bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibody recognition of a neutralization epitope on the major outer membrane protein of Chlamydia trachomatis
Authors: Zhong G , Berry J , Brunham R C
Published: January 2020

Two BALB/c mice were immunized with serovar C Chlamydia trachomatis elementary bodies, and 63 hybridomas producing monoclonal antibodies to C. trachomatis were recovered. Eight hybridomas which were specific for an identical peptide epitope (AGLQND) in serovar C major outer membrane protein variable domain I were identified. Detailed immunochemical study of the antigen-antibody interaction and genetic characterization of the antibody variable-region gene sequences showed that distinct B-cell clonal lineages were elicited by the epitope sequence. Since each antibody had a distinct pattern of fine specificity for recognition of the epitope and displayed different degrees of cross-reactivity with a related serovar (serovar A), we conclude that B-cell recognition of an immunodominant neutralization epitope can be pleiotropic. Differences in B-cell recognition of a neutralization epitope may delay the emergence by mutation of antigenic-drift variants of the C. trachomatis major outer membrane protein.
Infection dynamics and clinical features of cryptosporidiosis in SCID mice
Authors: Mead J R , Ilksoy N , You X , Belenkaya Y , Arrowood M J , Fallon M T , Schinazi R F
Published: January 2020

Cryptosporidial infections in severe combined immune deficient (SCID) mice produce a chronic disease state which in the later stages leads to extraintestinal involvement and hepatic dysfunction. To further characterize the infection dynamics in this model and monitor the changes in the hepatic system, a dose titration of the oocyst inoculum was performed and alkaline phosphatase levels in the sera were assayed. Ten SCID mice per dose were inoculated with 10(3), 10(4), 10(5), 10(6), or 10(7) oocysts. Oocyst shedding in the feces was quantified by microscopic enumeration. Mice inoculated with 10(6) oocysts and those inoculated with 10(7) oocysts demonstrated similar oocyst shedding patterns, but the 10(7)-oocyst group exhibited signs of distress (e.g., weight loss and icterus) earlier. The intensity of the infection increased markedly approximately 14 days postinoculation (p.i.) and continued to increase steadily over the next 6 weeks. Inoculation with lower oocyst doses produced a delay in patency (e.g., it occurred 7 days later with the 10(5)-oocyst inoculum and 14 days later with the 10(4)-oocyst inoculum). Mean serum alkaline phosphatase levels in the 10(7)-oocyst group were more than twice control values at 5 weeks p.i. and continued to increase over the next 8 weeks. Oocyst doses and alkaline phosphatase levels were positively correlated with hepatobiliary colonization (r = 0.71) and liver necrosis (r = 0.65) at 13 weeks p.i. A strong positive correlation between hepatobiliary colonization and liver necrosis at 13 weeks p.i. (r = 0.87) was observed.
Free hydroxyl groups are not required for endotoxic activity of lipid A
Authors: Tanamoto K
Published: January 2020

Previous studies demonstrated that lipid A from Salmonella abortusequi loses its B-cell mitogenicity for murine spleen cells as a result of the introduction of succinyl residues on hydroxyl groups and that the inactivated lipid A specifically antagonizes the mitogenicity of endotoxin. Hypothesizing that the hydroxyl groups are essential both for its biological activity and for producing nontoxic preparations having antagonistic activity, I tested the role of the hydroxyl groups in its activities by using well-characterized biologically active lipid A preparations synthesized chemically (Escherichia coli and Salmonella types 506 and 516, respectively) by the introduction of either succinyl or acetyl residues at the hydroxyl groups of each of these lipid A preparations. However, the biological activities of neither lipid A preparation were reduced at all after succinylation; in fact, succinylated 516 became much more potent than the original molecule with respect to most activities tested, i.e., lethal toxicity, Limulus gelation activity, and the induction of tumor necrosis factor release. On the other hand, when the hydroxyl groups were replaced with acetyl residues, the lethality and tumor necrosis factor-inducing activity of both lipid A preparations were decreased, whereas their Limulus gelation activity was increased. Mitogenicity was not affected much by the chemical modifications of either lipid A preparation. These findings indicate that although the residues introduced into the free hydroxyl groups of lipid A modulate its activities, the hydroxyl groups in lipid A need not exist in free form.
Localization of immunoglobulin A-binding sites within M or M-like proteins of group A streptococci
Authors: Bessen D E
Published: January 2020

Many strains of group A streptococci are capable of binding human immunoglobulin A (IgA) by a nonimmune mechanism. M or M-like proteins constitute a family of structurally diverse molecules which form surface fibrillae, and some of the M or M-like protein forms are responsible for the IgA-binding activity. In this report, the binding site for IgA is localized within two structurally distinct M or M-like proteins, ML2.2 and Arp4. Apart from those structural domains which are common to all M and M-like proteins, ML2.2 and Arp4 lack significant levels of amino acid sequence homology, with the exception of a short segment (ALXGENXDLR) located at residues 21 to 30 of the mature ML2.2 protein. Recombinant fusion polypeptides containing portions of the ML2.2 and Arp4 proteins were expressed in Escherichia coli and tested for binding of human myeloma IgA. A 58-residue polypeptide containing residues 14 to 71 of ML2.2 bound human IgA. The IgA-binding site of Arp4 could be localized to a 53-residue polypeptide containing residues 43 to 95, which encompasses the ALXGENXDLR consensus sequence of Arp4 positioned at residues 50 to 59. Site-specific mutagenesis at three codons within the ALXGENXDLR coding sequence of both the ML2.2 and Arp4 recombinant polypeptides leads to a loss in IgA-binding activity. Thus, the ALXGENXDLR consensus sequence is essential for the nonimmune binding of IgA by both ML2.2 and Arp4. However, the failure to bind IgA by polypeptides which partially overlap the 58- and 53-residue IgA-binding polypeptides of ML2.2 and Arp4, yet contain the ALXGENXDLR consensus sequence, strongly suggests that flanking regions are also critical for IgA binding. In summary, the results indicate that common functional domains bearing significant sequence homology are distributed within regions of M or M-like molecules that are otherwise highly divergent.
Variation in hydrogen peroxide sensitivity between different strains of Neisseria gonorrhoeae is dependent on factors in addition to catalase activity
Authors: Alcorn T M , Zheng H Y , Gunther M R , Hassett D J , Cohen M S
Published: January 2020

Catalase, which catalyzes the reduction of hydrogen peroxide to oxygen and water, is considered the primary defense of Neisseria gonorrhoeae against exogenous hydrogen peroxide. Recent reports have demonstrated drastically different sensitivities of the organism to hydrogen peroxide ranging from greater than 80% survival after challenge with 30 mM hydrogen peroxide to less than 0.001% survival after challenge with 10 mM hydrogen peroxide. In this study, we have examined the hydrogen peroxide sensitivities of six clinical gonococcal isolates. The study demonstrates that the variations in gonococcal hydrogen peroxide sensitivities previously reported can be attributed to (i) differences in experimental methods employed or (ii) variation among different gonococcal strains. All of the gonococcal isolates examined generated similar concentrations of catalase, implying that the differences in the H2O2 sensitivity observed may depend on factors in addition to catalase.
Purification and characterization of an elastinolytic metalloprotease from Aspergillus fumigatus and immunoelectron microscopic evidence of secretion of this enzyme by the fungus invading the murine lung
Authors: Markaryan A , Morozova I , Yu H , Kolattukudy P E
Published: January 2020

Extracellular proteases have been suggested to be virulence factors in invasive aspergillosis. Since serine protease gene-disrupted mutants retain virulence, other proteases are suspected to be also involved in the degradation of lung structural material. An elastinolytic neutral metalloprotease was purified 320-fold from the extracellular fluid of Aspergillus fumigatus grown on elastin by affinity chromatography on bacitracin-Sepharose 4B and gel filtration on Sephadex G-75. The molecular mass was determined to be 43 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. No carbohydrate was attached to this metalloprotease, and its first 22 N-terminal amino acids did not show any homology with the known metalloproteases. The enzyme was completely inhibited by EDTA, 1,10-phenanthroline, and phosphoramidon but not by inhibitors specific for serine, aspartate, and cysteine proteases. Zn2+ and, to a lesser extent, Co2+ reversed the inhibition caused by 1,10-phenanthroline. The protease hydrolyzed the peptide bonds His-Leu, Ala-Leu, Tyr-Leu, Gly-Phe, and Phe-Phe in the B chain of insulin. Synthetic substrate Abz-Ala-Ala-Phe-Phe-pNA could be used for the fluorimetric assay of the A. fumigatus metalloprotease. This enzyme had maximum activity in the pH range 7.5 to 8.0 and at 60 degrees C. It retained 50% of the protease activity when held at 60 degrees C for 1 h. Zn2+ and Co2+ at 1 mM did not inhibit the protease activity. The metalloprotease was able to hydrolyze elastin, and its elastinolytic activity was comparable to that of the serine protease from this organism. The presence of Zn2+ in the culture medium stimulated the metalloprotease production. Rabbit antibodies prepared against the enzyme severely inhibited the enzyme activity. Immunogold electron microscopy revealed that A. fumigatus invading neutropenic mouse lungs secretes this metalloprotease.
Proteolytic activity and fatal gram-negative sepsis in burned mice: effect of exogenous proteinase inhibition
Authors: Neely A N , Miller R G , Holder I A
Published: January 2020

Circulating proteolytic activity (PA) increases following burn or surgical trauma. Challenging traumatized mice with the yeast Candida albicans further increases PA. Once a PA threshold has been passed, mortality increases as PA increases. The purposes of this study were to determine (i) if gram-negative bacterial challenge affects circulating PA and mortality as Candida challenge does and (ii) if proteinase inhibitor treatment with aprotinin, antithrombin III, and alpha 1-proteinase inhibitor decreases circulating PA and increases the survival of burned mice infected with a bacterium. For all bacteria tested (Proteus mirabilis, Pseudomonas aeruginosa, and Klebsiella pneumoniae), burn plus challenge significantly elevated PA and mortality above levels in mice that were only burned or only challenged. Quantitative culture counts indicated that the mice died of sepsis. Proteinase inhibitor treatment of mice burned and challenged with K. pneumoniae significantly decreased circulating PA, decreased the hepatic microbial load, and increased survival. Hence, in traumatized mice challenged with either C. albicans or gram-negative bacteria, a relationship exists between proteolytic load and subsequent septic death. Parallels between these animal studies and human studies are discussed.
Effect of alterations of basic amino acid residues of Escherichia coli heat-stable enterotoxin II on enterotoxicity
Authors: Fujii Y , Okamuro Y , Hitotsubashi S , Saito A , Akashi N , Okamoto K
Published: January 2020

Escherichia coli heat-stable enterotoxin II (STII) is composed of 48 amino acid residues. Among these, one histidine, two arginine, and six lysine residues are basic. Isoelectric focusing showed that the isoelectric point of STII is 9.7, indicating that the side chains of some of these basic amino acid residues project outside the molecule. To understand the role that these basic amino acid residues play in toxicity, STII was chemically modified with ethoxyformic anhydride, maleic anhydride, and phenylglyoxal, which alter the side chains of basic amino acid residues in proteins. Maleic anhydride, which modifies the epsilon amino group, caused a significant loss of enterotoxic activity, but the other two modifiers did not. This indicated that lysine residues play an important role in the expression of the enterotoxic activity of STII and that the contribution of the other basic amino acid residues to the toxicity is relatively low. To confirm this hypothesis, we substituted these nine basic amino acid residues by oligonucleotide-directed site-specific mutagenesis and examined the enterotoxicity of these purified mutant STIIs. The enterotoxic activity was reduced when the lysine residues at positions 18, 22, 23, and 46 were substituted. In particular, the substitution at positions 22 and 23 induced a remarkable reduction. These results demonstrate that the lysine residues at positions 22 and 23 are very important in the expression of the enterotoxic activity of STII.
Protective role for heat shock protein-reactive alpha beta T cells in murine yersiniosis
Authors: Noll A , Roggenkamp A , Heesemann J , Autenrieth I B
Published: January 2020

To investigate the role of heat shock proteins (HSP) of Yersinia enterocolitica for the host immune response against this pathogen, we cloned and expressed a 60-kDa HSP of Y. enterocolitica serotype O8. A fragment of Y. enterocolitica O8 HSP60 encoded by amino acids 90 to 286 was sequenced and showed more than 90% homology with HSP60 of Y. enterocolitica O3 and GroEL of Escherichia coli and 59% homology with HSP65 of Mycobacterium bovis. The arthritogenic T-cell epitope of mycobacterial HSP65 (amino acid residues 180 to 188) was not found on Yersinia HSP60. To determine whether Yersinia HSP60 is an immunodominant antigen, the immune responses of Yersinia-infected C57BL/6 mice were analyzed. Yersinia-infected mice evolved a significant serum antibody and splenic T-cell response against Yersinia HSP60. CD4+ alpha beta T-cell clones which were generated from splenic T cells isolated from either Yersinia-infected or Yersinia HSP60-immunized mice, recognized both heat-killed Yersinia serotypes O3 and O8 as well as recombinant Yersinia HSP60 but not heat-killed Yersinia pseudotuberculosis, Salmonella typhimurium, or recombinant HSP65 of Mycobacterium bovis. The adoptive transfer of HSP60-reactive T-cell clones mediated significant protection against a lethal infection with Y. enterocolitica O8. These results indicate that HSP60 of Y. enterocolitica is an immunodominant antigen which is recognized by both antibodies and CD4+ alpha beta T cells. Moreover, this is the first report providing direct evidence that microbial HSP may elicit a protective immune response which is not associated with autoimmunity.
Binding and accumulation of hemin in Porphyromonas gingivalis are induced by hemin
Authors: Genco C A , Odusanya B M , Brown G
Published: January 2020

Although hemin is an essential nutrient for the black-pigmented oral bacterium Porphyromonas gingivalis, the mechanisms involved in hemin binding and uptake are poorly defined. In this study, we have examined the binding of hemin and Congo red (CR) to P. gingivalis whole cells and have defined the conditions for maximal binding. Additionally, the accumulation of hemin by P. gingivalis under growing conditions has been characterized. P. gingivalis A7436 was grown under hemin- or iron-deplete conditions (basal medium [BM] or Schaedler broth with dipyridyl [SBD]) or under hemin- or iron-replete conditions (BM with hemin [BMH] or Schaedler broth [SB]), and hemin and CR binding were assessed spectrophotometrically. Binding of hemin by P. gingivalis whole cells was rapid and was observed in samples obtained from cells grown under hemin- and iron-replete and hemin-deplete conditions but was not observed in cells grown under iron limitation. We also found that P. gingivalis whole cells bound more hemin when grown in BMH or SB than cells grown in BM or SBD. Binding of CR by P. gingivalis A7436 was also enhanced when cells were grown in the presence of hemin or when cells were incubated with hemin prior to CR binding. Hemin binding and accumulation were also assessed using [14C]hemin and [59Fe]hemin under growing conditions. Both [14C]hemin and [59Fe]hemin were accumulated by P. gingivalis, indicating that iron and the porphyrin ring were taken into the cell. Binding and accumulation of hemin under growing conditions were also induced by growth of P. gingivalis in hemin-replete media. Hemin accumulation was inhibited by the addition of KCN to P. gingivalis cultures, indicating that active transport was required for hemin uptake. [14C]hemin binding and accumulation were also inhibited by the addition of either cold hemin or protoporphyrin IX. Taken together, these results indicate that P. gingivalis transports the entire hemin moiety into the cell and that the binding and accumulation of hemin are induced by growth of cultures in the presence of hemin.
Cytokine sensitivity and methylation of lysine in Rickettsia prowazekii EVir and interferon-resistant R. prowazekii strains
Authors: Turco J , Winkler H H
Published: January 2020

Modified Rickettsia prowazekii strains have been derived from the avirulent Madrid E strain by passage in the lungs of white mice (strain EVir) or by selection for resistance to gamma interferon (IFN-gamma) (strains 427-19 and 87-17) or alpha/beta interferon (IFN-alpha/beta) (strains 83-2P, 60P, 103-2P, and 110-1P). Compared with the Madrid E strain, strain EVir has increased virulence (N. M. Balayeva and V. N. Nikolskaya, J. Hyg. Epidemiol. Microbiol. Immunol. 17:11-20, 1973) and a different lysine methylation profile in its surface protein antigen (A. V. Rodionov, M. E. Eremeeva, and N. M. Balayeva, Acta Virol. 35:557-565, 1991). The other six strains differ from the Madrid E strain in their resistance to IFN and their ability to grow well in untreated macrophagelike RAW264.7 cells. In the present study, to determine which properties are shared by these strains, we examined R. prowazekii EVir for the following: (i) the sensitivity of its growth in L929 cells to the cytokines IFN-alpha/beta, IFN-gamma, tumor necrosis factor alpha (TNF-alpha), and IFN-gamma plus TNF-alpha; (ii) the ability to grow in untreated RAW264.7 cells; and (iii) the ability to induce interferon in L929 cell cultures; we also evaluated strains 83-2P and 87-17 for lysine methylation. Multiplication of strain EVir in growing L929 cells was not markedly inhibited by either IFN-alpha/beta or IFN-gamma. In X-irradiated L929 cells, growth of strain EVir was slightly inhibited (11%) by TNF-alpha alone, somewhat inhibited (38%) by IFN-gamma alone, and markedly inhibited (87%) by IFN-gamma plus TNF-alpha. Nitrite production was induced in X-irradiated, strain EVir-infected L929 cell cultures treated with TNF-alpha alone or IFN-gamma alone; however, more nitrite was produced in infected cultures treated with IFN-gamma plus TNF-alpha. Nitrite production, the dramatic inhibitory effect of IFN-gamma plus TNF-alpha, and the modest inhibitory effect of IFN-gamma on the growth of strain EVir in X-irradiated L929 cells were all alleviated by the addition of the nitric oxide synthase inhibitor NG-methyl-L-arginine. Strain EVir grew very well in untreated macrophagelike RAW264.7 cells and appeared defective in the ability to induce IFN in L929 cell cultures. All strains grown in L929 cells in the presence of radiolabeled lysine had similar percentages of their radioactivity as methylated lysines.(ABSTRACT TRUNCATED AT 400 WORDS)
Humoral immune response to outer surface protein C of Borrelia burgdorferi in Lyme disease: role of the immunoglobulin M response in the serodiagnosis of early infection
Authors: Fung B P , McHugh G L , Leong J M , Steere A C
Published: January 2020

We determined the humoral immune response to outer surface protein C (OspC) of Borrelia burgdorferi in patients with early or late manifestations of Lyme disease and investigated the use of this antigen in the serodiagnosis of early infection. The ospC gene from the low-passage human isolate 297, a North American B. burgdorferi strain, was used to make a recombinant maltose-binding protein (MBP)-OspC fusion protein for serologic tests. This gene showed 84 to 85% nucleotide sequence identity and 76 to 79% amino acid identity with ospC of B. burgdorferi B31 and 2591. The antibody responses to MBP-OspC were determined in serial sera from 15 patients with Lyme disease who were monitored for 4 to 12 years of illness, in single-serum samples from 189 patients with early or late manifestations of the disorder, and in serum samples from 106 control patients. Early in the infection, patients with erythema migrans or meningitis commonly had weak to strong immunoglobulin M (IgM) responses to OspC and sometimes weak to moderate IgG responses. Months to years later, weak to strong IgG reactivity with this protein was often apparent in patients with arthritis, but this response was weak or absent in patients with chronic neuroborreliosis. When acute- and convalescent-phase serum samples from patients with erythema migrans were tested for reactivity against MBP-OspC, the sensitivity of the IgM test was 73% and the specificity was 98%, with either enzyme-linked immunosorbent assay (ELISA) or Western blotting. We conclude that the majority of patients with Lyme disease have a prominent IgM response to OspC early in the illness, which is often followed by a prominent IgG response in patients with arthritis. For the serodiagnosis of early infection, the sensitivity and specificity of IgM ELISA and Western blotting were comparable or slightly improved when MBP-OspC was used as the antigen compared with tests in which spirochetal lysates were used.
Pneumolysin activates phospholipase A in pulmonary artery endothelial cells
Authors: Rubins J B , Mitchell T J , Andrew P W , Niewoehner D E
Published: January 2020

Pneumolysin has been identified as a virulence factor in Streptococcus pneumoniae disease. In addition to producing tissue injury through its cytolytic effect, pneumolysin might injure tissues indirectly by eliciting an inflammatory response. We demonstrate for the first time that pneumolysin is a rapid and potent activator of cellular phospholipase A in bovine pulmonary artery endothelial cells. In contrast to other toxin-activated phospholipases, pneumolysin-stimulated phospholipase A showed no substrate specificity among major cellular membrane phospholipids. Phospholipase A activation required the formation of functional transmembrane pores by pneumolysin rather than membrane lipid perturbation. Pneumolysin stimulation of phospholipase A was calcium dependent; however, pneumolysin did not appear to function simply as a calcium ionophore. Pneumolysin was capable of stimulating purified bee and snake venom phospholipase A2s against a phospholipid substrate isolated from endothelial cells. Thus, pneumolysin stimulates cellular phospholipase A and the resulting products might further injure tissues by direct cytolytic effect or by evoking inflammatory responses.
Binding and activation of major histocompatibility complex class II-deficient macrophages by staphylococcal exotoxins
Authors: Beharka A A , Armstrong J W , Iandolo J J , Chapes S K
Published: January 2020

Macrophages from C2D transgenic mice deficient in the expression of major histocompatibility complex (MHC) class II proteins were used to identify binding sites for superantigens distinct from the MHC class II molecule. Iodinated staphylococcal enterotoxins A and B (SEA and SEB) and exfoliative toxins A and B (ETA and ETB) bound to C2D macrophages in a concentration-dependent and competitive manner. All four toxins increased F-actin concentration within 30 s of their addition to C2D macrophages, indicating that signal transduction occurred in response to toxin in the absence of class II MHC. Furthermore, ETA, ETB, SEA, and, to a lesser extent, SEB induced C2D macrophages to produce interleukin 6. Several molecular species on C2D macrophages with molecular masses of 140, 97, 61, 52, 43, and 37 kDa bound SEA in immunoprecipitation experiments. These data indicate the presence of novel, functionally active toxin binding sites on murine macrophages distinct from MHC class II molecules.
Shuttle mutagenesis of Legionella pneumophila: identification of a gene associated with host cell cytopathicity
Authors: Arroyo J , Hurley M C , Wolf M , McClain M S , Eisenstein B I , Engleberg N C
Published: January 2020

We performed shuttle mutagenesis of Legionella pneumophila. Mutants were screened for reduced cellular infectivity. Approximately 10% of the mutants had decreased cytopathicity. The DNA sequence of one locus was determined; the inferred amino acid sequence revealed homology with transport proteins including Escherichia coli TolC, Bordetella pertussis CyaE, and Alcaligenes eutrophus CzcC and CnrC.
Ultrastructural Studies of Treponemes: Location of Axial Filaments and Some Dimensions of
Treponema pallidum
(Nichols strain),
Treponema denticola
, and
Treponema reiteri
Authors: Sykes John A. , Miller James N.
Published: January 2020

Ultrathin sections of
Treponema pallidum
(Nichols strain),
T. denticola (microdentium)
, and
T. reiteri
have been studied in the electron microscope to determine the location of the axial filaments and some of the dimensions of these organisms. The axial filaments of
T. pallidum
(Nichols strain) have been seen to be tubular in cross section with an overall diameter of 21.0 ± 0.73 nm, and an electron-lucent core of 8.0 nm. The filaments were found to lie on the outside of the organism which had only one membranous structure surrounding the protoplasmic core. These findings were in contrast to those obtained for
T. denticola
and
T. reiteri
where the axial filaments did not exhibit a hollow core and were located between an outer membrane and an inner membrane surrounding the protoplasmic core. The outside diameter of
T. denticola
was determined to be 224.9 ± 2.83 nm, and that of
T. reiteri
as 331.0 ± 4.15 nm, contrasting with
T. pallidum
(Nichols strain) which had a diameter of 163.0 ± 1.9 nm.
Lack of Detectable Circulating Interferon in Mice Protected Against Vaccinia Virus by Induction and Elicitation with Bacterial Systems
Authors: Shayegani Mehdi , Mudd Stuart
Published: January 2020

Mice which had been subjected to mycobacterial infection and specific elicitation were bled from the orbital sinus at the time the mice were challenged intravenously with vaccinia virus. Assays of the sera were negative for interferon. Sera of rabbits sensitized with staphylococci and elicited by Staphage Lysate also lacked detectable circulating interferon.
Effect of Human Adenoviruses on the Response of Chickens to Sheep Erythrocytes
Authors: Béládi Ilona , Pusztai Rozália , Mucsi Ilona , Bakay Márta , Bajszár György
Published: January 2020

Human adenovirus types 6, 8, and 12 were immunosuppressive in chickens. A single intravenous injection of adenoviruses markedly depressed the 19
S
hemolytic plaque-forming cell response in the spleen to the immunization with sheep red blood cells. Hemagglutinin production was also decreased in adenovirus type 6-infected chickens. Adenoviruses caused a transient immunosuppression in chickens which could be detected 2 to 3 days after the virus infection, and no depressive effect was found 16 to 20 days after virus injection. The possible mechanism of immunosuppression observed is discussed.
Assay of Typhoid Vaccines with
Salmonella typhosa-Salmonella typhimurium
Hybrids
Authors: Diena B. B. , Johnson E. M. , Baron L. S. , Wallace R. , Greenberg L.
Published: January 2020

Salmonella typhimurium
hybrids expressing the
S. typhosa
antigens 9, d, and Vi were constructed by genetic crosses with an
S. typhosa
Hfr donor. The hybrids retained the same degree of mouse virulence as their
S. typhimurium
parent strain, the minimum lethal dose being less than 50 organisms when tested either in C
57
black mice or Swiss white mice. Vaccination of the Swiss white mice with
S. typhosa
Ty2 vaccines prepared by acetone treatment, alcohol treatment, or heat-killing conferred significant protection against challenge by the hybrid strains but not against their
S. typhimurium
parent. Both the acetone-treated and alcohol-treated typhoid vaccines were markedly more protective than the heat-killed, phenol-preserved vaccine.
Increased Toxicity of Double-Stranded Ribonucleic Acid in Virus-Infected Animals
Authors: de Clercq Erik , Stewart William E. , de Somer Pierre
Published: January 2020

Virus-infected mice were significantly more susceptible to the toxic effects of double-stranded ribonucleic acid (RNA) than uninfected mice. A dramatic increase in mortality was observed after injection of either synthetic (polyriboinosinic·polyribocytidylic acid) or natural (mycophage) double-stranded RNA in mice infected with Newcastle disease virus (NDV) or vesicular stomatitis virus (VSV). With the exception of endotoxin, interferon inducers other than double-stranded RNA, such as tilorone-hydrochloride and chlorite-oxidized oxyamylose, did not show this increased toxicity in virus-infected animals. The increased susceptibility of virus-infected animals to the toxic effects of double-stranded RNA appears to be related to the levels of interferon induced by the virus infection, either systemically, in the blood stream (after inoculation of NDV), or locally, in the brain (after infection with VSV).
Enhancement, by Two Carboxylic Acid Interferon Inducers, of Resistance Stimulated in Mice by Foot-and-Mouth Disease Vaccine
Authors: Campbell C. H. , Richmond J. Y.
Published: January 2020

Simultaneous injection of divinyl ether-maleic amhydride (DVE/MA) or itaconic-acrylic acid and foot-and-mouth disease virus vaccine enhanced the survival of infant mice to subsequent injections of virus. This enhanced resistance was obtained even with doses of interferon inducers which, when administered alone, failed to protect the mice. There was some increase in serum-neutralizing antibody in mice 7 days after injection of DVE/MA and vaccine, as compared with mice given vaccine alone, but there was no clear connection between antibody level and amount of DVE/MA administered.
Influence of Gonadal Factors on Skin Test Reactivity of CFW Mice to
Candida albicans
Authors: Rifkind David , Frey Janet A. , Davis John R.
Published: January 2020

Sex differences in the delayed skin test response to
Candida albicans
were studied in gonadectomized and control CFW mice sensitized either actively with sonically treated antigen or passively with lymphoid cells. In mice actively sensitized with antigen, the responses to candida skin testing were larger in the female. In both sexes, the skin test responses were larger in mice gonadectomized prior to sensitization than in controls of the same sex. In mice passively sensitized with male lymphoid cells, the responses to candida skin testing were essentially equal in the sexes. In both sexes, gonadectomy prior to passive sensitization with the male cells resulted in greater skin test reactivity. In mice passively sensitized with female lymphoid cells, the responses were larger in the males. In males, pre-sensitization gonadectomy resulted in smaller skin test responses, but in the females gonadectomy did not influence the responses. It is suggested that the greater skin test reactivity of the female to candida is due to a sex difference in the response of lymphoid cells to gonadal hormones. This difference may be important in the greater immune reactivity and resistance to infection which occur in the female.
Cell Attachment and Penetration by Influenza Virus
Authors: Hahon Nicholas , Booth James A. , Eckert Herbert L.
Published: January 2020

Attachment and penetration of influenza virus into clone 1-5C-4 cells were quantitatively determined by the immunofluorescent cell-counting assay. Aided by centrifugal force, more than 95% of virus inocula of five representative influenza virus strains (A
0
/PR8, A
1
/Ann Arbor, A
2
/Japan, B/Lee, B/Great Lakes) were attached to cells at a linear rate within 10 min, in contrast to approximately 35% after stationary incubation at 35 C for 2 h. By the former procedure, a proportionality between the number of infected cells and volume of inoculum was revealed which was not evident when stationary incubation was employed. Maximal binding of virus to cells occurred at 0.2 M NaCl. The salt requirement, added to evidence of pH dependence and temperature independence, indicated that the initial virus-cell union involved electrostatic forces. Virus penetration into cells, measured by the insensitivity of virus-cell complexes to antiviral serum, was linear and complete within 15 min at 35 C for all five virus strains tested. Maximal virus penetration occurred at 0.1 to 0.2 M NaCl; the process was pH- and temperature-dependent. Both virus attachment and penetration processes were partially inhibited in the presence of diethylaminoethyl-dextran.
Protection Against Meningococcal Challenge Afforded Mice After Immunization with Typhoid-Paratyphoid Vaccine USP
Authors: Banknieder A. R. , Devine L. F. , Faust C. A.
Published: January 2020

Mice immunized with typhoid-paratyphoid vaccine USP were found to be protected when challenged with serological groups A, B, and C of
Neisseria meningitidis
. Mice immunized with this vaccine both 14 and 7 days prior to challenge were protected against mean lethal doses (LD
50
) of 5,220 and 1,151 of groups A and B, respectively, and in two separate experiments they were protected against 3,568 and 268 LD
50
of group C. Mice immunized four or more times on successive days prior to challenge were also protected. They demonstrated tolerance and survived a much larger LD
50
challenge than mice immunized by any other immunization schedule. Mice immunized once or twice anytime within 7 days prior to challenge were not protected and thus failed to exhibit nonspecific resistance. Serum antibody probably was responsible for the protection afforded mice immunized 14 and 7 days prior to challenge. However, this was not demonstrated conclusively.
Effect of Pneumococcal Neuraminidase on Canine Cerebral Cortex in Experimental Meningitis
Authors: Carruthers M. M. , Kanokvechayant R.
Published: January 2020

We examined the effect of experimental meningeal infection with a neuraminidase-producing strain of
Diplococcus pneumoniae
on the
N
-acetylneuraminic acid (NANA) content of canine cerebral cortical gray matter. The Warren thiobarbituric acid assay for NANA was used. There was no significant difference between the free and bound NANA levels of the tissue from control animals and from those with meningitis. This finding suggests that the neurological impairment so frequent in clinical pneumococcal meningitis is not a result of the activity of this bacterial enzyme upon cortical glycolipids.
Common Enterobacterial Antigen II. Effect of Immunization on Challenge with Heterologous Bacilli
Authors: McCabe William R. , Greely Anna
Published: January 2020

Studies were carried out evaluating the protective activity of immunization with common enterobacterial antigen (CA) against challenge with heterologous gram-negative bacilli. Active immunization of mice with
Escherichia coli
0:14 elicited titers of antibody to CA of 1:640 or greater but completely failed to enhance resistance to challenge by mouse virulent strains of
Klebsiella pneumoniae
or
E. coli
. Similarly, two lots, 324 and 422, of rabbit antisera to CA failed to afford passive protection to mice challenged with
K. pneumoniae
or
E. coli
. A third lot, 166, of rabbit antisera to CA did passively protect mice. The protective activity of antisera 166 was demonstrated to reflect its content of antibody to another cross-reactive antigen, Re determinant, of gram-negative bacilli which has previously been shown to protect against infections with heterologous bacilli rather than any protective effect of antibody to CA. These studies failed to demonstrate any protective activity of antibody to CA against challenge with heterologous CA containing gram-negative bacilli.
Mechanism of Shope Fibroma Virus-Induced Suppression of Host Deoxyribonucleic Acid Synthesis
Authors: Chan James C. , Hodes M. E.
Published: January 2020

The effects of treatment with live or inactivated Shope fibroma virus on host cell deoxyribonucleic acid (DNA) synthesis were determined. The incorporation of
3
H-thymidine into nuclear DNA was suppressed by both active and inactivated virus, although live virus was more effective. During the early phase of infection, stimulation of host nuclear DNA synthesis of up to 240% of control value was observed in cells infected with active virus. Inhibition of DNA synthesis began at about the 8th h and was maximal by 12 h postinfection. Virus inactivated by ultraviolet-irradiation or heat treatment did not induce viral DNA synthesis but was, nevertheless, able to suppress host DNA synthesis.
Rickettsial Hemolysis: Effect of Metabolic Inhibitors upon Hemolysis and Adsorption
Authors: Ramm Louise E. , Winkler Herbert H.
Published: January 2020

The hemolysis of sheep red blood cells by typhus rickettsiae is initiated by a temperature-sensitive adsorption process that is dependent on the energy-generating metabolism of the rickettsaie but not that of the erythrocyte. Adsorption is followed by events dependent on the metabolism of both the rickettsaie and red blood cells. At 34 C the adsorption step is complete after about 4 min, at lower temperatures the time required for adsorption is increased. At 0 C no adsorption occurred. The addition of cyanide inhibited the catabolism of glutamate by the rickettsiae and, consequently, both adsorption and the subsequent steps in hemolysis. The starvation of the rickettsiae for glutamate also prevented adsorption. Fluoride had no demonstrable effect on rickettsial metabolism nor the adsorption step but inhibited glycolysis in the erythrocytes and the hemolysis of the erythrocytes by rickettsiae.
Studies on the Mode of Action of Diphtheria Toxin V. Protein Metabolism in a Guinea Pig Model Simulating Chronic Diphtheritic Toxemia
Authors: Bonventre Peter F.
Published: January 2020

An experimental model of “chronic” diphtheria intoxication in the guinea pig was developed. Adult guinea pigs, subjected to a regimen of multiple sublethal doses of purified diphtheria toxin (total of 1.4 minimum lethal doses divided equally in four daily doses), developed a toxemia which terminated in death between 6 and 8 days. During an advanced stage of illness, de novo protein synthesis was assessed by in vivo incorporation of tritiated leucine into tissue proteins. With the exception of pancreas and skeletal muscle, protein synthesis in healthy, control and toxin-treated guinea pigs was comparable. The absence of notable impairment of protein synthesis in this experimental situation is discussed in terms of the mode of action of the diphtheria toxin and the pathophysiology of the disease.
Use of Stable Sensitized Cells in an Improved Indirect Microhemagglutination Test for Malaria
Authors: Farshy David C. , Kagan Irving G.
Published: January 2020

Aldehyde-fixed cells sensitized with
Plasmodium knowlesi
and
P. falciparum
antigens were tested with sera from
P. vivax
and
P. falciparum
infections. Titers were improved by use of a mixture of cells sensitized with the two antigens.
Enhanced Effect of Repeated Administration of Bacterial Vaccine Against Viral Respiratory Infection
Authors: Degré Miklos , Dahl Helen
Published: January 2020

Administration of a standard bacterial vaccine (SBV) affords some protection against influenza infection in mice if given 4 to 5 h before inoculation of the virus. This effect was enhanced by repeated injections of SBV 7 and 14 days earlier, as measured by the length of survival, mortality rate, development of gross pneumonia, and virus multiplication in the lungs. Serum interferon levels were likewise enhanced by immunization with SBV, which may, at least in part, explain the increased preventive effect.
Isolation of
Rickettsia rickettsi
in Primary Bone Marrow Cell and Circulating Monocyte Cultures Derived from Experimentally Infected Guinea Pigs
Authors: Buhles William C. , Huxsoll David L. , Elisberg Bennett L.
Published: January 2020

Rickettsia rickettsi
was isolated and propagated in primary cell cultures derived from experimentally infected guinea pigs. Organisms were recognized as early as 3 days after cultures were initiated.
Inhibition of
Shigella flexneri
by Lysates of Cells Treated with Interferon-Containing Preparations
Authors: Green Jon A.
Published: January 2020

The in vitro extracellular multiplication of
Shigella flexneri
is inhibited by cell-free lysates prepared from mouse or human cells pretreated with interferon-containing preparations.
Enhanced Immune Response After Immunosuppression by Streptococcal Pyrogenic Exotoxin
Authors: Hanna Edgar E. , Watson Dennis W.
Published: January 2020

Streptococcal pyrogenic exotoxin (SPE) was shown previously to be a potent immunosuppressant. This paper presents data documenting that immunosuppression frequently was followed by elevated antibody and plaque-forming cell levels as noted in our earlier report. The data are interpreted as a differential effect of SPE upon suppressor T cells and secreting B cells.
Immunoelectrophoretic Analysis of
Mycoplasma mycoides
var.
mycoides
Authors: Stone S. S. , Razin S.
Published: January 2020

Acrylamide gel electrophoresis was used to show the similarities and differences in the membrane proteins of two vaccine and two virulent strains of
Mycoplasma mycoides
var.
mycoides.
Immunoelectrophoretic (IEP) analysis was also used to partially characterize the associated antigens. Antibody spectra to the antigens of
M. mycoides
differ in rabbit, pig, and cattle sera. Rabbits produce better precipitating antibody against the anodic migrating protein mycoplasma antigens than cattle and pigs as seen in IEP. However, rabbit anti-
M. mycoides
serum did not show precipitating antibody against the heat-stable carbohydrate antigen. As judged by IEP, the major carbohydrate antigen extracted from the media, or boiled whole organism, is similar to that present in the sera-infected cattle and knee joints of calves. This carbohydrate antigen has a cathodic migration in IEP at pH 8.6. Periodate oxidation, classically used to destroy carbohydrate, also destroys most of the protein antigens. Heating the antigens to 56 C for 10 min destroys many of the noncarbohydrate antigens and 100 C eliminates all but the carbohydrate antigen. Extraction of
M. mycoides
with chloroform-methanol, phenol, ethanol, or ethanol-acetone reduced or eliminated most of the protein antigens. Some of the isolated antigenic fractions of
M. mycoides
were tested to determine their activity in the diagnostic complement fixation test for contagious bovine pleuropneumonia and their inhibitory effect in this test by using bovine anti-
M. mycoides
antisera having precipitating antibody and circulating antigen. The complement fixation antigen is not the galactan, cannot be extracted by chloroform-methanol, but is stable to boiling at 100 C and may be extracted by phenol and partially precipitated by ethanol-acetone.
Leukocytosis-Promoting Factor of
Bordetella pertussis
II. Biological Properties
Authors: Sato Yuji , Arai Hideo , Suzuki Kenji
Published: January 2020

The leukocytosis-promoting factor (LPF), purified from materials extracted from agar in which
Bordetella pertussis
was grown, caused leukocytosis and an increased sensitivity to histamine when as little as 0.04 μg of protein was given intravenously to mice. LPF was adsorbed onto erythrocytes, causing hemagglutination. As little as 0.03 μg of LPF protein agglutinated chicken erythrocytes in 0.05 ml of a 0.5% suspension. The physicochemical, biological, and immunological properties indicated that leukocytosis, increased sensitivity to histamine in mice, and agglutination of erythrocytes are functions of a single substance.
Antibody Response of Hamsters to A2/Hong Kong Virus Vaccine after Priming by Heterotypic Virus Infection
Authors: Potter C. W. , Jennings R. , Rees R. C. , McLaren C.
Published: January 2020

Hamsters previously infected with influenza virus A1/FM/1/47 produced serum hemagglutination inhibition (HI) antibody in response to 1/100 the antigenic dose of inactivated influenza virus A2/Hong Kong vaccine necessary to induce antibody in normal animals. This priming effect was believed to be due to the virus infection which caused an immune response to a virus antigen common to both the infecting virus and the virus vaccine; this antigen acted as a carrier for the specific vaccine virus hemagglutinin and potentiated the immune response to the new antigen. This theory, which has been established in other immune systems, was tested, and the results obtained did not contradict the conditions imposed in the above explanation. Thus, the priming effect could be transferred to normal hamsters by inoculation of spleen cells from virus-infected animals, and the HI antibody response to the virus vaccine was characteristic of a secondary response. The theory also required that the new antigen be coupled to the carrier protein; however, primed hamsters produced serum HI antibody after inoculation with ether-Tween-split virus vaccine, but there was no proof that this vaccine was completely dissociated.
Production of Macrophage Migration Inhibition Factors by Virus-Infected Cell Cultures
Authors: Flanagan Thomas D. , Yoshida Takeshi , Cohen Stanley
Published: January 2020

Macrophage migration inhibitory (MIF-like) activity was demonstrated in the supernatant fluids from cultures of African green monkey kidney cells (BGM) infected with mumps virus or Newcastle disease virus. We could detect no such activity in noninfected cultures. The virus-induced activity reported here is not due to nonspecific cytotoxic material released by dead or dying cells, and it does not require cell replication for its production. Preliminary estimates of molecular weight by Sephadex G-100 chromatography revealed a broad band of activity associated with the 45,000 and 65,000 markers. These are significantly smaller than previously reported chemotactic substances from virus-infected cultures, and thus appear to represent different cell products. These MIF-like factors may be produced concomitantly with interferon. However, ultraviolet irradiation of appropriate duration abolishes the ability of viruses to induce substances with MIF-like activity while preserving the ability to induce interferon. This strongly suggests that interferon is not the agent responsible for the macrophage migration inhibition effect. The functional properties of these various cell products induced by virus infection suggest that they all may play a role in the response to virus infection in vivo.
Pyrogenicity and Immunogenicity of Lipid A Complexed with Bovine Serum Albumin or Human Serum Albumin
Authors: Rietschel E. T. , Kim Y. B. , Watson D. W. , Galanos C. , Lüderitz O. , Westphal O.
Published: January 2020

The lipid A component of bacterial lipopolysaccharides (endotoxins), when complexed to bovine serum albumin (BSA) or human serum albumin (HSA), was shown to be a potent pyrogen. Furthermore, rabbits could be protected against endotoxin fever by immunization with both lipid A·BSA and lipid A·HSA complexes. The results presented in this paper show that lipid A is responsible for the pyrogenic activity of endotoxins and their ability to induce pyrogenic immunity.