bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunosuppression associated with the development of chronic infections with Rickettsia tsutsugamushi: adherent suppressor cell activity and macrophage activation
Authors: Jerrells T R
Published: January 2020

Measures of general immunocompetency such as lymphocyte responses to mitogens and alloantigens and the ability to produce antibody to T-dependent and T-independent antigens were evaluated during the development of chronic infections with Rickettsia tsutsugamushi resulting from subcutaneous infection of BALB/c mice. It was found that a transient immunosuppression was demonstrable regardless of the infecting strain of rickettsiae; however, the immunosuppression produced by the Karp and Kato strains was more pronounced and longer lived. As a marked splenomegaly resulting from inflammatory macrophage influx accompanied this immunosuppression, mitogen- and antigen-induced lymphocyte proliferation was also evaluated after adherent cell depletion or in the presence of indomethacin, and both treatments significantly improved the responses. Isolated splenic macrophages were shown to suppress the responses of lymphocytes from naive mice as well as to exhibit parameters of activation including tumor cell cytolysis and cytostasis and the ability to inhibit the replication of R. tsutsugamushi in vitro. These data suggest an association between macrophage activation involved in rickettsial clearance and a transient immunosuppression.
Nucleotide sequences of four variants of the K88 gene of porcine enterotoxigenic Escherichia coli
Authors: Dykes C W , Halliday I J , Read M J , Hobden A N , Harford S
Published: January 2020

The nucleotide sequences of four variants of the Escherichia coli K88 antigen gene, K88ab1, K88ab2, K88ac, and K88ad, have been determined. The K88ab2 and K88ac sequences have not been reported previously. The K88ab1 sequence is very similar to that determined by other workers, but the K88ad sequence differs considerably from that described in a previous report. Comparison of the amino acid sequences inferred from the gene sequences revealed certain clusters of amino acid substitutions which have been correlated with areas of potential antigenicity in the mature proteins.
Mucosal antitoxin response in volunteers to immunization with a synthetic peptide of Escherichia coli heat-stable enterotoxin
Authors: Klipstein F A , Engert R F , Houghten R A
Published: January 2020

Peroral immunization of volunteers on four weekly occasions with 750 micrograms of a conjugate containing 3,000 antigen units of a synthetically produced peptide of hyperantigenic Escherichia coli heat-stable (ST) toxin, conjugated with the heat-labile toxin B subunit as a carrier, raised serum immunoglobulin G antitoxin titers to ST by fourfold and intestinal immunoglobulin A antitoxin titers to ST by sevenfold over control values at five weeks postimmunization. The ability of jejunal aspirates from the immunized volunteers to neutralize ST in the suckling mouse assay correlated with the intestinal immunoglobulin A ST antitoxin response determined by enzyme-linked immunosorbent assay.
Production and characterization of monoclonal antibodies against Clostridium perfringens type A enterotoxin
Authors: Wnek A P , Strouse R J , McClane B A
Published: January 2020

Hybridomas secreting monoclonal antibodies (MABs) specific for Clostridium perfringens type A enterotoxin were produced by fusion of P3X63Ag8.653 myeloma cells with spleen cells from BALB/c mice immunized with purified enterotoxin. Wells containing hybridomas secreting immunoglobulin G (IgG) antibodies against enterotoxin were specifically identified by an indirect enzyme-linked immunosorbent assay (ELISA), and 10 ELISA-positive hybridomas were selected and cloned twice by limiting dilution. All 10 hybridomas produced MABs containing immunoglobulin G1 heavy chains and kappa (kappa) light chains. These hybridomas were then grown as ascitic tumors in mice, and MABs were purified from the ascites fluids with DEAE Affi-gel blue. The specificity of the MABs for enterotoxin was demonstrated by immunoblotting and ELISA. Competitive radioimmunoassay with 125I-MABs suggests that these MABs recognized at least four epitopes on the enterotoxin molecule. The enterotoxin-neutralizing ability of MABs from both hybridoma culture supernatants and ascites fluids was assessed by using a 3H-nucleotide-release Vero (African green monkey kidney) cell assay. Only 2 of the 10 hybridomas produced MABs which completely (greater than 90%) neutralized the biologic activity of enterotoxin. Preincubation of 125I-enterotoxin with MABs demonstrated that MAB neutralizing ability correlated with MAB-specific inhibition of specific binding of enterotoxin to intestinal brush border membranes.
Monoclonal antibodies to enterobacterial common antigen and to Escherichia coli lipopolysaccharide outer core: demonstration of an antigenic determinant shared by enterobacterial common antigen and E. coli K5 capsular polysaccharide
Authors: Peters H , Jürs M , Jann B , Jann K , Timmis K N , Bitter-Suermann D
Published: January 2020

We established hybridoma cell lines producing monoclonal antibodies against enterobacterial common antigen (ECA) and a substructure of the outer core of different Escherichia coli lipopolysaccharides (LPSs). Anti-ECA antibodies 865 and 898 reacted with ECA in extracts of heated E. coli and with ECA-bound R1 and R4 core-containing LPS preparations, as well as with a purified sample of ECA from Salmonella montevideo. Antibody 865, but not antibody 898, cross-reacted with K5 capsular polysaccharide, suggesting that 4-linked alpha-N-acetylglucosamine is part of an antigenic determinant shared by both K5 polysaccharide and ECA. Anti-LPS antibody 786 recognized an outer core structure common to E. coli K-12, B, R2, and R4 core type LPS, but not to R1 and R3 core type LPS. Its most probable target is the trisaccharide sequence Hexp(1----2)-alpha-D -Glcp(1----3) alpha-D-Glcp----(Hepp) (where Hex is hexose, p is phosphate, Glc is glucose, and Hep is heptose), the first glucose being the immunodominant moiety. These monoclonal antibodies may be used not only for the detection of ECA, K5, and LPS core structures but also for analysis of the molecular forms resolved on polyacrylamide gels (banding patterns) of both ECA and LPS, independently of one another.
Pathogenicity of morphological and auxotrophic mutants of Candida albicans in experimental infections
Authors: Shepherd M G
Published: January 2020

The relative pathogenicities of yeast and mycelial forms of Candida albicans were determined after intravenous injection of the two forms into mice. Yeast and mycelial forms of C. albicans CMI45348 were prepared in chemostat culture. Both morphological forms were pathogenic, but the histology of kidney sections always showed a mixture of the yeast and mycelial elements of the organism. Similarly, infection of mice with prototrophic strains produced a mixture of morphological forms at the site of infection. The yeast (CA2) and mycelial (hOG301) morphological mutants of C. albicans were pathogenic, and sections from the kidneys of the infected mice showed that the mutants retained their original morphological forms. These data indicate that both the yeast and mycelial forms of C. albicans can adhere, invade, and proliferate in an infected host. Auxotrophic diploid mutants were nonpathogenic. However, construction of a prototrophic tetraploid strain from two auxotrophs restored the pathogenicity of the organism.
Mycobacterium bovis BCG vaccine fails to protect protein-deficient guinea pigs against respiratory challenge with virulent Mycobacterium tuberculosis
Authors: McMurray D N , Carlomagno M A , Mintzer C L , Tetzlaff C L
Published: January 2020

Specific-pathogen-free Hartley guinea pigs were maintained on isocaloric-purified diets either adequate (30%) or moderately deficient (10%) in protein. Half of each diet group was vaccinated with viable Mycobacterium bovis BCG. Six weeks later, all animals were challenged by the respiratory route with virulent Mycobacterium tuberculosis H37Rv. At intervals of 1, 2, and 3 weeks postchallenge, guinea pigs from each diet and vaccination group were skin tested with tuberculin and sacrificed. Protein deficiency resulted in loss of tuberculin hypersensitivity. Vaccination with M. bovis BCG protected control animals, as determined by significant reductions in the number of M. tuberculosis H37Rv organisms recovered from lungs, spleen, and bronchotracheal lymph nodes 2 and 3 weeks postchallenge. Based upon the same criteria, the degree of protection afforded protein-deficient animals by M. bovis BCG vaccine ranged from partial (spleen and lymph nodes) to none at all (lungs). Approximately the same numbers of tubercle bacilli were recovered from nonvaccinated guinea pigs in both diet groups. Protein deficiency appears to impair M. bovis BCG-induced immunity while not affecting primary pulmonary infection with virulent M. tuberculosis.
Characterization of monoclonal antibodies against Shiga-like toxin from Escherichia coli
Authors: Strockbine N A , Marques L R , Holmes R K , O'Brien A D
Published: January 2020

Three monoclonal antibodies, designated MAb 16E6, MAb 13C4, and MAb 19G8, were produced which recognize Shiga-like toxin (SLT) from Escherichia coli. All three monoclonal antibodies neutralized the cytotoxicity of E. coli SLT and were able to immunoprecipitate intact labeled toxin with Staphylococcus aureus protein A. The three antibodies were of the G1 heavy and kappa light chain classes. MAb 16E6 bound to the B subunit of SLT in Western blots and also neutralized the lethality of the toxin for mice and the enterotoxicity of the toxin in ligate rabbit ileal loops. The ability of MAb 16E6 to neutralize the cytotoxicity, lethality, and enterotoxicity of E. coli confirms the hypothesis that all three activities are associated with a single toxin. MAb 16E6 and MAb 13C4 also neutralized the cytotoxicity of purified Shiga toxin from Shigella dysenteriae type 1 and Shiga-like toxic activities in crude cell extracts from Shigella flexneri, Vibrio cholerae, Vibrio parahaemolyticus, and Salmonella typhimurium. Thus, Shiga toxin and the SLTs from E. coli, Shigella flexneri, V. cholerae, V. parahaemolyticus, and Salmonella typhimurium share a common B subunit epitope that is involved in neutralization. MAb 13C4 has been successfully used in a colony blot assay for the detection of bacterial colonies which produce high levels of SLT. Sixty-two different strains of bacteria were tested by both the cytotoxicity and colony blot assays for the presence of SLT. The colony blot assay detected all strains of bacteria which produce greater than or equal to 10(5) 50% cytotoxic doses of SLT per ml of sonic lysate. There were no false-positive results among the 62 samples tested.
Local passive immunization by monoclonal antibodies against streptococcal antigen I/II in the prevention of dental caries
Authors: Lehner T , Caldwell J , Smith R
Published: January 2020

Local passive immunization with monoclonal antibodies (Mc Ab) to Streptococcus mutans was attempted as an alternative approach to active systemic immunization. We prepared an immunoglobulin G class Mc Ab to the cell surface protein determinant of streptococcal antigen I/II and applied it repeatedly to the teeth of rhesus monkeys. This resulted in decreased colonization by S. mutans in fissures and smooth surfaces of teeth and no dental caries, unlike the results in control animals, which developed caries and showed a high proportion of S. mutans on their teeth. There was no significant difference in serum, salivary, or gingival fluid antibodies to S. mutans between the two groups of animals. Any objections raised over systemic immunization inducing cross-reactive antibodies are therefore overcome by local passive immunization. The mechanism of prevention of colonization has not been established, but we postulate that the Mc Ab which is directed against an important cell surface antigenic determinant of S. mutans (streptococcal antigen I/II) prevents adherence of S. mutans to the acquired pellicle on the tooth surface. S. mutans reacts with the Mc Ab and becomes opsonized, phagocytosed, and killed by the local gingival traffic of neutrophils.
Enhancement of growth of aerobic and facultative bacteria in mixed infections with Bacteroides species
Authors: Brook I
Published: January 2020

The potential for mutual enhancement of growth of the Bacteroides fragilis and B. melaninogenicus groups and the aerobic and facultative organisms commonly isolated with them in mixed infections was evaluated. Enhancement was studied by measuring the relative increase in CFU of the two bacterial components inducing subcutaneous abscesses in mice. Of the 42 combinations between three isolates each of the B. fragilis and B. melaninogenicus groups and seven aerobic or facultative organisms, Bacteroides spp. were enhanced in only 8 and inhibited in 4. The aerobic and facultative bacteria were enhanced in 31 of the 42 combinations and depressed in 2. The organisms uniformly enhanced by all of the Bacteroides spp. were group A streptococci and Escherichia coli (all six instances), followed by Staphylococcus aureus and Klebsiella pneumoniae (five of six instances), Pseudomonas aeruginosa (four instances), group D streptococci (in three instances only by the B. fragilis group), and Haemophilus influenzae (one instance). It is apparent that the growth rate of facultative and aerobic bacteria is enhanced much more in mixed infections with Bacteroides spp. than that of their anaerobic counterparts.
Effect of ciliostatic factors from Pseudomonas aeruginosa on rabbit respiratory cilia
Authors: Hingley S T , Hastie A T , Kueppers F , Higgins M L , Weinbaum G , Shryock T
Published: January 2020

Heat-stable factors released by Pseudomonas aeruginosa in culture supernatants inhibit functional cilia of rabbit tracheal epithelium. Chloroform extraction removed heat-stable factors from stationary-phase culture supernatants. The extracts contained at least seven components separable by thin-layer chromatography (TLC). Cilioinhibitory components were identified as a phenazine derivative, pyo compounds (2-alkyl-4-hydroxyquinolines), and a rhamnolipid, also known as a hemolysin. Fluorescence and absorption spectra, relative migration on TLC, staining characteristics, and gas chromatography were the basis for identification. Inhibitory concentrations of each active component were established by quantitative measures of percent motility and beat frequency. Corresponding damage to ciliary ultrastructure was examined by electron microscopy. The pyo compounds produced ciliostasis at concentrations of 50 micrograms/ml, but without obvious ultrastructural lesions. The phenazine derivative also inhibited ciliary motility and caused some membrane disruption, although at substantially greater concentrations of 400 micrograms/ml. Limited exposure of tracheal explants to the rhamnolipid resulted in ciliostasis which was associated with altered ciliary membranes. More extensive exposure to rhamnolipid was associated with removal of dynein arms from axonemes. Pyocyanin at a concentration of 0.5 mg/ml did not inhibit ciliary beating under our conditions. The data suggest that the pyo compounds are the most effective per weight ciliostatic factors released by P. aeruginosa and rhamnolipid is the most destructive of cilia ultrastructure. By interfering with normal ciliary function, these ciliostatic factors may enable P. aeruginosa to more easily colonize the respiratory tract.
Relationship of critical micelle concentrations of bacterial lipoteichoic acids to biological activities
Authors: Courtney H S , Simpson W A , Beachey E H
Published: January 2020

The critical micelle concentration (CMC) of lipoteichoic acid (LTA) was investigated with two dyes, rhodamine 6G and Coomassie brilliant blue R-250. Both dyes gave similar values for the CMC of LTA. The CMC of LTA from several species of bacteria ranged from 28 to 60 micrograms/ml in phosphate-buffered saline. The CMC values for the LTAs are in the range expected for an amphiphile containing a single, 16-carbon fatty acid residue. Formation of micelles was not detected with deacylated LTA. Salt decreased the CMC of LTA from 380 micrograms/ml in distilled water to 37 micrograms/ml in 0.5 M NaCl. At concentrations greater than the CMC, LTA induced the lysis of sheep erythrocytes and was cytotoxic for Girardi heart cells. The data suggest that LTA in the micellar state may cause disruption of the erythrocyte membrane and may be cytotoxic for cells in culture.
Influence of source and quantity of protein on the development of immunity and resistance to African trypanosomiasis
Authors: Norton J D , Yang S P , Diffley P
Published: January 2020

Although it is well documented that severe protein deprivation inhibits the development of the immune response and exacerbates certain infections, little has been done to study the effects of native diets on endemic diseases or immunity. Therefore, protein-restricted diets were formulated for mice to mimic the sources and amounts measured in human diets of the Batouri region of Cameroon, endemic for African trypanosomiasis. Weanling C57BL/6 female mice were fed a diet that contained 73% of the recommended daily allowance (RDA) of protein. The sources of protein were all plant (cornmeal), all animal (casein), or a ratio that reflected the native diet (2.2 parts plant to 1 part animal protein). Diets were isocaloric on a weight basis, equal in lipids, and adequate in vitamins and minerals. Control mice were fed laboratory chow or two times the RDA of animal protein (casein). Mice fed only cornmeal or the native diets consumed as much food but did not gain as much weight as mice fed only animal protein, indicating the poorer quality of protein in their diets. Upon infection with Trypanosoma brucei gambiense, however, significantly higher numbers of these mice controlled the first peak of parasitemia and survived the infection as compared with mice fed the other three diets. Since all mice developed patent infections and the parasite growth rate was unaffected by diet, innate immune factors were ruled out as the cause for the higher level of resistance to the parasite. To determine whether diet affected the development of the immune system, weanling mice were maintained on diets for 30 days before immunization with sheep erythrocytes or trinitrophenylated Ficoll. Mice fed only plant protein or native diets elicited higher direct plaque-forming-cell responses to both the T-cell-dependent and T-cell-independent antigens. Since variant-specific immunity which controls levels of African trypanosomes in the blood is a T-cell-independent humoral immunoglobulin M response, this suggests that cornmeal, a protein of poor quality, was adequate for the development of humoral immunity and resistance to African trypanosomiasis while casein, an animal protein of high quality, was not. This provides more evidence that diet plays an important role in infection and immunity.
Correlation of natural killer cell activity and clearance of Cryptococcus neoformans from mice after adoptive transfer of splenic nylon wool-nonadherent cells
Authors: Hidore M R , Murphy J W
Published: January 2020

Previous reports demonstrate that natural killer (NK) cells inhibit the growth of Cryptococcus neoformans in vitro, but conclusive evidence supporting the effectiveness of NK cells in host resistance to cryptococci is not available. The objective of these studies was to assess the ability of NK cells to clear C. neoformans from the lungs, livers, and spleens of infected mice. CBA/J mice were depleted of NK cells, as well as other natural effector cells, by an intraperitoneal injection of cyclophosphamide (Cy), 240 mg/kg of body weight. One day later, 7.5 X 10(7) nylon wool-nonadherent (NWN) spleen cells, either untreated or treated with anti-asialo GM1 and complement to remove NK cells, were adoptively transferred to Cy-pretreated mice. On day 2 after Cy treatment, the mice were injected intravenously with 2 X 10(4) cryptococci. At 4 and 6 days after Cy treatment, tissues were assayed for NK reactivity, using a 4-h 51Cr-release assay, and for in vivo clearance of cryptococci as reflected by mean log10 CFU per organ. We observed that Cy treatment depleted NK activity against YAC-1 targets and reduced in vivo clearance of C. neoformans from the tissues of infected mice. Additionally, Cy treatment depleted the total lung and spleen cellularity and the total number of peripheral blood lymphocytes when compared with those in normal untreated control mice. Also, spleen weights were significantly decreased in comparison with those of untreated animals 4 days after Cy treatment. Adoptive transfer of untreated NWN spleen cells into Cy-depressed mice restored the NK cell activity which correlated with enhanced clearance of cryptococci from lungs, livers, and spleens. In contrast, treatment of NWN spleen cells with anti-asialo GM1 and complement before adoptive transfer abrogated the ability of these cells to restore NK activity or reduce the numbers of cryptococci present in tissues of infected mice. Taken together, these data indicate that NK cells are the cells effective in diminishing the numbers of cryptococci in tissues of infected mice. Consequently, NK cells may play a role in first-line host resistance against C. neoformans.
Description and characterization of a surface lectin from Giardia lamblia
Authors: Farthing M J , Pereira M E , Keusch G T
Published: January 2020

The mechanisms by which the human enteric pathogen Giardia lamblia colonizes the proximal small intestine are poorly understood. Although the parasite possesses an attachment organelle on its ventral surface, the "sucking" disk, we considered that like many bacteria and some protozoa, G. lamblia might also have a surface membrane-associated modality for adherence to its host. Using an erythrocyte mixed-agglutination model, we demonstrated a parasite surface lectin with specificities for D-glucosyl and D-mannosyl residues. This lectin is soluble in Triton X-100, is calcium dependent, and is maximally active at pH 5.5 to 6.0. Partial purification was achieved by serial extraction of parasites in Triton X-100 followed by Sephadex G-150 affinity chromatography. The lectin could not be surface radiolabeled with 125I-Bolton-Hunter reagent, but radiolabeling of the hapten eluate from an affinity column produced four bands of 57,000 to 78,000 Mr on sodium dodecyl sulfate-polyacrylamide gels under reducing conditions. The biological function of this lectin is unknown. The presence of mannosyl residues on the luminal surface of human small intestinal epithelial cells suggests that there are receptors for Giardia lectin at the site of colonization.
Immunochemical and biochemical analysis of the polyvalent Pseudomonas aeruginosa vaccine PEV
Authors: MacIntyre S , McVeigh T , Owen P
Published: January 2020

The Pseudomonas aeruginosa polyvalent vaccine PEV and its 16 constituent monovalent extracts from International Antigenic Typing System serotypes 1 through 13 and 15 through 17 (J. J. Miler, J. F. Spilsbury, R. J. Jones, E. A. Roe, and E. J. L. Lowbury, J. Med. Microbiol. 10:19-27, 1977) were subjected to biochemical analysis and to detailed immunochemical analysis with rabbit anti-PEV immunoglobulins. The results of chemical analysis, of analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis performed in conjunction with silver staining, and of analysis by crossed immunoelectrophoresis, sodium dodecyl sulfate-polyacrylamide gel-crossed immunoelectrophoresis, and Western blotting showed clearly that lipopolysaccharide was a major constituent of each monovalent extract and that it was probably the dominant antigen present in at least 15 of the 16 monovalent extracts. A 16.2-kilodalton protein, which was pronase resistant and nonsedimentable at 105,000 X g and which appeared to be biochemically and antigenically unrelated to pili, was a common although minor antigen for all extracts. Several other proteins, some of outer membrane origin, were also detected in unformalinized extracts, but these were also minor antigenic constituents of the vaccine. Neither pilin nor flagellin appeared to be major protein constituents of tested monovalent extracts, although anti-flagella antibodies could be demonstrated in rabbit anti-PEV by Western blotting. Preliminary analysis by crossed immunoelectrophoresis of serum raised in volunteers to PEV also indicated the presence therein of antibodies to lipopolysaccharide antigens.
Antigenic determinants of the attachment protein of Mycoplasma pneumoniae shared by other pathogenic Mycoplasma species
Authors: Clyde W A , Hu P C
Published: January 2020

In previous studies with hyperimmune rabbit antisera, we found evidence of serologic cross-reactivity among Mycoplasma pneumoniae, Mycoplasma genitalium, and Mycoplasma gallisepticum. Because of certain biologic and morphologic similarities of these species, attempts were made to determine if this cross-reactivity related to the attachment protein (P1) of M. pneumoniae. Monoclonal and monospecific antibodies against P1 were used to probe proteins of the other species by immunoblotting. One of the P1 monoclonal antibodies was reactive with a smaller protein of M. genitalium; rabbit antiserum raised by immunization with P1 excised from a sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel was found to react with a similar-sized protein of M. gallisepticum. These preliminary findings suggest antigenic sharing among the species examined; however, limitations of the methods used are discussed.
Inhibition of neutrophil killing of Candida albicans pseudohyphae by substances which quench hypochlorous acid and chloramines
Authors: Wagner D K , Collins-Lech C , Sohnle P G
Published: January 2020

Using a microtiter plate killing assay, we investigated the in vitro killing of Candida albicans by human neutrophils and by hypochlorous acid/hypochlorite ion (HOCl/OCl-) or chloramine solutions to evaluate the inhibition of this process by quenchers of these oxidants. Methionine, tryptophan, and alanine were able to effectively inhibit neutrophil killing of candida pseudohyphae. These substances were capable of quenching the oxidant activity of NaOCl, monochloramine (NH2Cl), and to a lesser extent, taurine chloramine. NaOCl and NH2Cl were able to kill C. albicans in the absence of inhibitors in concentrations of less than 5 microns M, whereas greater than 100 microns M taurine chloramine was required for killing. Methionine and tryptophan were capable of markedly inhibiting killing by all three oxidants, whereas alanine affected only killing by NaOCl. The oxidant activity of NaOCl was more readily quenched by opsonized or unopsonized Candida yeast than was the oxidant activity of either NH2Cl or taurine chloramine. These results suggest that some substances which quench the oxidizing activity of the products of the neutrophil myeloperoxidase system can inhibit the killing of C. albicans by these cells.
Inhibition of a penetration-enhancing factor of Toxoplasma gondii by monoclonal antibodies specific for rhoptries
Authors: Schwartzman J D
Published: January 2020

The anterior organelles of the coccidian parasite Toxoplasma gondii have long been suspected of playing a role in the ability of this organism to actively penetrate a wide range of host cells. A series of four monoclonal antibodies (produced by spleen cells from mice immunized with whole, killed T. gondii fused with Sp 2/0-Ag14 myeloma cells) recognized anterior organelles of T. gondii in indirect immunofluorescence assays. These antibodies (Tg 13, Tg 31, Tg 49, and Tg 112) were of the immunoglobulin G (IgG) class, had different enzyme-linked immunosorbent assay titers, and partially competed with each other in a solid-phase immunoassay with whole, dried T. gondii as the antigen. It was observed by immunofluorescence that all antibodies detected anterior structures, which under some conditions of fixation and extraction appeared to be multiple rodlike organelles resembling rhoptries. As determined by ultrastructure immunocytology, Tg 49 recognized electron-dense bodies consistent with rhoptries or micronemes in parasites that had been fixed in 2% paraformaldehyde and extracted with Triton X-100 to allow antibody penetration. An assay of penetration enhancement, in which conditioned medium (from fibroblast monolayers completely lysed by T. gondii) increased the number of plaques produced by a standard inoculum of T. gondii on fresh monolayers, was inhibited by equal amounts of all four monoclonal antibodies, in degrees closely related to their enzyme-linked immunosorbent assay titers. These antibodies appeared to link a penetration-enhancing factor with the rhoptries of T. gondii.
Pseudomonas aeruginosa immunotype 5 polysaccharide-toxin A conjugate vaccine
Authors: Cryz S J , Furer E , Sadoff J C , Germanier R
Published: January 2020

Polysaccharide (PS) derived from Pseudomonas aeruginosa immunotype 5 lipopolysaccharide was covalently coupled to toxin A by reductive amination with adipic acid dihydrazide as a spacer molecule. The resulting PS-toxin A conjugate was composed of 27.5% PS and 72.5% toxin A. The conjugate was composed of heterogeneous high-molecular-weight species, all of which possessed an Mr greater than 670,000. The conjugate was nontoxic for mice and nonpyrogenic at a dose of 50 micrograms/kg of body weight when intravenously administered to rabbits. Immunization of rabbits with the conjugate evoked both an antilipopolysaccharide immunoglobulin G (IgG) and an anti-toxin A IgG response. Anticonjugate IgG was capable of neutralizing the cytotoxic effect of toxin A. Immunization of mice with the conjugate increased the mean lethal dose from 4.5 X 10(1) P. aeruginosa for control mice to 9.6 X 10(5) P. aeruginosa for vaccinated mice. Similarly, immunization raised the mean lethal dose for toxin A from 0.2 to 4.67 micrograms per mouse.
Ontogeny of macrophage function to release superoxide anion in conventional and germfree mice
Authors: Mitsuyama M , Ohara R , Amako K , Nomoto K , Yokokura T , Nomoto K
Published: January 2020

To determine whether the presence of bacterial flora contributes to the ontogenic development of macrophage function, the ability of macrophages to release superoxide anion (O2-) in response to stimulation with phorbol myristate acetate was compared in conventional and germfree mice of various ages after birth. One-week-old conventional mice showed a very low level of O2- release by their macrophages, and gradual increases were observed in 2-, 3-, and 4-week-old mice in an age-dependent manner. Macrophages from germfree mice always showed a significantly lower level of O2- release compared with conventional mice of the same age; however, age-dependent functional development was seen also in the germfree group. The poor level of O2- release by macrophages from adult germfree mice could be restored to more than the level by conventional mice when the mice were conventionalized for 3 weeks. These results suggested that the ontogenic development of macrophage function is not controlled by the presence of bacterial flora but that the full-scale expression of function at each age is under the influence of microflora.
Immunization studies with attenuated strains of Bacillus anthracis
Authors: Ivins B E , Ezzell J W , Jemski J , Hedlund K W , Ristroph J D , Leppla S H
Published: January 2020

Live, attenuated strains of Bacillus anthracis lacking either the capsule plasmid pXO2, the toxin plasmid pXO1, or both were tested for their efficacy as vaccines against intravenous challenge with anthrax toxin in Fischer 344 rats and against aerosol or intramuscular challenge with virulent anthrax spores in Hartley guinea pigs. Animals immunized with toxigenic, nonencapsulated (pXO1+, pXO2-) strains survived toxin and spore challenge and demonstrated postimmunization antibody titers to the three components of anthrax toxin (protective antigen, lethal factor, and edema factor). Immunization with two nontoxigenic, encapsulated (pXO1-, pXO2+), Pasteur vaccine strains neither provided protection nor elicited titers to any of the toxin components. Therefore, to immunize successfully against anthrax toxin or spore challenge, attenuated, live strains of B. anthracis must produce the toxin components specified by the pXO1 plasmid.
In vivo degradation of bacterial cell wall by the muralytic enzyme mutanolysin
Authors: Janusz M J , Esser R E , Schwab J H
Published: January 2020

The muralytic enzyme mutanolysin can act in vivo to eliminate chronic erosive arthritis induced in rats by polymers of peptidoglycan-polysaccharide isolated from group A streptococci (PG-APS). The amounts of PG-APS in the livers and spleens of rats treated with mutanolysin were significantly reduced compared with the amounts in control rats treated with phosphate-buffered saline. However, the amounts of PG-APS in the limbs of mutanolysin- and phosphate-buffered saline-treated rats were comparable. PG-APS polymers extracted from the livers, spleens, and limbs of mutanolysin-treated rats were extensively degraded, whereas PG-APS extracted from phosphate-buffered saline-treated rats had a high molecular weight. We propose that mutanolysin abrogates arthritis in rats by degrading PG-APS polymers to a size which is no longer able to induce chronic erosive arthritis, even though the polymers are still present in the limbs.
Opsonization of Listeria monocytogenes type 4b by human adult and newborn sera
Authors: Bortolussi R , Issekutz A , Faulkner G
Published: January 2020

We studied the requirements for opsonization of Listeria monocytogenes type 4b with chemiluminescence and bactericidal assays and electron microscopy. Preopsonization with 3% adult serum had good opsonic activity (27,300 +/- 11,000 [standard deviation] counts, chemiluminescence assay), while 3% newborn cord serum was not opsonically active (820 +/- 530 counts, P less than 0.001 versus adult serum). In addition, organisms opsonized with cord serum were not killed (0% bacterial killing) and were less frequently visualized intracellularly on electron micrographs (0 to 4 bacteria per cell) than organisms opsonized with adult serum (70% killing and 10 to 20 bacteria per cell). Opsonic requirements for L. monocytogenes type 4b at low concentrations of serum were studied in detail with Sepharose-protein A-treated adult serum to obtain immunoglobulin G (IgG) and IgM fractions and zymosan-absorbed and C4 inactivator-treated serum to obtain alternative and classical complement pathway-deficient sera, respectively. In the presence of complement, IgM was opsonically active (59% of control) while IgG was not (6% of control). In addition, classical complement activity was required for efficient opsonization (greater than 100% of control) while the alternative complement pathway was unnecessary (3% of control). Since IgM is absent and classical complement activity is low in neonatal serum and at the common sites of neonatal Listeria infection, the requirement for IgM and classical complement activity for efficient opsonization of L. monocytogenes type 4b at low serum concentrations may be a factor in the pathogenesis of neonatal disease.
Lack of biological significance of in vitro Brugia malayi microfilarial cytotoxicity mediated by Propionibacterium acnes ("Corynebacterium parvum")-and Mycobacterium bovis BCG-activated macrophages
Authors: Fanning M M , Kazura J W
Published: January 2020

The effect of nonspecific activation of host macrophages by Propionibacterium acnes ("Corynebacterium parvum") or Mycobacterium bovis BCG on Brugia malayi microfilariae was determined by in vitro and in vivo studies. Intraperitoneal injection of C. parvum or BCG stimulated peritoneal exudate cells, which were toxic to microfilariae. Microfilariae were equally susceptible to damage by C57BL/6J or BALB/cJ peritoneal exudate cells. Furthermore, inhibitors of oxidative metabolism and arginine supplementation did not prevent this toxicity, suggesting that the mechanism of microfilarial damage differs from that seen with another multicellular helminth, Schistosoma mansoni. In vivo studies with both BCG and C parvum, however, did not confirm the importance of nonspecific immunity in resistance to B. malayi microfilaremia. Despite the lack of biologic relevance of this phenomenon, in vitro studies may yield important knowledge about the mechanisms of microfilarial damage.
Low endotoxic activities of synthetic Salmonella-type lipid A with an additional acyloxyacyl group on the 2-amino group of beta (1-6) glucosamine disaccharide 1,4'-bisphosphate
Authors: Kotani S , Takada H , Takahashi I , Tsujimoto M , Ogawa T , Ikeda T , Harada K , Okamura H , Tamura T , Tanaka S
Published: January 2020

A synthetic lipid A (Salmonella type, compound 516), beta (1-6)-linked D-glucosamine disaccharide 1,4'-bisphosphate, with three acyloxyacyl groups and one hydroxyacyl group, i.e., (R)-3-hexadecanoyloxytetradecanoyl, (R)-3-hydroxytetradecanoyl, (R)-3-dodecanoyloxytetradecanoyl, and (R)-3-tetradecanoyloxytetradecanoyl groups at the 2-amino, 3-hydroxyl, 2'-amino, and 3'-hydroxyl groups, respectively, was less biologically active than the synthetic Escherichia coli-type lipid A (compound 506), which has only two acyloxyacyl groups at the 2' and 3' positions and is substituted with a (R)-3-hydroxytetradecanoyl group at the 2-amino group. Compound 516 exhibited considerably weaker pyrogenic and leukopenic activity than compound 506, and it scarcely prepared rabbit skin for the Shwartzman reaction and lacked lethal toxicity on chicken embryos, although its lethal toxicity in galactosamine-loaded mice was as strong as that of compound 506. Compound 516 was also less active than compound 506 or natural E. coli lipid A (from Restrain F515) in other biological test systems, such as the Limulus test, stimulation of macrophages and lymphocytes, and interferon-inducing activity but not for interleukin-1 induction or complement activation. This observation suggests that there is an optimal number of acyloxyacyl groups on the glucosamine backbone for producing the biological activities of lipid A, especially the endotoxic activities. The 4'-monophosphate analog (compound 514) of compound 516 in general had significantly weaker activity than compound 516 in the above assays, most probably because of its greater hydrophobicity and consequently lower solubility in assay systems. Bacterial R595 lipid A derived from S. minnesota Re-mutant, which is a mixture of compounds 516 and 506, their 4'-monophosphate analogs and other compounds, exerted intermediate degrees of activity between compounds 506 and 516 in the various test systems employed.
Black-pigmented Bacteroides spp. in human apical periodontitis
Authors: Haapasalo M , Ranta H , Ranta K , Shah H
Published: January 2020

The incidence of black-pigmented (BP) Bacteroides spp. in 62 human dental root canal infections (35 acute and 27 clinically asymptomatic cases of apical periodontitis) in 57 adults was studied. Altogether 37 strains of BP Bacteroides were found in 31 infections, always in mixed anaerobic infections. Two different BP Bacteroides species were present in six infections. B. intermedius was most frequently isolated (15 of 62 canals; 24%) followed by B. denticola which was present in 12 cases. Asaccharolytic BP Bacteroides species, B. gingivalis and B. endodontalis, were found in eight cases. BP Bacteroides species were found both from symptomatic and asymptomatic infections, but there were also several symptomatic cases from which BP Bacteroides species were not isolated. B. gingivalis and B. endodontalis were present only in acute infections, B. intermedius was found both in symptomatic and asymptomatic infections, and B. denticola occurred mostly in asymptomatic infections. BP Bacteroides species were isolated initially from 9 of the 11 teeth with symptoms at 1 week, but only from 22 of the 51 teeth that were symptomless at 1 week. Two strains of B. denticola were resistant to penicillin G at a concentration of 2.4 micrograms/ml, but the MIC of penicillin G for all other strains was 0.6 micrograms/ml or lower. Forty-two randomly selected patients received penicillin V (oral administration, 650 mg, three times daily) during the first week of endodontic therapy. Penicillin had no effect on the occurrence of symptoms after 1 week compared with the control group (20 patients).
Natural and experimental infection with an attaching and effacing strain of Escherichia coli in calves
Authors: Moxley R A , Francis D H
Published: January 2020

Gnotobiotic calves were inoculated with an O5:K4:H-, urease-positive strain of Escherichia coli isolated from a 2-day-old calf with diarrhea. The calves developed elevated temperatures and passed loose mucoid feces, with or without blood. The E. coli strain was negative for heat-stable and heat-labile enterotoxins but produced high levels of Shiga-like toxin. Bacteria attached diffusely to the epithelium of the large intestine and multifocally to the epithelium of the ileum. The duodenum and jejunum were not affected. At the sites of bacterial attachment, microvilli were effaced, enterocytes were degenerate, and necrosis and exfoliation had occurred. These results confirm a previous report from England that calves may naturally contract infections similar to those caused by enteropathogenic E. coli strains pathogenic to humans or rabbits. This suggests that the calf bacterial strains, like some enteropathogenic E. coli strains, produce high levels of Shiga-like toxin and cause attachment and effacement lesions in the colonic epithelium of the infected host.
Induction of tryptophan catabolism is the mechanism for gamma-interferon-mediated inhibition of intracellular Chlamydia psittaci replication in T24 cells
Authors: Byrne G I , Lehmann L K , Landry G J
Published: January 2020

Human uroepithelial (T24) cells were incubated for 24 h in the presence of various concentrations of human recombinant gamma interferon (Hu-rIFN-gamma) and then infected with the 6BC strain of Chlamydia psittaci. This resulted in a reduction of intracellular chlamydial inclusion development in proportion to the concentration of Hu-rIFN-gamma present when Giemsa-stained cells were examined by light microscopy 24 h after infection. When tryptophan was added to Hu-rIFN-gamma-treated cells just after infection, reversal of the Hu-rIFN-gamma-mediated inhibition occurred in proportion to the concentration of tryptophan added. Addition of either isoleucine or lysine did not result in reversal of the antichlamydial state. Transport of L-[3H]tryptophan into acid-soluble intracellular pools was found to be greatly enhanced in Hu-rIFN-gamma-treated T24 cells compared with the rates measured for untreated cells. Transport of [3H]leucine was not increased in treated cells. Cells treated with Hu-rIFN-gamma also degraded L-[3H]tryptophan to catabolites that cochromatographed with N-formylkynurenine and kynurenine as measured by high-performance liquid chromatography. We conclude that Hu-rIFN-gamma-mediated inhibition of intracellular C. psittaci replication in T24 cells occurs by depletion of the essential amino acid tryptophan, most likely via the induction of indoleamine-2,3-dioxygenase, the initial enzyme of tryptophan catabolism.
Characterization of a secretory proteinase of Candida parapsilosis and evidence for the absence of the enzyme during infection in vitro
Authors: Rüchel R , Böning B , Borg M
Published: January 2020

The opportunistic yeastlike fungi of the genus Candida comprise three species which are proteolytic in vitro. Among them, C. albicans and C. tropicalis are of foremost medical importance. However, a strict correlation between extracellular proteolytic activity and virulence is opposed by the low virulence of the third proteolytic species, C. parapsilosis. We purified the secretory acid proteinase of C. parapsilosis (clinical isolate 265). The enzyme is a carboxyl proteinase (EC 3.4.23) like all other secretory Candida proteinases handled so far. Proteinase 265 is distinguished by a lower molecular weight (approximately 33,000); it has increased hydrophobicity, which accounts for inhibition of the enzyme by hemin, and required the presence of nonionic detergent in the initial steps of purification. The enzyme already undergoes alkaline denaturation at neutrality. Its activity is thus confined to the acid microenvironment of the fungal cell wall. Within this range, the enzyme may degrade immunoglobulins like immunoglobulin A1 (IgA1), IgA2, and secretory IgA. No indication was found for glycosylation of proteinase 265 and the related enzyme of C. albicans CBS 2730. However, the comparable proteinase of C. tropicalis 293 was identified as a manno protein. Antiserum against proteinase 265 cross-reacted strongly with corresponding enzymes from other Candida species. Antisera against proteinases of C. albicans and C. tropicalis reacted only weakly with proteinase 265. Thus, secretory Candida proteinases are likely to possess common and species-specific antigenic sites. In contrast to C. albicans, infection of phagocytes by C. parapsilosis 265 was not accompanied by secretion of fungal proteinase. This lack of induction of the enzyme under conditions of infection may account for the low virulence of most isolates of C. parapsilosis.
Mycobacterium bovis BCG-induced human T-cell clones from BCG-vaccinated healthy subjects: antigen specificity and lymphokine production
Authors: Mustafa A S , Kvalheim G , Degre M , Godal T
Published: January 2020

A total of 121 human T-cell clones were raised from nine Mycobacterium bovis BCG-vaccinated healthy individuals. Three clones were autoreactive, 74 responded to BCG in the presence of antigen-presenting cells, and the others required in addition exogenous interleukin 2. Only one clone was CD8+ CD4-, and the rest were CD4+ CD8-. Testing with a panel of mycobacteria suggested that the clones were recognizing epitopes of varied specificity. Out of 44 clones tested, 15 were specific to BCG and Mycobacterium tuberculosis, 22 showed limited cross-reactivity, and 8 were broadly cross-reactive. None of the 22 BCG responder clones could differentiate between Danish, French, Prague, and Moreau strains of BCG. BCG and M. tuberculosis H37Rv also paralleled very closely; however, 6 of 18 BCG- and M. tuberculosis H37Rv-responding clones did not proliferate to Mycobacterium africanum. BCG- and M. tuberculosis H37Rv-specific as well as cross-reactive T-cell clones could be induced to produce interleukin 2, gamma interferon, and granulocyte-macrophage colony-stimulating factor activity.
Passive transfer of mucosal antibody to Streptococcus equi in the foal
Authors: Galan J E , Timoney J F , Lengemann F W
Published: January 2020

Passive transfer of mucosal antibody to Streptococcus equi was studied in foals during the first 2 months of life. Immunoglobulin G (IgG) and IgA antibodies were found in sera and nasal secretions of foals shortly after colostrum intake. Titers were highest 2 days after birth; IgG predominated in sera, and IgA predominated in nasal washes. Intragastrically administered 99mTc-labeled IgA was transported from the bloodstream to the nasal mucosa of a newborn foal within a few hours of colostrum intake. Western blot analysis of the specificities of colostral and serum antibodies showed that selective transfer of immunoglobulins of defined specificity did not occur. Antibodies from milk samples taken a month or more into lactation had different specificities than those of colostrum or serum samples. Acid-extracted M protein fragments of S. equi recognized by milk antibodies were the same as those recognized by IgG and IgA from nasopharyngeal mucus of horses recently recovered from strangles. We postulate that passive antibody protection of the foal is derived both by secretion of colostral immunoglobulins onto the nasopharyngeal mucosa and by immunoglobulins ingested in milk that directly coat the upper respiratory and oral mucosa during the first months of life.