bluuebunny/crossref_metadata_2025 huggingface dataset:
Differences in cross-protection in rats immunized with the B subunits of cholera toxin and Escherichia coli heat-labile toxin
Authors: Klipstein F A , Engert R F , Clements J D , Houghten R A
Published: January 2020

Although cholera toxin (CT), Escherichia coli heat-labile toxin (LT), and their B subunits are known to be immunologically related, the ability of each to raise an antitoxin response that provides equally strong cross-protection against active challenge with pure heterologous toxin has not been examined previously. We immunized rats with pure preparations of the B subunits of human LT, porcine LT, and CT. Immunization with either of the LT B subunits raised greater than or equal to fourfold increases in specific mucosal immunoglobulin A antitoxin titers to homologous and heterologous LT and CT B subunits, thereby providing strong protection against active challenge in ligated ileal loops with all three respective holotoxins and with a viable LT-producing E. coli strain. In contrast, immunization with the CT B subunit raised a greater than or equal to fourfold increase in antitoxin titers only to itself and provided strong protection only against challenge with the CT holotoxin. Conjugation of the CT B subunit with the E. coli heat-stable toxin by the carbodiimide reaction yielded a cross-linked immunogen with equal antigenicity for both components; immunization with this conjugate raised greater than or equal to fourfold increases in antitoxin titers to both components, but it provided significant protection only against challenge with a viable heat-stable toxin-producing E. coli strain and not to an LT-producing E. coli strain. These observations indicate that immunization with the LT B subunits raises a heterologous antitoxin response that extends to the CT B subunit, thereby providing equally strong protection against LT and CT; however, immunization with the CT B subunit raises principally a homologous antitoxin response, so that this immunogen provides strong protection only against CT.
Conservation of peptide structure of outer membrane protein-macromolecular complex from Neisseria gonorrhoeae
Authors: Hansen M V , Wilde C E
Published: January 2020

The structural conservation of an outer membrane protein of Neisseria gonorrhoeae called OMP-MC (outer membrane protein-macromolecular complex) was investigated by determining the isoelectric point and amino-terminal amino acid sequence of the protein and by using high-performance liquid chromatography for comparative tryptic peptide mapping. The 76,000-dalton subunits generated by reduction and alkylation of the native 800,000-dalton complex from six test strains focused in ultrathin gels as bands of restricted heterogeneity at an approximate pI of 7.6. Dansyl chloride labeling indicated that all strains shared glycine as the amino-terminal amino acid. Sequence analysis of OMP-MC from two strains revealed no amino acid differences within the first 11 residues. Dual-label peptide maps revealed an extremely high degree of conservation of peptide structure. The results indicate that (i) OMP-MCs isolated from various strains of N. gonorrhoeae share structural homology and (ii) the 800,000-dalton complex is a homopolymer composed of 10 to 12 apparently identical 76,000-dalton subunits.
Phosphorylcholine determinants in six pneumococcal capsular polysaccharides detected by monoclonal antibody
Authors: Sørensen U B , Agger R , Bennedsen J , Henrichsen J
Published: January 2020

The presence of phosphorylcholine in pneumococcal capsular polysaccharides was examined by using monoclonal antiphosphorylcholine antibody. Of the 83 known capsular types of Streptococcus pneumoniae, 6 types, viz., 24A, 27, 28F, 28A, 32F, and 32A, gave a positive capsular reaction (quellung) which could be inhibited by phosphorylcholine. The capsular polysaccharides of these six types, therefore, contain phosphorylcholine.
Pseudomonas aeruginosa clearance in mice: comparison of tissue, strain, and corticosteroid effects
Authors: Nugent K M , Cox C D , Pesanti E L
Published: January 2020

We used a murine model to determine whether chronic corticosteroid therapy has uniform effects on bacterial clearance processes in different tissues. After a 2-week regimen of oral prednisolone, Swiss Webster mice were challenged with Pseudomonas aeruginosa strain PAO1 or virulent derivatives of PAO1 (IP-8 and IT-10). Chronic corticosteroid therapy delayed the clearance of strain PAO1 from the peritoneal cavity. However, steroid treatment did not reduce the neutrophil influx, did not reduce the in vivo phagocytic capacity of neutrophils, and did not alter bactericidal activity of peritoneal exudate cells in vitro. Virulent isolates (IP-8 and IT-10) replicated in the peritoneal cavity in steroid-treated mice even though the neutrophil influx was similar to control mice. In contrast to the abnormal peritoneal clearance, all strains were rapidly cleared from the lungs of control and steroid-treated mice after aerosol challenge. Neutrophil influx into bronchoalveolar spaces was greater in steroid-treated mice than in control mice. All mice (control and steroid treated) survived these challenges, except for some steroid-treated mice infected intraperitoneally with IP-8. These results demonstrate that chronic steroid therapy alters bacterial clearance processes on the peritoneal surfaces to a greater extent than in the lower respiratory tract. The explanation for this altered clearance in the peritoneum is unclear, but cannot be explained by reductions in neutrophil migration to inflammatory stimuli. Therefore, the infectious risk associated with chronic corticosteroid therapy appears to depend on both the tissue and the virulence of the bacterial strain and may reflect alterations in clearance processes other than neutrophil migration.
Resistance to subcutaneous infection with Mycobacterium lepraemurium is controlled by more than one gene
Authors: Curtis J , Turk J L
Published: January 2020

The resistance of C57BL (high) and BALB/c (low) mice, their F1 hybrids, and the offspring derived from backcrosses of the F1 to both parental strains was assessed at 20 weeks after subcutaneous infection with 10(7) Mycobacterium lepraemurium organisms. The numbers of bacilli recovered from the infected foot and draining lymph node indicated that resistance to subcutaneous infection is controlled by more than one non-H-2-linked gene of intermediate dominance. In general, female mice were more resistant than males.
Effect of oxygen radical scavengers on K-cell cytolysis
Authors: Bowman B U , Shoeb H A
Published: January 2020

We have shown that the hydroxyl radical scavengers sodium benzoate, phenol, dimethyl sulfoxide, sodium formate, and mannitol protect chicken erythrocyte (Ec) target cells from lysis by K-cells in plaque assays. The protection afforded by benzoate, phenol, mannitol, and dimethyl sulfoxide was abrogated if the target cells were pretreated with sodium chromate. Neither superoxide dismutase nor catalase protected Ec target cells, indicating that superoxide and H2O2 are not involved in lysis. The lysis obtained on chromium-treated Ec target cells in the presence of benzoate, phenol, and mannitol is likely due to singlet oxygen, because 1,4-diazabicyclo[2.2.2]octane and bilirubin, singlet oxygen scavengers, protected chromium-treated Ec target cells in the presence of phenol. Ec target cells not treated with chromium were not protected by either of the singlet oxygen scavengers.
Association of high levels of serum antibody to staphylococcal toxic shock antigen with nasal carriage of toxic shock antigen-producing strains of Staphylococcus aureus
Authors: Ritz H L , Kirkland J J , Bond G G , Warner E K , Petty G P
Published: January 2020

Forty-four asymptomatic male subjects were examined for their nasal carriage of strains of Staphylococcus aureus capable of producing staphylococcal toxic shock antigen (TSA), an exotoxin implicated in the pathogenesis of toxic shock syndrome. In addition, the levels of antibody to TSA in sera from these subjects were determined by an enzyme-linked immunosorbent assay. S. aureus was isolated from the anterior nares of 23 subjects. Of those 23 isolates of S. aureus, 9 were found to produce TSA. All individuals carrying strains of S. aureus capable of producing TSA had high to moderate levels of antibody to TSA. In contrast, those individuals carrying strains not producing TSA had levels of antibody to TSA ranging from high to nondetectable. A second examination of nasal samples from 42 of these subjects revealed that 86% of those carrying S. aureus initially still carried S. aureus after a period of 3 months; all subjects found to carry TSA-producing strains initially and that were examined a second time yielded TSA-producing strains once again.
Characterization of new hydrophobic pili of human enterotoxigenic Escherichia coli: a possible new colonization factor
Authors: Honda T , Arita M , Miwatani T
Published: January 2020

Enterotoxigenic Escherichia coli strains were divided into five groups on the basis of their bacterial surface hydrophobicity (Honda et al., FEMS Microbiol. Lett. 17:273-276, 1983). Strains in group III showed heat-stable high hydrophobicity, although they did not show mannose-resistant hemagglutination with either human or bovine erythrocytes. E. coli strain 260-1 in group III was characterized. Electron microscopic examination revealed the presence of pili on the surface of this strain, but not on that of strain 260-1a, which is a mutant of 260-1 showing low hydrophobicity. When strain 260-1 was grown at 18 degrees C, it did not produce pili or show high hydrophobicity. On homogenization of strain 260-1 grown at 37 degrees C the high hydrophobicity and the pili on its surface were lost. These results indicate that the pili of strain 260-1 are associated with the hydrophobicity. Strain 260-1 pili were purified to homogeneity by successive column chromatographies on Sepharose 4B and phenyl-Sepharose CL-4B. Their molecular weight was estimated to be about 18,000. An antigenic difference between purified pili of strain 260-1 and colonization factor antigens I and II was demonstrated. The colonization ability of E. coli 260-1 was shown by animal experiments on suckling mice and infant rabbits. From these results it is concluded that the pili of strains in group III of human enterotoxigenic E. coli, which may play a role in colonization, are of a new type.
Variability in expression of a cell surface determinant on Candida albicans as evidenced by an agglutinating monoclonal antibody
Authors: Brawner D L , Cutler J E
Published: January 2020

The expression of a surface immunodeterminant of Candida albicans was investigated with an agglutinating immunoglobulin M monoclonal antibody. The 96 strains of C. albicans tested, of which 76% were recent clinical isolates, were capable of expressing the antigen. The antigen was also produced by strains of Candida tropicalis and Torulopsis glabrata, but not by other yeast species. Expression of the surface immunodeterminant in C. albicans varied as a function of growth as indicated by agglutinin reactions and indirect immunofluorescence tests. When yeast cells were tested with the agglutinin, three patterns of reactivity were observed. In general, cells in the early logarithmic phase were less reactive than cells in the mid-logarithmic phase. Antigen expression, as determined by agglutinin reactivity, was also influenced by the nutritional composition of the growth medium, and in general, cells from broth cultures were usually more reactive than cells grown on solid media. The antigen was solubilized from the cell surface of C. albicans by hot 1 M NaCl. These water-soluble extracts were capable of binding antibody, and a single precipitin band formed when soluble antigen was reacted with the monoclonal antibody in an Ouchterlony double-diffusion test. Whole cell preparations and hot NaCl extracts from yeast strains which did not agglutinate when mixed with the antibody also did not absorb the agglutinin from solution. These data indicate that the expression of surface antigens on C. albicans is a dynamic process which may be influenced by a number of environmental factors. The use of monoclonal antibodies may allow characterization of surface antigens presented to the host during candidiasis.
Toxoplasma-induced activities of peritoneal and spleen natural killer cells from beige mice against thymocytes and YAC-1 lymphoma targets
Authors: Kamiyama T
Published: January 2020

Homozygous (bg/bg) and heterozygous (bg/+) beige mice were infected with Toxoplasma gondii, and splenic and peritoneal natural killer (NK) cell activities were assayed against YAC-1 lymphoma (NK-YAC) and thymocyte (NK-THY) targets. Although uninfected bg/bg mice were devoid of NK-YAC activity when compared with bg/+ mice, NK-THY activity was at a completely normal level. Both effector cells showed NK-1.2+ Thy-1.2 +/- asialo GM1+ asialo GM2+ phenotype. T. gondii infection induced a marked augmentation in splenic NK-YAC activity of bg/+ mice, whereas a slight increase was shown in the bg/bg mouse spleen cells. On the other hand, the infection did not change the splenic NK-THY activity of either strain of mice. An increased expression of Thy-1.2 antigen was shown on both NK-THY and NK-YAC effector cells from the infected mouse spleen. The T. gondii-induced augmentation was dramatic in the peritoneal cavity of the both mice. The activated peritoneal NK cells were of the NK-1.2- Thy-1.2+ asialo GM1 +/- asialo GM2+ phenotype and were considered to be generated from functionally inactive peritoneal cells. Splenic effector cells obtained from the infected mice were selectively depleted with target cell monolayer, whereas peritoneal cells from the infected mice were strongly absorbed by the target monolayers without selectivity. A weak but significant interferon (IFN) titer was detected in the peritoneum, but not in the spleen, of the infected mice. Most of the IFN titer was acid labile. Treatment with anti-IFN-alpha/beta resulted in partial decline of both NK and IFN activities of bg/bg mice, but not bg/+ mice. Thus, involvement of both IFN-alpha/beta and IFN-gamma in the generation of peritoneal NK cells and IFN-independent augmentation of splenic NK cells in toxoplasmosis were suggested.
Susceptibility of CXB recombinant inbred mice to murine plasmodia
Authors: Hoffmann E J , Weidanz W P , Long C A
Published: January 2020

The genetic control of susceptibility to two species of murine malarial parasites was investigated with recombinant inbred (RI) mouse strains as a model system. Initially, the nonlethal Plasmodium yoelii 17X strain was cloned by limiting dilution to minimize parasite variability. This cloned P. yoelii was used to infect C57BL and BALB/c mice, strains which are the progenitors of the CXB RI strains. Since these two strains displayed consistent differences in the kinetics of parasitemia, the seven CXB RI strains were compared for their susceptibility to the same parasite. The RI strains varied considerably when infected with P. yoelii and could be divided into susceptible and resistant groups based on mortality observed with this normally mild infection. This suggests a complex, multigenic inheritance determining susceptibility to this parasite. However, when the susceptible and resistant CXB RI mice were infected with another, unrelated plasmodial species, Plasmodium chabaudi adami, all the mice showed identical patterns of disease. Since susceptibility to different murine plasmodia does not cosegregate in the CXB RI mice, different mechanisms of resistance may be required for different plasmodial species.
Campylobacter jejuni outer membrane proteins are antigenic for humans
Authors: Blaser M J , Hopkins J A , Vasil M L
Published: January 2020

All Campylobacter jejuni strains have a major outer membrane protein (OMP) that migrates between a molecular weight of 41,000 (41K) and 45K and represents more than 50% of protein present, plus several more minor bands. Using 125I-radiolabeled C. jejuni cells in a radioimmunoprecipitation procedure to assess whether the OMPs were antigenic, we studied serum from rabbits immunized with C. jejuni cells, from humans convalescent after C. jejuni infection, and from appropriate controls. In this assay, the major OMP was the major antigen for both homologously and heterologously immunized rabbits and infected humans but not for controls. Minor bands at 29K and 50K were also antigenic. We tested human and animal sera in a Western blot procedure using anti-immunoglobulin A (IgA), anti-IgG, or anti-IgM conjugates. Homologous and heterologous immune rabbit serum, but not control serum, recognized a large number of membrane proteins between 15K and 91K, including the major OMP. Both Campylobacter spp.-infected and healthy humans showed IgA, IgG, and IgM responses to the major OMP, although the response was more pronounced in the former group. Sera from infected humans recognized several minor bands to a significantly greater extent than control sera did. Our data suggest that there is antigenic similarity between the OMPs of different C. jejuni strains and that some of these OMPs recognized by infected animals and humans have vaccinogenic potential.
Proliferative response of immune mouse T-lymphocytes to the lymphocytosis-promoting factor of Bordetella pertussis
Authors: Fish F , Cowell J L , Manclark C R
Published: January 2020

Immunization of mice with a whole-cell pertussis vaccine or with the purified, detoxified lymphocytosis-promoting factor (LPF) of Bordetella pertussis resulted in an increased in vitro proliferative response to LPF in immune lymph node cells. The proliferative response was detected above the nonspecific mitogenic activity of LPF. That the proliferative response of the immune lymph node cells was a demonstration of a specific cell-mediated immunity to LPF was supported by the following: (i) the specificity of the response to the immunizing antigen; (ii) the ability of chemically modified, nonmitogenic LPF to induce proliferation in immune lymph node cells; and (iii) a dependence on T-cells for the demonstration of the proliferative response of immune cells to LPF. Immunization of mice with protective doses of detoxified LPF resulted in serum antibody and cell-mediated responses to LPF. Immunization of mice with protective doses of whole-cell pertussis vaccine resulted in a cell-mediated response but not a detectable antibody response to LPF. The LPF of B. pertussis is believed to play an important role in pathogenesis and immunity in pertussis, and the demonstration of a cell-mediated immune response to LPF suggests a possible role for cell-mediated immunity to LPF in protection from pertussis disease.
Characterization of a human pararotavirus
Authors: Espejo R T , Puerto F , Soler C , González N
Published: January 2020

A virus isolate with the properties of a pararotavirus was found after routine analysis by RNA electrophoresis of 658 samples of diarrheic feces from hospitalized infants and young children in Mexico City. Of the patients included in this survey, which was initiated in 1977, 29% excreted rotaviruses which were detected by their characteristic RNA pattern after gel electrophoresis. The morphology and sedimentation coefficient of this pararotavirus, which was the apparent cause of a diarrhea with moderate dehydration in a 2-year-old male infant, were indistinguishable from those of rotaviruses, but its buoyant density in CsCl was slightly higher than that of simian rotavirus SA11. By electron microscopy, the viral particles showed a regular pattern of cavities or holes that constituted the 5- and 6-coordinated units of the virion with a structure characteristic of T = 12. The virion also was apparently composed of protein classes similar to those found in rotaviruses. Seroconversion in the patient and presence of anti-pararotavirus antibodies in most of the members of the family of the patient was shown by immunoelectron microscopy. Of the sera from 12 healthy adults which were examined by this technique, seven were negative, three were slightly positive, and only two were strongly positive.
Murine malaria: immune complexes inhibit Fc receptor-mediated phagocytosis
Authors: Shear H L
Published: January 2020

Immune complexes have been partially purified from the serum of Plasmodium berghei-infected mice by ultracentrifugation on 10 to 40% linear sucrose gradients, by precipitation with polyethylene glycol, and by gel filtration through Sephacryl S-300. The complexes contain gamma 1, gamma 2a, gamma 2b, and gamma 3 subclasses of mouse immunoglobulin G in differing amounts, as well as malarial antigen. Complexes isolated by all three methods inhibit Fc receptor-mediated phagocytosis by normal mouse peritoneal macrophages but do not inhibit attachment to the Fc receptor or to the C3 receptor or the ingestion of latex particles. The phagocytosis-inhibiting activity of the immune complexes can be partially removed by prior incubation with protein A-Sepharose CL-4B. Splenic macrophages, isolated from P. berghei-infected mice, may be already coated with immune complexes in vivo. Attachment of mouse erythrocytes sensitized with immunoglobulin G to these macrophages is greatly enhanced during malaria, but ingestion is not. These results suggest that immune complexes modulate the immune response to malaria by inhibiting immune phagocytosis and perhaps by interfering with other effector mechanisms. Further understanding of the influence of immune complexes and the antigens involved in these complexes may be useful in vaccine development and prophylaxis.
Isolation of a Streptococcus mutans strain producing a novel bacteriocin
Authors: Hillman J D , Johnson K P , Yaphe B I
Published: January 2020

A strain of Streptococcus mutans has been isolated that produces a bacteriocin with novel properties. Its antibiotic spectrum includes 123 of 124 strains of S. mutans tested and a variety of other gram-positive microorganisms. Experiments with dialysis membranes indicate that the molecular weight of the bacteriocin is less than 1,000. Mutants of the producer strain were obtained that are deficient in bacteriocin production or produce twofold elevated amounts. The ability of these strains to superinfect or preemptively colonize the oral cavities of rats correlated with the amount of bacteriocin they produced.
Purification and characterization of Staphylococcus aureus FRI 1169 and 587 toxic shock syndrome exotoxins
Authors: Igarashi H , Fujikawa H , Usami H , Kawabata S , Morita T
Published: January 2020

An exotoxin was purified from a toxic shock toxin (TST)-producing Staphylococcus aureus strain, FRI 1169, and another exotoxin was purified from a pyrogenic exotoxin C (PEC)-producing S. aureus strain, 587. Both strains had been isolated from toxic-shock syndrome patients. The two exotoxins were purified by the same method of ion-exchange chromatography, chromatofocusing, and gel filtration. After purification, those exotoxins gave a line of identity against an anti-TST serum and also were immunologically similar to TST in a double-diffusion test. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, each exotoxin gave a single band with a relative mobility identical to that of the other. Their molecular weights (24,000), isoelectric points (7.0), amino acid compositions, and NH2-terminal amino acid sequences (the first four residues) were identical. Both produced fever and enhanced host susceptibility to lethal endotoxin shock in rabbits, comparable with PEC. These findings show that the two exotoxins are the same protein, which is assumed to be TST. When injected into rabbits, the culture supernatant of strain 587 showed biological activity like that described above, whereas the culture supernatant neutralized with anti-TST immunoglobulin did not. This showed that PEC-producing strain 587 does not produce any toxin with these biological activities in rabbits except TST.
Monoclonal antibodies reactive with all strains of Haemophilus ducreyi
Authors: Hansen E J , Loftus T A
Published: January 2020

We have isolated plasma cell hybridomas which secrete monoclonal antibodies directed against Haemophilus ducreyi. Two of these monoclonal antibodies recognize all strains of H. ducreyi tested to date and are capable of detecting the presence of H. ducreyi in skin lesions produced by this pathogen in experimental animals. These monoclonal antibodies which react with apparently all strains of H. ducreyi have the potential to be developed into a rapid immunodiagnostic test for chancroid.
Role of pili in the adherence of Pseudomonas aeruginosa to injured tracheal epithelium
Authors: Ramphal R , Sadoff J C , Pyle M , Silipigni J D
Published: January 2020

Pili have been demonstrated to be the adhesins of nonmucoid Pseudomonas aeruginosa for buccal cells. In this study, we examined their role in the adherence of both mucoid and nonmucoid strains to injured tracheal cells. Pili incubated with tracheal cells inhibited the adherence of a nonmucoid strain in a dose-dependent manner. Both homologous and heterologous pili inhibited this nonmucoid strain. Antibody against pili from the nonmucoid strain inhibited adherence of the homologous but not a heterologous strain. Pili failed to inhibit two mucoid strains, but inhibited nonmucoid variants derived from mucoid strains. These studies suggest that pili mediate the adherence of nonmucoid strains to injured tracheal cells but that they are not the final mediators of adherence of mucoid strains. It is also inferred that there are differences in the receptor for mucoid and nonmucoid strains.
Toxic interactions of benzyl alcohol with bacterial endotoxin
Authors: Cebula T A , El-Hage A N , Ferrans V J
Published: January 2020

Acute toxic interactions of intravenously administered benzyl alcohol and Escherichia coli O55:B5 (Boivin preparation) endotoxin were examined in rodents. Lethality studies in male CD-1 mice demonstrated that these agents were more toxic when administered in combination than when either was administered alone. Prophylactic treatment with diazepam (5 mg/kg intraperitoneally) protected against lethality induced by either the combination or the endotoxin yet offered little, if any, protection against the lethal effects of benzyl alcohol. Similar treatments with naloxone (5 mg/kg intraperitoneally) failed to protect against either endotoxin-induced or benzyl alcohol-induced lethality, but they significantly protected against the lethal effects of the combination. Although hexobarbital-induced sleeping time was prolonged in endotoxin-treated mice (but was normal in benzyl alcohol-treated mice), a more protracted effect on sleeping time was observed in mice treated with both benzyl alcohol and endotoxin. Moreover, male Wistar rats treated with benzyl alcohol (40 mg) showed no evidence of hepatic lesions, but rats treated in combination with sublethal doses of the alcohol (40 mg) and the endotoxin (0.4 mg) developed hepatic lesions which were severe than those observed in rats treated with endotoxin (0.4 mg) alone. A correlation between altered blood chemistry values and severity of hepatic lesions was demonstrated. These data show in vivo toxic interactions between benzyl alcohol and bacterial endotoxin. In addition, our results indicate that the toxic effects induced by the benzyl alcohol-endotoxin combination are due to an enhancement of the lethal properties of bacterial endotoxin.
Effect of saliva on coaggregation of oral Actinomyces and Streptococcus species
Authors: Kolenbrander P E , Phucas C S
Published: January 2020

Human oral actinomyces and streptococci that exhibit specific coaggregation patterns when the cells are suspended in buffer were tested for their ability to coaggregate in saliva. Of 53 paired combinations of actinomyces (Actinomyces viscosus, A. naeslundii, or Actinomyces sp. WVa 963) and streptococci (Streptococcus sanguis or S. morbillorum) that exhibited coaggregation in buffer, all but 4 pairs also coaggregated when suspended in saliva. Twenty-four pairs exhibited lactose-inhibited coaggregation in buffer: 19 of these were identical in saliva. The other five pairs either did not coaggregate or formed coaggregates that were not inhibited by lactose. Highly specific coaggregations known to occur with buffer-suspended cells (e.g., a streptococcal strain that coaggregates with a single strain of actinomyces) were unchanged when cells were suspended in saliva. These results indicate that the coaggregation properties of both oral actinomyces and streptococci are very similar with cells suspended in either saliva or coaggregation buffer. Thus, the potential for coaggregation among bacteria in the oral cavity is evident. The possible mechanisms which mediate coaggregation in saliva are discussed.
Growth and serial passage of Pneumocystis carinii in the A549 cell line
Authors: Cushion M T , Walzer P D
Published: January 2020

Pneumocystis carinii obtained from infected rats and patients was cultured in the A549 cell line, a presumptive alveolar type 2 cell line derived from a human lung carcinoma. Standard criteria were established for organism sampling, quantitation, and growth. The trophozoite form of P. carinii was a more sensitive indicator of growth than was the cyst. Rat P. carinii increased 10-fold in primary culture and could be serially passed three additional times to new cultures; success in growing human P. carinii was limited and appeared to be related to the quality of the specimen received for culture. Growth pattern experiments suggested that close interaction of P. carinii with the cell monolayer is an important step in the life cycle of the organism. Thus, the A549 culture system should be useful for in vitro studies of the immunobiology of P. carinii.
Class specificity of naturally acquired and vaccine-induced antibody to type III group B streptococcal capsular polysaccharide: determination with a radioimmunoprecipitin assay
Authors: Edwards M S , Fuselier P A , Rench M A , Kasper D L , Baker C J
Published: January 2020

A radioimmunoprecipitin test was developed to determine the immunoglobulin class distribution of naturally acquired and vaccine-induced antibody to the native capsular polysaccharide of type III group B streptococci (III-GBS). In sera from adults and pregnant women with naturally acquired antibody, the mean percentage of antigen bound by immunoglobulin G (IgG) was 74.9 and 78.6, respectively, whereas antigen bound by IgM comprised less than 10% of the total. In contrast, early-convalescent-phase sera (mean, 16.3 days) from neonates responding to III-GBS infection with an increase in specific antibody had significantly more IgM (mean, 36%; P less than 0.001, unpaired t test). However, in late convalescence, the immunoglobulin class distribution in sera from these neonates was similar to that of naturally immune adults. Four weeks after immunization with III-GBS polysaccharide vaccine, sera from adults with low (less than 2 micrograms/ml) preimmunization antibody levels in their sera and from those with moderate (mean, 5.5 micrograms/ml) preimmunization levels contained specific antibody predominantly of the IgG class. Although the percentage of IgG-specific antibody was greater in sera from naturally immune adults than in that from vaccinees with a presumed primary immune response, the major portion of antigen bound by sera at 4 weeks postimmunization (62.5%) was associated with IgG. These observations support the opinion that immunization of pregnant women with III-GBS capsular polysaccharide could be efficacious for the prevention of invasive neonatal III-GBS disease.
Human serum antibody response to Campylobacter jejuni infection as measured in an enzyme-linked immunosorbent assay
Authors: Blaser M J , Duncan D J
Published: January 2020

An enzyme-linked immunosorbent assay was adapted to measure immunoglobulin A (IgA), IgG, and IgM classes of human serum antibody to Campylobacter jejuni. Sera were tested from healthy controls, from ill persons at various intervals after exposure to an epidemiologically implicated vehicle for Campylobacter sp. enteritis, from persons exposed to these same vehicles who remained well, and from persons who chronically drank raw milk. The major antigens in the C. jejuni acid-washed antigen preparations from three different strains all migrated at about 30,000 and 63,000. Persons with Campylobacter enteritis developed rising serum IgA, IgG, and IgM antibodies during the second week after infection; IgG and IgM elevations persisted longer than did IgA. Exposed persons who remained well showed similar, but lower, antibody rises. Chronic raw milk drinkers had elevated IgG levels, but not IgM or IgA levels, whether or not they were acutely exposed to an implicated vehicle.
Interaction between murine natural killer cells and trypanosomes of different species
Authors: Albright J W , Hatcher F M , Albright J F
Published: January 2020

The involvement of natural killer (NK) cells in the immunological resistance of mice to murine-specific Trypanosoma musculi was evaluated. Murine NK cells were found to be unable to kill or inhibit T. musculi or to protect recipients from infection. In addition, the ability of spleen cells from normal mice and from mice on day 3 of T. musculi infection, at the time of maximum NK augmentation, to kill Trypanosoma cruzi and Trypanosoma lewisi was evaluated. Spleen cells from normal mice displayed significant killing of both T. cruzi and T. lewisi. Furthermore, augmented spleen cells from T. musculi-infected mice were considerably more effective than normal spleen cells in killing both T. cruzi and T. lewisi. The activity of NK cells toward YAC-1 tumor target cells was inhibited in a dose-dependent fashion by either live T. musculi or extracts of T. musculi, but not by extracts of rat-specific T. lewisi. The results suggest that well-adapted protozoan parasites may be nonsusceptible to the natural cell-mediated resistance mechanisms of their hosts. Their nonsusceptibility could result from the ability to elaborate substances that either inactivate NK cells or block NK cell interaction with complementary sites on the parasite surface.
Mechanism of impaired iron release by the reticuloendothelial system during the hypoferremic phase of experimental Neisseria meningitidis infection in mice
Authors: Letendre E D , Holbein B E
Published: January 2020

Hypoferremia, the reduction of plasma transferrin iron levels during infection, has been shown to control Neisseria meningitidis infection in mice. The exact nature of the mechanism that regulates this response has been obscure. We have previously shown that hypoferremia does not result from an accelerated removal of iron from the plasma transferrin pool. In this study, we have examined the processing of iron by the reticuloendothelial system during infection. Normal and hypoferremic meningococcus-infected mice were injected with 59Fe-labeled erythrocytes. Kinetics of uptake and redistribution of the label indicated that during the hypoferremic phase of the infection, reticuloendothelial system-processed iron was not returned to the plasma transferrin pool. Fractionation of hepatic cellular compartments showed that this impaired release of iron resulted from a preferential incorporation of heme-derived iron into the intracellular ferritin pool during the hypoferremic phase of the infection. These findings indicate that this withholding of iron within the intracellular pool leads to hypoferremia and therefore denies the extracellular pathogen its essential iron.
Compared colonizing and immunizing efficiency of toxinogenic (A+ B+) Vibrio cholerae and an A- B+ mutant (Texas Star-SR) studied in adult rabbits
Authors: Tokunaga E , Cray W C , Pierce N F
Published: January 2020

Four strains of Vibrio cholerae O1 were compared for their ability to colonize and immunize adult rabbit intestine. Three were virulent, toxinogenic (A+ B+) isolates, and one, an A- B+ mutant (Texas Star-SR), was derived by mutagenesis with nitrosoguanidine. When given orally to nonimmune rabbits, virulent strains colonized the small bowel with similar efficiency, whereas Texas Star-SR colonized poorly. Rabbits fed less than 50 CFU of an A+ B+ strain developed marked serotype-specific resistance to recolonization. In contrast, Texas Star-SR evoked resistance to reinfection less efficiently, with a minimum immunizing dose of 10(5) CFU when given once or 10(3) CFU when given twice. Oral inoculation with an A+ B+ strain also evoked vigorous, dose-dependent mucosal antitoxin responses; comparable inocula of Texas Star-SR were much less effective, causing antitoxin responses that were 90 to 95% smaller. Finally, rabbits inoculated once with 10(4) CFU of an A+ B+ strain were markedly protected against experimental cholera or fecal shedding of V. cholerae when challenged with 10,000 times the 50% effective dose of a virulent strain by the RITARD technique. In contrast, an inoculum of 10(4) CFU of Texas Star-SR was nonprotective, and 10(10) CFU was only partially protective. These studies reveal the remarkable efficiency with which virulent V. cholerae evokes intestinal immunity to recolonization or experimental cholera and show that the A- B+ mutant, Texas Star-SR, is substantially less effective.
Chemotactic and candidacidal responses of rabbit alveolar macrophages during postnatal development and the modulating roles of surfactant in these responses
Authors: Zeligs B J , Nerurkar L S , Bellanti J A
Published: January 2020

Chemotactic responses of alveolar macrophages from 1-, 7-, and 28-day-old rabbits to various concentrations of endotoxin-activated serum and n-formyl-methionyl-phenylalanine were tested utilizing both blind well and agarose plate assay systems. A dramatic increase in both the chemotactic response and responsiveness to various concentrations of chemoattractant was observed during postnatal maturation. The pattern of result was similar with both methods of assay. An age-related increase was also found to occur in the candidacidal activity of alveolar macrophages in contrast to their phagocytic uptake, which showed no age-related increases. Furthermore, the decreased function of macrophages from newborn animals correlated with a morphologically and biochemically less mature cell population which contained large amounts of phagocytosed surfactant-related material. Moreover, pretreatment of macrophages from 7- and 28-day-old animals with vesicles of surfactant-related material resulted in decreases in both chemotactic and candidacidal activity, with a paradoxical increase in their phagocytic activity. The resulting activities were similar to those of macrophages from 1-day-old animals treated with buffer alone. These data suggest that there is an age-related increase in the chemotactic and candidacidal activity of alveolar macrophages during maturation and that the decreased activity of macrophages from newborn animals is related in part to the large amount of surfactant-related material present at that time.
Isolation of a major cell envelope protein from Fusobacterium nucleatum
Authors: DiRienzo J M , Rosan B
Published: January 2020

A major, heat-modifiable cell envelope protein was identified in Fusobacterium nucleatum FDC 364 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This protein, designated HM-1, had apparent molecular weights of 38,500 and 50,000 when heated in sodium dodecyl sulfate at 50 and 100 degrees C, respectively. Whole cells were labeled with 125I, and the results suggested that the HM-1 protein may be exposed on the bacterial surface. The HM-1 protein was isolated in association with the peptidoglycan by extraction of whole cells or cell envelopes with 2% sodium dodecyl sulfate at 55 degrees C. Heating the peptidoglycan-HM-1 protein complex in the detergent at 100 degrees C resulted in the quantitative release of the protein. Isoelectric focusing experiments and amino acid analysis revealed that the HM-1 protein had a basic character and was moderately hydrophilic. Various strains of F. nucleatum as well as three oral fusiform isolates contained a serologically related protein. The abundance and location of the HM-1 protein in F. nucleatum suggest that it has the potential to participate in cell surface-related interactions of this bacterium.
Enhancement of host resistance against Listeria infection by Lactobacillus casei: role of macrophages
Authors: Sato K
Published: January 2020

Among the 10 species of the genus Lactobacillus, L. casei showed the strongest protective action against Listeria monocytogenes infection in mice. The activity of L. casei differed with regard to the dose of administration. The anti-L. monocytogenes resistance in mice intravenously administered 5.5 X 10(7), 2.8 X 10(8), or 1.1 X 10(9) L. casei cells was most manifest at ca. 2, 2 and 13, and 3 to 21 days after its administration, respectively. The growth of L. monocytogenes in the liver of mice injected with L. casei (10(7), 10(8), or 10(9) cells) 48 h after infection was suppressed, particularly when 10(8) or 10(9) L. casei cells were given 2 or 13 days before the induced infection, respectively. This suppression of L. monocytogenes growth was overcome by carrageenan treatment or X-ray irradiation. [3H]thymidine incorporation into the liver DNA increased 13 days after administration of L. casei, and augmentation of [3H]thymidine incorporation during 6 to 48 h after infection was dependent on the dose of L. casei. Peritoneal macrophage accumulation observed 1 to 5 days after intraperitoneal injection of UV-killed L. monocytogenes was markedly enhanced when the mice were treated with L. casei cells 13 days before macrophage elicitation. Therefore, the enhanced host resistance by L. casei to L. monocytogenes infection may be mediated by macrophages migrating from the blood stream to the reticuloendothelial system in response to L. casei injection before or after L. monocytogenes infection.
Interaction of leptospires with human polymorphonuclear neutrophils
Authors: Wang B , Sullivan J , Sullivan G W , Mandell G L
Published: January 2020

The role of the polymorphonuclear neutrophils (PMN) in defense against leptospires has not been adequately studied, in part, because of difficulty in quantitating pathogenic leptospires. By using pour plates to quantitate nonpathogenic leptospires and the most-probable-number procedure to quantitate the pathogenic leptospires, we examined the interactions of nonpathogenic Leptospira biflexa and pathogenic Leptospira interrogans serovar icterohemorrhagiae with human neutrophils. Phase-contrast, scanning electron, and transmission electron microscopic observations were made. Leptospires were incubated with PMN at 37 degrees C and tumbled together. There was no ingestion or killing of nonpathogenic leptospires (with no serum) or of pathogenic organisms (with 10% normal serum). However, when leptospires were incubated with PMN (without serum) in a pellet and then resuspended, 91 +/- 6% of nonpathogenic leptospires were removed from the supernatant, and 93 +/- 4% of these organisms were killed. The pathogenic leptospires became cell associated in a pellet, but were not killed by PMN even in the presence of 10% normal serum. Observations of morphological interactions indicated that PMN phagocytized the nonpathogenic leptospires in the absence of serum and that the pathogenic leptospires attached to but were not ingested by neutrophils in the presence of 10% normal serum. PMN do not seem to be an efficient defense factor for pathogenic leptospires in nonimmune hosts. The virulence of leptospires appears to be related to their ability to resist killing by serum and to resist ingestion and killing by neutrophils.
Resistance of bovine colostral anti-cholera toxin antibody to in vitro and in vivo proteolysis
Authors: McClead R E , Gregory S A
Published: January 2020

Pregnant cows immunized with cholera enterotoxin produce an immunoglobulin G class 1 antibody that enters the colostrum in high titer. After exposure to intestinal enzymes, this antibody remains immunologically reactive and inhibits intestinal fluid secretion in infant and adult rabbits exposed to cholera enterotoxin. Specific bovine colostral antibodies may be a source of passive immune protection for human infants and adults at risk for cholera and other enteric diseases.
Naturally occurring pasteurellosis in laboratory rabbits: chemical and serological studies of whole cells and lipopolysaccharides of Pasteurella multocida
Authors: Manning P J
Published: January 2020

Whole cells and lipopolysaccharides (LPS) of 10 isolates of Pasteurella multocida from laboratory rabbits were subjected to chemical and serological analysis. LPS of most of these isolates possessed pyrogenic potency comparable to LPS from Salmonella minnesota 9700, although their average ketodeoxyoctonate content was only 18% of that of salmonella. A gel diffusion precipitin test for somatic antigens extracted in a formal-saline solution demonstrated several isolates with three to four somatic antigens, with some variation in the major somatic type from one test to another. Conversely, the use of LPS as antigen in the gel diffusion precipitin test (i) eliminated cross-reactivity with reference antisera and (ii) often resulted in the organism being typed as serotype 12 even when the type 12 antigen was a minor antigen in the formal-saline extracts. Antisera from specific pathogen-free rabbits immunized with either whole cells or LPS of two isolates were tested against whole cells of LPS of the 10 isolates by enzyme immunoassay and indirect hemagglutination. Both whole cells and LPS of one of the isolates (isolate 2) were serologically specific, whereas those of the other isolate (isolate 1) were moderately to strongly cross-reactive with other isolates. The data indicate that although LPS is the major antigen responsible for typing based on the gel diffusion precipitin test, substances other than LPS (probably capsular polysaccharide) are responsible for the type specificity that forms the basis for the A, B, D, or E classification of this organism.
Role of lipopolysaccharide in virulence of Pseudomonas aeruginosa
Authors: Cryz S J , Pitt T L , Fürer E , Germanier R
Published: January 2020

The role of lipopolysaccharide (LPS) in the virulence of Pseudomonas aeruginosa was studied. The virulence of several P. aeruginosa strains for burned mice was found to be directly related to the dispersion of LPS into either the phenol or the water phase after extraction. Virulence decreased as the proportion of LPS recovered from the phenol phase increased. No similar correlation was observed when several other strain characteristics were investigated. This phenomenon was studied in greater detail by using the "smooth"-specific phage E79 to select mutants altered in LPS structure. One such mutant, PA220-R2, was extensively characterized. LPS isolated from PA220-R2 was found to be completely deficient in high-molecular-weight polysaccharide material. This alteration rendered the strain serum sensitive and dramatically changed the reaction with O-specific typing sera and sensitivity to typing phages. However, motility, toxin A and elastase production, and 22 metabolic functions remained unchanged. PA220-R2 was found to be comparatively nonvirulent, with a 50% lethal dose more than 1,000-fold higher than that of its parent for burned mice. This was due to the inability of PA220-R2 to establish an infection in burned skin.