skamene E , Gros P , Forget A , Kongshavn P A , Wax J S
Published: January 2020

BALB/c.DBA/2 Idh-1b-Ityr-Pep-3b congenic mice were developed by introgressively backcrossing the Idh-1b and Pep-3b markers of DBA/2 mice onto the BALB/c pi mice. This introduced a 30-centimorgan chromosome 1 segment of DBA/2 chromatin that contained the Ityr gene. BALB/c.DBA/2 Idh-1b-Ityr-Pep-3b mice were resistant to in vivo infections by Salmonella typhimurium, Mycobacterium bovis, and Leishmania donovani.
Immunogenic properties in mice of hexasaccharide from the capsular polysaccharide of Streptococcus pneumoniae type 3
Authors: Snippe H , van Houte A J , van Dam J E , De Reuver M J , Jansze M , Willers J M
Published: January 2020

Hexasaccharide (HS) containing 3 U of cellobiuronic acid was isolated from Streptococcus pneumoniae type 3 capsular polysaccharide S3 and coupled to bovine serum albumin (BSA), keyhole limpet hemocyanin (KLH), or tetanus toxoid (TT). The immunogenicity of these HS-protein conjugates in BALB/c mice was studied by measuring the production of circulating antibodies and the induction of protective immunity to viable S. pneumoniae type 3. Immunization of BALB/c mice with 0.5 micrograms of S3 resulted in the induction of immunoglobulin M (IgM) antibodies and complete protection against 25 U of a mean lethal dose of S. pneumoniae type 3 for 19 weeks after immunization. BALB/c mice immunized with 100 micrograms of HS9-BSA (containing 12 micrograms of HS) were also protected due to circulating IgM antibodies. Repeated injections with either 100 micrograms of HS9-BSA (three immunizations) or 100 micrograms of HS6-KLH (two immunizations) resulted in high levels of circulating IgG antibodies. These HS-protein conjugates induced complete protection which lasted at least 14 (HS9-BSA), 23 (HS6-KLH), or 8 (HS16-TT) weeks after the last immunization. Protection against viable S. pneumoniae type 3 could be passively transferred to nonimmunized mice by antisera containing IgM or IgG antibodies or both. Sera containing both IgM and IgG antibodies gave better protection than sera containing only IgM antibodies. The specificity of the induced protection was confirmed by challenge with the non-cross-reacting S. pneumoniae type 11.
Resistance of O-acetylated gonococcal peptidoglycan to human peptidoglycan-degrading enzymes
Authors: Rosenthal R S , Folkening W J , Miller D R , Swim S C
Published: January 2020

Two naturally occurring forms of gonococcal peptidoglycan (PG) were tested for their susceptibility to human PG hydrolases. Purified 3H-labeled PG substituted extensively with O-acetyl derivatives (O-PG; from Neisseria gonorrhoeae FA19) and 14C-labeled O-acetyl-deficient PG (non-O-PG; from N. gonorrhoeae RD5) were mixed together and treated with either normal human sera (NHS) or with lysozyme purified from human polymorphonuclear leukocytes (PMN-LZ). The initial rate of hydrolysis of O-PG by NHS or by PMN-LZ was two- to fourfold less than that of its non-O-PG counterpart in the same tube. When the reactions were allowed to go to completion. NHS solubilized both PGs completely, whereas PMN-LZ solubilized all of the non-O-PG and left ca. 60% of the O-PG insoluble. The PMN-LZ-soluble fraction of O-PG consisted largely of glycosidically linked fragments with molecular weights greater than ca. 10(4), whereas the corresponding non-O-PG was degraded to lower-molecular-weight fragments, exclusively. At completion, NHS hydrolyzed both PGs to fragments whose size was equal to or smaller than that of the free disaccharide unit of PG, suggesting that human sera contain a peptide-splitting (amidase) activity and a glycosidase activity, in addition to that of the well-known muramidase. NHS also promoted the release of high-molecular-weight PG fragments from intact gonococci. The persistence of human hydrolase-resistant PG in the form of soluble macromolecular fragments may potentiate the biological effects of gonococcal PG in vivo.