bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of a two-sited monoclonal antibody assay to detect a heat-stable malarial antigen in the sera of mice infected with Plasmodium yoelii
Authors: Taylor D W , Evans C B , Hennessy G W , Aley S B
Published: January 2020

Antigens, circulating in the blood during malarial infections, have been implicated in immune protection, immunosuppression, and immune-complex formation. We used a monoclonal antibody (MAb 7H8) to identify an antigen (Ag-7H8) in the sera of mice infected with Plasmodium yoelii. The major form of the antigen has a molecular weight of approximately 120,000 in P. yoelii, with minor components of 220,000; 65,000 to 75,000; and 45,000. Ag-7H8 remains antigenic after boiling for 5 min. A two-sited assay was developed with MAb 7H8 that demonstrated that the Ag-7H8 has at least two similar epitopes per molecule. The two-sited assay was used to follow Ag-7H8 in the blood of mice during lethal (strain 17XL) and nonlethal (strain 17XNL) P. yoelii infections. Ag-7H8 appeared on days 6 and 7 after infection with 10(6) and 10(4) 17XL P. yoelii parasites, respectively, and remained until the animals died. It was in plasma samples between days 6 and 14 after 17XNL P. yoelii injections in several inbred strains of mice, regardless of the course of parasitemia. Thus, the kinetics of antigenemia correspond with early stages of infection and not with the number of circulating parasites. Indirect immunofluorescence assays demonstrated that MAb 7H8 detects a cross-reactive antigen in other malarial parasites, including Plasmodium berghei and Plasmodium falciparum. Thus, this two-sited assay may have general application for the serodiagnosis of malaria and may be beneficial in determining the relationship of circulating antigens to malarial immunity.
Human and animal serotypes of Bacteroides gingivalis defined by crossed immunoelectrophoresis
Authors: Parent R , Mouton C , Lamonde L , Bouchard D
Published: January 2020

The antigenic complexity of three strains of Bacteroides gingivalis and four strains resembling B. gingivalis isolated from animals was analyzed and compared by crossed immunoelectrophoresis. Thirteen antigens of the human biotype were present in all human strains and six antigens of the animal biotype were present in all animal strains, indicating a marked serological homogeneity within each biotype. Four antigens cross-reacting between the human B. gingivalis and the animal strains were identified. This antigenic relatedness defined the serological homogeneity of the two biotypes within the species and allowed recognition of four species-specific antigens. Two antigens specific to the human strains and two antigens specific to the animal strains were identified, indicating that serotype-specific antigens can distinguish each biotype. It is thus proposed that the oral, black-pigmented asaccharolytic Bacteroides strains of animal origin be classified as catalase-positive variants of B. gingivalis. It is also proposed that two serotypes be recognized within the species B. gingivalis. Serotype 1 includes the catalase-negative human biotype, and serotype 2 includes the catalase-positive animal biotype.
Influence of blood group on the availability of receptors for attachment of uropathogenic Escherichia coli
Authors: Lomberg H , Cedergren B , Leffler H , Nilsson B , Carlström A S , Svanborg-Edén C
Published: January 2020

Escherichia coli strains with defined receptor specificity were used as probes to analyze the individual variation in host cell receptors with respect to blood groups. The adhesins were initially characterized as mannose sensitive (MS), mannose resistant (MR), or nonagglutinating (-). The receptor specificity of the strains with MR adhesins was defined by agglutination of synthetic Gal alpha 1----4Gal beta covalently linked via a spacer arm, (CH2)2S(CH2)2CO approximately H-bovine serum albumin (BSA) to BSA-latex beads as specific for the globoseries glycolipid receptors (MR:GS). Strains with MR adhesins not reacting with Gal alpha 1----4Gal beta-BSA-latex were designated MR:nonGS. The attachment and hemagglutination of the MR:GS strains was strictly dependent on Gal alpha 1----4Gal beta-containing receptors, as shown by the absence of binding to cells from individuals of blood group P lacking these structures. Previous reports showed differences in the composition of globoseries glycolipids between erythrocytes from individuals of P1 and P2. No significant difference was found, However, in the mean adhesion to P1 and P2 epithelial cells or in the agglutination titer for P1 and P2 erythrocytes. The MR:GS receptors were equally distributed on squamous and transitional epithelial cells. In contrast, the distribution of MR:nonGS receptors was skewed. Attachment occurred mostly to squamous epithelial cells. The attachment of strains with MR:nonGS adhesins was independent of the P blood group of the cell donor. The binding ability of MR:GS and MR:nonGS adhesins appeared independent and additive. The attachment was not influenced by the ABH blood group. However, increased binding to epithelial cells from nonsecretors occurred regardless of the P blood group, suggesting a shielding of receptors by products controlled by the secretor genes. These results illustrate how individual variation in cell surface components with and without receptor activity determine the interaction of a ligand with a known receptor.
Enhancement of hematopoietic response of mice by subcutaneous administration of Lactobacillus casei
Authors: Yokokura T , Nomoto K , Shimizu T , Nomoto K
Published: January 2020

Mice that had received heat-killed Lactobacillus casei (LC 9018) subcutaneously (s.c.) showed enhanced resistance to systemic (i.e., intravenous) infection with Listeria monocytogenes, but the antilisterial resistance of mice was less augmented by s.c. administration of Propionibacterium acnes ("Corynebacterium parvum"). Though there was little change in the total number of splenic leukocytes after s.c. administration of LC 9018, the monocyte-macrophage ratio increased after treatment, reaching its peak on day 5 to 7 after injection. The number of progenitor cells that form macrophage colonies under the stimulus of L-cell-conditioned medium in a semisolid agar culture system increased in the spleens of mice pretreated s.c. with LC 9018, showing a peak response on day 5 after injection. The increase corresponded to the increase in the dose administered, and increased numbers were detected even 10 days after treatment. The number of macrophage colonies in the femurs of mice pretreated s.c. with LC 9018 showed a temporary increase on day 3 after injection but then a decrease until day 10. Colony-stimulating activity was detected in the sera of mice administered LC 9018 s.c. 18 h previously, and the colonies produced were of three types: granulocyte (8%), macrophage (56%), and granulocyte-macrophage (36%). Administration of C. parvum s.c. had little effect on these hematopoietic responses of mice.
Protective effects of the glutathione redox cycle and vitamin E on cultured fibroblasts infected by Mycoplasma pneumoniae
Authors: Almagor M , Kahane I , Gilon C , Yatziv S
Published: January 2020

The role of the glutathione (GSH) redox cycle and vitamin E as antioxidant defense systems was studied in normal human cultured skin fibroblasts infected by virulent Mycoplasma pneumoniae. In cells infected for 20 h, catalase activity was inhibited by 75% and the intracellular GSH decreased to 32% of its normal values. GSH peroxidase and oxidized glutathione (reductase activities in the infected cells were unaffected.) GSSG glutathione in the medium of the infected cells rose in accordance with the intracellular GSH decrease. The observed elevation in GSSG/GSH ratio was attributed to the increase in intracellular H2O2 content in M. pneumoniae-infected cells due to the marked inhibition in their catalase activity. The protective effect of the GSH redox cycle in infected cells was studied by depletion of cellular GSH, prior to their infection with M. pneumoniae, using buthionine sulfoximine (BSO), a selective inhibitor of gamma-glutamyl cysteine synthetase. After 16 h of incubation with BSO, the GSH levels were reduced to 38% of their normal value and recovered to 55% during 24 h after removal of the inhibitor. BSO had no effect on GSH peroxidase and catalase activities in either infected or noninfected cells. The level of malonyldialdehyde (an indicator of membrane lipid peroxidation) in BSO-treated cells infected by M. pneumoniae was 1.8 times higher than in infected controls. Cells enriched with 0.25 and 2.25 micrograms of vitamin E per mg of protein prior to their infection by M. pneumoniae revealed the following: a lesser degree of catalase inhibition, 46 and 30%, respectively, versus 64% in infected control cells that were not supplemented with vitamin E; lower levels of malonyldialdehyde, 55 and 20% increments, respectively, versus a 140% increment in infected controls; higher residual activity of lactate dehydrogenase, 76 and 96%, respectively, versus 58% in infected controls. Our data indicate that the oxidative damage induced in M. pneumoniae-infected cells due to the increase in intracellular levels of H2O2 and O2- is limited by the host cell GSH redox cycle and by supplementation with vitamin E.
Role of pyocyanin in the acquisition of iron from transferrin
Authors: Cox C D
Published: January 2020

Pseudomonas aeruginosa produces a blue pigment called pyocyanin. In the presence of oxidizable substrates, bacteria reduce this pigment to a colorless product, leukopyocyanin. Pyocyanin can also be nonenzymatically reduced by NADH. Leukopyocyanin formed by cell- or NADH-mediated reduction nonenzymatically reduces oxygen or Fe(III). Pyocyanin-dependent iron reduction by whole bacterial cells was measured by the formation of the ferrous-ferrozine complex. In addition, leukopyocyanin reduced chelated Fe(III) including ferric iron in complex with transferrin, the serum iron-binding protein. High-pressure liquid chromatography was used to display the reductive removal of iron from transferrin and the accumulation of iron in the ferrous-ferrozine complex. Pyocyanin stimulated the accumulation of 55Fe from [55Fe]transferrin when it was added to bacteria incubated under low-oxygen conditions. Although bacteria grown in the presence of 100 microM FeCl3 reduced pyocyanin just as rapidly as iron-limited bacteria, these cells did not accumulate iron in the presence or absence of pyocyanin. Therefore, P. aeruginosa participates indiscriminantly in the reduction of pyocyanin, but soluble or available iron generated by the pyocyanin is taken up specifically by iron-limited bacteria.
Quantitative and temporal analyses of murine antibody response in serum and gut secretions to infection with Giardia muris
Authors: Snider D P , Underdown B J
Published: January 2020

We analyzed the appearance and level of Giardia muris-specific antibody of immunoglobulin A (IgA), IgG, and IgM isotypes, at weekly intervals, over the course of a 7-week infection in BALB/c and C57BL/6 mice. Using sensitive immunoradiometric assays, we observed that IgA antibody was the only detectable anti-G. muris antibody in intestinal secretions throughout the course of infection. No secreted IgG or IgM anti-G. muris antibody was detected even in concentrated intestinal secretions. The expulsion of G. muris by the mice was associated closely with the appearance and increasing levels of secreted anti-G. muris IgA antibody. Both IgG and IgA serum antibody to G. muris were detected, but no serum IgM antibody was detected. Serum IgA and IgG anti-G. muris antibody remained at high levels up to 10 weeks following clearance of the parasite. An interesting observation indicated that serum IgA antibody to G. muris developed more slowly in response to infection than secreted IgA antibody. An analysis of the molecular weight distribution of total serum IgA in infected mice determined that infection produced a transient but significant shift in serum IgA to high-molecular-weight (greater than or equal to dimeric IgA) forms. The results indicate that a substantial IgA antibody response occurs in sera and in gut secretions of G. muris-resistant mice and that IgA antibody is the dominant and possibly the only effector antibody active in intestinal secretions during G. muris infection in mice.
Inhibition of mitogenesis induced by phytohemagglutinin and Lens culinaris lectin in adherent-cell supernatants treated with protein extract of Mycobacterium tuberculosis
Authors: Parra C , Montaño L F , Huesca M , Rayón I , Willms K , Goodsaid F
Published: January 2020

Specific stimulation of T cells by phytohemagglutinin and Lens culinaris lectin was inhibited by a soluble factor(s) secreted by normal adherent cells stimulated with culture filtrate protein extract (CFPE) derived from bacterial cultures of Mycobacterium tuberculosis H37Ra (avirulent) and H37Rv (virulent). The induction of the inhibitory factor was blocked by the presence of hyperimmune antisera to H37Rv or H37Ra CFPE. The inhibitory factor did not seem to be a CFPE reprocessed by the adherent cells. Inhibitory activity was maximal in supernatants of adherent-cell cultures incubated for 48 h; the inhibitory factor was heat labile, and its production was dependent on the concentration of M. tuberculosis CFPE. A mouse monocyte-macrophage cell line, ATCC J774A.1, produced an identical inhibitory factor, thus excluding a non-macrophage-contaminating adherent cell as the source of the factor. This inhibitory factor also interfered with the recognition of phytohemagglutinin and Lens culinaris lectin by T cells.
Induction of protective immunity to monoclonal-antibody-defined Plasmodium falciparum antigens requires strong adjuvant in Aotus monkeys
Authors: Siddiqui W A , Tam L Q , Kan S C , Kramer K J , Case S E , Palmer K L , Yamaga K M , Hui G S
Published: January 2020

Monoclonal antibodies to the major Plasmodium falciparum merozoite surface coat and rhoptry antigens were produced. A combination of the affinity-purified polypeptides with Freund complete adjuvant which was given three times completely protected an Aotus lemurinus azure (karotype VI) monkey against homologous challenge; however, immunization with the same polypeptides with a muramyl dipeptide derivative [MDP-Lys(L18)] did not protect a second Aotus monkey, even though comparable high antibody titers were induced.
Production and characterization of cloned T-cell hybridomas that are responsive to Rickettsia conorii antigens
Authors: Jarboe D L , Eisemann C S , Jerrells T R
Published: January 2020

T-cell hybridomas produced by the fusion of Rickettsia conorii immune T cells to the AKR thymoma BW 5147 produced interleukin-2 when stimulated with the antigens of three different R. conorii strains. One cloned hybridoma responded only to R. conorii antigens, whereas a second and third cloned hybridoma also responded to the antigens of Rickettsia rickettsii Sheila Smith and Rickettsia sibirica 246, respectively. Antigen responses required antigen-presenting cells, and this interaction was major histocompatibility complex restricted. Fluorescence-activated cell-sorter analysis demonstrated that all three hybridomas were of the Thy-1.2+, Lyt-2- phenotype and that two of the three were L3T4+. These data demonstrated the presence of an antigenic epitope that is R. conorii species specific and other epitopes that are common to various members of the spotted fever group which can stimulate interleukin-2 production by T-cell hybridomas.
Flow cytometric analysis of the effects exerted by monoclonal antibodies on binding and uptake of Leishmania mexicana subsp. mexicana promastigotes by murine peritoneal macrophages
Authors: Williams K M , Sacci J B , Anthony R L
Published: January 2020

A flow cytometric assay was developed to quantitate the binding kinetics of Leishmania mexicana subsp. mexicana promastigotes to murine peritoneal macrophages and to determine if selected membrane-specific monoclonal antibodies would exert an effect on the binding process. A total of three monoclonal antibodies, all reactive with a similar 42-kilodalton surface membrane component by Western blot analysis, enhanced parasite-macrophage binding at levels greater than 45%. An additional three monoclonal antibodies that identified low-molecular-weight antigens of the promastigote (15 to 20 kilodaltons) had no effect on the binding process. Of these antibodies, however, one did appear to inhibit the internalization of the parasites after it attached to the macrophage membrane.
Monoclonal antibody to a major surface glycoprotein immunogen differentiates isolates and subpopulations of Trichomonas vaginalis
Authors: Alderete J F , Suprun-Brown L , Kasmala L
Published: January 2020

To produce monoclonal antibodies (MAbs) to highly immunogenic membrane proteins of Trichomonas vaginalis NYH286, the sera of subcutaneously infected BALB/c mice were first monitored for antibody to trichomonad surface proteins. The sera possessed antibody to one major surface protein by 7 days and antibody to numerous other trichomonad membrane proteins by 4 weeks postinfection. A hybridoma was then generated that synthesized an MAb, designated C20A3, which reacted to a parasite-derived glycoprotein possessing a molecular weight of 267,000 (267K glycoprotein). The immunogen corresponded to the single high-molecular-weight immunogenic surface protein recognized by 7-day mouse antisera. The MAb differentiated T. vaginalis isolates by a whole-cell enzyme-linked immunosorbent assay and by indirect immunofluorescence, using either fixed or live organisms. All isolates, however, possessed C20A3-reactive material when tested by enzyme-linked immunosorbent assay, using detergent extracts of the isolates incubated with MAb-coated microtiter well plates. The epitope was accessible to antibody binding on live T. vaginalis organisms expressing the major immunogen, and the 267K glycoprotein was readily removed from the parasite membranes by trypsinizing the intact trichomonads. The antigen incorporated radiolabeled glucose, mannose, and acetate. Also, an unlabeled 267K glycoprotein on nitrocellulose blots was detected by 125I-concanavalin A and 125I-wheat germ agglutinin, confirming the glycoprotein nature of the immunogen. Finally, of seven isolates used in this study, one possessed a cross-reactive 170K, rather than 267K, antigen. The data reinforce the idea that antigenic heterogeneity among T. vaginalis isolates may be a function of the presence or absence of high-molecular-weight glycoprotein immunogens from trichomonal membranes.
Serum and salivary antibody responses in rats orally immunized with Streptococcus mutans carbohydrate protein conjugate associated with liposomes
Authors: Wachsmann D , Klein J P , Scholler M , Ogier J , Ackermans F , Frank R M
Published: January 2020

In this study we describe the preparation of a Streptococcus mutans vaccine consisting of a purified polysaccharide antigen, derived from S. mutans OMZ175 serotype f, covalently coupled through reductive amination to a previously isolated 74,000-molecular-weight (74K) cell wall protein which interacts with saliva proteins (74K-SR). We also investigated the local and systemic immune response to the poly-74K-SR conjugate after oral administration of the conjugate associated with liposomes. Intragastric administration of liposome-associated poly-74K-SR conjugate in rats produced a local immunoglobulin A (IgA) response directed against the polysaccharide and the cell surface protein, whereas liposome-associated polysaccharide was unable to induce any detectable local IgA response. The antigenicity of the polysaccharide in the conjugate was not affected by the coupling reaction, while that of the cell surface protein was reduced. We showed that the immunogenicity of S. mutans polysaccharide could be improved by chemical coupling with a carrier cell surface protein. If such a conjugate were orally administered with liposomes it could constitute a potential vaccine against dental caries.
Identification of a nonfimbrial adhesive factor of an enterotoxigenic Escherichia coli strain
Authors: Darfeuille-Michaud A , Forestier C , Joly B , Cluzel R
Published: January 2020

An enterotoxigenic Escherichia coli strain (strain 2230), isolated from a patient with acute infantile diarrhea, was found to adhere only to the brush border of human intestinal epithelial cells. This strain does not hemagglutinate human, bovine, chicken, or guinea pig erythrocytes. The adhesion of E. coli 2230 appears to be mediated by a nonfimbrial bacterial surface protein of 16,000 daltons which can be extracted by heating the bacteria at 60 degrees C for 20 min. This surface protein is implicated as an adhesive factor because pretreatment of enterocytes with this protein extract completely inhibits the adhesion of E. coli 2230. This adhesive factor is serologically distinct from other adhesive factors found in enterotoxigenic E. coli strains. A plasmid DNA of 66 megadaltons is involved in the synthesis of this nonfimbrial adhesive factor.
Inhibition of macrophage phagocytosis by Bacteroides fragilis in vivo and in vitro
Authors: Rodloff A C , Becker J , Blanchard D K , Klein T W , Hahn H , Friedman H
Published: January 2020

A number of investigators have provided experimental evidence for synergistic effects in mixed infections with Escherichia coli and Bacteroides fragilis. In vitro studies have suggested that competition for serum opsonins and diminished subsequent phagocytosis by polymorphonuclear leukocytes might explain these effects. In the present study we evaluated the effect of B. fragilis on macrophage phagocytosis. It was shown that peritoneal macrophages from mice injected intravenously 6 to 12 h earlier with 10(8) CFU of encapsulated B. fragilis were markedly suppressed in their phagocytic ability. Injections of laboratory-passaged, less-encapsulated B. fragilis, other bacteria, or latex particles were either not suppressive of macrophage phagocytosis or less effective. When peritoneal macrophages were treated in vitro for 24 h with the same challenge organisms prior to assessing their phagocytic capacity, encapsulated B. fragilis also proved significantly more suppressive than challenges with other organisms or latex particles. We conclude that suppression of macrophage phagocytosis by B. fragilis seems to be an important mechanism contributing to synergistic effects described for mixed aerobic and anaerobic infections.
Opsonic requirements for hepatic clearance of pneumococci
Authors: Reed W P , Albright E L
Published: January 2020

An in situ isolated, perfused rat liver system was used to evaluate various opsonins for hepatic trapping and killing of encapsulated, virulent, type 3 pneumococci. Pneumococci were rapidly trapped in the liver in the presence of all potential opsonins including Hanks balanced salt solution with added colloid. However, with some of the potential opsonins the organisms remained viable and could be recovered from the liver. With others there was killing of pneumococci. The combination of rat antibody and complement was effective as an opsonin and produced about the same degree of killing as the same human components. When tested separately killing was not promoted by rat complement, human complement, or human antibody. However, when ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid-Mg2+ was added to block the classical pathway and preserve the alternative pathway there was significant pneumococcal killing which may have been complement mediated or due to an adverse effect of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid-Mg2+ on the organisms. Fibronectin and C-reactive protein reduced the number of surviving microorganisms, although the change was not significant. Immunoglobulin G (IgG)-IgM, IgG, or IgM with complement, and antibody + the classical complement pathway, significantly reduced survival of the organisms. The best killing occurred with antibody plus complement plus fibronectin, which reduced mean survival to 24% during the 1-h perfusion.
Recombination near the antibiotic resistance locus penB results in antigenic variation of gonococcal outer membrane protein I
Authors: Danielsson D , Faruki H , Dyer D , Sparling P F
Published: January 2020

In gonococci, the nonspecific antimicrobial resistance locus penB is known to be closely linked to loci designated nmp that alter the Mr and antigenicity of the outer membrane porin protein I (P.I). We report that after selection for the linked donor penB locus, occasional recombinants expressed P.I with some epitopes from each parent. These hybrid P.I antigens were stable on subculture and were transformed at a locus closely linked to penB. The hybrid P.I antigens were detected with monoclonal antibodies in both coagglutination and Western blot assays. The alterations of P.I antigenicity may have resulted from recombination between structural genes for P.I that are closely linked to penB.
Variable colonization by oral streptococci in molar fissures of monoinfected gnotobiotic rats
Authors: van Houte J , Russo J
Published: January 2020

Germfree Sprague-Dawley rats, fed a high-sucrose diet, were monoinfected with strains of Streptococcus mitis, Streptococcus sanguis, and Streptococcus mutans. Viable cell recoveries from six molar teeth, considered to reflect mainly bacterial colonization of intact fissures, were in the order of 10(6), 10(7), and 10(8) CFU, respectively. Some of the implications of the variation of bacterial plaque-forming ability in the rat model are discussed.
Sensitization with Fusobacterium nucleatum targets antibody-dependent cellular cytotoxicity to mammalian cells
Authors: Lopatin D E , Blackburn E
Published: January 2020

Incubation of mammalian tumor cells with either soluble of insoluble fractions (10 to 100 micrograms/ml) of Fusobacterium nucleatum sensitizes them to the destructive activity of antibody-dependent cellular cytotoxicity (ADCC) effector cells in the presence of anti-F. nucleatum antisera. All three types of ADCC effector cells are capable of destroying F. nucleatum-sensitized target cells with varying degrees of effectiveness (lymphocytes much greater than monocytes greater than neutrophils). Hyperimmune rabbit anti-F. nucleatum antisera were active at a dilution as high as 1/100,000. Our studies indicated that F. nucleatum must be bound to the target cells since if either the effector cells are treated with F. nucleatum or F. nucleatum is directly to an ADCC reaction, there is no significant effect on cytotoxicity. The kinetics of F. nucleatum-targeted ADCC are identical to those of classical ADCC, suggesting a similar mechanism. The specificity of F. nucleatum-targeted ADCC was demonstrated by cold target inhibition studies and by showing that other antibacterial antisera were incapable of mediating the activity.
Local active gingival immunization by a 3,800-molecular-weight streptococcal antigen in protection against dental caries
Authors: Lehner T , Mehlert A , Caldwell J
Published: January 2020

Local gingival immunization was attempted in an effort to confine the immune response to the oral cavity and bypass the systemic immune response. A low-molecular-weight (3.8K) streptococcal antigen (SA) I/II was applied 10 times over a period of 1 year to the gingival crevices of rhesus monkeys. The antigen was maintained in situ by means of silicone rubber appliances. Serial examinations over a period of 1 year showed that topical gingival immunization with the 3.8K SA results in a significantly lower incidence of dental caries and colonization of Streptococcus mutans compared with that of the sham-immunized controls. This was associated with an increase in gingival crevicular immunoglobulin G and salivary immunoglobulin A anti-SA I/II antibodies, whereas no change occurred in serum antibodies to SA I/II. The immune mechanism which prevents the colonization of S. mutans and the development of caries may involve antibodies that prevent the adherence of S. mutans to the teeth and facilitate phagocytosis and killing by the local neutrophils. This novel route of local immunization is noninvasive, does not cause side effects, and bypasses systemic immunization.
Serum amyloid P-component-induced enhancement of macrophage listericidal activity
Authors: Singh P P , Gervais F , Skamene E , Mortensen R F
Published: January 2020

Purified serum amyloid P component (SAP), the major acute-phase reactant of mice, augmented the in vitro listericidal activity of inflammatory (elicited) macrophages, bone marrow-derived monocytes, and macrophages from a subcutaneous site of inflammation. Monocytes and macrophages from C57BL/B6 mice, which are relatively resistant to Listeria monocytogenes, exhibited a significantly greater enhanced killing capacity for listeria than macrophages from listeria-susceptible A/J mice. SAP did not alter the extent of phagocytosis by macrophages of opsonized L. monocytogenes, nor was SAP opsonic for listeria. Mannose-derived simple sugars inhibited the binding of SAP to macrophages and consequently prevented the enhanced SAP-dependent listericidal activity. Macrophages from lipopolysaccharide-hyporesponsive mice also had increased microbicidal activity following incubation with SAP. SAP activated macrophages independently of lymphokine. Therefore, SAP may serve as a mediator of the heightened nonspecific host defense response that is associated with the acute phase of the systemic inflammatory response.
Cutaneous infection in normal and immunocompromised mice
Authors: Kraft W G , Johnson P T , David B C , Morgan D R
Published: January 2020

Since a model of staphylococcal skin infection adequately reflecting human disease was unavailable, a self-limiting animal infection model specific for virulent Staphylococcus species was developed. A virulent strain of S. aureus, NCTC 9789 (ATCC 27700), was used to develop an infection model in adult, male CF-1 mice treated with 0 to 150 mg of cyclophosphamide (CY) per kg 4 days before challenge. Bacteria were inoculated onto the dorsal side of shaved mice at 0 to 10(6) CFU per mouse. Simultaneously, the skin was gently scraped to remove the superficial layers without drawing blood. The wound was occluded with impermeable film secured with surgical tape. At a CY dose of 50 mg/kg and an inoculum of 10(5) CFU, 89% of the mice (96 of 108) developed large abscesses (approximately 15-mm diameter). Mice which were not immunocompromised developed fewer abscesses (20 of 68). Generally, no abscesses formed when the mice were not wounded (1 of 62), occluded (0 of 89), or inoculated (11 of 50). The abscesses developed 24 to 48 h after challenge and persisted for 2 to 3 weeks. The challenge organism was isolated from the abscesses. The rates of abscess formation of three additional S. aureus strains varied widely in normal and CY-treated mice. Three strains of S. epidermidis, one of Micrococcus varians, and one of S. saprophyticus failed to cause abscesses. Bacterial proliferation studies demonstrated that a strain of S. aureus and a strain of S. epidermidis proliferated to the same levels 48 h after challenge. Immunosuppression and wounding had little effect on the levels of proliferation of S. aureus (P greater than 0.2). Without occlusion, however, S. aureus proliferated to significantly lower levels (P less than 0.005). This model may be be useful for screening topical anti-infective agents or studying the mechanisms of bacterial pathogenesis and host response.
Estimation of growth parameters for some oral bacteria grown in continuous culture under glucose-limiting conditions
Authors: Rogers A H , de Jong M H , Zilm P S , van der Hoeven J S
Published: January 2020

The coexistence of bacteria in natural environments can often be explained in terms of competition for a growth-limiting substrate(s), and the outcome of such competition depends upon relevant growth parameters such as substrate affinity and yield. Dental plaque bacteria are frequently carbon and energy limited. Growth parameters for seven oral Streptococcus species and one Actinomyces viscosus strain were estimated under glucose-limited conditions in continuous culture. In all strains, mixed-acid fermentation occurred at low growth rates, while amounts of lactate increased at higher growth rates. Two important growth parameters, mumax and Y glucose, were very similar in the two serotype c Streptococcus mutans strains (T8 and Ingbritt), one of the serotype d/g Streptococcus mutans strains (OMZ65), and the two Streptococcus milleri strains (699B3 and B448). Two other serotype d/g S. mutans strains (KIR and B13) were divergent from this group and had lower mumax values and a lower Y glucose. The maintenance energy coefficients were lower in the S. mutans serotype c strains, and the highest values were observed in the S. milleri strains. While A. viscosus had a lower mumax, its lower maintenance rate and significantly higher yield indicate that it deals much more efficiently with glucose than do the streptococci. The most striking feature of amino acid utilization was that arginine was completely consumed by S. milleri strains; similarly, A. viscosus used up all available asparagine as did one of the S. milleri strains at faster growth rates. It is suggested that the ability of strains of S. milleri and S. sanguis to utilize arginine in addition to carbohydrate as a source of energy may explain why such organisms increase in proportion in the plaque of subjects consuming diets almost devoid of fermentable carbohydrate.
Comparative analysis of infection and transformation of lymphocytes from African buffalo and Boran cattle with Theileria parva subsp. parva and T. parva subsp. lawrencei
Authors: Baldwin C L , Malu M N , Kinuthia S W , Conrad P A , Grootenhuis J G
Published: January 2020

This study compared infection and transformation of peripheral blood mononuclear cells (PBM) of Boran cattle and African buffalo in vitro to determine whether differences occurred which could account for the greater susceptibility of Boran cattle to infection with Theileria parva subsp. parva and T. parva subsp. lawrencei. PBM from buffalo and cattle had a similar percentage of cells which bound T. parva subsp. parva sporozoites (24 to 34%) and in which schizonts developed during the first week after infection (18 to 23%). Using a limiting dilution culture system, it was established, however, that a significantly higher proportion of cattle PBM transformed into continuously replicating cell lines after infection with T. parva subsp. parva than did buffalo PBM. The evidence suggests that the low capacity of T. parva subsp. parva to establish infections in buffalo compared with cattle is related to the lower frequency of buffalo cells which undergo transformation. With T. parva subsp. lawrencei, however, the frequency of transformation of buffalo PBM was higher than that for cattle PBM. The frequency of cells transformed by T. parva subsp. lawrencei, therefore, cannot account for the greater resistance of buffalo to infections with T. parva subsp. lawrencei. Buffalo must have other mechanisms, either innate or acquired, which control infection with T. parva subsp. lawrencei more efficiently than in cattle.
Exocellular components of Paracoccidioides brasiliensis: identification of a specific antigen
Authors: Puccia R , Schenkman S , Gorin P A , Travassos L R
Published: January 2020

Yeast forms of Paracoccidioides brasiliensis grown in liquid medium produced exocellular components. Immunodiffusion reactions and immunoprecipitations of 131I-radiolabeled antigenic components with sera from patients having paracoccidioidomycosis (PCM) were used to monitor the isolation of specific constituents. Components having the main antigenic activity (fCon A) were isolated by exclusion from a Bio-Gel P30 column, followed by successive binding of eluted material to a Sepharose-concanavalin A column, and elution. The product contained, from sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, a minor 43,000-molecular-weight (MW) component (gp43), a polydisperse high-MW glycoconjugate, and a diffusely migrating 55,000-MW glycoprotein (gp55). Other components, including a 72,000-MW glycoprotein, were irregularly expressed. The high-MW glycoconjugate complex contained, on the basis of methylation and 13C nuclear magnetic resonance data, a branched structure of mainly mannopyranosyl units. These were nonreducing ends, 6-O-, 2-O-, and 2,6-di-O-substituted, and the specific rotation of +16 degrees indicated that the glycosidic configurations of the units were alpha and beta in a ratio of ca. 1:1 (concanavalin A binding indicated that nonreducing ends or 2-O-substituted units or both of alpha-D-mannopyranose were present). A small proportion of nonreducing end units of D-galactopyranose were also present in this polysaccharide. gp55 is a glycoprotein containing a complex carbohydrate moiety with fucose, mannose, galactose, and glucose, either as terminal nonreducing units or substituted in positions indicated by methylation data. Both PCM and normal human sera precipitated the high-MW glycoconjugate from 131I-labeled fCon A preparations, whereas gp55 was unreactive with human sera. gp43 was a specific antigenic component of P. brasiliensis culture filtrates which could be isolated in a pure form by gel filtration column chromatography (Sephadex G150) or by Sepharose-patient immunoglobulin G affinity chromatography. 131I-labeled gp43 reacted equally well with 10 PCM sera and hyperimmune rabbit serum against the band E antigen of Yarzabal at a 10(-3) dilution. At the same dilution, no reaction was detected with sera from normal individuals and from patients with other mycoses. Similarly, only PCM sera and the hyperimmune anti-E serum gave precipitin lines with gp43 in the less sensitive immunodiffusion tests. gp43 consisted of three components, with pI 6.7, 6.4 and 6.2, all of which reacted with PCM serum.
Enhancement of Escherichia coli adherence to epithelial cells derived from estrogen-stimulated rats
Authors: Sobel J D , Kaye D
Published: January 2020

The effect of exogenous estrogen administered to male and oophorectomized female rats was investigated with regard to in vitro adherence of eight uropathogenic strains of Escherichia coli to exfoliated bladder and vaginal epithelial cells. Uroepithelial cells obtained from estrogenized male and estrogenized oophorectomized female rats and vaginal cells obtained from estrogenized oophorectomized female rats demonstrated significantly enhanced (P less than 0.005) host cell avidity for E. coli attachment, irrespective of bacterial adhesin expressed, when compared with such cells from nonestrogenized male and female oophorectomized rats. These animal studies suggest that female reproductive hormones may contribute to urinary-tract infection in premenopausal females by enhancing susceptibility to E. coli colonization of uroepithelial cells.
Composition of affinity-purified alpha-hemolysin of Escherichia coli
Authors: Bohach G A , Snyder I S
Published: January 2020

Escherichia coli alpha-hemolysin was purified from culture supernatants by affinity chromatography, using a hemolysis-neutralizing monoclonal antibody ligand. Purified hemolysin contains several proteins and lipopolysaccharides. Thus, alpha-hemolysin exists as a macromolecular complex and may be exported from E. coli cells by outer membrane fragmentation.
Adjuvant activity of 6-O-acyl-muramyldipeptides to enhance primary cellular and humoral immune responses in guinea pigs: adaptability to various vehicles and pyrogenicity
Authors: Tsujimoto M , Kotani S , Kinoshita F , Kanoh S , Shiba T , Kusumoto S
Published: January 2020

Thirteen 6-O-acyl-N-acetylmuramyl-L-alanyl-D-isoglutamines (6-O-acyl-MDPs), including four inactive D-isoasparagine and L-isoglutamine analogs, were tested for their pyrogenicity and immunopotentiating activity to stimulate primary humoral and cellular immune responses in guinea pigs to a model protein antigen, ovalbumin, when administered in various vehicles. Among them, derivatives whose muramic acid residue was substituted by alpha-branched (and beta-hydroxylated) higher fatty acids at the carbon-6 position, especially 6-O-(2-tetradecylhexadecanoyl)-MDP (B3O-MDP) and, to a lesser extent, 6-O-(3-hydroxy-2-docosylhexacosanoyl)-MDP (BH48-MDP) and its L-serine analog [BH48-MDP(L-Ser)], were found to exert strong adjuvant activity in both the induction of delayed-type hypersensitivity and the stimulation of circulating precipitating antibody levels when combined with nonirritating vehicles (liposomes, squalene-in-water emulsion, and phosphate-buffered saline). These vehicles did not efficiently support the adjuvant activity of MDP, the parent molecule of the above lipophilic derivatives. Pyrogenicity tests showed that introduction of alpha-branched higher fatty acid groups but not of straight, long-chain fatty acids at the 6-position of the muramic acid residue resulted in marked decrease of the pyrogenicity inherent to MDP via intravenous administration.
Differences in sensitivity of Schistosoma mansoni schistosomula, Dirofilaria immitis microfilariae, and Nematospiroides dubius third-stage larvae to damage by the polyamine oxidase-polyamine system
Authors: Ferrante A , Ljungstrom I , Rzepczyk C M , Morgan D M
Published: January 2020

The effect of the polyamine oxidase (PAO)-polyamine system on some helminths was examined in vitro. Both Schistosoma mansoni schistosomula and Dirofilaria immitis microfilariae were highly sensitive to this system, the latter more so than the former. In contrast, exsheathed third-stage larvae of Nematospiroides dubius were resistant to the effects of the PAO-polyamine system. After incubation of microfilariae with either spermine or spermidine in the presence of serum containing PAO (bovine serum or human retroplacental serum) or partially purified PAO, damage of worms occurred, compatible with our criteria for worm death. Similar results were obtained with schistosomula by using spermine. The damage seemed to be mediated by PAO products other than hydrogen peroxide because catalase did not protect either parasite. Our data demonstrate that helminths may be damaged by products of the PAO-polyamine system.
Late intraphagosomal hydrogen ion concentration favors the in vitro antimicrobial capacity of a 37-kilodalton cationic granule protein of human neutrophil granulocytes
Authors: Shafer W M , Martin L E , Spitznagel J K
Published: January 2020

We described previously (W.M. Shafer, L.E. Martin, and J.K. Spitznagel, Infect. Immun. 45:29-35, 1984) the presence of a 37-kilodalton cationic antimicrobial protein (37K CAP) in extracts of granules prepared from human polymorphonuclear granulocytes (PMN). In this investigation, we prepared 37K CAP from PMN granule extracts by sequential ion-exchange and molecular-sieve chromatography and examined its antimicrobial activity against a number of gram-negative and gram-positive bacteria. At concentrations of 5 micrograms/ml or lower, 37K CAP exerted selective antimicrobial activity against gram-negative bacteria. These bacteria included Acinetobacter lwoffii, Escherichia coli, Neisseria gonorrhoeae, Pseudomonas aeruginosa, Pseudomonas cepacia, Salmonella typhi, Salmonella typhimurium, and Shigella sonnei. However, at 5 micrograms of 37K CAP per ml, Proteus mirabilis, Proteus vulgaris, and Serratia marcescens resisted this antimicrobial activity. The bactericidal activity of 37K CAP was greatest in acidic (pH 5.5) as opposed to alkaline (pH 7.5) media. The level of S. typhimurium resistance to 37K CAP correlated with the presence of O antigen in the lipopolysaccharide. In the absence of O antigen repeat units, resistance was proportional to the length of the core oligosaccharide. These results suggest that 37K CAP may contribute significantly to the ability of PMN to kill gram-negative bacteria by nonoxidative means, particularly as the maturing phagolysosome becomes acidified.
Receptor-binding function of type 1 pili effects bladder colonization by a clinical isolate of Escherichia coli
Authors: Keith B R , Maurer L , Spears P A , Orndorff P E
Published: January 2020

The role of type 1 pili in promoting bladder colonization was examined by constructing two mutant strains of a clinical Escherichia coli isolate. One mutant was isogenic to the parental strain save for a lesion in a gene required for pilus receptor binding; the other mutant was isogenic save for a lesion in the gene encoding the pilus structural subunit. Using mixed infections of the parental and mutant strains in an ascending rat cystitis model, we found that type 1-piliated mutants that lacked the receptor-binding function were as ineffective in bladder colonization as were mutants lacking the entire organelle.
Effect of monophosphoryl lipid A on host resistance to bacterial infection
Authors: Chase J J , Kubey W , Dulek M H , Holmes C J , Salit M G , Pearson F C , Ribi E
Published: January 2020

The ability of monophosphoryl lipid A (MPLA) to enhance nonspecific host resistance to bacterial infections was studied. Mice were treated with MPLA prior to intraperitoneal challenge with Escherichia coli or Staphylococcus epidermidis. Animals received additional MPLA for 2 days postinfection, and survival rates were determined. Ten micrograms of MPLA per mouse significantly improved the survival of animals infected with either bacterial species. Dose-response studies showed significant MPLA-induced protection at doses of 6 micrograms/kg against E. coli challenge and 60 micrograms/kg against S. epidermidis challenge.
Interaction of a 60-kilodalton D-mannose-containing salivary glycoprotein with type 1 fimbriae of Escherichia coli
Authors: Babu J P , Abraham S N , Dabbous M K , Beachey E H
Published: January 2020

A 60-kilodalton glycoprotein previously isolated and purified from human saliva (J. B. Babu, E. H. Beachey, D. L. Hasty, and W. A. Simpson, Infect. Immun. 51: 405-413, 1986) was found to interact with type 1 fimbriae and prevent adhesion of type 1 fimbriated Escherichia coli to animal cells in a D-mannose-sensitive manner. Purified salivary glycoprotein agglutinated type 1 fimbriated E. coli and, at subagglutinating concentrations, blocked the ability of type 1 fimbriated E. coli to attach to human buccal epithelial cells or agglutinate guinea pig erythrocytes. Both interactions were inhibited by alpha-methyl-D-mannoside but not by alpha-methyl-D-glucoside. Complexing of the glycoprotein to type 1 fimbriae was demonstrated by molecular sieve chromatography and modified Western blots. When mixed with type 1 fimbriae, the radiolabeled salivary glycoprotein coeluted with type 1 fimbriae from a column of Sepharose 4B. When blotted from a sodium dodecyl sulfate gel to nitrocellulose sheets, the glycoprotein interacted directly with type 1 fimbriae applied to the blots. Both of the latter interactions also were blocked by alpha-methyl-D-mannoside but not by alpha-methyl-D-glucoside. Chemical modification of the glycoprotein with sodium metaperiodate abolished its ability to interact with isolated type 1 fimbriae or type 1 fimbriated E. coli. These results suggest that the carbohydrate moiety of the 60-kilodalton glycoprotein serves as a receptor for type 1 fimbriae in the oral cavity, and we postulate that the interaction may cause agglutination and early removal of E. coli, thereby preventing colonization by these organisms of oropharyngeal mucosae and dental tissues.