bluuebunny/crossref_metadata_2025 huggingface dataset:
Outer membrane proteins of Brucella abortus: isolation and characterization
Authors: Verstreate D R , Creasy M T , Caveney N T , Baldwin C L , Blab M W , Winter A J
Published: January 2020

Outer membrane proteins were derived from one rough and four smooth strains of Brucella abortus by sequential extraction of physically disrupted cells with N-lauroylsarcosinate and dipolar ionic detergent. Extraction of outer membrane proteins was ineffective, however, without predigestion with lysozyme. Three groups of proteins were present and could be separated in their native state by sequential anion-exchange chromatography and gel filtration. Membrane proteins contained substantial quantities of tightly adherent lipopolysaccharide which could be reduced but not eliminated by extraction of cells with trichloroacetic acid before disruption. Group 2 proteins, apparently trimers in their native state, gave rise to 43,000- and 41,000-molecular-weight bands after complete denaturation in sodium dodecyl sulfate. They were antigenically identical among all the strains, showed close resemblance in amino acid composition to each other and a general similarity to OmpF of Escherichia coli, and are proposed to be the porins of B. abortus. Group 3 proteins occurred as 30,000-molecular-weight bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, although additional bands were frequently observed in this region. In none of the strains did group 3 proteins manifest heat-modifiable characteristics. Proteins of different strains bore a high degree of similarity to each other in amino acid composition, except in methionine, isoleucine, tyrosine, and histidine. Differences occurred consistently in amino acid composition between group 2 and 3 proteins, and some of these correspond to differences between OmpF and OmpA. Group 2 and 3 proteins were antigenically distinct from each other, but the principal group 3 antigens were shared among all the strains. Despite the lack of heat modifiability, perhaps influenced by adherent lipopolysaccharide, group 3 proteins are proposed as counterparts to OmpA. Most of the group 1 proteins, minor components, were physically associated with those of group 3 unless in sodium dodecyl sulfate. Group 1 proteins produced a major band at 94,000 and exhibited heat modifiability. No evidence was found of a low-molecular-weight lipoprotein in the outer membrane of B. abortus, but this is not taken to exclude its occurrence.
Identification of coprogen B and its breakdown products from Histoplasma capsulatum
Authors: Burt W R
Published: January 2020

Iron added to a chemically defined liquid medium suppressed hydroxamic acid production at 37 degrees C by yeast cells of Histoplasma capsulatum. Four hydroxamic acids, HA-I, HA-II, HA-III, and HA-IV, present in the low-iron fluid after the culture of H. capsulatum were isolated by extraction and cation-exchange chromatography through cellulose phosphate (0.35% formic acid). Visible spectra of prepared ferrihydroxamates indicated that HA-II and HA-III were monohydroxamates, whereas HA-I and HA-IV were identified as di- and trihydroxamates, respectively. Reductive hydrolysis of HA-I (the major hydroxamic acid isolated) yielded ornithine. Hydrolysis of HA-IV in water or in 0.1 N NaOH resulted in the formation of HA-I (dihydroxamic acid) and HA-II (monohydroxamic acid). Based on their charge at pH 5.2 and 2 determined by paper electrophoresis, Rf values on thin-layer chromatography, infrared spectra, and reactivity to ninhydrin, three of the isolated hydroxamic acids were identified as deferricoprogen B (HA-IV) and its breakdown products, dimerumic acid (HA-I) and trans fusarinine (HA-II). HA-I and HA-IV exhibited growth factor activity for both yeast and mycelial forms of growth of H. capsulatum.
Ability of Macrophages to Process and Present
Treponema pallidum
Bosnia A Strain Antigens in Experimental Syphilis of Syrian Hamsters
Authors: Bagasra Omar , Damjanov Ivan
Published: January 2020

The ability of macrophages to process and present treponemal antigens to T-lymphocytes was studied in early stages of experimental syphilis produced by
Treponema pallidum
Bosnia A strain (the causative agent of endemic syphilis) infection of inbred Syrian hamsters (LSH/Ss Lak strain). A difference was noticed in the response of macrophages obtained from the peritoneal cavity, lymph nodes, and spleens of the infected animals. In all of these locations, a general increase in the population of Ia

k

-positive macrophage was seen during the entire period of infection, i.e., 3 to 18 weeks after inoculation. Peritoneal cavity-derived macrophages showed no difference in antigen presentation to sensitized and nonsensitized T-lymphocytes for the first 7 weeks of infection. However, at 18 weeks after infection, peritoneal macrophages lost their ability to process treponema antigens. Spleen- and lymph node-derived macrophages did not exhibit a parallel loss in their ability to process treponema antigens. A fluctuation without a consistent pattern was noticed in the antigen processing and presentation by macrophages from the spleen and lymph nodes. In general, the sensitized T-lymphocytes responded to treponema antigen presented by macrophages more vigorously than the nonsensitized T-lymphocytes. An increased ability of spleen-derived macrophages to process and present antigens was noticed throughout the entire period of infection. The macrophages from the lymph nodes showed such an increase only temporarily at 3 weeks after infection. These data suggest that the processing and presentation of treponema antigens by macrophages in acute syphilitic infection fluctuates considerably and depends on the source of macrophages and the duration of the infection. The differences in the response of peritoneal cavity-, spleen-, and lymph node-derived macrophages probably reflect the complex interactions between the macrophage and other cells involved in the immune response to treponema infection.
In vitro amoebicidal activity of immune cells
Authors: Ghadirian E , Meerovitch E
Published: January 2020

The amoebicidal activity of peripheral blood lymphocytes and spleen and peritoneal cells from hamsters vaccinated against or protected from hepatic amoebiasis and from those with hepatic amoebiasis was investigated. Peripheral blood lymphocytes and peritoneal and spleen cells from vaccinated or protected animals can kill trophozoites of Entamoeba histolytica in vitro. In contrast, spleen cells from infected hamsters showed no significant cytotoxic effect on the parasite. These data suggest that cellular immunity plays an important role in host defense against hepatic amoebiasis.
Transfer of Salmonella resistance and delayed hypersensitivity with murine-derived transfer factor
Authors: Smith R A , Esa A , Stiff M
Published: January 2020

Protective host immunity and delayed hypersensitivity were transferred to nonimmune ICR and C3H/HeJ mice with transfer factor prepared from the splenic lymphocytes of ICR Swiss mice immune to Salmonella typhimurium. Only mice injected with the "immune" dialysate exhibited significant footpad swelling (P less than 0.01) to a spent medium antigen of S. typhimurium, but not Listeria monocytogenes. Host survival to a lethal Salmonella challenge infection was seen only in transfer factor-injected mice. Also, these challenged animals had fewer numbers of bacteria present in their spleens (P less than 0.01) than did challenged mice previously injected with either control dialysates or commercial endotoxin. Neither the Salmonella antigens nor endotoxin present in the sterile transfer factor preparation was responsible for the transfer of host protection and delayed hypersensitivity, since none of the control dialysates resulted in any positive responses when injected into either the ICR Swiss or endotoxin-resistant C3H/HeJ mice.
Opposite effects of human monocytes, macrophages, and polymorphonuclear neutrophils on replication of Blastomyces dermatitidis in vitro
Authors: Brummer E , Stevens D A
Published: January 2020

The purpose of this study was to determine the effects of human monocytes, macrophages, and polymorphonuclear neutrophils (PMN) on the fungal pathogen Blastomyces dermatitidis in vitro. Peripheral blood monocyte monolayers significantly inhibited the replication of a virulent strain (V) and an avirulent strain (AV) of B. dermatitidis by 35 and 28%, respectively. Macrophage monolayers, derived from monocytes by in vitro culturing for 9 days, also inhibited the replication of V and AV in 24-h cocultures; in 72-h cocultures, the inhibition was increased (85 and 88%, respectively). By contrast, PMN stimulated the replication of V and AV in 24-h cocultures (i.e., 45%; AV, 18%) and in 72-h cocultures (V, 68%; AV, 65%). No effect was observed in 2-h cocultures of PMN and B. dermatitidis, even though Candida albicans was killed by PMN in concurrent experiments. PMN stimulated replication of V in a dose-dependent manner, and viability of PMN was not a requirement for the achievement of this effect. These results indicate that monocytes and macrophages significantly inhibited the replication of B. dermatitidis, whereas PMN had an opposite effect. Our findings raise the possibility that these phagocytic cells may have similar opposing effects on the replication of B. dermatitidis in vivo.
Cryptococcal capsular polysaccharide-induced modulation of murine immune responses
Authors: Breen J F , Lee I C , Vogel F R , Friedman H
Published: January 2020

Cryptococcus neoformans, an opportunistic fungal pathogen, often causes serious and life-threatening infections in immunocompromised hosts as well as in normal individuals. In the present study, purified cryptococcal capsular polysaccharide antigen was examined for its effect on several parameters of immune response and its ability to induce immune response to itself. Injection of the antigen into mice resulted in a dose-related specific antibody response which was detected at the individual antibody plaque-forming-cell level by a hemolytic assay in gel. Relatively low doses of cryptococci induced a maximal response, whereas higher doses resulted in a markedly depressed response. The antibody response to the cryptococcal capsular polysaccharide antigen appeared to be T cell independent and regulated by suppressor T cells, since mice injected with antilymphocyte serum or antithymocyte serum showed specific antibody responses to the antigen that were higher than those of untreated mice. It also markedly affected the in vitro mixed-lymphocyte reaction when added to cultures of mouse spleen cells being challenged in vitro with mitomycin C-treated allogeneic cells. The lower doses stimulated the response, whereas higher doses suppressed it. The macrophage response to yeast cells but not opsonized sheep erythrocytes was also modulated by the cryptococcal antigen.
Effect of splenic sequestration of erythrocytes on splenic clearance function and susceptibility to septic peritonitis
Authors: Grover G J , Loegering D J
Published: January 2020

The effect of splenic sequestration of erythrocytes (RBC) on splenic clearance function and susceptibility to septic peritonitis was studied. Homologous RBC were treated with 20 mM phenylhydrazine hydrochloride in vitro and injected into rats at doses of 5, 15, 75, and 150 mg of hemoglobin per 100 g. Splenic 93, 23, and 13% of the injected dose, respectively, whereas less than 2.1% of the same doses of washed RBC were localized in the spleen. The total quantity of phenylhydrazine-treated RBC sequestered by the spleen was similar for the three larger doses (40 to 45 mg of hemoglobin per g of tissue), indicating that this is the capacity of the spleen to take up this type of RBC in 234 h. The phenylhydrazine-treated RBC in doses of 15, 75, and 150 mg of hemoglobin per 100 g depressed the clearance rate and splenic localization of a test dose of phenylhydrazine-treated RBC, whereas splenic clearance function was unchanged after a dose of 5 mg of hemoglobin per 100 g. Splenectomy or injection of doses of phenylhydrazine-treated RBC which depressed splenic clearance function increased the susceptibility to septic peritonitis induced by cecal ligation and puncture. After thermal injury, splenic clearance function was found to be depressed. Also, splenic localization of RBC 24 h after thermal injury was found to be approximately equal to that after injection of the doses of phenylhydrazine-treated RBC which depressed splenic clearance function. It is concluded that splenic sequestration of RBC can depress splenic clearance function and increase susceptibility to peritonitis, and that this may be one mechanism for the increased susceptibility to infection seen after thermal injury.
Inhibitory effect of dietary soybean meal on the establishment of a Clostridium strain in the gastrointestinal tract of mice
Authors: Lhuillery C , Demarne Y , Ducluzeau R , Clara A
Published: January 2020

The presence of soybean meal in the diet of gnotobiotic mice was shown to prevent the establishment of a clostridial strain in the gastrointestinal tract. Soybean meal did not inhibit the growth of Clostridium in vitro, suggesting that the host plays a role in the observed inhibition of bacterial growth. The inhibitory factor in the soybean meal contains at least two components.
Antigenic analysis of Giardia lamblia from Afghanistan, Puerto Rico, Ecuador, and Oregon
Authors: Smith P D , Gillin F D , Kaushal N A , Nash T E
Published: January 2020

The trophozoite antigens of Giardia lamblia to which host humoral and cellular immune responses are directed have not been identified. Therefore, we initiated studies to characterize these antigens in strains of G. lamblia from Afghanistan, Oregon, Ecuador, and Puerto Rico. By polyacrylamide gel electrophoresis, the electrophoretic mobility patterns of proteins of the four strains were similar; molecular weights of protein bands ranged between 12,000 and 140,000. The antigens which reacted with rabbit and anti-G. lamblia antisera by immunoelectrophoresis were also similar for the four strains. However, comparison by crossed immunoelectrophoresis showed the Oregon strain, which has been the longest in culture, lacked a set of anodic antigens and the single neutral antigen which were present in the other three strains. In addition, other minor antigen differences between the strains were detected by this technique. When we employed trophozoites from each strain as antigen in an enzyme-linked immunosorbent assay against 10 human antisera of various liters, we also detected some differences between the strains. Although polyacrylamide gel electrophoresis and immunoelectrophoresis revealed gross similarity among G. lamblia from widely differing geographic locations, subtle differences detected by crossed electrophoresis and enzyme-linked immunosorbent assay suggest the existence of potentially important antigenic differences among these strains.
Damage to
Aspergillus fumigatus
and
Rhizopus oryzae
Hyphae by Oxidative and Nonoxidative Microbicidal Products of Human Neutrophils In Vitro
Authors: Diamond Richard D. , Clark Robert A.
Published: January 2020

Our previous studies established that human neutrophils could damage and probably kill hyphae of
Aspergillus fumigatus
and
Rhizopus oryzae
in vitro, primarily by oxygen-dependent mechanisms active at the cell surface. These studies were extended, again quantitating hyphal damage by reduction in uptake of
14
C-labeled uracil or glutamine. Neither
A. fumigatus
nor
R. oryzae
hyphae were damaged by neutrophils from patients with chronic granulomatous disease, confirming the importance of oxidative mechanisms in damage to hyphae. In contrast, neutrophils from one patient with hereditary myeloperoxidase deficiency damaged
R. oryzae
but not
A. fumigatus
hyphae. Cell-free, in vitro systems were then used to help determine the relative importance of several potentially fungicidal products of neutrophils. Both
A. fumigatus
and
R. oryzae
hyphae were damaged by the myeloperoxidase-hydrogen peroxide-halide system either with reagent hydrogen peroxide or enzymatic systems for generating hydrogen peroxide (glucose oxidase with glucose, or xanthine oxidase with either hypoxanthine or acetaldehyde). Iodide with or without chloride supported the reaction, but damage was less with chloride alone as the halide cofactor. Hydrogen peroxide alone damaged hyphae only in concentrations ≥1 mM, but 0.01 mM hypochlorous acid, a potential product of the myeloperoxidase system, significantly damaged
R. oryzae
hyphae (a 1 mM concentration was required for significant damage to
A. fumigatus
hyphae). Damage to hyphae by the myeloperoxidase system was inhibited by azide, cyanide, catalase, histidine, and tryptophan, but not by superoxide dismutase, dimethyl sulfoxide, or mannitol. Photoactivation of the dye rose bengal resulted in hyphal damage which was inhibited by histidine, tryptophan, and 1,4-diazobicyclo(2,2,2)octane. Lysates of neutrophils or separated neutrophil granules did not affect
A. fumigatus
hyphae, but did damage
R. oryzae
hyphae. Similarly, three preparations of cationic proteins purified from human neutrophil granules were more active in damaging
R. oryzae
than
A. fumigatus
hyphae. This damage, as with the separated granules and whole cell lysates, was inhibited by the polyanion heparin. Damage to
R. oryzae
hyphae by neutrophil cationic proteins was enhanced by activity of the complete myeloperoxidase system or by hydrogen peroxide alone in subinhibitory concentrations. These data support the importance of oxidative products in general and the myeloperoxidase system in particular in damage to hyphae by neutrophils. Cationic proteins may also contribute significantly to neutrophil-mediated damage to
R. oryzae
hyphae.
Effects of endogenous and exogenous inhibitors on the incorporation of labeled precursors into DNA by human mononuclear cells
Authors: Sims T J , Page R C
Published: January 2020

The degree of responsiveness of lymphoid cells to activation by mitogens and antigens is commonly assessed in vitro by measuring radioactive DNA precursor incorporation. Several lines of evidence indicate that artifacts affect the results and that these measurements may not be an accurate reflection of cell activation. Cultures of blastogenically activated lymphocytes contain soluble, noncytotoxic factors that inhibit the incorporation of radioactive nucleosides into DNA by dividing cells without affecting their rate of DNA synthesis. Inhibitors were found in the serum component of the medium and in the bacterial homogenates used to activate the cells, and they were produced by the activated cells. Inhibitor activity in serum has properties expected of a nucleoside such as thymidine, including a molecular weight of less than 10(3). The inhibitor activity present in some bacterial homogenates and that produced by activated cells enzymically degrade labeled DNA precursors, thereby preventing their availability for incorporation. Other bacterial preparations contain DNA precursors, which compete with labeled nucleosides for incorporation, and additional low-molecular-weight inhibitor is produced when the preparations are incubated. Preparations of various bacteria differ greatly with regard to the potency of their inhibitor activity. In some cases incorporation of label in activated cultures is reduced to background levels. Inhibition by these substances leads to erroneous conclusions regarding the proliferative activity of cultured lymphocytes, since the amount of label incorporated does not accurately indicate the true rate of DNA synthesis of the cells.
Failure to Detect Hemagglutination-Inhibiting Antibodies with Intact Avian Influenza Virions
Authors: Lu Bao-Lan , Webster Robert G. , Hinshaw Virginia S.
Published: January 2020

Avian influenza viruses replicate in a variety of mammals and birds, yet hemagglutination inhibition tests show that postinfection sera from these animals (e.g., ferrets and ducks) have insignificant levels of antibodies (Hinshaw et al., Infect. Immun. 34:354-361, 1981). This suggested that avian influenza viruses, in contrast to mammalian viruses, may not induce a significant humoral response. Studies reported here indicate that avian influenza viruses do induce high levels of antibodies in ferrets, ducks, and mice and produce long-lived memory for cytotoxic T-cells in mice. The failure to detect hemagglutination-inhibiting antibodies to avian viruses was explained by the finding that antibodies to avian influenza viruses were not detectable in hemagglutination inhibition tests with intact virus yet were readily demonstrable when hemagglutinin subunits were used. In addition, these sera contained high levels of neutralizing antibodies to the avian virus. These findings suggest that the hemagglutinins of avian and mammalian influenza viruses may differ in their accessibility to antibodies or the biological consequence of antibody attachment or both. The practical consequence of these studies is that hemagglutination inhibition tests with intact avian viruses fail to detect antibody and do not correlate with virus neutralization. The avian virus used in these studies, A/Mallard/NY/6870/78 (H2N2), replicated and caused mortality in BALB/c mice, emphasizing that the host range and virulence of avian viruses extends to mammals. The above findings suggest that avian viruses could infect mammals in nature, yet seroepidemiological studies with conventional hemagglutination inhibition tests could give misleading results.
Dissemination of gonococcal infection is associated with delayed stimulation of complement-dependent neutrophil chemotaxis in vitro
Authors: Densen P , MacKeen L A , Clark R A
Published: January 2020

Gonococci isolated from patients with uncomplicated gonorrhea or disseminated infection were examined for their ability to stimulate neutrophil chemotaxis in vitro. A neutrophil chemotactic response was not observed when as many as 10(9) colony-forming units of gonococci were incubated in buffer alone. However, a striking response was observed when 4 x 10(7) colony-forming units were incubated in 10% pooled normal human serum. Activation of complement was required for chemotaxis as demonstrated by complement consumption and failure of chemotactic activity generation in serum treated with heat or EDTA. Chromatography of activated serum demonstrated a single peak of chemotactic activity with an apparent molecular weight of 15,000 and was shown to be due to C5a. Examination of the kinetics of chemotactic factor generation demonstrated that local isolates stimulated a rapid response (about 60% maximal in 5 min), whereas the response to disseminated isolates was delayed (50% maximal in 20 to 30 min). Chemotactic activity generated by both types of isolates was suppressed at early time periods in agammaglobulinemic serum, indicating that immunoglobulins contribute to the generation of activity. Both pathways of complement activation were utilized by the two types of gonococci, but there was preferential dependence on the alternative pathway for disseminated strains and on the classical pathway for local isolates. We suggest that delayed stimulation of complement-dependent neutrophil migration may account in part for the infrequency of genital symptoms and may contribute to the mechanism of dissemination in patients with systemic gonococcal infection.
Bacteriology of experimental gingivitis in young adult humans
Authors: Moore W E , Holdeman L V , Smibert R M , Good I J , Burmeister J A , Palcanis K G , Ranney R R
Published: January 2020

From replicate trials of experimental gingivitis in four periodontally healthy subjects, 166 bacterial species and subspecies were detected among 3,034 randomly selected isolates from 96 samples. Of these bacteria, Actinomyces naeslundii (serotype III and phenotypically similar strains that were unreactive with available antisera), Actinomyces odontolyticus (serotype I and phenotypically similar strains that were unreactive with available antisera), Fusobacterium nucleatum, Lactobacillus species D-2, Streptococcus anginosus, Veillonella parvula, and Treponema species A appeared to be the most likely etiological agents of gingivitis. Statistical interpretations indicated that the greatest source of microbiological variation of the total flora observed was person-to-person differences in the floras. The next greatest source of variation was the inflammatory status of the sample sites. Person-to-person differences were smallest at experimental day 4. The floras became more diverse with time and as gingivitis developed and progressed. Analyses indicated that sequential colonization by certain species was repeatable and therefore probably predictable. Variation was relatively small between replicate trials, between two sites on the same teeth sampled on the same day, and between the same sites sampled at the same relative time in a replicate trial.
Neutralization of Chlamydia trachomatis infectivity with antibodies to the major outer membrane protein
Authors: Caldwell H D , Perry L J
Published: January 2020

Rabbit immunoglobulin G (IgG) antibodies raised against the major outer membrane protein of the Chlamydia trachomatis lymphogranuloma venereum strain 434 neutralized the infectivity of the parasite for HeLa 229 cells. The mechanism by which anti-major outer membrane protein IgG prevented C. trachomatis from establishing infection was studied by using intrinsically 14C-radiolabeled elementary bodies. Neutralized elementary bodies were filterable through a polycarbonate filter (pore diameter, 600 nm), demonstrating that reduction in infectivity was not due to the aggregation of elementary bodies by cross-linking IgG. Antibody-neutralized elementary bodies attached to and penetrated HeLa cells at rats nearly identical to those for infectious organisms exposed to nonneutralizing control IgG. These results suggest that antibody interferes with the infectious process of the parasite after its internalization. Anti-major outer membrane protein Fab fragments could not be substituted for neutralizing IgG antibodies. The requirement for intact IgG implies that cross-linking of antibodies to the major outer membrane protein on the surfaces of the organisms may be instrumental in neutralization.
Immune Responses to
Candida albicans
in Genetically Distinct Mice
Authors: Hector Richard F. , Domer Judith E. , Carrow Emily W.
Published: January 2020

Mice from six genetically distinct strains were examined for their immune responses to
Candida albicans
in in vitro and in vivo assays, and naive mice and mice immunized with the fungus were challenged intravenously with three different doses of
C. albicans
to determine differences in susceptibility. Naive mice from the six groups showed substantial differences in resistance to challenge based on mortalities and quantitative cultures of kidneys, with mice from strains C57BL/6J and BALB/cByJ showing the most resistance; mice from strains A/J, C3H/HeJ, and CBA/J showing moderate susceptibility; and mice from strain DBA/2J showing the highest degree of susceptibility to challenge. Unimmunized mice from strains C57BL/6J and BALB/cByJ did not produce detectable levels of
Candida
-specific antibody by the end of the 28-day observation period when challenged intravenously, but the other strains did. Immunized mice showed a degree of protection to challenge, with all groups except mice from strain BALB/cByJ showing a reduction of two to three log units in the level of colonization in their kidneys and all strains producing significant levels of antibody. Additionally, the immunized mice of all strains developed substantial levels of delayed-type hypersensitivity and demonstrated nearly identical lymphocyte proliferative responses to
Candida
antigens. The results indicate that resistance to systemic candidiasis is dependent upon a combination of innate factors, predominately an intact complement system, and the acquisition of an immune response, most likely of a cell-mediated type. Additionally, the findings suggest that genetic control of acquired resistance to
C. albicans
may not be associated with the
H-2
complex.
Selective cytotoxicity of Clostridium perfringens delta toxin on rabbit leukocytes
Authors: Jolivet-Reynaud C , Cavaillon J M , Alouf J E
Published: January 2020

Clostridium perfringens delta toxin was selectively cytotoxic for various rabbit leukocyte populations. The sensitivity of these populations to the toxin varied, depending on the tissue from which they were derived, from 28% (appendix) to 41% (bone marrow) and 32% (spleen). Macrophages were uniformly killed by delta toxin, whereas thymocytes were essentially resistant. Selective cytotoxicity was correlated to the specific binding of the radiolabeled toxin by target cells. The relationship between sensitivity to the toxin and the presence of GM2 ganglioside in the cell membrane of rabbit leukocytes is discussed. Delta toxin might prove a useful new tool for separating leukocyte subpopulations based on their differential sensitivity to the cytolethal effect of this protein.
Delayed-type hypersensitivity and immunoglobulin E in American cutaneous leishmaniasis
Authors: Lynch N R , Yarzábal L , Verde O , Avila J L , Monzon H , Convit J
Published: January 2020

Delayed-type hypersensitivity (DTH) and both total and specific immunoglobulin E (IgE) antibody levels were studied during an outbreak of American cutaneous leishmaniasis. Direct correlations were detected between DTH reactivity and either age or the period of evolution of the infection, and a clear association with sex (strongest response in females) was observed. Extremely high, age-dependent, total serum IgE levels were measured in the study group, probably due to concurrent intestinal helminthiasis. A low proportion of the group also had detectable levels of specific anti-Leishmania IgE antibody. Total and specific IgE levels were also sex dependent (lowest in females), and an inverse correlation was found between these levels and DTH responsiveness, possibly reflecting the intervention of regulatory influences of T-lymphocyte activity.
Antigenic differences among isolates of Plasmodium falciparum demonstrated by monoclonal antibodies
Authors: Schofield L , Saul A , Myler P , Kidson C
Published: January 2020

Hybridomas raised against two Papua New Guinea (PNG) isolates of Plasmodium falciparum secreted monoclonal antibodies which bound to schizonts of all seven PNG isolates tested but not to schizonts of four non-PNG isolates from Thailand, Nigeria, Ghana, and The Netherlands. Some of the monoclonal antibodies were tested for their ability to inhibit the growth of one PNG isolate, one Thai isolate, and one Nigerian isolate in vitro. Only the growth of the PNG isolate was inhibited, thus demonstrating functional antigenic differences among isolates of P. falciparum.
Outer membrane characteristics of Campylobacter jejuni
Authors: Logan S M , Trust T J
Published: January 2020

Outer membranes were isolated from type strains and wild-type isolates of Campylobacter jejuni and Campylobacter coli by sodium lauryl sarcosinate extraction, and the polypeptide complement and lipopolysaccharide (LPS) content were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The protein profiles exhibited by membranes from both species were quite similar, but could be distinguished from the type strain of the genus, C. fetus subsp. fetus CIP5396. The sodium dodecyl sulfate electrophoretograms of C. jejuni and C. coli were dominated by a major polypeptide band. In the reference strain C. jejuni VC74, this polypeptide had an apparent molecular weight of 45,000, was heat modifiable, and was shown to be transmembrane by virtue of its peptidoglycan association and surface exposure. Two other proteins with approximate molecular weights of 37,000 and 73,000 were also surface exposed on C. jejuni VC74 and represented potential surface antigens. The LPS of C. jejuni and C. coli was of low molecular weight, suggesting that serotypic differences due to LPS were based on different carbohydrate compositions of core LPS. In contrast, the LPS of C. fetus CIP5396 exhibited O antigen polysaccharide chains of intermediate chain length. Fragments of outer membranes released during growth of C. jejuni VC74 displayed a polypeptide profile which differed from that of sarcosinate-extracted outer membranes. Radiolabeling demonstrated that the proteins exposed on the surface of this released membrane differed from those exposed on the cell surface and would likely contribute to the antigenic complexity of C. jejuni.
Evidence for reactive oxygen intermediates causing hemolysis and parasite death in malaria
Authors: Clark I A , Hunt N H
Published: January 2020

A rapid reduction in parasitemia associated with damage to intraerythrocytic parasites was observed in Plasmodium vinckei-infected mice after they had received a single intravenous injection of alloxan. This was not prevented by prior injection of glucose, but was prevented by desferrioxamine or diethyldithiocarbamate. Prior injection of propanol partially blocked the phenomenon. A transient hemolysis was observed in malaria-infected mice, but not in controls, after injection of alloxan. This was also blocked by desferrioxamine, but not by glucose. Both the fall in parasitemia and hemolysis occurred, but less dramatically, when phenylhydrazine or hydrogen peroxide was injected into parasitized mice. Again, the hemolysis was blocked by desferrioxamine. These observations are consistent with the parasite death and hemolysis being mediated by reactive oxygen species, possibly hydroxyl radicals, and have implications for our understanding of hemolysis, endothelial damage, and parasite suppression in acute malaria. Our evidence that malaria parasites are susceptible to free oxygen radicals supports the view that high intraerythrocytic oxidative stress may contribute to the high frequencies in malarial areas of genes for certain erythrocyte-related traits and suggests that some antimalarial drugs may suppress parasites partly through oxidative damage.
Opsonizing and bactericidal effects of normal human serum on nontypable Haemophilus influenzae
Authors: Musher D M , Hague-Park M , Baughn R E , Wallace R J , Cowley B
Published: January 2020

The observation that nontypable (NT) Haemophilus influenzae causes serious infection in adults has stimulated interest in mechanisms that may protect the human host against NT H. influenzae infection. Incubating NT H. influenzae with normal human serum (NHS) caused dose- and time-dependent killing that varied with the individual NHS and NT H. influenzae. Adsorption of NHS with NT H. influenzae removed bactericidal activity against the adsorbing isolate but not necessarily that against others, suggesting antigenic diversity and supporting recent studies that show different outer membrane protein profiles among NT H. influenzae. Heating NHS to 56 degrees C for 30 min abolished bactericidal activity; this activity was not restored by complement-rich guinea pig serum or NT H. influenzae-adsorbed NHS. This is analogous to the "third factor" needed for intraleukocytic killing of pneumococci. Optimal opsonization of NT H. influenzae for phagocytosis by human polymorphonuclear leukocytes required antibody and complement, but other serum factors also played a role. Bactericidal activity generally, but not uniformly, correlated with opsonizing activity of individual NHS. Humoral factors may be important in host defenses against NT H. influenzae infection; their emergence during convalescence warrants further study.
Humoral Immune Response in Acquired Immunity to Chlamydial Genital Infection of Female Guinea Pigs
Authors: Rank Roger G. , Barron Almen L.
Published: January 2020

Immunity to reinfection in the genital tract of female guinea pigs with the agent of guinea pig inclusion conjunctivitis was found to be dependent upon an intact humoral immune response. Cell-mediated immunity in the absence of humoral immunity had no apparent role in resistance to challenge infection.
Immunoglobulin G subclass restriction of antibodies against hepatitis B surface antigen
Authors: Morell A , Roth-Wicky B , Skvaril F
Published: January 2020

Immunoglobulin G (IgG) antibodies against hepatitis B surface antigen were found to be restricted to subclasses IgG1 and IgG3 in serum samples of 17 individuals. Quantitative determinations showed that in 10 samples the minor serum subclass IgG3 contained more antibodies than the predominant subclass IgG1. Ranges of concentrations were between 0.72 and 16.50 micrograms/ml for IgG3 antibodies and between 0.55 and 6.19 micrograms/ml for antibodies of subclass IgG1.
Suppression of in vitro lymphocyte DNA synthesis by killed Pseudomonas aeruginosa
Authors: Rubin H R , Sorensen R U , Chase P A , Klinger J D
Published: January 2020

Whole antibiotic-killed classic Pseudomonas aeruginosa organisms elicited human lymphocyte [3H]thymidine (TdR) uptake in vitro after 5 days in culture. However, high concentrations of the same preparation did not elicit [3H]TdR incorporation. The investigation of this lymphocyte unresponsiveness revealed that a high dose of P. aeruginosa, when added to lymphocyte cultures together with optimal concentrations of lymphocyte activators (e.g., plant lectins or whole killed Staphylococcus aureus Cowan 1), caused a potent, nonspecifically expressed inhibition of lymphocyte [3H]TdR uptake in response to these mitogens. High doses of P. aeruginosa were not cytotoxic to lymphocytes, and the inhibition caused was reversed when lymphocytes were washed free of bacteria. The inhibition of [3H]TdR uptake by high-dose P. aeruginosa did not require the generation of adherent suppressor cells or prostaglandin-mediated, steroid-sensitive or radiation-sensitive suppressor mechanisms. At optimal lymphocyte stimulatory concentrations of P. aeruginosa, the addition of indomethacin or the depletion of adherent cells caused an increase in lymphocyte [3H]TdR incorporation. This is consistent with an adherent-cell population regulating [3H]TdR uptake in response to P. aeruginosa via a prostaglandin-dependent pathway. This population was not involved in the inhibition of lymphocyte [3H]TdR uptake by high concentrations of P. aeruginosa.
Acute iron overload in mice: pathogenesis of Salmonella typhimurium infection
Authors: Sawatzki G , Hoffmann F A , Kubanek B
Published: January 2020

The bacterial growth in the tissues of C3D2F1 male mice was measured during an experimental infection with two Salmonella typhimurium strains (high virulence, strain 2386/74; low virulence, strain L15403). This experimental model was used for evaluation of the pathogenesis in normal and iron-overloaded animals. Acute iron overload was accomplished by intramuscular injections of chelated iron (with 2,3-dihydroxybenzoic acid and citrate) with a single dose of 100 micrograms of iron per mouse. Bacteria were given intraperitoneally 1 h after the iron injection. Serum iron levels, transferrin levels, and the bacteria counts in blood and liver were measured simultaneously in all animals. There was a significant increase of bacterial growth in all tissues in the iron-treated animals. Iron abolished the normal clearance of the bacteria with low virulence from the blood. This study demonstrates that a general iron overload, as determined by an increased serum iron level, resulting from preinjection of iron, enhances bacterial growth.
Mechanisms That Control Bacterial Populations in Continuous-Flow Culture Models of Mouse Large Intestinal Flora
Authors: Freter Rolf , Brickner Howard , Botney Mitchell , Cleven Diane , Aranki Alexander
Published: January 2020

A previous study had established that anaerobic continuous-flow (CF) cultures of conventional mouse cecal flora were able to maintain the in vivo ecological balance among the indigenous bacterial species tested. This paper describes experiments designed to determine the mechanisms which control the population sizes of these species in such CF cultures. One strain each of
Escherichia coli, Fusobacterium
sp., and
Eubacterium
sp. were studied. Growth of these strains in filtrates of CF cultures was considerably more rapid than in the CF cultures themselves, indicating that the inhibitory activity had been lost in the process of filtration. Growth rates to match those in CF cultures could be obtained, however, by restoring the original levels of H
2
S in the culture filtrates. The inhibitory effect of H
2
S in filtrates and in dialysates of CF cultures could be abolished by adding glucose or pyruvate, but not formate or lactate. The fatty acids present in CF cultures matched those in the cecum of conventional mice in both quality and concentration. These acids could not account for the slow rates of growth of the tested strains in CF cultures, but they did cause a marked increase in the initial lag phase of
E. coli
growth. The results obtained are compatible with the hypothesis that the populations of most indigenous intestinal bacteria are controlled by one or a few nutritional substrates which a given strain can utilize most efficiently in the presence of H
2
S and at the prevailing conditions of pH and anaerobiosis. This hypothesis consequently implies that the populations of enterobacteria, such as the
E. coli
strain tested, and those of the predominant anaerobes are controlled by analogous mechanisms.
Enhancement of Antigen-Specific Suppression by Muramyl Dipeptide
Authors: Ferguson Thomas A. , Krieger Nancy J. , Pesce Amadeo , Michael J. Gabriel
Published: January 2020

The effect of the synthetic adjuvant MDP (
N
-acetyl-muramyl-L-alanyl-D-isoglu-tamine) on the generation of antigen-specific suppression was investigated. Suppression of the anti-bovine serum albumin response, which was achieved by intravenous administration of a peptic fragment of the antigen, was greatly enhanced by simultaneous administration of MDP. Induction of suppression by a combination of bovine serum albumin fragments and MDP was found to be antigen specific and appeared to occur via the generation of antigen-specific suppressor T cells.
Effect of Micropolyspora faeni cells and cell wall fractions on rabbit alveolar macrophages
Authors: Learn D B , Snyder I S
Published: January 2020

The reactivity of alveolar macrophages (AM) to cells and cell wall fractions (CWF) of Micropolyspora faeni was investigated. Exposure of cultured AM to M. faeni and its CWF caused the AM to form clumps or aggregates which remained attached to the culture dish surface. Other gram-positive and gram-negative bacteria as well as yeast, zymosan, latex microspheres, and isolated peptidoglycan from Listeria monocytogenes did not cause this response. The response was independent of species source and antibody content of the serum used in culture. The use of heat-inactivated sera negated the role of complement activation in the aggregation of AM. AM cultures required a period of culture before exposure to cells or CWF for this response to occur. This response was both time and dose dependent. Rabbit peritoneal macrophages also exhibited the clumping response. Degradation of a purified CWF, fraction 3, with lysozyme greatly diminished the clumping response. Chemical purification of fraction 3 with periodate, formamide, or trichloracetic acid also decreased this activity. These data suggest that the major active component causing this response is peptidoglycan but that other materials associated with the cell wall may also be important. A soluble-factor chemotactic for normal rabbit AM was found in the culture fluid of AM exposed to fraction 3. M. faeni cells and CWF also caused normal rabbit AM to chemiluminesce.
Replication of Mouse Hepatitis Viruses with High and Low Virulence in Cultured Hepatocytes
Authors: Taguchi Fumihiro , Kawamura Seiji , Fujiwara Kosaku
Published: January 2020

Ten strains of mouse hepatitis virus with different levels of virulence and hepatotropism were examined for the ability to replicate in cultured mouse hepatocytes. All of these viruses multiplied well in hepatocytes, attaining a maximum of 10
5
to 10
7
PFU per 0.2 ml, with cytopathic effects characterized by the formation of polykaryocytes. However, in nonparenchymal adherent cells of the liver (liver macrophages), highly virulent mouse hepatitis virus type 2 multiplied to a titer 1,000 times higher than that of mouse hepatitis virus S with a low virulence. These results suggest that the virulence of mouse hepatitis virus in infected mice is determined by its potential for replication not in hepatocytes, but in macrophages, including Kupffer cells in the liver.
Inhibition of bacterial adherence to hydrocarbons and epithelial cells by emulsan
Authors: Rosenberg E , Gottlieb A , Rosenberg M
Published: January 2020

Acinetobacter calcoaceticus RAG-1 and BD413, as well as Streptococcus pyogenes M-5, adhered to octane. Adherence was inhibited by emulsan (100 micrograms/ml), the polymeric emulsifying agent produced by A. calcoaceticus RAG-1. Emulsan also inhibited adherence of S. pyogenes and RAG-1 to buccal epithelial cells. The mean values of bound S. pyogenes per epithelial cell were 57.2 and 20.7 for the control and emulsan-containing suspensions, respectively; mean values of bound RAG-1 per epithelial cell were 221 for the control and 40 for the suspension containing 100 micrograms of emulsan per ml. Desorption of previously bound RAG-1 from epithelial cells by emulsan was concentration dependent: a maximum of 80% desorption was obtained with 200 micrograms of emulsan per ml. The data showing that emulsan desorbed 70% of the indigenous bacterial flora from buccal epithelial cells suggest that hydrophobic interactions mediate not only the in vitro adherence of laboratory strains to epithelial cells, but actually govern the adherence of the majority of the bacteria that colonize this surface. The advantages of using emulsan as an antiadherence agent include its chemical purity, stability, and polymeric nature.
Advantages of measuring changes in the number of viable parasites in murine models of experimental cutaneous leishmaniasis
Authors: Hill J O , North R J , Collins F M
Published: January 2020

Previously published studies of experimental cutaneous leishmaniasis in the mouse have relied almost exclusively on measuring changes in lesion size to follow the course of the infection. The purposes of the studies reported here were to develop a technique to quantitate the number of viable organisms in the tissues and to use the technique to follow the development and resolution of the primary infection as well as the development of acquired resistance to Leishmania tropica in a resistant (C3H/He) and a susceptible (BALB/c) mouse strain. It was found that individual L. tropica amastigotes derived from infected tissues would transform to promastigotes and repeatedly divide to form discrete, countable colonies on rabbit blood agar. The plating efficiency was approximately 88%. Using the blood agar plating technique to quantitate the organism against time of the infection, we obtained data that suggest that acquired resistance develops in C3H/He mice earlier than is suggested by reduction in lesion size. In addition, although this resistance eliminates the parasites from the primary lesion in 10 weeks, 1,000 to 10,000 parasites persist for months in the lymph node draining the lesion site. In these studies, we found no evidence of acquired resistance in the susceptible BALB/c mice. The organism grows progressively, and the infection can disseminate to the spleen within 2 weeks. These studies illustrate the advantages of quantitating viable parasites in studies of immunity in cutaneous leishmaniasis.