bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection in antisera of antibodies that cross-react with herpes simplex virus type 1 glycoprotein gC
Authors: Zweig M , Heilman C J , Bladen S V , Showalter S D , Hampar B
Published: January 2020

Herpes simplex virus type 1 (HSV-1) glycoprotein gC was purified by affinity chromatography with an immunosorbent column containing monoclonal antibody to HSV-1 gC, and its reactivity with rabbit antisera was measured by enzyme-linked immunosorbent assay and sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of radioimmunoprecipitates. Positive reactions were detected between HSV-1 gC and rabbit hyperimmune antisera to both HSV-1 and HSV-2. Electrophoretic analysis also revealed reactivity between the rabbit antisera and peptides of HSV-1 gC generated by partial digestion with trypsin. These findings indicate that HSV-1 gC has one or more cross-reactive or type-common determinants that are readily detected, and therefore, the presence of antibodies reacting with HSV-1 gC in sera may not necessarily be indicative of an earlier infection with HSV-1.
Stimulation of complement production in mice by N alpha-(N-acetylmuramyl-L-alanyl-D-isoglutamine)-N epsilon-stearoyl-L-lysine
Authors: Endo N , Okuda T , Osada Y , Zen-Yoji H
Published: January 2020

N alpha-(N-acetylmuramyl-L-alanyl-D-isoglutamine)-N epsilon-stearoyl-L-lysine, a synthetic muramyl dipeptide analog, stimulated the production of the third component of complement (C3) in mice. The serum concentration of C3 was elevated significantly by subcutaneous treatment with a single dose (10 to 100 micrograms per mouse) of the adjuvant 24 h before assay of the serum. Thereafter, the concentration decreased gradually with time and returned to the normal level on day 4 to 5. Immunoelectrophoretic analysis of the serum revealed that the decrease in serum C3 could not be accounted for by the cleavage to C3a and C3b. By intermittent treatment with the adjuvant on every fifth day, a significant increase in serum C3 was repeated. However, no continuous retention of the serum level of C3 was established even during continuous treatment with the adjuvant once a day for 10 consecutive days. Instead, in this case, the level of C3 increased repeatedly at almost 5-day intervals.
Vibrio cholerae soluble hemagglutinin/protease is a metalloenzyme
Authors: Booth B A , Boesman-Finkelstein M , Finkelstein R A
Published: January 2020

A soluble hemagglutinin/protease produced by Vibrio cholerae, which has previously been shown to hydrolyze fibronectin and ovomucin and to cleave lactoferrin and the A subunit of the heat-labile enterotoxin of Escherichia coli, appears to be a zinc metalloendopeptidase. Both its hemagglutinative and protease functions are inhibited by chelating agents, including Zincov, a hydroxamic acid derivative specifically designed to inhibit zinc metalloproteases. Thermolysin, a known zinc-containing protease, also causes hemagglutination of responder chicken erythrocytes. This activity is inhibited by Zincov, which does not affect the hemagglutination activity of trypsin and pronase. The hemagglutinin/protease is active on furylacryloyl-Gly-Leu-NH2, a synthetic substrate for thermolysin and other similar proteases. The hemagglutination activity of V. cholerae-infected or cholera toxin-treated infant rabbit intestinal fluid is not inhibited by Zincov, which suggests that this activity is not due to the hemagglutinin/protease, as formerly proposed.
Relationship between oxygen tension and subgingival bacterial flora in untreated human periodontal pockets
Authors: Loesche W J , Gusberti F , Mettraux G , Higgins T , Syed S
Published: January 2020

The predominance of anaerobic bacteria in subgingival plaque samples suggests that the pocket environment is anaerobic. In the present investigation, a small oxygen tension (pO2) electrode was inserted into the base of the pocket and the pO2 was recorded. In addition, the plaque in these pockets was examined culturally and microscopically. The oxygen tension at the bottom of 36 pockets (5 to 10 mm in depth) ranged from 5 to 27 mmHg (1 mmHg congruent to 133.3 Pa) with a mean value of 13.3 mmHg. Moderate pockets (5 and 6 mm) exhibited a mean pO2 of 15.7 mmHg, which was significantly higher than the 12.0 mmHg found in the deeper pockets. The deep pockets had higher percentages of spirochetes and Bacteroides intermedius, whereas the moderate pockets had elevated proportions of Actinomyces naeslundii and Streptococcus mutans. The sites with oxygen tensions equal to or less than 15 mmHg had significantly higher percentages of spirochetes, whereas the microaerophilic Capnocytophaga species were found in pockets with a pO2 greater than 15 mmHg. The presence of bleeding in the pocket was associated with higher proportions of B. intermedius, Capnocytophaga sp., and A. naeslundii. These pO2 readings of periodontal pockets indicated that there is a spectrum of pO2 values which seem to define, in a general way, the microbiological composition of the pocket.
Participation of complement in host defense against capsule-deficient Haemophilus influenzae
Authors: Zwahlen A , Winkelstein J A , Moxon E R
Published: January 2020

To investigate the role of complement in immunity to capsule-deficient Haemophilus influenzae, rats were depleted of C3 with cobra venom factor and challenged with three different strains of capsule-deficient H. influenzae. Two of them (Rd and U1) did not elaborate type b capsular antigen, whereas the other (S2) elaborated 0.16% of the amount made by its type b parent strain. Depletion of C3 significantly enhanced early intravascular bacterial survival after intravenous inoculation and strikingly increased the susceptibility of rats to infection with capsule-deficient H. influenzae. After intraperitoneal inoculation with strain Rd or U1, C3-depleted rats developed bacteremia, whereas control rats did not; challenge with strain S2 resulted in transient bacteremia in normal rats and in death in C3-depleted animals. To determine whether the greater virulence of strain S2, as compared with strain Rd or U1, was accounted for by the small amounts of capsular antigen it elaborated, we also compared its relative virulence to that of three genetically closely related capsule-deficient variants elaborating either small amounts of type b capsule or producing no detectable b antigen. No difference in virulence was observed among these four variants; all C3-depleted rats inoculated developed bacteremia of similar magnitude followed by similar mortality rates. These studies demonstrate a significant role for complement in host defense mechanisms against capsule-deficient H. influenzae and suggest that interstrain differences of virulence are not attributable to residual elaboration of small amounts of type b capsule.
Effect of infectious bursal disease on natural killer cell activity and mitogenic response of chicken lymphoid cells: role of adherent cells in cellular immune suppression
Authors: Sharma J M , Lee L F
Published: January 2020

A pathogenic isolate of infectious bursal disease virus (IBDV) caused persistent and extensive lesions in the bursa but mild and transient lesions in the thymuses of chickens of lines 63 and P. The effect of IBDV on two cellular immune functions, namely, natural killer cell cytotoxicity and mitogenic response, was studied. The natural killer cell activity was not consistently influenced, but the virus, during the first 2 weeks of infection, caused transient depression of the blastogenic response of spleen cells to phytohemagglutinin. Studies on mitogenic hyporesponsiveness revealed that the functional impairment was mediated by a suppressor cell that shared several characteristics with macrophages; i.e., the suppressor cell was adherent to plastic, was phagocytic, and resisted treatment with antithymocyte and antibursa cell sera. Removal of suppressor cells from the spleens of virus-infected chickens resulted in restoration of the mitogenic response of cells. Further, in mixing experiments, the suppressor cell isolated from the spleens of virus-infected chickens also inhibited the mitogenic response of normal spleen cells. We concluded that reduced mitogenic response of lymphocytes in IBDV-infected chickens was not due to a lack of functional T-cells, as suggested previously by others, but was due to macrophage-like suppressor cells. The suppressor cells, although present in certain normal chickens, became activated during early stages of IBDV infection.
Effects of lincomycin and tetracycline on production and properties of enterotoxins of enterotoxigenic Escherichia coli
Authors: Yoh M , Yamamoto K , Honda T , Takeda Y , Miwatani T
Published: January 2020

Enterotoxigenic Escherichia coli grown in the presence of lincomycin and tetracycline produced an increased amount of heat-labile enterotoxin (LT). These antibiotics increased the production of not only extracellular LT but also intracellular LT. On the other hand, lincomycin did not stimulate the production of heat-stable enterotoxin by enterotoxigenic E. coli. The extracellular LTs produced in the presence of lincomycin and tetracycline were purified and analyzed by sodium dodecyl sulfate-polyacrylamide gel disc electrophoresis. Results showed that the A subunits of the purified LTs were not nicked, unlike that of extracellular LT produced in the absence of the antibiotics.
Association of neuraminidase-sensitive receptors and putative hydrophobic interactions with high-affinity binding sites for Streptococcus sanguis C5 in salivary pellicles
Authors: Gibbons R J , Etherden I , Moreno E C
Published: January 2020

The relationship of neuraminidase-sensitive receptors and putative hydrophobic interactions to high- and low-affinity binding sites in experimental salivary pellicles for Streptococcus sanguis C5 was investigated. NaSCN, an inhibitor of hydrophobic interactions, reduced the number of cells which adsorbed to pellicles to a greater extent than NaCl or KCl when both low and high streptococcal concentrations were used in assays. However, NaSCN was not more effective than NaCl or KCl in desorbing 3H-labeled salivary pellicle components from hydroxyapatite, and NaSCN pretreatment of either strain C5 cells or the salivary pellicles did not destroy or remove either the streptococcal adhesions or the pellicle receptors. Neuraminidase treatment of pellicles or the presence of sialic acid-containing gangliosides only inhibited S. sanguis adsorption when low streptococcal concentrations were used. At these concentrations, S. sanguis adsorbs primarily to high-affinity pellicle binding sites. Adsorption isotherms indicated that neuraminidase-sensitive interactions were mainly responsible for the high affinity of these binding sites, whereas putative hydrophobic interactions inhibitable by NaSCN were mainly associated with the numbers of binding sites available. Sugar inhibition studies suggested that the two classes of binding sites previously demonstrated in untreated salivary pellicles for S. sanguis C5 are not the result of a partial conversion of high-affinity sites to low-affinity sites due to removal of sialic acid residues.
Inhibition of Neisseria gonorrhoeae attachment to HeLa cells with monoclonal antibody directed against a protein II
Authors: Sugasawara R J , Cannon J G , Black W J , Nachamkin I , Sweet R L , Brooks G F
Published: January 2020

This study showed that a protein II (PII) of Neisseria gonorrhoeae FA1090 appeared to act as a mediator of attachment to HeLa cells. Two colony variants of FA1090 were selected. Both gonococcal variants were nonpiliated, but one contained a PII and the other did not. A monoclonal antibody (1090-10.1), which was directed against the PII, inhibited the apparent PII-mediated attachment to HeLa cells. Antibodies produced from clone 1035-4, which had no PII specificity, did not inhibit the attachment and were used as controls. Inhibition of gonococcal attachment by the 1090-10.1 monoclonal antibodies was demonstrated by fluorescent microscopy analysis. Monoclonal antibody 1090-10.1 appeared to cause agglutination of the PII-containing organism. To block the clumping caused by the PII-specific monoclonal antibodies, Fab fragments of goat anti-mouse IgG were incubated with gonococci and the 1090-10.1 monoclonal antibodies. The results showed that the goat anti-mouse IgG Fab fragments partially blocked the agglutination caused by the PII-specific monoclonal antibody. The effect of the 1090-10.1 antibodies on attachment was also determined by monitoring the HeLa cells with attached iodinated gonococci. The monoclonal antibody appeared to inhibit the PII-mediated attachment.
P-fimbriated clones among uropathogenic Escherichia coli strains
Authors: Väisänen-Rhen V , Elo J , Väisänen E , Siitonen A , Orskov I , Orskov F , Svenson S B , Mäkelä P H , Korhonen T K
Published: January 2020

A total of 237 Escherichia coli strains isolated from the urine of patients with various forms of urinary tract infection or from feces of healthy children were analyzed for O group, possession of K1 capsule, type 1 fimbriae, P fimbriae, X adhesin, and production of hemolysin. Some of the strains were also analyzed for K and H antigens, outer membrane protein pattern, and plasmid content. P fimbriation, hemolysin production, and certain O groups were found to be significantly correlated with pyelonephritogenicity. Possession of type 1 fimbriae or of K1 capsule or plasmid content did not significantly correlate with virulence. Outer membrane protein patterns in 139 strains of the more common O groups were analyzed. Only one to three patterns, which varied between serotypes, were usually found within any one O group. Distinctive groups (clones) were found when the strains were grouped according to complete serotype, fimbriation, hemolysin production, and outer membrane protein pattern; also, the mean number of plasmids was typical of the strains in a given clone. Seven clones associated with pyelonephritis were found; together they accounted for 57% of the O serotypable strains from the pyelonephritis patients. The seven clones were P fimbriated but differed in their serotypes as follows: O1:K1:H7, O4:K12:H1, O4:K12:H5, O6:K2:H1, O16:K1:H6, or O18ac:K5:H7. All O1:K1:H7 strains observed fell into two clones according to the presence or absence of type 1 fimbriae and hemolysin production. One clone associated with cystitis was also found; this consisted of O6:K13:H1 strains lacking P fimbriae. Not a single representative of these eight clones was found among the fecal strains from the healthy children. They are proposed to represent virulent clones with special ability to cause human urinary tract infection.
Interaction of Pseudomonas aeruginosa alkaline protease and elastase with human polymorphonuclear leukocytes in vitro
Authors: Kharazmi A , Döring G , Høiby N , Valerius N H
Published: January 2020

Little is known about the interaction of Pseudomonas aeruginosa extracellular products and human polymorphonuclear leukocytes. The present study was designed to examine the effect of alkaline protease and elastase purified from P. aeruginosa on human neutrophil function. Neutrophil chemotaxis, oxygen consumption, glucose oxidation, superoxide production, and nitro blue tetrazolium reduction were studied. It was found that alkaline protease and elastase at fairly low concentrations (0.05 and 0.0025 micrograms/ml, respectively) inhibited chemotaxis. The inhibitory effect of both enzymes was increased at higher concentrations. The chemotaxis of preincubated and washed cells was also inhibited. Alkaline protease but not elastase inhibited opsonized zymosan-stimulated neutrophil oxygen consumption, whereas neither of the enzymes had any effect on glucose oxidation and nitro blue tetrazolium-reducing activity of stimulated neutrophils. The data on superoxide production ability of the cells indicated that the cells preincubated with enzyme and washed were capable of producing superoxide equal to the amount produced by untreated cells when they were stimulated with phorbol myristate acetate or zymosan. However, when elastase was present in the reaction mixture, the reduction of cytochrome c as a measure of superoxide production was inhibited. Inhibition of neutrophil function, particularly chemotaxis, will have important bearing on the escape of the microorganism from the phagocytic defense system of the host. The role of these products in localized infections and avascular areas such as skin burns, cornea, and, at least initially, in chronic lung colonization in cystic fibrosis patients becomes important.
Antibody-dependent cellular cytotoxicity of Coxiella burnetii-infected J774 macrophage target cells
Authors: Koster F T , Kirkpatrick T L , Rowatt J D , Baca O G
Published: January 2020

Cell-mediated immunity is clearly the critical host defense mechanism against human Coxiella burnetii infection (Q fever); the role of specific antibody is unclear. By using a mouse macrophage tumor cell line, J774, persistently infected with C. burnetii phase I organisms, in a standard 51Cr-release cytotoxicity assay, we explored the possibility that antibody-dependent cellular cytotoxicity may be immune mechanism in Q fever. After 16 h of incubation in the presence of immune sera from Q fever hepatitis or endocarditis patients, nonimmune human peripheral blood effector cells specifically lysed infected J774 target cells; no 51Cr release was seen in the presence of nonimmune sera or uninfected target cells. An effector/target ratio of at least 5:1 was required, and monocytes were more efficient effector cells than lymphocytes. Cytotoxicity was blocked by preincubation of effector cells with purified aggregated human immunoglobulin G, indicating the role of Fc receptor-bearing effector cells. Two nonphagocytic lymphoid tumor cell targets, passively coated with C. burnetii, did not induce substantial immune-specific cytolysis, suggesting that bystander lysis does not explain the observation of specific lysis. Although antibody-dependent cellular cytotoxicity may participate in primary defense, alternatively, it may facilitate the dissemination of C. burnetii or surreptitiously participate in granuloma formation.
Inhibition of blood clearance and hepatic tissue binding of Escherichia coli by liver lectin-specific sugars and glycoproteins
Authors: Perry A , Ofek I
Published: January 2020

The effects of sugars and glycoproteins that are known to bind to lectins of liver tissue on the clearance of cells of Escherichia coli from mouse blood was investigated. The administration of 100 mg per mouse of methyl-alpha-D-mannoside, methyl-alpha-D-glucoside, or methyl-alpha-D-fucoside, but not of methyl-alpha-D-galactoside or L-rhamnose, markedly inhibited the blood clearance of cells of E. coli 346. Clearance was similarly inhibited by 0.1 and 1.0 mg per mouse of asialofetuin or ovalbumin, respectively, whereas fetuin had no effect. The inhibitory effects of the sugars on blood clearance was abolished by pretreating the E. coli cells with antibodies against whole organisms. All of these effects were equal for fimbriated and nonfimbriated phenotypes of E. coli 346. Homogenates of mouse liver tissue coaggregated with nonfimbriated cells of E. coli. The aggregation was blocked by 100 mM solutions of methyl-alpha-D-mannoside, or methyl-alpha-D-glucoside, 1 mg of bacterial lipopolysaccharide per ml, or 10 mM EDTA but not by L-rhamnose. These results suggest that the mannose-N-acetylglucosamine hepatic lectin recognizes specific sugars on the surface of E. coli and may be centrally involved in the nonimmune clearance of nonfimbriated E. coli from the blood of the infected host.
Immune response to atypical mycobacteria: immunocompetence of heavily infected mice measured in vivo fails to substantiate immunosuppression data obtained in vitro
Authors: Orme I M , Collins F M
Published: January 2020

The results of in vitro experiments designed to measure the immunocompetence of mice heavily infected with the atypical mycobacterial pathogens Mycobacterium avium and Mycobacterium simiae were compared with the results of experiments which used in vivo approaches. Blastogenic responsiveness in vitro both to mitogen and to alloantigen was severely depressed in the heavily infected mice; this responsiveness could be restored by removal of an inhibitory Thy-1.2-, nylon wool-adherent cell population. No evidence was found to support the previous contention that suppressor T cells may play a role in the inhibition of this responsiveness. These results were then compared with experiments which measured the ability of the infected animal to elicit a delayed-type hypersensitivity response to sheep erythrocytes in vivo. However, although delayed-type hypersensitivity responses in vivo were also depressed, evidence was obtained which suggested that this unresponsiveness was due to inadequate sensitization of T cells, possibly due to catabolism of antigen, rather than due to the influence of an active, immunosuppressive mechanism. Finally, despite the severely depressed ability of cells from infected mice to respond to alloantigenic stimulation in vitro, infected animals were fully able to cause the regression of a tumor implant in vivo.
Conjugation of meningococcal lipopolysaccharide R-type oligosaccharides to tetanus toxoid as route to a potential vaccine against group B Neisseria meningitidis
Authors: Jennings H J , Lugowski C , Ashton F E
Published: January 2020

Oligosaccharides were obtained by the mild acid hydrolysis of the lipopolysaccharides from a number of different strains of Neisseria meningitidis, serotypes L2, L3, L4, L5, and L10. The dephosphorylated oligosaccharides were conjugated to tetanus toxoid as their 2-(4-isothiocyanatophenyl)-ethylamine derivatives, which resulted in the incorporation of from 18 to 38 oligosaccharides per molecule of tetanus toxoid. When injected in rabbits, the conjugates produced oligosaccharide-specific antibodies which were predominantly serologically specific but which also exhibited some cross-reactivity. These serological results can be attributed to regions of structural dissimilarity and similarity within the oligosaccharides. The oligosaccharide-specific antibodies were also lipopolysaccharide serotype specific, thus indicating that the oligosaccharides are the determinants associated with this serotype specificity. Consistent with the serological results, the conjugate antisera were bactericidal for the homologous serotype meningococcal organisms and in some cases for heterologous serotype organisms.
Chlamydia trachomatis stimulates human peripheral blood B lymphocytes to proliferate and secrete polyclonal immunoglobulins in vitro
Authors: Bard J , Levitt D
Published: January 2020

Infectious Chlamydia trachomatis (LGV strain), obligate intracellular bacteria, stimulated human peripheral blood lymphocytes to proliferate and secrete immunoglobulins in vitro. In contrast, mock-infected preparations were unable to induce similar responses in peripheral blood lymphocytes. Although levels of immunoglobulin secreted into the media of LGV-stimulated cultures were greater than 10 micrograms/ml, we estimated that less than 1% of these molecules were directed against the bacteria itself, suggesting polyclonal antibody production. Since stimulation with Formalin-killed bacteria resulted in comparable numbers of plaque-forming cells (PFC) as infectious particles, we concluded that the polyclonal immunoglobulin response was not dependent on the in vitro chlamydial infectious process. The polyclonal PFC response induced by LGV was highly sensitive to monocyte inhibition. Although LGV induced proliferation of predominantly B cells, the numbers of generated PFC was increased by the addition of autologous T cells. Neither lymphocyte proliferation nor PFC responses of normal human volunteers correlated significantly with the presence or titer of antichlamydial antibodies in their sera.
Macrophage activation by cord factor (trehalose 6,6'-dimycolate): enhanced association with and intracellular killing of Trypanosoma cruzi
Authors: Kierszenbaum F , Zenian A , Wirth J J
Published: January 2020

Cord factor (trehalose 6,6'-dimycolate[TDM] ), a mixture of 6,6'-diesters of alpha, alpha-D-trehalose with natural mycolic acids, has been described as having immunoregulatory and antitumor activities in vivo, although the relevant mechanisms of action remain unelucidated. In this work, we measured the effects of TDM on both mouse macrophage association with (i.e., the combined result of surface binding and uptake) and subsequent intracellular killing of Trypanosoma cruzi, the causative agent of Chagas' disease. Pretreatment of macrophage cultures with TDM for 16 h markedly increased both the ability of these cells to associate with T. cruzi and the rate of killing of parasites. The results obtained with macrophages treated with TDM after exposure to the parasites did not differ from those obtained with untreated macrophages, indicating that macrophage activation did not occur immediately after TDM treatment and was time dependent. The TDM effect was reversible since the extents of macrophage-parasite association and intracellular killing returned to normal levels 4 h after TDM treatment. Neither catalase, which scavenges hydrogen peroxide, nor sodium azide or potassium cyanide, which are inhibitors of peroxidase activity, significantly reduced the level of trypanosome killing by TDM-treated macrophages. TDM also increased the uptake of glutaraldehyde-killed T. cruzi and latex particles, suggesting that TDM could act mostly by enhancing phagocytosis and that increased cell association with the living trypanosomes did not necessarily depend on the macrophages becoming more susceptible to parasite invasion. These results indicate that TDM modulates macrophage function by augmenting both internalization and intracellular destruction. Hydrogen peroxide and peroxidase activity, postulated to be involved in phagocytic killing of T. cruzi, did not appear to be an absolute requirement for the killing of T. cruzi in TDM-treated macrophages.
Antigen from Francisella tularensis: nonidentity between determinants participating in cell-mediated and humoral reactions
Authors: Sandström G , Tärnvik A , Wolf-Watz H , Löfgren S
Published: January 2020

After tularemia vaccinations, most individuals respond with cell-mediated and humoral immunity as disclosed by the lymphocyte stimulation test and enzyme-linked immunosorbent assay (ELISA), respectively. There is, however, no correlation between the magnitudes of the two responses, and some individuals show one of the responses only. We now report that the two responses are directed towards different antigenic determinants of the bacterium. Ether-water extraction of the live vaccine strain of Francisella tularensis gave a high yield of material reacting in ELISA as well as in the lymphocyte stimulation test. However, the specificity of the extract was low insofar as it reacted not only with lymphocytes and antibodies of tularemia-vaccinated individuals but also to a fairly high extent with those of nonvaccinated individuals. By using the extract as a starting material, a preparatory procedure was developed, resulting in antigen of high specificity in the two tests. The antigen prepared was a high-molecular-weight, carbohydrate-protein complex. Proteinase K treatment of the antigen abolished the lymphocyte-stimulating activity but did not decrease ELISA activity at all. Periodate treatment, on the other hand, greatly reduced ELISA activity but did not decrease the lymphocyte-stimulating activity. Thus, determinants of F. tularensis responsible for immunospecific lymphocyte stimulation seem to reside in protein, whereas ELISA activity seems to be due mostly to carbohydrate determinants.
Partially purified antigen preparations of Toxoplasma gondii protect against lethal infection in mice
Authors: Araujo F G , Remington J S
Published: January 2020

Antigens of Toxoplasma gondii eluted from polyacrylamide gels after electrophoresis under reducing conditions were examined for their capacity to react with antibodies from infected humans, to induce antibody formation, and to protect mice against T. gondii. Antigens with approximate molecular weights of 35,000 and 14,000 strongly reacted in an enzyme-linked immunosorbent assay of human immunoglobulin M (IgM) and IgG antibodies to T. gondii. Mice injected with the eluted antigen preparations formed antibodies that reacted differently in four serological tests for Toxoplasma antibodies. All mice formed antibodies that reacted in the IgG and IgM enzyme-linked immunosorbent assay. Antibodies reacting in the conventional indirect immunofluorescent antibody test were detected in all mice except those injected with low-molecular-weight (14,000 or less) antigens. Sabin-Feldman dye test antibodies were not detected in any of the mice. Antibodies reacting in the latex agglutination test were detected mainly in mice injected with antigens with an approximate molecular weight of 66,000. Challenge of the injected mice with a lethal inoculum of T. gondii revealed that the highest survival rate was in animals that received antigens with approximate molecular weights of 35,000 and 14,000.
Resistance to cutaneous leishmaniasis: acquired ability of the host to kill parasites at the site of infection
Authors: Hill J O
Published: January 2020

The purpose of these studies was to follow the development of acquired resistance in experimental cutaneous leishmaniasis by measuring changes, against time, in the ability of mice infected with Leishmania tropica to inhibit the growth of a challenge inoculum of parasites. In addition, the development of T lymphocytes that mediate the acquired response was followed by adoptive immunization. It was found that acquired resistance developed rapidly and reached a maximum level at the time when the progressive multiplication of the parasites in the primary lesion stopped. Systemic immunity, however, as determined by the ability of splenic T cells to adoptively immunize normal recipients, did not develop fully until 4 weeks later. Acquired resistance is expressed systemically in the animal and probably nonspecifically, in that mice expressing resistance to a homologous challenge with L. tropica were also capable of destroying Listeria monocytogenes. These data, obtained from in vivo studies, are consistent with the hypothesis that the immunity which causes the destruction of L. tropica is mediated by T lymphocytes and expressed, nonspecifically, through macrophages.
Disseminated tetracycline resistance in oral streptococci: implication of a conjugative transposon
Authors: Hartley D L , Jones K R , Tobian J A , LeBlanc D J , Macrina F L
Published: January 2020

A DNA sequence specifying tetracycline resistance (Tcr) has been previously cloned from a clinical isolate of Streptococcus mutans designated U202 (J. A. Tobian and F. L. Macrina, J. Bacteriol. 152:215-222, 1982). We used this sequence as a molecular probe in studying the dissemination of Tcr among oral streptococcal species isolated from patients treated with tetracycline. Eleven strains (including S. sanguis I, S. sanguis II, S. mitis, and S. salivarius) from seven patients were examined by Southern blot analysis. Seven strains showed strong hybridization to the Tcr probe, two showed weak hybridization, and two did not display detectable hybridization. Based on previous characterization of the cloned sequence, our data suggest the dissemination of the tetM class of resistance determinants among these oral streptococci. One of the clinical S. sanguis I isolates studied was able to transfer its Tcr phenotype to other oral streptococci and to enteric streptococci in the absence of plasmid DNA. This transfer appeared to be conjugation-like on the basis of its insensitivity to DNase and its dependence on intimate cell-to-cell contact. Using the cloned Tcr sequence, we were able to study the progeny of the matings. Our data suggest that this resistance transfer element occupies a chromosomal location in streptococcal cells and that it strongly resembles the conjugative transposon Tn916 in its behavior.
Non-O1 Vibrio cholerae hemolysin: purification, partial characterization, and immunological relatedness to El Tor hemolysin
Authors: Yamamoto K , Al-Omani M , Honda T , Takeda Y , Miwatani T
Published: January 2020

Hemolysin of a non-O1 Vibrio cholerae strain was purified and characterized. The purified hemolysin gave a single protein band on conventional and sodium dodecyl sulfate-gel electrophoresis. Its molecular weight was estimated as 60,000 by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis. It had a pI of 5.7. The purified hemolysin caused increased vascular permeability of rabbit skin and rapid death of mice on intravenous injection and also lysed erythrocytes of various animal species. An Ouchterlony double gel diffusion test using antiserum against the purified hemolysin indicated that the hemolysin from non-O1 V. cholerae was immunologically related, but not identical, to the hemolysin from El Tor V. cholerae. Antiserum against the purified hemolysin neutralized the hemolytic activity of the hemolysins from not only non-O1 but also El Tor V. cholerae.
Acquired resistance to facultative intracellular bacteria: relationship between persistence, cross-reactivity at the T-cell level, and capacity to stimulate cellular immunity of different Listeria strains
Authors: Kaufmann S H
Published: January 2020

C57BL/6 mice were infected with different strains of Listeria sp., and bacterial survival in spleens was assessed. Six strains (EGD, NCTC 5348, ATCC 19113, ATCC 19114, NCTC 10527, and ATCC 19116) were able to persist in spleens (persistent strains), whereas with five other strains (ATCC 19111, ATCC 19119, ATCC 33090, ATCC 33091, and ATCC 14870), only few if any bacteria were demonstrable after infection with up to 10(8) organisms (nonpersistent strains). Immunization of mice with persistent listeriae induced strong immune responses as determined in vitro (antigen-induced proliferation and interleukin production) and in vivo (protection and delayed-type hypersensitivity), whereas immunization with nonpersistent bacteria resulted in weaker responses. On the other hand, T lymphocytes from mice immunized with live organisms of the persistent strain EGD were stimulated equally well by heat-killed listeriae of all strains. Furthermore, three T-cell clones which were able to adoptively mediate antibacterial protection in vivo could be stimulated by heat-killed organisms of persistent as well as nonpersistent Listeria strains. It is concluded that both persistent and nonpersistent listeriae express antigenic epitopes which are recognized by protective T cells, although nonpersistent strains are not effective in inducing cellular immune responses due to rapid elimination in the host.
A single gene determines rapid expulsion of Trichinella spiralis in mice
Authors: Bell R G , Adams L S , Ogden R W
Published: January 2020

In rats and some inbred mouse strains, one immune response, rapid expulsion, confers up to 95% protection against a challenge infection with Trichinella spiralis. Strain analysis in mice has shown that only three inbred strains, all originating from Swiss-line mice at the National Institutes of Health, Bethesda, Md., express rapid expulsion. Crosses between responder strain mice (NFR/N) and nonresponders (C3H/HeJ or B10 X BR) have indicated that rapid expulsion is dominant and autosomal (Bell et al., Exp. Parasitol. 53:301-314, 1982). In this study a segregation analysis of rapid expulsion in the F2 and backcross conformed to the Mendelian ratios expected of a single gene. This gene was not linked to the major histocompatibility complex (MHC) (chromosome 17) or the gene for albinism (c/c locus on chromosome 7). This locus has not previously been identified as conferring resistance to any infectious agent, and we have therefore designated the gene Ihe-1 (intestinal helminth expulsion 1).
Species differences in Kupffer cells and endotoxin sensitivity
Authors: McCuskey R S , McCuskey P A , Urbaschek R , Urbaschek B
Published: January 2020

The relative species sensitivity to Escherichia coli O111:B4 endotoxin was found to be guinea pig greater than hamster greater than mouse greater than rat. The 50% lethal dose of this endotoxin correlated with both the rate at which single latex particles were phagocytosed by individual Kupffer cells and the number of Kupffer cells in hepatic lobules that phagocytosed latex. The results suggests that the intrahepatic density and the level of activation of Kupffer cells participate in determining endotoxin sensitivity.
Cloning of the thermostable direct or Kanagawa phenomenon-associated hemolysin of Vibrio parahaemolyticus
Authors: Kaper J B , Campen R K , Seidler R J , Baldini M M , Falkow S
Published: January 2020

Genes encoding the thermostable direct or Kanagawa phenomenon hemolysin of Vibrio parahaemolyticus were cloned in Escherichia coli. DNA hybridization experiments with the cloned genes showed that none of the five Kanagawa phenomenon-negative environmental isolates tested possessed DNA sequences homologous to the probe.
Relationship between cell surface composition, adherence, and virulence of Candida albicans
Authors: McCourtie J , Douglas L J
Published: January 2020

A comparison was made of the adherence to acrylic and to human buccal epithelial cells of seven strains of Candida albicans isolated from active infections (I strains) and two strains obtained from asymptomatic carriers (C strains). After growth in defined medium containing a relatively low concentration (50 mM) of glucose as the carbon source, the adherence of I and C strains to either surface was similar and all strains were sensitive to spheroplast formation with Zymolyase 5000. Growth in medium containing a high concentration (500 mM) of sucrose or galactose enhanced the adherence of I strains up to 5- and 11-fold, respectively, and there were corresponding increases in resistance to spheroplast formation. Sucrose- or galactose-grown C strains showed only small increases in adherence and remained relatively sensitive to spheroplast formation. When inoculated intravenously into mice, I strains grown in 500 mM sucrose were up to five times more virulent than organisms grown in 50 mM glucose, while I strains grown in 500 mM galactose showed a 5- to 24-fold increase in virulence. Fifty percent lethal doses obtained for C strains were similar after growth on all three carbon sources. We conclude that I strains are able to modify their surface composition in response to high concentrations of certain sugars in the growth environment. Such modification can enhance both their ability to adhere to surfaces and their virulence. C strains lack this capability, or possess it to a lower degree, and may therefore have a lower pathogenic potential.
In vitro interaction of Mycobacterium avium with intestinal epithelial cells
Authors: Mapother M E , Songer J G
Published: January 2020

Human intestinal epithelial cell monolayers were inoculated with cultures of Mycobacterium avium serotype 2, 8, or 10 that were viable, autoclaved, Formalin killed, exposed to UV light, or suspended in anti-M. avium serotype 2 serum. The effects of four reagents known to block phagocytosis or endocytosis (cytochalasin B, dibutyryl cyclic adenosine monophosphate, iodoacetate, and 2,4-dinitrophenol) on the bacteria-cell interaction were also studied. The maximum uptake of pathogenic M. avium by human intestinal epithelial cells occurred after 2 to 3 h of incubation. Serotype 2 was taken up in greater quantity than serotype 8 or 10. Saprophytic mycobacteria did not attach to or penetrate the host cells. The data showed that viable mycobacteria are ingested by host cells, whereas dead organisms are not. Components of the bacterial cells are partially, but not solely, responsible for the phagocytosis of M. avium serotype 2 by human intestinal epithelial cells. Furthermore, uptake of M. avium by human intestinal epithelial cells was suppressed by reagents which inhibit uptake by known phagocytic cells, suggesting that the mechanism of uptake is an endocytic process induced by virulent mycobacteria.
Effect of fluoride on growth and acid production by Streptococcus mutans in dental plaque
Authors: van der Hoeven J S , Franken H C
Published: January 2020

The aim of this study was to measure the effect of fluoride on the production of organic acids by Streptococcus mutans in dental plaque. The effect was studied in a simplified model of dental plaque with gnotobiotic rats monoinfected with S. mutans Ny341. Adaptation of S. mutans to fluoride was induced by feeding one group of the rats on fluoride-containing diet and drinking water. No difference was found in the accumulation of S. mutans on the teeth between the fluoride-adapted and the control groups. However, there was a significant difference in the amount of lactic acid in metabolically resting plaque between the groups, lactic acid being lower in the fluoride-adapted plaque. At 5 min after a rinse containing 10% sucrose, a high level of lactic acid was found in plaque from animals not exposed to fluoride. Rinses containing 4 or 20 mM fluoride before the sucrose rinse significantly inhibited the lactic acid production in the control group. In the plaque from rats on fluoridated diet and drinking water the sucrose-induced production of lactic acid was not inhibited by a 4 mM fluoride rinse. Moreover, the production of lactic acid in the fluoride-adapted plaque was prolonged. The results indicate that due to fluoride adaptation the inhibition of acid production is unlikely to be important for the caries-preventive action of fluoride.
Activation of murine polymorphonuclear neutrophils for fungicidal activity with supernatants from antigen-stimulated immune spleen cell cultures
Authors: Brummer E , Stevens D A
Published: January 2020

An in vitro model of in vivo immunological activation of murine polymorphonuclear neutrophils (PMN) was developed. Culture supernatants of spleen cells from Blastomyces dermatitidis-immunized mice stimulated with B. dermatitidis antigens in vitro were studied. Incubation of the supernatants with thioglycolate-elicited PMN enabled the cells to significantly reduce (31 +/- 6%) B. dermatitidis inoculum CFU. Optimum production of active supernatants occurred after 4 to 6 days of stimulation in vitro and required 200 micrograms of nonviable B. dermatitidis cells per ml. Generation of activity by immune spleen cells was shown to be antigen specific in that stimulation with a heterologous antigen or stimulation of nonimmune spleen cells with B. dermatitidis antigen did not produce active supernatants. The activity in supernatants was dose dependent, nondialyzable (molecular weight greater than or equal to 14,000), and relatively heat labile (80 degrees C, 30 min). Activation of PMN by supernatants for fungicidal activity against B. dermatitidis required only a short incubation period (1 h) followed by a 2-h coculture (challenge) period. Stimulation of normal spleen cells with concanavalin A also resulted in the production of supernatants capable of activating PMN for significant fungicidal activity (31.1 +/- 8.5%). These findings demonstrate for the first time a link between soluble factors produced by antigen stimulation of sensitized lymphoid cells and activation of PMN for enhanced microbicidal activity. Such a process defines an additional immune defense mechanism whereby the immune host may clear specific microorganisms.
Heterogeneity of molecular size and antigenic expression within lipooligosaccharides of individual strains of Neisseria gonorrhoeae and Neisseria meningitidis
Authors: Schneider H , Hale T L , Zollinger W D , Seid R C , Hammack C A , Griffiss J M
Published: January 2020

We determined the Mr of neisserial lipooligosaccharides (LOS) by using discontinuous sodium dodecyl sulfate-polyacrylamide gel electrophoresis, minimal loading concentrations, and Salmonella isogenic rough mutant LOS as Mr standards. Salmonella LOS were resolved into three components. The migration distance of each component was linearly related to its theoretical Mr (r = 0.99). Neisserial LOS also contained multiple components whose calculated Mr ranged from 3,200 to 7,100. The relative abundance of components and their MrS varied greatly among strains. Meningococcal LOS were composed almost exclusively of two closely migrating components; gonococcal LOS were more heterogeneous. LOS from a gonococcus selected for resistance to a Pseudomonas pyocin contained only a single component that was different from and of intermediate Mr among the three components of the parent strain. A monoclonal antibody directed against the meningococcal L8 LOS epitope was used to determine whether heterogeneity of antigen expression reflected Mr heterogeneity. Single components of the L8 meningococcal LOS and of the LOS of 3 of 19 gonococcal strains bound the monoclonal antibody. Gonococcal LOS components that expressed the L8 epitope were of a similar Mr (4,800). Smaller components of these same LOS did not express the epitope.
Vibrio cholerae hemagglutinin/protease nicks cholera enterotoxin
Authors: Booth B A , Boesman-Finkelstein M , Finkelstein R A
Published: January 2020

Unnicked cholera enterotoxin was isolated from culture supernatants of Vibrio cholerae 569B by either rapid processing of flask-grown cultures or by growing and processing fermentor cultures in the presence of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetra acetic acid, an inhibitor of the previously described V. cholerae hemagglutinin/protease. When unnicked cholera enterotoxin was incubated with purified hemagglutinin/protease, the unnicked A subunit was converted to a molecular weight consistent with that of the A1 subunit as demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its specific activity for Y1 adrenal cells increased.
Molecular cloning of the major outer membrane protein of Chlamydia trachomatis
Authors: Allan I , Cunningham T M , Lovett M A
Published: January 2020

A gene library of Chlamydia trachomatis (serovar L1) DNA has been prepared in the phage vector lambda 1059. From this bank, 20 recombinant phage-expressing components which reacted with serum from a patient with a C. trachomatis (L1) infection were chosen. Selective expression and radiolabeling of phage polypeptides in irradiated Escherichia coli demonstrated that one of these clones encoded a polypeptide doublet with an apparent molecular weight similar to that of the C. trachomatis (L1) major outer membrane protein. Both species of this cloned doublet (40 and 41 kilodaltons) could be immunoprecipitated by serum from a patient with a C. trachomatis (L1) infection but not by normal human serum. Components of this apparent molecular weight were not precipitated from irradiated E. coli infected with vector phage lambda 1059 by either of these sera. Comparison of the Staphylococcus aureus-V8 protease peptide maps of these two cloned polypeptides and chlamydial major outer membrane protein extracted from elementary bodies showed all three polypeptides to produce peptide fragments of 15.5, 13.8, and 11.5 kilodaltons. Due to the identical apparent molecular weights of the fragments produced from the 40- and 41-kilodalton cloned polypeptides, these were concluded to be different conformational forms of the same molecular species. These cloned components were indistinguishable from C. trachomatis (L1) major outer membrane protein.
Yersinia pestis grows within phagolysosomes in mouse peritoneal macrophages
Authors: Straley S C , Harmon P A
Published: January 2020

Transmission electron microscopy was used to determine the intracellular localization of Yersinia pestis growing within cultured resident peritoneal macrophages of mice. Monolayers fixed immediately, or as long as 4.5 h, after infection contained yersiniae closely surrounded by a membrane. The vesicles containing the yersiniae were determined to be phagolysosomes by labeling secondary lysosomes of macrophages with electron-dense particles of thorium dioxide. The presence of the label within vesicles containing yersiniae indicates that this pathogen grows within the lysosomal compartment of its target host cell.