bluuebunny/crossref_metadata_2025 huggingface dataset:
Variable adherence of fimbriated Haemophilus influenzae type b to human cells
Authors: Sable N S , Connor E M , Hall C B , Loeb M R
Published: January 2020

The attachment of isogenic fimbriated and nonfimbriated Haemophilus influenzae type b variants to human cells was studied by using a radioactive assay and an indirect immunofluorescent assay. As described previously, fimbriated H. influenzae variants adhered to a greater extent than nonfimbriated variants to human buccal epithelial cells (2.1 and 0.29 bacteria per cell, respectively, as determined by the radioactive assay [P less than 0.05]; 7.6 and 1.6 bacteria per cell, respectively, as determined by the immunofluorescent assay [P less than 0.01]). As the concentration of fimbriated bacteria was increased, so were the numbers of adherent bacteria; in contrast, increasing the bacterial concentration had a much smaller effect on adherence of nonfimbriated H. influenzae type b. The distribution of bacteria on the buccal cells also differed. Whereas 37% of the buccal cells failed to bind nonfimbriated H. influenzae type b, failure to bind was observed for only 4% of the buccal cells exposed to fimbriated H. influenzae. In contrast, adherence to human foreskin fibroblasts was low regardless of the presence of fimbriae. On the other hand, fimbriated H. influenzae type b adhered less well than nonfimbriated variants to HEp-2 cells (1.6 and 3.8 bacteria per cell, respectively, as determined by the radioactive assay [P less than 0.05]; 1.3 and 4.8 bacteria per cell, respectively, as determined by the immunofluorescent assay [P less than 0.02]). Whereas adherence to HEp-2 cells increased considerably as the concentration of nonfimbriated bacteria was increased, there was only a small enhancement of adherence with an increase in the concentration of fimbriated H. influenzae type b. Furthermore, only 16% of the HEp-2 cells failed to bind nonfimbriated H. influenzae type b, whereas 50% failed to bind fimbriated H. influenzae type b. These data indicate that H. influenzae type b may contain two adhesins. One is associated with fimbriae and enables adherence to buccal cells, whereas the other is nonfimbrial and is associated with adherence to HEp-2 cells. It is not known whether either of these adhesins plays a role in pathogenesis.
Microbe-induced lymphocyte blastogenesis enhancement after preculture
Authors: Lopatin D E , Martel L M , Mangan D F
Published: January 2020

The in vitro blastogenic response of human peripheral blood mononuclear cells to Fusobacterium nucleatum and other oral microorganisms was enhanced if the peripheral blood mononuclear cells were cultured for 24 h at 37 degrees C prior to the addition of stimulant. The enhancement which occurred at optimal and supraoptimal concentrations of F. nucleatum (10 to 100 micrograms/ml) was detected after a preculture period of as little as 2 h. The blastogenic response was a result of T-cell proliferation, and enhancement occurred independently of monocytes. Suppressor activity was induced by culturing fresh lymphocytes for 24 h in the presence of supraoptimal concentrations of F. nucleatum. The enhancement phenomenon occurred independently of the prostaglandin effects on lymphocyte blastogenesis and was not abrogated by treatment with indomethacin.
Expression of the temperature-inducible outer membrane proteins of yersiniae
Authors: Bölin I , Portnoy D A , Wolf-Watz H
Published: January 2020

The expression of the temperature-inducible plasmid-coded outer membrane proteins (YOPs) of Yersinia pseudotuberculosis was studied. These proteins were not recovered in the outer membrane fraction when the strain was grown in minimal medium at 37 degrees C, but they were expressed under these conditions. A strict correlation was found between Ca2+ dependency in the virulent strain, YPIII(pIB1), and ability to express YOPs. Ca2+-independent plasmid mutants or RNA-polymerase mutants harboring the virulence plasmid were unable to express YOPs, in contrast to the wild-type strain. These strains were also found to be avirulent. Sera recovered from patients or animals undergoing infection with either Y. pseudotuberculosis, Y. pestis, or Y. enterocolitica possessed antibodies directed against YOPs, indicating that they were expressed in all three pathogenic Yersinia species during infection. The YOPs of the three different species showed high immunological relatedness.
Binding of fibronectin to human buccal epithelial cells inhibits the binding of type 1 fimbriated Escherichia coli
Authors: Simpson W A , Hasty D L , Beachey E H
Published: January 2020

The interaction of purified human plasma fibronectin (FN) with human buccal epithelial cells was studied. Maximal binding of FN occurred at pH 5. The majority of the binding was specific and reversible. The binding of FN to buccal cells was saturable, reaching a maximum when 10(5) buccal cells were incubated with approximately 200 micrograms of radiolabeled protein per ml. The adherence of a type 1 fimbriated strain of Escherichia coli to buccal epithelial cells was inhibited by the addition of FN in a dose-related manner. Our results indicate that exogenous FN can bind to human buccal epithelial cells and block the attachment of a type 1 fimbriated strain of E. coli.
Plasmid-mediated factors conferring diffuse and localized adherence of enteropathogenic Escherichia coli
Authors: Nataro J P , Scaletsky I C , Kaper J B , Levine M M , Trabulsi L R
Published: January 2020

Histopathological evidence suggests that the adherence of enteropathogenic Escherichia coli (EPEC) to the mucosa of the small bowel is an important step in pathogenesis. Several reports have shown that many EPEC isolates adhere to HEp-2 and HeLa cells in tissue cultures. In the HeLa cell assay, there are at least two distinct patterns of adherence: localized adherence, which is characterized by the formation of bacterial microcolonies, and diffuse adherence, in which bacteria cover the cell uniformly. We have found that these two patterns can be demonstrated in HEp-2 cells as well as in HeLa cells and that the results of the two assays are closely correlated. Using a DNA probe which is sensitive and specific for localized adherence to HEp-2 cells, we provide evidence that localized adherence and diffuse adherence by EPEC are due to at least two genetically distinct adhesions which confer phenotypic differences in both the morphology of HEp-2 cell adherence and in surface hydrophobicity. The two factors are each encoded on plasmids which vary in size from 55 to 70 megadaltons; one strain exhibiting localized adherence carried these genes on the chromosome.
Effects of Pseudomonas aeruginosa cytotoxin on human serum and granulocytes and their microbicidal, phagocytic, and chemotactic functions
Authors: Baltch A L , Hammer M C , Smith R P , Obrig T G , Conroy J V , Bishop M B , Egy M A , Lutz F
Published: January 2020

The effect of Pseudomonas aeruginosa cytotoxin on human granulocytes (PMNs) and pooled human serum was studied by hemacytometer counts, phagocytic, bactericidal, and chemotaxis assays, and by transmission electron microscopy. The optimal assay conditions for phagocytosis of 75Se-labeled P. aeruginosa 1348A included 20% pooled human serum and a ratio of one PMN to between 10 and 20 bacteria. For the bactericidal assay, 20% pooled human serum and a ratio of one PMN to between one and five bacteria were used. Chemotaxis of PMNs was studied by agarose gel technique with 10(-7) M f-Met-Leu-Phe or 0.01 to 35 micrograms of cytotoxin per ml as a chemoattractant. The degree of PMN destruction was dependent on cytotoxin concentrations and PMN exposure time to cytotoxin. Virtually complete PMN lysis was observed after a 2-h exposure to 6 to 10 micrograms of cytotoxin per ml. PMN exposure to 2 micrograms of cytotoxin per ml for as long as 2 h had no adverse effect on phagocytosis. PMN exposure to greater than or equal to 4 micrograms of cytotoxin per ml for 2 h demonstrated a significant decrease in the percentage of bacteria killed. The results of experiments designed to separate cytotoxin effect on PMN lysis from the effect on PMN bactericidal capacity showed that there is an effect of cytotoxin on PMN bactericidal function. PMN exposure to 4 micrograms of cytotoxin per ml for 30 min caused a significant decrease in PMN migration. Cytotoxin had no chemoattractant qualities or effect on pooled human serum as studied by chemotaxis and phagocytosis assays. Although a cytotoxin concentration of greater than or equal to 2 micrograms/ml was required to demonstrate PMN ultrastructural changes observed in transmission electron microscopy studies, at a concentration of 0.1 microgram/ml, cytotoxin caused an impairment in the integrity of the PMN membrane, allowing a low-molecular-weight substance (ruthenium red) to enter into the cytoplasm. Cytotoxin may be an important factor in the pathogenesis and in the high mortality rate of patients with P. aeruginosa infections.
Diffusion of target cell membrane proteins allows recognition of cryptic binding sites by Mycoplasma pulmonis hemagglutinin
Authors: Minion F C , Goguen J D
Published: January 2020

Previously, we showed that Mycoplasma pulmonis can agglutinate trypsin-treated but not untreated erythrocytes (RBCs). This suggested that cryptic RBC binding sites were blocked by glycophorin, which is anchored to the RBC cytoskeletal network. In this report we show that RBCs from ankyrin-deficient mice in which the linkage between glycophorin and cytoskeleton is disrupted are agglutinated by M. pulmonis without trypsin treatment. This result demonstrates that diffusion of glycophorin is sufficient to allow recognition of cryptic binding sites by M. pulmonis. It also suggests that diffusion of surface proteins away from the area of close contact may play an important role in M. pulmonis-host cell interactions.
Immune responses of CBA/J mice to graded infections with Toxocara canis
Authors: Kayes S G , Omholt P E , Grieve R B
Published: January 2020

The immunological responsiveness of CBA/J mice infected with various numbers of the canine ascarid, Toxocara canis, was characterized after a single infection to ascertain the smallest infection capable of perturbing the immune system of the host. Mice receiving the lowest inoculations (5 eggs per mouse or 0.25 larvae per g of body weight) had detectable alterations in the number of circulating peripheral blood eosinophils and spleen weight-to-body weight ratios. Mice infected with 25 eggs each (1.25 larvae per g of body weight) showed augmented concanavalin A-elicited splenic lymphocyte transformation and a positive lymphocyte transformation in response to a toxocaral antigen preparation in addition to even higher eosinophil counts and heavier spleens. Spleen cells from mice receiving the two largest inocula (125 eggs and 250 eggs per mouse or 6.25 and 12.5 larvae per g of body weight, respectively) had in addition to the above responses a sixfold increase in spontaneous DNA synthesis. An enzyme-linked immunosorbent assay for mouse antibody responses to T. canis indicated that the time of onset as well as the magnitude of the antitoxocaral humoral response is directly proportional to the size of the inoculation used to initiate the infection. Finally, we showed that allowing the infection to become protracted results in some responses increasing somewhat in magnitude, but regardless of length of infection, the magnitude of any of the responses examined is proportional to the size of the infection. The results indicate that different host responses have different thresholds of sensitization and suggest that larvacidal reactions which require intricate interactions among several components of the immune system may not occur in very small infections.
Inhibition of serum bactericidal reaction by lipopolysaccharide
Authors: Sansano M , Reynard A M , Cunningham R K
Published: January 2020

An Rc-mutant of Escherichia coli that lacks UDPgalactose 4-epimerase grows normally without galactose but makes lipopolysaccharide lacking most of its carbohydrate. Exogenous galactose overrides the mutation and results in the formation of a complete lipopolysaccharide, thereby producing a smooth phenocopy. The smooth phenocopy was much more resistant to the bactericidal activity of normal human serum than was the rough phenotype. More complement was utilized by the rough mutant in the bactericidal process than by the smooth phenocopy. An antiserum was prepared in rabbits to a specific outer membrane protein in the mutant bacterium, the lambda receptor, whose expression could be suppressed by the addition of 10 mM maltose. The effect of the O-antigen in the lipopolysaccharide produced by the smooth phenocopy on the binding of antibody to the lambda receptor was determined. The smooth phenocopy exhibited significantly less binding of antibody than did the rough phenocopy. In addition, expression of the lambda receptor had little effect on the binding of antibody to the lambda receptor in the smooth phenocopy but caused significantly increased binding in the rough mutant. The results suggest that the increased resistance to the lethal action of normal human serum shown by the smooth phenocopy may be due to the blocking of antibody binding sites by the O-antigen of lipopolysaccharide, thereby preventing activation of the classical pathway of complement.
Activity of rabbit leukocyte peptides against Candida albicans
Authors: Selsted M E , Szklarek D , Ganz T , Lehrer R I
Published: January 2020

Six related cysteine-rich, low-molecular-weight peptides were purified from rabbit peritoneal granulocytes and tested in vitro for fungicidal activity against Candida albicans. Two peptides (NP-1 and NP-2) were highly effective, one (NP-3a) was moderately active, and three (NP-3b greater than NP-4 much greater than NP-5) had substantially less potency. There was a general, but imperfect, correlation between the candidacidal potency of each peptide and its net cationic charge. Candidacidal activity by NP-1 was concentration and time dependent and occurred rapidly under optimal low-ionic-strength conditions. It was inhibited by increasing either the ionic strength or Ca2+ concentration of the incubation mixtures, but was relatively unaffected by Mg2+. Candidacidal activity was independent of H+ concentrations between pH 5 and 8, but decreased below pH 5. Candidacidal activity was temperature sensitive and was virtually abolished when NP-1 was incubated with C. albicans at 0 degrees C. Cysteine-rich antimicrobial peptides such as NP-1 and NP-2 may equip leukocytes to deal with infections caused by C. albicans and other fungi that are susceptible to their microbicidal effects.
Variation of Neisseria gonorrhoeae protein II among isolates from an outbreak caused by a single gonococcal strain
Authors: Schwalbe R S , Sparling P F , Cannon J G
Published: January 2020

Gonococci isolated from localized urogenital infections usually possess one or more protein II (P.II) species in the outer membrane, but the structural and antigenic variation of these proteins among different gonococcal strains has made it difficult to determine if specific proteins of the P.II class are associated with particular sites or types of infection. A recent outbreak of gonorrhea in Durham, N.C., was unusual in that over 200 isolates were derived from a single strain, which provided an opportunity to address these questions. The P.II profile of 54 isolates was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of outer membrane proteins. At least seven distinct P.II proteins were seen; no single protein or combination of proteins predominated in the different isolates, and there was no association of P.II profile with site of isolation. Gonococci recovered from the same patient at different times had different P.II profiles, confirming that P.II variation occurred in vivo.
Subcellular localization and further characterization of a new elastase inhibitor from pneumococci
Authors: Vered M , Simon S R , Janoff A
Published: January 2020

Streptococcus pneumoniae contains an inhibitor of human neutrophil elastase. The agent does not inhibit other proteases, including neutrophil cathepsin G and pancreatic elastase. It is active in the presence of insoluble elastin as well as synthetic elastase substrates. The inhibitor is present in the pneumococcal cell membrane. [125I]elastase binding studies and inhibition experiments with intact bacterial autoplasts suggest that this agent has its elastase-binding site(s) exposed on the outside of the bacterial cell membrane. Native and randomized membrane vesicles also show equal inhibitory activity. Active inhibitor can be solubilized from pneumococcal membranes by treatment with a dipolar ionic detergent and can then be reconstituted, in active form, within artificial liposomes. Complex formation between the neutrophil elastase inhibitor and neutrophil elastase may involve noncovalent associations. Although elastase containing a covalently bound substrate analog no longer binds the pneumococcal inhibitor, the present study shows that complex formation is nevertheless independent of neutrophil elastase catalytic activity. Specific inhibitor activity and inhibitor release during bile salt-stimulated autolysis are greater in a nonnecrotizing pneumococcal strain (type I) than they are in a necrotizing strain (type III) or in Klebsiella pneumoniae. These results may help explain the frequent resolution of some pneumococcal pneumonias, despite the presence in the early pneumonic exudate of many neutrophils containing an elastolytic protease capable of injuring lung connective tissue.
Frequency and properties of naturally occurring adherent piliated strains of Haemophilus influenzae type b
Authors: Mason E O , Kaplan S L , Wiedermann B L , Norrod E P , Stenback W A
Published: January 2020

We found that 41 of 75 (55%) children with Haemophilus influenzae type b disease (70 cases of meningitis, 2 of cellulitis, 2 of septic arthritis, and 1 of epiglottitis) and 2 of 120 (1.7%) children with upper respiratory infection were colonized with H. influenzae type b in the nasopharynx (NP). Of these 43 NP strains from children with systemic H. influenzae type b disease, 7 (16%) adhered to human buccal epithelial cells. The strains isolated from the systemic site of all children, including children from whose NP adherent bacteria were isolated, did not adhere to buccal epithelial cells in vitro. Each adherent NP strain had biotype (I), serotype (b), and antibiotic susceptibility (sensitive) similar to that of the corresponding nonadherent systemic isolate. With one exception, all NP-systemic pairs had similar major outer membrane proteins. Six of the seven NP strains had a protein band in the whole cell lysate preparation with a molecular weight between 22,000 and 23,000, which could not be seen in the nonadherent cerebrospinal fluid strains. Electron micrographs of all adherent strains showed that more than 95% of the organisms examined were highly piliated, whereas the nonadherent strains were not piliated. All piliated strains agglutinated human erythrocytes. Adherence to buccal epithelial cells and agglutination of erythrocytes could not be blocked by mannose or alpha-methyl-D-mannoside. We speculate that piliation is not important for NP colonization by H. influenzae type b and that the loss of pili may be required for host invasion.
Suppression of cellular immunity to Listeria monocytogenes by activated macrophages: mediation by prostaglandins
Authors: Petit J C , Richard G , Burghoffer B , Daguet G L
Published: January 2020

We previously demonstrated the suppression of cell-mediated immunity to Listeria monocytogenes by Pseudomonas aeruginosa-induced, macrophage-like cells. The present study was undertaken to evaluate the mechanism for this suppression. P. aeruginosa supernatant was shown to activate macrophages by the criteria of increased bactericidal capacities and increased attachment to glass surfaces. Acquired cellular resistance to L. monocytogenes could also be inhibited by macrophages from L. monocytogenes-pretreated mice. The depression of acquired immunity by P. aeruginosa- or L. monocytogenes-activated macrophages did not appear to be due to a reduction of antigenic stimulus after nonspecific macrophage activation. In contrast, our findings suggest that suppression is mediated by activated macrophages through a prostaglandin-dependent mechanism. In vivo administration of aspirin blocked the immunosuppressive effect of P. aeruginosa- or L. monocytogenes-activated cells. Moreover, the suppressive activity of supernatants of macrophages from Listeria-infected mice was reversed when indomethacin was present during supernatant generation. Finally, prostaglandin E1 treatment in vivo profoundly inhibited the induction of cell-mediated immunity to L. monocytogenes. The possible role and mechanism of prostaglandin in suppressing cellular immunity to intracellular bacteria are discussed.
Quantitative analysis of cell walls of nutritionally variant streptococci grown under various growth conditions
Authors: van de Rijn I
Published: January 2020

Strains of nutritionally variant streptococci are usually isolated from patients with subacute bacterial endocarditis. Only recently have these strains been subdivided into three serotypes; however, no group-specific antigen has been described. To understand the immunochemical basis for the serology of these microorganisms as well as set the groundwork for adherence studies, quantitative analysis of the cell walls of nutritionally variant streptococci was undertaken. The bacteria were grown in semisynthetic medium or pyridoxal-supplemented Todd-Hewitt broth and harvested during the exponential or stationary phase. Cell walls were isolated and analyzed for amino sugars, sugars, polyalcohols, amino acids, and phosphorus by gas chromatography, high-pressure liquid chromatography, or colorimetric assays. The peptidoglycans of the cell walls of the prototype strains from the three serotypes were representative of other streptococcal cell walls, including the presence of alanine as the possible cross-bridge. The composition of the peptidoglycan was similar for all three strains and included a decreased concentration of peptidoglycan in their cell walls during the stationary phase. Glucosamine, glucose, galactose, ribitol, and a small amount of rhamnose were found in each of the cell wall polysaccharides. Galactosamine was only found in serotype II and III cell walls and might be responsible for the previously described cross-reaction between these strains. The concentration of the other sugars and amino sugars varied in each of the cell wall preparations, depending on the growth conditions. Finally, all three strains expressed both ribitol and phosphorus in their cell walls, characteristic of the presence of a ribitol teichoic acid. Therefore the cell wall composition of the nutritionally variant streptococci varies depending on the growth conditions, and their composition appears similar to that of strains of Streptococcus mitis.
Role of anti-pilus antibodies in host defense against gonococcal infection studied with monoclonal anti-pilus antibodies
Authors: Virji M , Heckels J E
Published: January 2020

Several monoclonal antibodies directed against gonococcal pili have been used to investigate the potential contribution of anti-pilus antibodies to host defense against gonococcal infection. Included were two antibodies (SM1 and SM2) which reacted with conserved determinants present on pili from all strains tested and others which exhibited antigenic specificity. Immunoblotting experiments revealed that antibodies SM1 and SM2 recognize epitopes on two different peptides derived by CNBr cleavage of alpha-pili from Neisseria gonorrhoeae P9-2. All antibodies used were capable of activating complement, as shown by their ability to bind Clq, and one type-specific antibody was effective in complement-mediated bactericidal killing. Antibodies directed against at least some pilus epitopes may therefore contribute to bactericidal activity during the course of natural infection. The opsonic effect of type-specific antibodies was demonstrated by their ability to stimulate luminol-dependent chemiluminescence of human polymorphonuclear leukocytes and promote phagocytic killing of variant P9-2. Phagocytic killing in the presence of each monoclonal antibody paralleled the increase in chemiluminescence, suggesting that for this variant killing was an inevitable consequence of the interaction of polymorphonuclear leukocytes with gonococci opsonized with anti-pilus antibodies. Antibody-mediated chemiluminescence of polymorphonuclear leukocytes was enhanced in the presence of human complement, and a weak opsonic effect was detected with one of the cross-reacting antibodies (SM1) when this system was used. Although cross-reacting antibody SM1 and type-specific antibody SM13 showed considerable differences in biological properties, they were of the same isotype and bound to native pili on intact gonococci in similar numbers and with similar avidity.
Recombinant and natural gamma-interferon activation of macrophages in vitro: different dose requirements for induction of killing activity against phagocytizable and nonphagocytizable fungi
Authors: Brummer E , Morrison C J , Stevens D A
Published: January 2020

Recombinant murine gamma-interferon (IFN) and supernatants from concanavalin A (ConA)-stimulated spleen cells were tested for their ability to activate resident peritoneal macrophages (M phi) for fungicidal activity. M phi monolayers pulsed overnight with IFN exhibited significantly enhanced fungicidal activity against Candida albicans (44 +/- 12 versus 0.0%) and Blastomyces dermatitidis (34 +/- 1 versus 3 +/- 3%). The effect of IFN was dose dependent; however, less IFN (10 U/ml) was required to activate M phi to kill phagocytizable C. albicans than to kill nonphagocytizable B. dermatitidis (1,000 U/ml). ConA-stimulated spleen cell supernatants were also able to activate M phi for fungicidal activity against both fungi. The capacity of ConA-stimulated spleen cell supernatants to activate M phi for fungicidal activity was neutralized in the presence of antibody to murine IFN. ConA-treated monolayers acquired the ability to kill C. albicans, but not B. dermatitidis, which was shown to be associated with residual (10%) lymphocytes in the monolayers. Lipopolysaccharide (0.001 to 10 micrograms/ml) failed to consistently activate M phi for fungicidal activity. These data show that IFN can exert an immunoregulatory role on M phi defense against these fungal pathogens.
Assessment of serum antibody patterns and analysis of subgingival microflora of members of a family with a high prevalence of early-onset periodontitis
Authors: Williams B L , Ebersole J L , Spektor M D , Page R C
Published: January 2020

In a study of members of a large family with a high prevalence of early-onset periodontitis, we sampled the subgingival microflora and characterized 40 isolates from each sample. We surveyed serum samples by enzyme-linked immunosorbent assay for antibodies reacting with any of a panel of 21 periodontal bacteria. The mother and 7 of her 13 children had early-onset periodontitis. Bacteroides gingivalis was not detected in the subgingival flora of any affected or unaffected family member, and Actinobacillus actinomycetemcomitans was isolated from only one affected child. Capnocytophaga ochracea was isolated from five of seven affected children and from none of their normal siblings. We found no significant differences among the floras from family members who had rapidly progressive, juvenile, and prepubertal forms of periodontitis. Elevated levels of serum antibody reacting with one or more of the bacteria tested were found in all family members with disease, but in only one periodontally normal family member. Both children with prepubertal periodontitis had antibodies reacting with C. sputigena, a species not found in their subgingival floras, but with none of the other bacteria tested. All remaining affected family members had antibodies to one or more serotypes of A. actinomycetemcomitans, and four had antibodies reacting with additional bacteria, including C. sputigena, Eikenella corrodens, Fusobacterium nucleatum, and Haemophilus aphrophilus. Sera from patients contained antibodies specific for putative periodontal pathogens not found in their pocket flora, and conversely, putative periodontal pathogens for which no serum antibodies were found frequently comprised a large proportion (10% or more) of the pocket flora. In no case were both the bacterium and its antibody found. These observations are suggestive of sequential infection in the early-onset forms of periodontitis and of induction of protective immunity against reinfection by the same microorganism.
Coprecipitation of lipopolysaccharide and the 39,000-molecular-weight major outer membrane protein of Haemophilus influenzae type b by lipopolysaccharide-directed monoclonal antibody
Authors: Gulig P A , Hansen E J
Published: January 2020

The major outer membrane protein of Haemophilus influenzae type b (Hib) with an apparent molecular weight of 39,000 (39K) was purified from three different Hib strains and was shown to be free from detectable contamination with other proteins. However, these purified 39K protein preparations were found to contain Hib lipopolysaccharide (LPS). Immunization of rats with these 39K protein preparations resulted in the production of antisera containing both 39K protein-directed and LPS-directed antibodies, as determined by Western blot analysis. The reactivity pattern of the LPS-directed serum antibodies with different Hib strains was identical to the reactivity of these Hib strains with a set of monoclonal antibodies (mabs) previously shown to immunoprecipitate the 39K protein in a radioimmunoprecipitation (RIP) system. Examination of the antigenic specificities of the 39K protein-immunoprecipitating mabs by using Western blot analysis showed that these mabs were actually directed against Hib LPS. RIP analysis of 125I-labeled Hib cells and 32P-labeled Hib cells revealed that the 39K protein and LPS existed as a complex in a RIP system, which resulted in the coprecipitation of both antigens by LPS-directed mabs. The interaction between LPS and the 39K protein was highly selective for this protein and did not involve other outer membrane proteins. The LPS/39K protein complex could be reconstituted by mixing purified LPS and purified 39K protein; it could also be reconstituted with 39K protein from one Hib strain and LPS from another Hib strain. These findings have necessitated the reinterpretation of previous studies involving the 39K protein-immunoprecipitating mabs. Of primary importance is the fact that the demonstrated immunoprotective ability of a 39K protein-immunoprecipitating mab (E. J. Hansen, S. M. Robertson, P. A. Gulig, C. F. Frisch, and E. J. Haanes, Lancet i:366-368, 1982) must now be regarded as evidence that antibody directed against Hib LPS can be protective against experimental Hib disease.
In vitro and in vivo interaction between trophozoites of Entamoeba histolytica and gerbil lymphoid cells
Authors: Chadee K , Meerovitch E , Moreau F
Published: January 2020

The in vitro and in vivo antiamoebic cytotoxic effects of peritoneal exudate cells and mesenteric lymph node lymphocytes of gerbils with cecal amoebiasis or those immunized with amoebic extract were investigated. A differential effect of the lymphoid cells against trophozoites of nonpathogenic and pathogenic strains of Entamoeba histolytica was observed. Nonpathogenic amoebae were more susceptible to killing by lymphoid cells than pathogenic amoebae in vitro and in vivo in infected or immunized animals. These data suggest that during the course of cecal amoebiasis in gerbils, a differential stimulation or depletion of cytotoxic cells in the lymphoreticular tissues occurs, resulting in an impaired cell-mediated immune response.
In Vitro Bactericidal and Associated Metabolic Activities of Mouse Spleen Cells
Authors: Strauss R. R. , Paul B. B. , Jacobs A. A. , Sbarra A. J.
Published: January 2020

Spleen cell suspensions from AKR and CD-1 mice are able to kill
Escherichia coli
in vitro. The optimal ratio of splenocytes to bacteria for this activity is 1: 1. Incubation of these cells with inert polystyrene latex spherules (0.81 μm diameter) results in a fourfold increase in glucose-
1
-
14
C
oxidation. Under these conditions, there is also a 2.5-fold increase in both reduced nicotinamide adenine dinucleotide phosphate oxidase activity and formate oxidation. Spleen cell fractions have been shown to have significant peroxidase activity. This has been quantitated by the guaiacol oxidation method. The 20,000 ×
g
pellet fraction of spleen cell homogenate can kill
E. coli
when H
2
O
2
and chloride ions are added and the reaction is carried out at
p
H 5.5 and 37 C.
Mycoplasmosis: Serology of Infections in the Genital Tract of Bulls
Authors: Ernø H.
Published: January 2020

An investigation was carried out to determine the extent to which serology may contribute a means of elucidating the possible etiological significance of the presence of
Mycoplasma bovigenitalium
in bulls with genital tract disease. Experimentally infected bulls showed a significant serological response with maximum titers of antibody as early as 12 days after inoculation as measured by the indirect hemagglutination test. The tetrazolium reduction inhibition test, even as modified, was less suitable because this method did not reveal antibodies in all inoculated animals. The indirect hemagglutination test revealed high titers of antibody in serum of most bulls from bull stations in Denmark and Luxembourg although young bulls were often serologically negative. It is concluded that indirect hemagglutination is useful in experimental work and also in estimating the incidence of infection with mycoplasmas in bulls from artificial breeding stations. For diagnostic purposes, use of the indirect hemagglutination test is largely restricted to young bulls and on condition that the first blood sample is drawn very early in the course of the disease.
Relationship of Serogroups of
Neisseria meningitidis
II. R Variants of
Neisseria meningitidis
Authors: Devine Leonard F. , Rhode Solon L. , Hagerman Cline R.
Published: January 2020

Meningococci isolated in primary cultures from nasopharyngeal carriers occasionally consisted of mixtures of smooth (S) and rough (R) strains. The R strains were separated from the S strains and their morphological and serological characteristics were studied. Some of these R strains reverted spontaneously to S strains which subsequently produced group-specific polysaccharide. Several R strains, grown in the presence of deoxyribonucleic acid from either an R strain of known parentage or an S strain, formed recombinants with serological group specificity.
Serological Typing of
Staphylococcus epidermidis
Strains by the Serum-Soft Agar Technique
Authors: Yoshida Kosaku , Smith Melvin R. , Naito Yoshiko
Published: January 2020

Antisera to five different diffuse forms of
Staphylococcus epidermidis
were prepared in rabbits as a mean of serological differentiation of
S. epidermidis
strains. These antisera converted the growth types of the homologous strains from diffuse to compact form in serum-soft agar but did not convert the heterologous strains. The converting activities of the antisera were absorbed out with homologous organisms and not by heterologous strains, indicating the specific serological properties of these strains. Further, the converting activity was absorbable with cell surface substance extracted by sonic oscillation and was not absorbed with cells from which this surface substance had been removed. With these factor sera and the serum-soft agar technique,
S. epidermidis
strains were differentiated, and it was found that 102 of 116 strains or 87.9% were typable. Within the 102 typable strains, 49 and 53 typed as monovalent and polyvalent, respectively. No correlation between source and strain types of
S. epidermidis
was found.
Field Studies of an Attenuated Venezuelan Equine Encephalomyelitis Vaccine (Strain TC-83)
Authors: Eddy Gerald A. , Martin David H. , Reeves William C. , Johnson Karl M.
Published: January 2020

A series of field studies using strain TC-83 attenuated Venezuelan equine encephalomyelitis vaccine in horses was made to determine the rate of seroconversions, the postvaccination viremia, and the possibility of adverse reactions to the vaccine. The rate of seroconversions varied from 50% in one study to 91 and 100% in two others. The highest level of viremia measured was 7 × 10
3
to 8 × 10
3
plaqueforming units per ml. No adverse reactions to the vaccine were observed in any horses, including 42 pregnant mares and their resulting foals.
Effect of Exposure to the Atmosphere on the Infectivity of Group A Streptococci
Authors: Srisuparbh Kiti , Sawyer William D.
Published: January 2020

During exposure to the atmosphere, type 14 group A streptococci lost infectivity for mice more rapidly than they declined in viability. The loss of infectivity resulted from phenotypic, not genotypic, changes. Comparison of rates of loss of infectivity during exposure of capsulated and noncapsulated streptococci suggested that the principal effect of atmospheric exposure was on the capsule, a known determinant of infectivity. Accelerated drying promoted the loss of infectivity.
Ultrastructural Changes in Cells of the Mouse Footpad Infected with
Mycobacterium leprae
Authors: Evans Michael J. , Levy Louis
Published: January 2020

Ultrastructural changes in cells of the mouse footpad are described which occurred during the log phase of multiplication, the plateau, and the stationary phase of growth of
Mycobacterium leprae.
BALB
/c mice were inoculated in the right hind footpad with 5 × 10
3
organisms and sacrificed in pairs at 86 to 173 days after inoculation. Tissue samples were prepared for electron microscopy by standard techniques. During the early growth phase of
M. leprae
in the mouse footpad, few organisms can be detected. Those present are in macrophages and are bound by a single membrane. The cytoplasm of the macrophage is less dense around the organism. There are few lysosomes, and the bacteria do not appear to be degenerating. At the peak of the growth phase, the organisms within a macrophage are bound by either a single or double membrane. There is an increased number of vacuoles, which are also bound by a double membrane, and lysosomes. During the stationary phase, most of the macrophages have taken on a vacuolar appearance and contain lysosomes. The vacuoles are bound by a double membrane, as are most of the organisms within the macrophage. Many of these organisms appear to be degenerating. Occasionally, organisms are encountered in the sarcoplasm of striated muscle. They are usually bound by a single membrane and do not appear to be degenerating.
Complement-Fixing Antigens of Herpes Simplex Virus Types 1 and 2: Reactivity of Capsid, Envelope, and Soluble Antigens
Authors: Martin Mary Lane , Palmer Erskine L. , Kissling Robert E.
Published: January 2020

Capsid, envelope, and nonvirion-associated soluble components of type 1 and type 2 herpes simplex virus (HSV) were obtained from infected monolayer cell cultures and used as complement fixation (CF) antigens. Capsids were prepared by treatment of cells with the nonionic detergent Nonidet-P40, envelope material by treatment of virions with ether and high
p
H, and soluble components were obtained from culture fluids of untreated cells. Serological studies with experimental anti-herpesvirus sera indicate that these serotypes share cross-reacting envelope, capsid, and soluble antigens with each other and with herpesvirus B but not with varicella virus. In addition, animals immunized with crude HSV preparations contain high levels of CF antibody (1:32 to 1:64) to soluble antigens, whereas sera from humans who have experienced natural infection contain low levels of antibody (≤1:8) to this antigen. Further testing with reference, capsid, and envelope antigens indicates that antibody levels to reference and capsid antigens are about the same in sera from healthy humans, whereas antibody to the envelope is decidedly lower in these sera. Herpes convalescent-phase sera contain higher levels of antibody to reference and envelope antigens than to capsid antigen.
Inhibition of In Vitro Plaque Formation by
l
-Lysine
Authors: Malveaux F. J. , Smith J. J.
Published: January 2020

Accumulation of dental plaque was inhibited by
l
-lysine, but not by
l
-arginine or
l
-histidine. The monohydrochoride form was twice as effective as free amino acid.
Infection-Immunity in Tularemia: Specificity of Cellular Immunity
Authors: Claflin J. Latham , Larson Carl L.
Published: January 2020

The relationship between hypersensitivity and cellular resistance to infection with facultative intracellular parasites was studied in mice by using infection-immunity in tularemia as a model system. Delayed hypersensitivity to antigenic fractions of
Francisella tularensis
was first detected 6 to 7 days after immunization with viable
F. tularensis
vaccine, at which time immunity against challenge infection developed. Both immunity and delayed-type sensitivity reached maximal levels by 9 to 10 days. Immediate hypersensitivity occurred after immunization with both viable and nonviable tularemia vaccines but could not be correlated with resistance since nonviable antigens were not protective. Attempts to relate resistance to
F. tularensis
with nonspecific immunity factors were unsuccessful. Immunization of mice with BCG vaccine stimulated protection against infection with
F. novicida
and
Salmonella typhimurium
but provided no protection against infection with
F. tularensis.
Moreover, viable tularemia vaccine, while inducing marked protection against challenge with specific organisms, afforded no protection against infection with
S. typhimurium
or
S. enteritidis.
It is concluded that cellular immunity in tularemia involves an immunologically specific component.
Ocular Pathogenicity of Types 1 and 2
Herpesvirus hominis
in Rabbits
Authors: Oh J. O. , Moschini G. B. , Okumoto M. , Stevens T.
Published: January 2020

Type 2 strains of
Herpesvirus hominis
produced more severe lesions in rabbit corneas than type 1 strains.
Association of
Escherichia coli
with the Small Intestinal Epithelium II. Variations in Association Index and the Relationship Between Association Index and Enterosorption in Pigs
Authors: Bertschinger Hans U. , Moon Harley W. , Whipp Shannon C.
Published: January 2020

The association between small intestinal epithelium and enteropathogenic
Escherichia coli
(EEC) was studied in ligated intestinal loops of pigs and rabbits. The association indexes (degree of association) for each of two porcine EEC strains varied widely among pigs and independently of each other. Significant litter-to-litter variations in association indexes among colostrum-deprived newborn pigs were interpreted to be the result of congenital resistance to association with specific EEC in some pigs. Since enterosorption occurred in loops with low association indexes, it was not necessary for EEC to establish a high association index for them to cause enterosorption in ligated intestinal loops. Two strains of EEC which are enteropathogenic for humans caused enterosorption in ligated loops in pigs 3 weeks old or less but not in 6-week-old pigs.
Amino Acid Oxidase in Leukocytes: Evidence Against a Major Role in Phagocytosis
Authors: DeChatelet Lawrence R. , McCall Charles E. , Cooper M. Robert
Published: January 2020

The addition of either
d
- or
l
-amino acids fails to increase hexose monophosphate shunt activity of resting or phagocytizing neutrophils. This is presumptive evidence against a major role for amino acid oxidase in the bactericidal activity of the cell.
Sensitivity of Capnocytophaga species to bactericidal properties of human serum
Authors: Wilson M E , Burstein R , Jonak-Urbanczyk J T , Genco R J
Published: January 2020

Capnocytophaga is a newly described genus of gram-negative bacteria which can cause serious oral and extraoral infections in the susceptible host. In the present study, sensitivity of Capnocytophaga spp. to the bactericidal properties of human serum was investigated. Laboratory strains representative of Capnocytophaga sputigena, C. ochracea, and C. gingivalis and seven oral isolates of Capnocytophaga spp. obtained in primary culture were determined to be sensitive to killing by pooled normal serum. In contrast, little or no killing of Capnocytophaga spp. was observed when these organisms were incubated in the presence of hypogammaglobulinemic serum despite evidence for alternative pathway activation. However, hypogammaglobulinemic serum could be reconstituted to bactericidal activity by the addition of the immunoglobulin M fraction of normal serum. Capnocytophaga spp. failed to activate the classical pathway in hypogammaglobulinemic serum, thus ruling out an antibody-independent mechanism of killing. In contrast, good correlation was observed between serum-mediated killing and antibody-dependent classical pathway consumption. These results indicate that complement in the presence of bactericidal antibody may be an important determinant of host resistance to intra- and extraoral infections caused by Capnocytophaga spp.
Subspecies-specific surface antigens of promastigotes of the Leishmania donovani complex
Authors: Lemesre J L , Rizvi F S , Afchain D , Sadigursky M , Capron A , Santoro F
Published: January 2020

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns of proteins and externally exposed labeled surface constituents were analyzed in promastigotes of three etiological agents of kala azar (Leishmania donovani, HS70 strain from India; L. chagasi, Imperatriz strain from Brazil; L. infantum, ITMPA K263 strain from Morocco and MO strain from France). Coomassie blue-stained gels showed similar protein patterns for L. donovani and L. chagasi and a more distinct one for L. infantum. Surface radioiodination with two different methods, lactoperoxidase and IODO-GEN, gave identical autoradiographic patterns for each parasite. Four major labeled proteins with apparent Mr values of 65,000, 60,000, 50,000, and 26,000 were detected in both L. chagasi and L. donovani. However, the radioiodinated polypeptide pattern of L. infantum only showed two major bands with an apparent Mr of 62,000 and a doublet of 26,000 to 23,000. Immunoprecipitation of detergent extracts of labeled promastigote subspecies with immune sera from rabbits immunized with either L. chagasi or L. infantum and from patients and mice infected with these two parasites, as well as with a monoclonal antibody against the surface of L. donovani promastigotes, demonstrated that the surface antigenic expression of L. infantum is different from that noticed in the two other subspecies, which are similar. Immunofluorescence experiments with some of these antibodies confirmed these results. The present findings should be considered in taxonomic and immunological studies in visceral leishmaniasis.