bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation and characterization of alkaline protease-deficient mutants of Pseudomonas aeruginosa in vitro and in a mouse eye model
Authors: Howe T R , Iglewski B H
Published: January 2020

Mutants of Pseudomonas aeruginosa are described which are markedly deficient in alkaline protease production. Characterization of these mutants in vitro suggests that the mutations in two of these strains are specific for alkaline protease production. Examination of these mutants in a mouse eye model demonstrates that alkaline protease is required for the establishment of corneal infections with P. aeruginosa PA103. Mutants deficient in alkaline protease production could not colonize traumatized cornea and did not produce the corneal damage characteristic of infection by the parental strain. Addition of subdamaging amounts of alkaline protease to eyes infected with the protease-deficient mutants resulted in infections which were indistinguishable from infections caused by the parental strain.
Impaired function of immune reactivity to Listeria monocytogenes in diet-fed mice
Authors: Kos W L , Kos K A , Kaplan A M
Published: January 2020

Mice fed a diet high in cholesterol, lard, and sucrose were shown to exhibit an impairment of specific immunity to Listeria monocytogenes. Whereas titers of L. monocytogenes in livers of normal mice decreased rapidly after 6 days of infection, L. monocytogenes persisted in livers of diet-fed mice. Adoptive transfer experiments indicated that L. monocytogenes-immune spleen cells are generated in diet-fed mice. However, the function of immune spleen cells from donors of either nutritional status was impaired in diet-fed recipients. The results indicate that the site(s) of impairment of specific immunity to L. monocytogenes in diet-fed mice occurs at a stage beyond the generation of immune T-cells.
Crossed immunoelectrophoretic analysis of anti-Salmonella typhi antibodies in sera of typhoid patients and carriers: demonstration of the presence of typhoid-specific antibodies to a non-O, non-H, non-Vi antigen
Authors: Chau P Y , Wan K C , Tsang R S
Published: January 2020

A veronal buffer extract of Salmonella typhi was used as the reference antigen and its corresponding rabbit antiserum as the reference antibody in crossed immunoelectrophoresis to analyze antibodies in sera obtained from typhoid patients and carriers. Four precipitating antibodies were regularly detected. Three were against antigens common to other gram-negative bacteria and one appeared to be typhoid specific. Of the three common antigens, one (antigen no. 7) formed a precipitin resembling in mobility and morphology the lipopolysaccharide antigen seen in crossed immunoelectrophoresis analysis of other gram-negative bacteria. The other (antigen no. 19) was heat labile and antigenically similar to the reported common antigen of Pseudomonas aeruginosa. The third (antigen no. 14), also heat labile, was present in members of the family Enterobacteriaceae but not the family Pseudomonas. The typhoid-specific precipitating antibody present in sera of most typhoid patients and carriers but not patients infected with nontyphoid salmonella was directed to a heat-labile, non-O, non-H, and non-Vi antigen (antigen no. 28), probably protein in nature.
Human polymorphonuclear leukocyte interaction with cyclosporine A
Authors: Weinbaum D L , Kaplan S S , Zdziarski U , Rinaldo C R , Schroeder K K
Published: January 2020

The effects of cyclosporin A (cyA) on human polymorphonuclear leukocyte function, including phagocytosis, its associated metabolic burst, bacterial killing, and chemotaxis, were evaluated. Both Pseudomonas aeruginosa and Staphylococcus aureus were used as test particles. Polymorphonuclear leukocytes incubated in 10 and 50 micrograms of cyA per ml behaved normally with respect to phagocytosis and hexose monophosphate shunt activity at both high (10:1) and low (2:1) S. aureus/leukocyte ratios. With a small bacterial inoculum, killing of S. aureus was slightly impaired at early times only in the presence of 50 micrograms of cyA per ml. Phagocytosis and killing of P. aeruginosa with both large and small bacterial inocula were unaffected by cyA. Chemotaxis was within normal limits under all conditions. In addition, polymorphonuclear leukocytes from four renal transplant recipients receiving both cyA and prednisone demonstrated normal metabolic bursts and bacterial killing with both small and large inocula of S. aureus.
Treatment of human peripheral blood leukocytes with proteases does not affect Sendai virus-induced interferon production
Authors: Tsukui K , Miura T , Tokunaga E
Published: January 2020

Trypsinization of human peripheral blood leukocytes was found to have no effect on Sendai virus adsorption or on interferon induction by the virus. alpha-Chymotrypsin and papain also did not affect interferon induction, although the three proteases did remove part of the leukocyte surface material. In contrast, treatment of leukocytes with neuraminidase reduced virus adsorption and thoroughly abolished interferon induction. We conclude that protease-resistant structures on leukocyte surfaces serve as the receptor of Sendai virus for the induction of interferon.
Lipid A and resistance of Salmonella typhimurium to antimicrobial granule proteins of human neutrophil granulocytes
Authors: Shafer W M , Casey S G , Spitznagel J K
Published: January 2020

Granule extracts from human polymorphonuclear leukocytes were prepared and fractionated by chromatography on Sephadex G75-SF. One fraction exhibited potent antimicrobial activity against an Rd1 lipopolysaccharide (LPS) mutant of Salmonella typhimurium. Susceptibility of the mutant to antimicrobial activity appeared to be due to binding of granule proteins to lipid A because isolated native LPS succeeded in blocking the antimicrobial activity of granule extracts whereas base-hydrolyzed LPS failed to do so. Centrifugation of control and base-hydrolyzed LPS-protein mixtures in cesium chloride gradients suggested that only control LPS formed complexes with antimicrobial proteins. Further evidence that bactericidal proteins from polymorphonuclear leukocyte granules interact with lipid A was that sublethal concentrations of polymyxin B (an antibiotic known to bind to lipid A) rendered target bacteria phenotypically resistant to granule proteins. Moreover, a mutant of S. typhimurium which synthesized a lipid A with decreased electronegativity due to increased 4-amino-4-deoxy-L-arabinosylation at the 4'-phosphate exhibited increased resistance to both polymyxin B and granule proteins. These results suggest that polymyxin B and antimicrobial proteins derived from polymorphonuclear leukocyte granules interact with lipid A in an analogous manner.
Persistent Cryptosporidium infection in congenitally athymic (nude) mice
Authors: Heine J , Moon H W , Woodmansee D B
Published: January 2020

Nude (nu/nu) BALB/c mice and their white (nu/+) littermates were experimentally infected with Cryptosporidium sp. at 6 days of age. In white mice, the infection was transient, but in nude mice a persistent infection developed that was characterized by diarrhea and, occasionally, death. There were villus atrophy and crypt hyperplasia in the small intestine of infected nude and white mice necropsied at 11 days of age. Persistently infected nude mice had, in addition to the above small intestinal lesions, diffuse cystic mucosal hyperplasia and crypt abscesses in the large intestine at 56 days of age. These results suggest that T cells are required for recovery from the Cryptosporidium infection but are not required for epithelial cell loss in cryptosporidiosis. Both nude and white mice appeared to be relatively more resistant to Cryptosporidium infection at 42 days of age than at 6 days of age.
Binding of cryptococcal polysaccharide to Cryptococcus neoformans
Authors: Kozel T R , Hermerath C A
Published: January 2020

Radioiodinated cryptococcal polysaccharide was used to study binding of the soluble polysaccharide to encapsulated and non-encapsulated cryptoccoci. Binding of polysaccharide to non-encapsulated cryptococci occurred rapidly over a 30-min period and was largely complete after 2 h. Bound, labeled polysaccharide was slowly eluted from Cryptococcus neoformans after the addition of unlabeled polysaccharide, indicating reversibility of binding. Non-encapsulated cryptococci bound polysaccharide in two ways. Specific binding to the yeast was saturable by ca. 82 ng of polysaccharide per 10(6) yeast cells. Nonspecific binding also occurred which was not saturable under the conditions used in our experiments. Phagocytosis of the non-encapsulated yeast strain was inhibited when the specific binding was ca. 50% saturated. Binding of polysaccharide to an encapsulated strain showed nonspecific, nonsaturable binding, but little specific binding occurred. Presumably the specific binding sites were saturated in the encapsulated strain. Polysaccharides obtained from a hypocapsular mutant (A61) and a normally encapsulated strain competed effectively with labeled serotype D polysaccharide for binding sites on non-encapsulated cryptococci and had identical phagocytosis-inhibiting properties. Similarly, polysaccharides from all four cryptococcal serotypes competed effectively with labeled serotype D polysaccharide for binding sites on the non-encapsulated strain, and all four polysaccharides inhibited phagocytosis of non-encapsulated Cryptococcus neoformans. Unmodified, de-O-acetylated, carboxyl-reduced, periodate-oxidized and reduced (polyalcohol), and Smith-degraded polysaccharides competed with labeled polysaccharide for binding sites on the cell. The unmodified, de-O-acetylated and carboxyl-reduced polysaccharides inhibited phagocytosis of non-encapsulated cells, but the polyalcohol and Smith product were unable to inhibit phagocytosis.
A macromolecular structure produced by Pseudomonas aeruginosa is recognized by antibody to exotoxin A
Authors: Klinger K W , Shuster C W
Published: January 2020

Organized particulate structures (rods) identified in purified preparations of exotoxin A from culture supernatants of Pseudomonas aeruginosa PA103 were found to be immunochemically cross-reactive with exotoxin A. The rods were visualized by electron microscopy after negative staining as hollow tubes or sheaths (45 by 15 nm). Purified rods were not toxic and not enzymatically active in the ADP-ribosylation assay. Antigenic cross-reactivity between exotoxin A and rods was demonstrated by using monoclonal antibodies directed against either rods or a toxoid of exotoxin A. Hybridoma clones derived from mice immunized with rods or toxoid reacted with both antigens in the enzyme-linked immunosorbent assay. Rods could be dissociated by boiling and resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis into three subunit polypeptides with molecular weights of 70,000, 45,000, and 27,000. Two of the three subunit polypeptides reacted both with antirod and antitoxin monoclonal antibodies after electrophoretic transfer of sodium dodecyl sulfate-polyacrylamide gel electrophoresis-separated proteins to nitrocellulose filters. The results indicate that rods and exotoxin A share common antigenic determinants.
Enumeration of Treponema pallidum cells cultivated in vitro by an enzyme-linked immunosorbent assay
Authors: Cox D L , Moeckli R A , Keaney K M
Published: January 2020

An enzyme-linked immunosorbent assay was developed to enumerate Treponema pallidum cells. The assay could detect from 2 X 10(7) to 4 X 10(8) treponemes per ml. Reactive rabbit serum and goat anti-rabbit immunoglobulin G (peroxidase conjugate) were used in the assay. Optimum results were obtained when 2,2'-azino-di(ethylbenzthiazolinesulfonic acid) was used as the dye for the enzyme reaction and the reactions were allowed to run for 45 min. Interestingly, assays in which in vivo-cultivated T. pallidum was used produced lower absorbance values than those in which T. pallidum was cultivated in vitro.
Trypanosoma rhodesiense: analysis of the genetic control of resistance among mice
Authors: Greenblatt H C , Diggs C L , Rosenstreich D L
Published: January 2020

Inbred mouse strains differ in their resistance to infection with the human pathogen Trypanosoma rhodesiense. Of the strains tested, C57BL/6 (B6) mice were the most resistant, and BALB/c (C) mice were among the most susceptible. The genetic basis underlying the different susceptibility of these two strains was analyzed. (CXB6)F1 progeny of either sex were more resistant than the BALB/c parent. Also, the backcross of F1 mice to the susceptible male or female BALB/c parent resulted in 52.0% susceptible (i.e., death on or before day 24) progeny, as compared with only 0.64% susceptible F1 progeny. The data suggested that resistance was the dominant phenotype and that the resistant allele was carried by the B6 parent. The presence of another locus regulating resistance to death was suggested by the facts that only a small percentage of F2 mice were susceptible and that a number of F1 and F2 mice were more resistant than their B6 parent. The locus responsible for these phenomena was presumably hypostatic in nature and carried by BALB/c mice, and its effects were only evident in the presence of other resistance genes. In addition, the observation that many of the susceptible individuals among F2 and backcross mice were more resistant than the BALB/c mice suggested that other minor genes also modulated the response of mice to infection. A set of CXB recombinant inbred mice was tested as well, and the individual strains within this set could also be placed into four groups: susceptible, intermediate, resistant, or hyperresistant. These findings are compatible with the multigenic model suggested by the Mendelian analyses.
Significance of encapsulated Bacteroides melaninogenicus and Bacteroides fragilis groups in mixed infections
Authors: Brook I , Walker R I
Published: January 2020

Organisms of the Bacteroides melaninogenicus and Bacteroides fragilis groups are often found mixed with facultatively anaerobic organisms in infections. The relative importance of these Bacteroides groups and facultative anaerobic pathogens in mixed infections was investigated in a subcutaneous abscess model in mice. This was determined by observing the effect of antimicrobial therapy directed against one or both organisms present in the abscess. Clindamycin or metronidazole was used for treatment of infections caused by Bacteroides species, and either gentamicin, penicillin, ampicillin, or oxacillin was used for treatment of infections caused by facultative flora. In almost all instances the aerobic counterparts in the infection were more important than the unencapsulated Bacteroides species. On the other hand, encapsulated B. melaninogenicus group organisms were found to be more important in abscess formation than were group A streptococci, Streptococcus pneumoniae, Klebsiella pneumoniae, Haemophilus influenzae, and Staphylococcus aureus. Encapsulated B. fragilis group organisms were found to be more important than or as important as Escherichia coli and group D streptococci and less important than S. aureus, group A streptococci, and K. pneumoniae in induction of subcutaneous abscesses. This study demonstrates that encapsulated Bacteroides species are a factor that should be considered in the treatment of mixed infections with antibiotics.
Introduction of pAM beta 1 into Listeria monocytogenes by conjugation and homology between native L. monocytogenes plasmids
Authors: Flamm R K , Hinrichs D J , Thomashow M F
Published: January 2020

The broad host range antibiotic resistance plasmid pAM beta 1 was transferred from Streptococcus faecalis to 9 of 15 Listeria monocytogenes strains by conjugation. L. monocytogenes transconjugates could transfer the plasmid either among L. monocytogenes strains or back to S. faecalis. Transfer between the various strains occurred without any detectable plasmid DNA rearrangements. The pAM beta 1 replicon was stable in L. monocytogenes--it was retained without antibiotic selection when the bacteria were grown in culture media or passed in mice--and the presence of pAM beta 1 had no major effect on L. monocytogenes virulence. These data suggest that pAM beta 1 or its derivatives might serve as useful L. monocytogenes cloning vehicles. The data presented also demonstrate that pAM beta 1 is compatible with two different native L. monocytogenes plasmids and that Listeria species harbor native plasmids in addition to the 38.5-megadalton plasmid pRYC16 previously reported by Pérez-Díaz et al. (J. C. Pérez-Díaz, M. F. Vicente, and F. Banquero, Plasmid 8:112-118, 1982). Of 29 L. monocytogenes strains screened, 7 contained plasmid DNA. Four strains had similar if not identical plasmids that were 34 megadaltons in size, whereas three other strains contained either a 53-, 44-, or 32-megadalton plasmid; none of these plasmids has the same restriction patterns as pRYC16. DNA homology experiments indicate that the various plasmids are related and suggest that there may be a common set of sequences present in all of the plasmids examined.
Cerebral mucormycosis in diabetic mice after intrasinus challenge
Authors: Waldorf A R , Diamond R D
Published: January 2020

Rhinocerebral involvement is the most common form of mucormycosis in uncontrolled diabetic patients. Streptozotocin-induced diabetic and normal mice were challenged by intrasinus inoculation of Rhizopus oryzae to determine their susceptibility to infection by this route. Ninety percent of diabetic mice and no normal mice died after inoculation with 10(6) spores. Intrasinus inoculations caused minimal direct trauma and low levels of brain inocula, but progressive cerebral infections were induced in diabetic mice.
Implications of Freter's model of bacterial colonization
Authors: McKay I C , Speekenbrink A
Published: January 2020

A recent mathematical model (Freter et al., Infect. Immun. 39:686-703, 1983) provided a plausible simulation of both the mouse gut and continuous-flow mixed cultures. We show here that in certain circumstances Freter's equations are soluble, giving simple formulae that can be applied to particular problems without resort to computers or numerical simulation.
Efficacy of Mycobacterium bovis BCG vaccination in mice undergoing prior pulmonary infection with atypical mycobacteria
Authors: Orme I M , Collins F M
Published: January 2020

The efficacy of Mycobacterium bovis BCG immunization in mice with established pulmonary infections caused by atypical mycobacteria was studied. In all four strains of Mycobacterium tested (M. kansasii, M. simiae, M. avium, and M. scrofulaceum), intravenous inoculation with 10(6) BCG had no discernible effect upon the course of atypical mycobacterial infection within the lungs; despite this, however, all BCG-vaccinated groups of mice were fully resistant to a subsequent acute aerogenic challenge with M. tuberculosis H37Rv, regardless of the presence of the pulmonary atypical mycobacterial infections. Furthermore, animals infected with M. kansasii, M. simiae, or M. avium but not vaccinated with BCG expressed considerable antituberculous resistance within the lungs, resulting in significant prolonged survival of these animals. The relevance of these findings to the expression of antituberculous resistance in human populations in areas in which atypical mycobacteria are endemic and the failure of these findings to support the hypothesis that prior contact with atypical mycobacteria might in some way jeopardize or interfere with the efficacy of subsequent BCG vaccination are discussed.
Characteristics of lymphoid cells that adoptively transfer immunity to Rickettsia mooseri infection in mice
Authors: Crist A E , Wisseman C L , Murphy J R
Published: January 2020

The capacity of adoptively transferred immune lymphoid cells or passively transferred immune serum to alter the course of an established Rickettsia mooseri (R. typhi) infection in the spleen was evaluated in BALB/c mice. Immune cells, but not immune serum, controlled the established infection. An effective lymphocyte was a T-cell which had to possess a capacity to divide.
Biochemical and immunological differences between hydrophobic and hydrophilic strains of Streptococcus mutans
Authors: McBride B C , Song M , Krasse B , Olsson J
Published: January 2020

Hydrophobic strains of Streptococcus mutans were compared with paired variants showing reduced hydrophobicity. Extracts of hydrophobic cells contained a number of high-molecular-weight proteins which were not present on cells with decreased hydrophobicity. The proteins were found in purified cell walls, suggesting that they are located on the bacterial surface. Trypsin treatment of whole cells destroyed the proteins and reduced the hydrophobicity. Chemical analysis did not reveal any marked differences in the proportion of cell wall constituents. The amino acid compositions and lipoteichoic acid contents of hydrophobic and hydrophilic cell walls were similar. Culture supernatants from the hydrophilic variants contained high-molecular-weight proteins similar to those extracted from the cell walls of the hydrophobic parent strains, indicating that the variants were impaired in their ability to incorporate the hydrophobicity-associated proteins into the cell wall. The dominant protein had a molecular weight of 190,000, similar to that of antigen I/II (B) of S. mutans.
Developmental interrelationship of specific Lyt 123 and Lyt 1 cell sets in expression of antibacterial immunity to Listeria monocytogenes
Authors: Näher H , Sperling U , Hahn H
Published: January 2020

Lyt phenotypes of peritoneal exudate T lymphocytes from Listeria monocytogenes-immune mice were determined with respect to their capacity to confer protection upon local or systemic transfer. It is shown that, locally, Lyt 1 T cells provide protection, whereas only unselected native populations, containing adequate numbers of Lyt 123 T cells, were effective in transferring systemic protection. When Lyt 1 T cells were the crucial cell type (local transfer), admixture of Lyt 123-containing peritoneal exudate T-lymphocyte-enriched cells did not enhance protection, save for slight additive effects. Likewise, when Lyt 123-containing peritoneal exudate T lymphocyte-enriched cells were the crucial cell type (systemic transfer), admixture of various numbers of Lyt 1 cells was without marked effect. A change in Lyt phenotype from Lyt 123 to Lyt 1 paralleled by an increase of protective capacity upon local transfer was observed when sensitivity of early and late exudate T cells to anti-Lyt 2.2 antiserum plus complement treatment was investigated. The data suggest that (i) the propensity of specific T cells to enter exudates is associated with the Lyt 123 phenotype, (ii) the actual effector cell of antibacterial protection is an Lyt 1 T cell, and (iii) a developmental interrelation exists between Lyt 123 T cells and Lyt 1 T cells in T-cell-dependent protection of mice against L. monocytogenes.
Susceptibility and resistance of inbred mice to Giardia muris
Authors: Belosevic M , Faubert G M , Skamene E , MacLean J D
Published: January 2020

The susceptibility and resistance of inbred mice to Giardia muris was studied during the acute and elimination phases of infection. The infection in susceptible A/J and C3H/He mice was characterized by a short latent period, high cyst output during the acute phase of infection, and prolonged periods of cyst release. In contrast, resistant B10.A and DBA/2 mice had a longer latent period, a lower cyst output during the acute phase, and relatively rapid resolution of infection. The trait of susceptibility and resistance during both acute and elimination phases of the infection was found to be under complex multigenic control as determined by examination of the response of F1 hybrid mice and backcross analyses. The genes controlling this trait did not appear to be linked to the H-2 locus. In addition, the control of the response of mice to G. muris during the acute phase of infection was probably mediated by mechanisms independent from those controlling the response during the elimination phase of infection.
Monoclonal antibody against a genus-specific antigen of Chlamydia species: location of the epitope on chlamydial lipopolysaccharide
Authors: Caldwell H D , Hitchcock P J
Published: January 2020

Monoclonal antibodies were prepared by the fusion of murine myeloma NS1 cells with spleen cells of BALB/c mice immunized with Formalin-killed elementary bodies of the Chlamydia trachomatis L2 serovar. The specificity of these monoclonal antibodies was determined with a solid-phase immunoassay in which HeLa 229 cells infected with C. trachomatis serovars D, G, H, I, L2 and the Chlamydia psittaci meningopneumonitis strain Cal-10 were used. An immunoglobulin G3 monoclonal antibody (L2I-6) was identified that reacted with both C. trachomatis- and C. psittaci-infected HeLa cells. The immunoreactivity of the genus-specific epitope was heat resistant (100 degrees C, 10 min) but was destroyed by sodium metaperiodate treatment. Further characterization of the chlamydial specificity of monoclonal antibody L2I-6 by microimmunofluorescence showed that it was reactive with all 15 C. trachomatis serovars and seven C. psittaci strains isolated from five different animal species. We undertook studies to identify the biochemical nature of the chlamydial component on which the genus-specific epitope was located. The immunoreactive component was isolated by hot phenol-water extraction of dithiothreitol-reduced chlamydial elementary bodies. The component was positive in the Limulus amoebocyte lysate test (results of Limulus amoebocyte lysate assay were identical with those of Salmonella typhimurium LT2 SAI 377 Re lipopolysaccharide [LPS]), contained 8.8% 2-keto-3-deoxyoctulosonic acid, was resistant to proteinase K, and possessed electrophoretic mobility and silver-staining characteristics in sodium dodecyl sulfate-polyacrylamide gel electrophoresis consistent with a rough LPS or glycolipid. On the basis of these findings, we conclude that the genus-specific epitope recognized by monoclonal L2I-6 is located on chlamydial LPS. We further characterized the antigenic properties of the chlamydial LPS epitope by examining the immunoreactivity of monoclonal antibody L2I-6 by immunoblotting analyses against isolated LPSs extracted from Neisseria gonorrhoeae, S. typhimurium, and Escherichia coli. Monoclonal antibody L2I-6 did not bind LPS of these organisms, demonstrating that the chlamydial genus-specific LPS epitope is apparently not shared by these gram-negative bacteria. We were able, however, to show that the chlamydial LPS does share antigenic determinants with LPS of gram-negative organisms. Polyclonal rabbit antisera raised against S. typhimurium Re LPS or lipid A showed intense immunological cross-reactivity with chlamydial LPS by immunoblotting.(ABSTRACT TRUNCATED AT 400 WORDS)
In vitro sorption of albumin, immunoglobulin G, and lysozyme to enamel and cementum from human teeth
Authors: Fine D H , Wilton J M , Caravana C
Published: January 2020

Sorption of three 125I-labeled human proteins (albumin, immunoglobulin G, and lysozyme) to enamel and cementum was investigated. All three proteins sorped most when suspended in 0.0005 M solution of phosphate or calcium chloride where the least competition between solute ions and label occurred. The addition of human serum to labeled proteins caused a decrease in their sorption which could be partially reversed by increasing the concentration of label. Kinetic experiments demonstrated that sorption was dependent on protein concentration and incubation time and that most of the sorption occurred within the first minute of the reaction. In conclusion, the binding of the three labeled proteins was affected by the charge of the solute ions and was dependent on ion concentration and reaction time. Sorption correlated for the most part with the pK values of the proteins and thus lysozyme, the most basic protein, sorped more than immunoglobulin G, which sorped more than albumin. In all cases, cementum bound more basic protein than did enamel. Increased levels of albumin sorption to enamel occurred when the protein was suspended in the CaCl2 solution rather than in phosphate. In addition, based on Scatchard analysis, approximately twice as many potential protein binding sites were found for cementum versus enamel.
Two adjuvant-active muramyl dipeptide analogs induce differential production of lymphocyte-activating factor and a factor causing distress in guinea pigs
Authors: Byars N E
Published: January 2020

Many adjuvant-active analogs of muramyl dipeptide (MDP) have been described. Unfortunately, most have been found to induce pyrexia or other adverse side effects in several species. In the guinea pig, these side effects include the guinea pig distress syndrome, which lasts 24 to 48 h, and enhancement of endotoxin shock. A dose-related response to MDP or N-acetylmuramyl-L-alpha-aminobutyryl-D-isoglutamine [( Abu1]-MDP) was observed. However, we found several adjuvant-active analogs which were completely innocuous in guinea pigs. 2-(2-Acetamido-2-deoxy-D-glucose-3-O-yl)-D-hexanoyl-L-alanyl-D-isoglutam ine (3'-n-propyl-MDP) was one such compound. To understand the differences between the toxic and nontoxic compounds, macrophage stimulation in vitro was studied. Both compounds stimulated guinea pig peritoneal macrophages to produce lymphocyte-activating factor in vitro. However, the supernatant from 3'-n-propyl-MDP-stimulated macrophages had no observable effects on guinea pigs, whereas the dialyzed supernatant from [Abu1]-MDP-stimulated cells readily induced the guinea pig distress syndrome. Sephadex G-150 chromatography showed that both analogs stimulated production of a major (60,000) and minor (11,000) peak of lymphocyte-activating factor activity. The factor causing the guinea pig distress syndrome was found only in the low-molecular-weight fraction of [Abu1]-MDP-treated cell supernatants. Thus, one difference between the nontoxic and toxic compounds is their ability to produce lymphocyte-activating factor in the absence of the toxic factor. The lack of toxicity of 3'-n-propyl-MDP makes it an attractive compound for use in vaccines.
Role of the H-2s haplotype in survival of mice after infection with Trypanosoma cruzi
Authors: Wrightsman R A , Krassner S M , Watson J D , Manning J E
Published: January 2020

In studies of the resistance of inbred mice to infection with Trypanosoma cruzi Peru, mouse strain B10.S was the only strain which survived the infection resulting from the inoculation of 10(3) trypomastigotes. This is the only inbred mouse strain studied to survive infection. To investigate the effect of the H-2 haplotype on survival, C57BL/10 congenic mouse strains bearing H-2S recombinant haplotypes and mouse strains A.SWSn/J and SJL/J were tested for their ability to overcome the T. cruzi infection. None of the recombinant strains tested, including B10.S(7R), B10.S(8R), B10.S(9R), and B10.HTT, survived the infection, indicating that at least two or more regions of the H-2 locus must be H-2S to ensure survival. Strains A.SWSn/J and SJL/J with the H-2S haplotype did not survive, indicating that the genetic background outside the H-2 complex also influences survival. The congenic F1 hybrid (C57BL/10 X B10.S) F1 exhibited intermediate survival levels when compared with the parental strains, indicating that H-2S survival is affected by gene dosage. The F1 hybrid strain [B10.S(7R) X B10.S(8R)]F1, which possesses the complete H-2S haplotype in the trans configuration, did not survive T. cruzi infection, suggesting that H-2S-mediated survival does not operate by trans complementation.
Immunochemical characterization of a heat-stable surface antigen of Mycoplasma pulmonis expressing both species-specific and strain-specific determinants
Authors: Nichols E J , Kenny G E
Published: January 2020

We sought to characterize the strain-specific antigens of four strains of Mycoplasma pulmonis (47, 63, Negroni, and 19612) by crossed immunoelectrophoresis. Although the strains possessed a number of common antigens, type-specific antigens of 0.32 mobility (bovine albumin was assigned a value of 1) were detected in strains 47 and 63. Strains 19612 and Negroni cross-reacted and represented a third group. Each strain possessed a major heat-stable antigen complex of 0.32 mobility characterized by a faster-moving component of 0.55 mobility. Monospecific antiserum to heat-stable antigen 0.32 of strain 63 demonstrated that this antigen complex consisted of at least three antigen-antibody precipitating systems characterized by type-specific and group-specific determinants. Adsorption of antiserum with whole cells revealed that the 0.32 antigen complex was surface exposed. The antigen complex is pronase sensitive and only partially sensitive to periodate. Purification of antigen 0.32 from detergent-extracted cells by affinity chromatography using monospecific antiserum revealed two major polypeptides of 86,500 and 83,500 dalton which reacted strongly with monospecific antiserum by immunoblotting. These reactive polypeptides were present in all strains examined. Additional polypeptides of different molecular weights in strains 19612 and Negroni produced strong reactions with monospecific antiserum, although sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles of the two strains were strikingly similar. Common heat-stable antigens were observed also. This study demonstrates that M. pulmonis strains possess an antigenically variable heat-stable surface antigen which is unique in that it contains not only strain-specific determinants but also species-specific determinants.
Effect of lodoxamide on the secretory response induced by Escherichia coli and Vibrio cholerae enterotoxins in infant mice
Authors: Knoop F C , Thomas D D
Published: January 2020

The effect of lodoxamide tromethamine, a calcium antagonist, on intestinal fluid accumulation induced by Escherichia coli heat-stable (ST) and Vibrio cholerae (CT) enterotoxins in infant mice was investigated. The simultaneous administration of lodoxamide with ST or CT enterotoxin resulted in a significant (P less than 0.01) inhibition of the intestinal fluid response. A minimum concentration of 10(-7) or 10(-8)M lodoxamide caused an inhibition (P less than 0.01) of the ST- or CT-mediated fluid response, respectively. Treatment of infant mice with buffer or drug alone did not result in fluid accumulation. A significant inhibition of ST and CT enterotoxic activities was also observed when lodoxamide was administered 30 min before (P less than 0.02) or 30 min after (P less than 0.01) toxin challenge. These data suggest that calcium may be important in the ST- or CT-mediated induction of fluid accumulation. Further studies on the potential use of lodoxamide tromethamine in both the prophylaxis and treatment of diarrheal disease appear warranted.
Antibody-dependent alternative pathway killing of Haemophilus influenzae type b
Authors: Steele N P , Munson R S , Granoff D M , Cummins J E , Levine R P
Published: January 2020

The bactericidal activities of human complement and human antibody directed against specific Haemophilus influenzae type b cell surface determinants were investigated. Strain Eagan, a laboratory isolate, and strain Kn, a clinical isolate, were used as the test organisms and gave qualitatively similar results. In the absence of antibody, both isolates were resistant to killing by 60% agammaglobulinemic serum (AGS) containing normal complement levels. The addition of affinity-purified immunoglobulin G anticapsular antibody was bactericidal with 15% AGS as the complement source. Bactericidal activity was also demonstrated with this antibody when the complement source was AGS-Mg-EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid], C2-deficient human serum (alternative complement pathway), or AGS in which factor D and properdin had been selectively inactivated (classical pathway). Immunoglobulin G fractions from a human serum pool or from serum from an adult who had recovered from H. influenzae type b (Kn) sepsis were absorbed to remove anticapsular antibody. The absorbed fractions containing noncapsular antibodies also activated complement-dependent bactericidal activity. But, in contrast to the results with anticapsular antibody, noncapsular antibodies did not elicit alternative pathway bactericidal activity. Incubation of cells of H. influenzae type b in C2-deficient serum or AGS-Mg-EGTA did not cause complement consumption (total hemolytic complement and C3). The addition of immunoglobulin G anticapsular antibody (but not noncapsular antibody) increased consumption of total complement and C3, paralleling the results of the bactericidal assays. These studies demonstrated an absolute requirement for anticapsular antibody in alternative pathway activation and killing of H. influenzae type b.(ABSTRACT TRUNCATED AT 250 WORDS)
Enhanced mucosal priming by cholera toxin and procholeragenoid with a lipoidal amine adjuvant (avridine) delivered in liposomes
Authors: Pierce N F , Sacci J B
Published: January 2020

The mucosal adjuvant activity of avridine, a synthetic lipoidal amine [N,N-dioctadecyl-N',N'-(2-hydroxymethyl) propanediamine, previously designated CP-20,961), was studied in rats immunized intraintestinally with cholera toxin or procholeragenoid. Avridine was most efficient as an adjuvant when incorporated into liposomes; liposomes that lacked avridine had no adjuvant effect. Coadministration of avridine-containing liposomes with enteric priming doses of cholera toxin or procholeragenoid enhanced the efficiency of priming for secondary mucosal anti-cholera toxin responses, i.e., the establishment of memory, five- to sevenfold. Avridine-containing liposomes had no significant effect, however, on either the primary mucosal anti-cholera toxin response, when given with the primary dose of antigen, or on the secondary response, when given with the booster dose to previously primed animals. Little or no adjuvant effect occurred when avridine-containing liposomes were given concurrently with antigen, but at a separate mucosal site or parenterally, or at the site of enteric immunization, but 1 day earlier or later. These results support the notion that adjuvants may be developed which enhance the mucosal immunogenicity of locally applied antigens and suggest that liposomes may be effective vehicles for delivery of such adjuvants.
Passive antibody therapy of Lassa fever in cynomolgus monkeys: importance of neutralizing antibody and Lassa virus strain
Authors: Jahrling P B , Peters C J
Published: January 2020

Lassa virus-infected cynomolgus monkeys were passively immunized with immune plasma of primate or human origin to gain insight into criteria for plasma selection and administration to human Lassa fever patients. Protective efficacy was correlated with neutralizing antibody concentrations, expressed as a log10 neutralization index (LNI). Convalescent Lassa-immune monkey plasma was titrated for protective efficacy in monkeys by intravenous inoculation with dilutions of plasma on the day of subcutaneous Lassa virus inoculation (day 0) and again on days 3 and 6. Monkeys that received undiluted plasma (LNI = 4.1) (1 ml/kg per treatment) survived a lethal viral dose, whereas those given a 1:3 dilution (LNI = 2.6) of this same plasma (1 ml/kg per treatment) died. Protection was restored when the volume of the 1:3 plasma dilution was increased to 3 ml/kg per treatment. Plasma diluted 1:9 or more (LNI = 1.5 or less) delayed onset and suppressed the magnitude of viremia but failed to confer protection at 3 ml/kg per treatment. Immunological enhancement, defined as increased viremia or accelerated death, did not occur following inadequate treatment. Human convalescent plasma also protected recipient monkeys; reductions in mortality and viremia were accurately predicted by the LNI of the plasma. Plasma of Liberian origin neutralized a Liberian Lassa strain more effectively than a Sierra Leone strain in vitro (LNI = 2.8 and 1.6, respectively) and protected monkeys more effectively against the Liberian strain. Geographic origin is thus a factor in the selection of optimal plasma for treatment of human Lassa fever, since geographically matched plasma is more likely to contain adequate LNI titers against homologous Lassa virus strains.(ABSTRACT TRUNCATED AT 250 WORDS)
Plasmid-associated cell surface charge and hydrophobicity of Yersinia enterocolitica
Authors: Lachica R V , Zink D L
Published: January 2020

Virulent strains of Yersinia enterocolitica and their plasmidless, avirulent derivatives were examined for their cell surface properties. Increased surface charge and hydrophobicity of Y. enterocolitica were found to be associated with the possession of a 40- to 48-megadalton plasmid. These surface properties were expressed, as were other plasmid-associated properties, at 37 but not at 22 degrees C. The concentration of calcium in the growth medium had a moderate effect on the expression of the cell surface properties. These cell surface properties were greatly reduced among plasmid-bearing cells grown on tryptic soy agarose regardless of growth temperatures. These properties were also associated with the ability of Y. enterocolitica to colonize the gastrointestinal tract of mice.
Proteins IA and IB exhibit different surface exposures and orientations in the outer membranes of Neisseria gonorrhoeae
Authors: Barrera O , Swanson J
Published: January 2020

Exposure of whole gonococci to proteinase K resulted in cleavage of protein I (P.I) of the organism in situ. P.I subunits in the P.IB group were cleaved into two membrane-associated fragments, whereas P.IA subunits were cleaved by proteinase K to yield a single membrane-associated fragment slightly smaller in apparent size than the intact P.IA subunit. These data suggest that P.IA and P.IB subunits are quite different in their surface exposures and orientations in the gonococcal outer membrane; P.IB subunits likely have both termini buried in the membrane, whereas P.IA subunits have one of their termini exposed on the surface of the organism.
Macrophages as effector cells of protective immunity in murine schistosomiasis: macrophage activation in mice vaccinated with radiation-attenuated cercariae
Authors: James S L , Natovitz P C , Farrar W L , Leonard E J
Published: January 2020

Cell-mediated immune responses contributing to macrophage activation were compared in mice that demonstrated partial resistance to challenge Schistosoma mansoni infection as a result of vaccination with radiation-attenuated cercariae or of ongoing low-grade primary infection. Vaccinated mice developed significant delayed hypersensitivity reactions to soluble schistosome antigens in vivo. Splenocytes from vaccinated animals responded to in vitro culture with various specific antigens (soluble adult worm extract, living or disrupted schistosomula) by proliferation and production of macrophage-activating lymphokines as did lymphocytes from S. mansoni-infected animals. Macrophage-activating factors produced by spleen cells from vaccinated mice upon specific antigen stimulation eluted as a single peak on Sephadex G-100 with a molecular weight of approximately 50,000 and contained gamma interferon activity. Moreover, peritoneal macrophages with larvicidal and tumoricidal activity were recovered from vaccinated mice after intraperitoneal challenge with soluble schistosome antigens, a procedure also observed to elicit activated macrophages in S. mansoni-infected animals. These observations demonstrate that vaccination with irradiated cercariae stimulates many of the same cellular responses observed after primary S. mansoni infection, and suggest that lymphokine-activated macrophages may participate in the effector mechanism of vaccine-induced and concomitant immunity to challenge schistosome infection. This is the first demonstration of a potential immune effector mechanism in the irradiated vaccine model.
Pseudomonas aeruginosa exoproteases inhibit human neutrophil chemiluminescence
Authors: Kharazmi A , Høiby N , Döring G , Valerius N H
Published: January 2020

The present study was designed to examine the effect of Pseudomonas aeruginosa alkaline protease and elastase on human polymorphonuclear leukocyte chemiluminescence. Both a luminol-enhanced and a nonenhanced chemiluminescence system using opsonized zymosan were utilized. It was found that alkaline protease and elastase at concentrations of 25 micrograms/ml strongly inhibited luminol-enhanced myeloperoxidase-mediated chemiluminescence, whereas inhibition of the nonenhanced chemiluminescence response was about 50%. In an attempt to determine the mechanism of inhibition of neutrophil chemiluminescence by these proteases, we examined the effect of various inhibitors of neutrophil oxidative metabolism on chemiluminescence, namely, superoxide dismutase, sodium azide, and catalase. It was shown that the pattern of inhibition of chemiluminescence by alkaline protease and elastase was similar to that of sodium azide, inhibitor of myeloperoxidase. The present study demonstrates that alkaline protease and elastase, extracellular products of P. aeruginosa, are capable of inhibiting myeloperoxidase-mediated chemiluminescence, one of the major antimicrobial systems of polymorphonuclear leukocytes. These findings provide further evidence for the role of P. aeruginosa exoproteases as virulence factors in the pathogenesis of infections caused by this microorganism.
Characterization of nonfimbrial mannose-resistant protein hemagglutinins of two Escherichia coli strains isolated from infants with enteritis
Authors: Williams P H , Knutton S , Brown M G , Candy D C , McNeish A S
Published: January 2020

Escherichia coli strains 444-3 and 469-3, isolated from patients with severe infantile enteritis, are able to adhere to and penetrate human epithelial cells in culture. In addition to type 1 fimbriae and glycocalyces , both strains elaborate mannose-resistant nonfimbrial protein hemagglutinins specific for human erythrocytes. Purified agglutinins are aggregates (greater than 4 X 10(6) daltons) of a single protein subunit of apparent Mr 14,000 (469-3) to 14,500 (444-3). The optimal temperature for expression of the agglutinins is 37 degrees C. Bacteria grown at 22 degrees C, which show 1% or less of maximal activity, and mutants deficient in the ability to agglutinate human erythrocytes do not synthesize detectable levels of these surface proteins and, moreover, do not adhere to cultured epithelial cells. Coupled with the observation that purified agglutinins competitively inhibit bacterial adherence to cultured cells, these data indicate that the nonfimbrial surface proteins expressed by strains 444-3 and 469-3 are essential for adherence both to erythrocytes and to cultured epithelial cells.
Local cellular immune response in ascending urinary tract infection: occurrence of T-cells, immunoglobulin-producing cells, and Ia-expressing cells in rat urinary tract tissue
Authors: Hjelm E M
Published: January 2020

The local immune response was studied in rats with ascending urinary tract infection that was induced by Escherichia coli 06K13H1 . The occurrence in urinary tract tissue of cells reacting with monoclonal antibodies to T-cell markers and Ia antigen and with antibodies to immunoglobulin G (IgG), IgM, and IgA was studied by immunohistochemical methods. Serum antibody response and antibody coating of bacteria in the urine were also followed. Infection increased the number of irregular Ia-expressing cells in both bladder submucosa and the intertubular space in the kidney. The epithelial cells of some tubules were induced to express Ia antigens. A slight increase of what were most probably T-"helper" cells in the bladder was noted during the initial phase of infection. These cells soon disappeared, and there was instead an increase in irregular W3/25-reactive cells that may be identical to the observed Ia-positive cells. In the pyelonephritic lesions there were large amounts of T-cells, mainly T-helper cells, Ia-expressing cells, both rounded and irregular, and also IgG-and IgM-producing cells. IgA-producing cells were demonstrated in the infected bladders. The results indicate that distinct differences exist between the immune reactions in bladder and kidney tissue which may be important for the development of infections in these organs.