bluuebunny/crossref_metadata_2025 huggingface dataset:
Construction of a Single-Chain Interleukin-12-Expressing Retroviral Vector and Its Application in Cytokine Gene Therapy against Experimental Coccidioidomycosis
Authors: Jiang Chengyong , Magee D. Mitchell , Cox Rebecca A.
Published: December 2019

T-cell-mediated immunity is an important determinant in protection against primary infection withCoccidioides immitis, a dimorphic fungal pathogen that causes the disease coccidioidomycosis. To determine if interleukin-12 (IL-12) gene therapy could potentiate host response againstC. immitis, we constructed a single-chain cDNA encoding the p40 and p35 subunits linked by a polylinker and, using a retroviral vector, transfected J774 macrophages with the construct. The transduced J774 cells expressed IL-12 in vitro, with a mean concentration of 28,440 pg from 106cells in 48 h as measured by an IL-12 (p75)-specific enzyme-linked immunosorbent assay. The secreted IL-12 was biologically active, as judged by its ability to induce the production of gamma interferon (IFN-γ) by spleen cells from BALB/c mice. Treatment of the highly susceptible BALB/c mouse strain with the IL-12-transduced J774 cells inhibitedC. immitisgrowth in tissues from mice challenged by a pulmonary route, as evidenced by 1.37-, 2.59-, and 1.22-log reductions in the number of CFU in the lungs, spleens, and livers, respectively, compared to the fungal load in mice given vector-transduced J774 cells. The protective effect of IL-12 gene therapy was accompanied by increased levels of IFN-γ in the lungs and sera of mice treated with IL-12-transduced J774 cells and the constitutive production of IFN-γ by their spleen cells cultured in vitro. These results suggest that IL-12 gene therapy could be used as adjunct therapy for coccidioidomycosis.
Tumor Necrosis Factor Alpha Is a Key Mediator in the Regulation of ExperimentalTrypanosoma bruceiInfections
Authors: Magez Stefan , Radwanska Magdalena , Beschin Alain , Sekikawa Kenji , De Baetselier Patrick
Published: December 2019

In order to evaluate during experimentalTrypanosoma bruceiinfections the potential role of tumor necrosis factor alpha (TNF-α) in the host-parasite interrelationship, C57BL/6 TNF-α knockout mice (TNF-α−/−) as well as C57BL/6 wild-type mice were infected with pleomorphicT. bruceiAnTat 1.1 E parasites. In the TNF-α−/−mice, the peak levels of parasitemia were strongly increased compared to the peak levels recorded in wild-type mice. The increased parasite burden did not reflect differences in clearance efficacy or in production ofT. brucei-specific immunoglobulin M (IgM) and IgG antibodies. Trypanosome-mediated immunopathological features, such as lymph node-associated immunosuppression and lipopolysaccharide hypersensitivity, were found to be greatly reduced in infected TNF-α−/−mice. These results demonstrate that, during trypanosome infections, TNF-α is a key mediator involved in both parasitemia control and infection-associated pathology.
Differential Roles of Segmented Filamentous Bacteria and Clostridia in Development of the Intestinal Immune System
Authors: Umesaki Yoshinori , Setoyama Hiromi , Matsumoto Satoshi , Imaoka Akemi , Itoh Kikuji
Published: December 2019

The presence of microflora in the digestive tract promotes the development of the intestinal immune system. In this study, to evaluate the roles of two types of indigenous microbe, segmented filamentous bacteria (SFB) and clostridia, whose habitats are the small and large intestines, respectively, in this immunological development, we analyzed three kinds of gnotobiotic mice contaminated with SFB, clostridia, and both SFB and clostridia, respectively, in comparison with germfree (GF) or conventionalized (Cvd) mice associated with specific-pathogen-free flora. In the small intestine, the number of αβ T-cell receptor-bearing intraepithelial lymphocytes (αβIEL) increased in SFB-associated mice (SFB-mice) but not in clostridium-associated mice (Clost-mice). There was no great difference in Vβ usage among GF mice, Cvd mice, and these gnotobiotic mice, although the association with SFB decreased the proportion of Vβ6+cells in CD8β−subsets to some extent, compared to that in GF mice. The expression of major histocompatibility complex class II molecules on the epithelial cells was observed in SFB-mice but not in Clost-mice. On the other hand, in the large intestine, the ratio of the number of CD4−CD8+cells to that of CD4+CD8−cells in αβIEL increased in Clost-mice but not in SFB-mice. On association with both SFB and clostridia, the numbers and phenotypes of IEL in the small and large intestines changed to become similar to those in Cvd mice. In particular, the ratio of the number of CD8αβ+cells to that of CD8αα+cells in αβIEL, unusually elevated in the small intestines of SFB-mice, decreased to the level in Cvd mice on contamination with both SFB and clostridia. The number of immunoglobulin A (IgA)-producing cells in the lamina propria was more elevated in SFB-mice than in Clost-mice, not only in the ileum but also in the colon. The number of IgA-producing cells in the colons of Clost-mice was a little increased compared to that in GF mice. Taken together, SFB and clostridia promoted the development of both IEL and IgA-producing cells in the small intestine and that of only IEL in the large intestine, respectively, suggesting the occurrence of compartmentalization of the immunological responses to the indigenous bacteria between the small and large intestines.
Dynamics of Actin-Based Movement by
Rickettsia rickettsii
in Vero Cells
Authors: Heinzen Robert A. , Grieshaber Scott S. , Van Kirk Levi S. , Devin Clinton J.
Published: December 2019

Actin-based motility (ABM) is a virulence mechanism exploited by invasive bacterial pathogens in the genera
Listeria
,
Shigella
, and
Rickettsia
. Due to experimental constraints imposed by the lack of genetic tools and their obligate intracellular nature, little is known about rickettsial ABM relative to
Listeria
and
Shigella
ABM systems. In this study, we directly compared the dynamics and behavior of ABM of
Rickettsia rickettsii
and
Listeria monocytogenes
. A time-lapse video of moving intracellular bacteria was obtained by laser-scanning confocal microscopy of infected Vero cells synthesizing β-actin coupled to green fluorescent protein (GFP). Analysis of time-lapse images demonstrated that
R. rickettsii
organisms move through the cell cytoplasm at an average rate of 4.8 ± 0.6 μm/min (mean ± standard deviation). This speed was 2.5 times slower than that of
L. monocytogenes
, which moved at an average rate of 12.0 ± 3.1 μm/min. Although rickettsiae moved more slowly, the actin filaments comprising the actin comet tail were significantly more stable, with an average half-life approximately three times that of
L. monocytogenes
(100.6 ± 19.2 s versus 33.0 ± 7.6 s, respectively). The actin tail associated with intracytoplasmic rickettsiae remained stationary in the cytoplasm as the organism moved forward. In contrast, actin tails of rickettsiae trapped within the nucleus displayed dramatic movements. The observed phenotypic differences between the ABM of
Listeria
and
Rickettsia
may indicate fundamental differences in the mechanisms of actin recruitment and polymerization.
Expression and Immunogenicity of a Mutant Diphtheria Toxin Molecule, CRM
197
, and Its Fragments in
Salmonella typhi
Vaccine Strain CVD 908-
htrA
Authors: Orr Nadav , Galen James E. , Levine Myron M.
Published: December 2019

Mutant diphtheria toxin molecule CRM
197
and fragments thereof were expressed in attenuated
Salmonella typhi
CVD 908-
htrA
, and the constructs were tested for their ability to induce serum antitoxin. Initially, expressed proteins were insoluble, and the constructs failed to induce neutralizing antitoxin. Soluble CRM
197
was expressed at low levels by utilizing the hemolysin A secretion system from
Escherichia coli.
Cloning and Molecular Characterization of Plasmid-Encoded Antigens of
Borrelia burgdorferi
Authors: Skare Jonathan T. , Foley Denise M. , Hernandez Santiago R. , Moore Deanna C. , Blanco David R. , Miller James N. , Lovett Michael A.
Published: December 2019

Thirteen independent clones that encode
Borrelia burgdorferi
antigens utilizing antiserum from infection-immune rabbits were identified. The serum was adsorbed against noninfectious
B. burgdorferi
B31 to enrich for antibodies directed against either infection-associated antigens of
B. burgdorferi
B31 or proteins preferentially expressed during mammalian infection. The adsorption efficiency of the immune rabbit serum (IRS) was assessed by Western immunoblot analysis with protein lysates derived from infectious and noninfectious
B. burgdorferi
B31. The adsorbed IRS was used to screen a
B. burgdorferi
expression library to identify immunoreactive phage clones. Clones were then expressed in
Escherichia coli
and subsequently analyzed by Western blotting to determine the molecular mass of the recombinant
B. burgdorferi
antigens. Southern blot analysis of the 13 clones indicated that 10 contained sequences unique to infectious
B. burgdorferi
. Nucleotide sequence analysis indicated that the 13 clones were composed of 9 distinct genetic loci and that all of the genes identified were plasmid encoded. Five of the clones carried
B. burgdorferi
genes previously identified, including those encoding decorin binding proteins A and B (
dbpAB
), a
rev
homologue present on the 9-kb circular plasmid (cp9), a
rev
homologue from the 32-kb circular plasmid (cp32-6),
erpM
, and
erpX
. Additionally, four previously uncharacterized loci with no known homologues were identified. One of these unique clones encoded a 451-amino-acid lipoprotein with 21 consecutive, invariant 9-amino-acid repeats near the amino terminus that we have designated VraA (for “virulent strain-associated repetitive antigen A”). Since all the antigens identified are recognized by serum from infection immune rabbits, these antigens represent potential vaccine candidates and, based on the identification of
dbpAB
in this screen, may also be involved in pathogenic processes operative in Lyme borreliosis.
Staphylococcus aureusIsolates from Patients with Kawasaki Disease Express High Levels of Protein A
Authors: Wann Elisabeth R. , Fehringer Amy P. , Ezepchuk Yuri V. , Schlievert Patrick M. , Bina Paul , Reiser Raoul F. , Höök Magnus M. , Leung Donald Y. M.
Published: December 2019

Kawasaki disease (KD) is an acute vasculitis of young children that can be complicated by coronary artery abnormalities. Recent findings suggest that a superantigen(s) may play an important role in stimulating the immune activation associated with the disease, although the origin of this superantigen(s) is unclear.Staphylococcus aureus, isolated from the rectum or pharynx of patients with KD, secretes toxic shock syndrome toxin 1 (TSST-1). The KD isolates express low levels of other exoproteins compared to isolates from patients with toxic shock syndrome (TSS). Thus, it was previously suggested that the KD isolates may be defective in the global regulatory locusagr(for accessory gene regulator), which positively regulates these factors (D. Y. M. Leung et al., Lancet 342:1385–1388, 1993). Here we describe another characteristic of KD isolates. When considered collectively, the KD isolates were found to express higher levels of staphylococcal protein A than the TSS isolates, another characteristic of anagr-defective phenotype. This correlated with a higher level ofspamRNA in these isolates. In contrast, the KD and TSS isolates expressed comparable levels of TSST-1, consistent with previous findings (D. Y. M. Leung et al., Lancet 342:1385–1388, 1993). Analysis of RNAIII transcript levels and nucleotide sequence analysis of the RNAIII-coding region suggested that the KD isolates are not defective in RNAIII, the effector molecule of theagrregulatory system. However, induction of RNAIII transcription in the KD isolates did not result in a dramatic decrease in the amount ofspamRNA, as has been reported for other strains (F. Vandenesch, J. Kornblum, and R. P. Novick, J. Bacteriol. 173:6313–6320, 1991).
Activation of Caspase 3 duringLegionella pneumophila-Induced Apoptosis
Authors: Gao Lian-Yong , Abu Kwaik Yousef
Published: December 2019

The hallmark of Legionnaires’ disease is replication ofLegionella pneumophilawithin cells in the alveolar spaces. The mechanisms by whichL. pneumophilareplicates intracellularly and kills the host cell are largely not understood. We have recently shown that within 3 h of initiation of the infection and prior to intracellular replication,L. pneumophilainduces apoptosis in macrophages, alveolar epithelial cells, and peripheral blood monocytes, which correlates with cytopathogenicity (L.-Y. Gao and Y. Abu Kwaik, Infect. Immun. 67:862–870, 1999). In this report, we show that the ability ofL. pneumophilato induce apoptosis is, largely, not growth phase regulated. We demonstrate that the induction of apoptosis byL. pneumophilain macrophages is mediated through the activation of caspase 3. The enzymatic activity of caspase 3 to cleave a specific synthetic substrate in vitro is detected inL. pneumophila-infected macrophages at 2 h after infection and is maximal at 3 h, with over 900% increase in activity. The activity of caspase 3 to cleave a specific substrate [poly(ADP-ribose) polymerase, or PARP] in vivo is also detected at 2 h and is maximal at 3 h postinfection. The activity of caspase 3 to cleave the synthetic substrate in vitro and PARP in vivo is blocked by a specific inhibitor of caspase 3. The kinetics of caspase 3 activation correlates with that ofL. pneumophila-induced nuclear apoptosis. Inhibition of caspase 3 activity blocksL. pneumophila-induced nuclear apoptosis and cytopathogenicity during early stages of the infection. Consistent with the ability to induce apoptosis, extracellularL. pneumophilaalso activates caspase 3. ThreedotA/icmWXYZmutants ofL. pneumophilathat are defective in inducing apoptosis do not induce caspase 3 activation, suggesting that expression and/or export of the apoptosis-inducing factor(s) is regulated by thedot/icmvirulence system. This is the first description of the role of caspase 3 activation in induction of nuclear apoptosis in the host cell infected by a bacterial pathogen.
Migration Inhibitory Factor and Interferon in the Circulation of Mice with Delayed Hypersensitivity
Authors: Salvin S. B. , Youngner J. S. , Lederer W. H.
Published: January 2020

When mice infected with
Mycobacterium tuberculosis
strain BCG were inoculated intravenously with old tuberculin (OT) or living BCG cells, both migration inhibitory factor (MIF) and interferon appeared in the circulation within a few hours. In such animals, which showed delayed hypersensitivity by footpad tests, as little as 1.5 mg of OT or as few as 1.7 × 10
6
bacteria per mouse were capable of eliciting circulating MIF and interferon. Uninfected animals inoculated with large doses of OT or living BCG cells did not produce MIF or interferon. When nonspecific stimuli such as bacterial lipopolysaccharide (LPS; from
Salmonella typhimurium
strain LT-2), heat-killed
Brucella abortus
, Newcastle disease virus (NDV), and polyinosinic acid:polycytidilic acid (poly I:C) were inoculated intravenously into BCG-infected mice, MIF was produced in the circulation of animals challenged with LPS or
Brucella
but not in those challenged with NDV or poly I:C, although all the stimuli were capable of eliciting an interferon response. The interferon elicited in BCG-infected mice by specific antigen differed in at least one important property from the viral inhibitor produced by the nonspecific stimuli. The interferon which appeared after injection of OT or living BCG cells was destroyed by treatment at
p
H 2 for 24 hr at 4C, whereas the interferons produced after injection of the nonspecific stimuli were stable under the same conditions. The MIF activity in plasma from sensitized mice inoculated with specific antigen was also destroyed by treatment at
p
H 2. When mouse plasma containing both MIF and interferon activity was filtered through Sephadex G-100, both mediators were excluded in the same peak fractions. Sensitization of mice with complete Freund adjuvant instead of infection with BCG cells produces a different pattern of response. Although hypersensitive to specific antigen by footpad swelling tests, mice sensitized with complete Freund adjuvant failed to produce MIF or interferon when they were inoculated intravenously with OT or living BCG cells.
In Vivo Studies with Collagenase from
Pseudomonas aeruginosa
Authors: Diener Bruce , Carrick Lee , Berk Richard S.
Published: January 2020

An extracellular protease from
Pseudomonas aeruginosa
having collagenase activity was assayed in vivo. The lethality of the enzyme for white female mice was determined by use of intravenous, intraperitoneal, intranasal, and subcutaneous routes, respectively. The collagenase exhibited the following 72-hr mean lethal dose values: intranasally, 55 collagenase units; intraperitoneally, 148 collagenase units; and intravenously, 288 collagenase units. In the concentrations tested, no lethality was obtained when the subcutaneous route was employed. Gross and microscopic studies revealed that the collagenase was capable of eliciting a variety of tissue responses in mice depending upon its route of administration. Intranasal instillation resulted in confluent pulmonary hemorrhage, whereas intraperitoneal injections resulted in severe abdominal hemorrhage with foci on the intestinal serosa. Intravenous injections elicited abdominal hemorrhage and petechial hemorrhage with focal necrosis of the lungs, whereas subcutaneous injections resulted in necrotic, ulcerating lesions.
An Antiphagocytic Factor Associated with Group E Streptococcus
Authors: Daynes Raymond A. , Armstrong Charles H.
Published: January 2020

Group E streptococci (GES) grown in Tryptose phosphate broth (TPB) were highly susceptible to nonspecific phagocytosis by porcine leukocytes, whereas GES grown in serum-supplemented TPB (STPB) were resistant to nonspecific phagocytosis. It was concluded that serum supplementation induced the elaboration of an antiphagocytic factor (APF). The APF was distinct from the group-specific and type-specific polysaccharide antigens, and it was destroyed by trypsin. Electron photomicrographs revealed that GES grown in STPB possessed a fimbriated surface component similar to M protein-positive stains of group A streptococcus. The surface component was absent when GES were propagated in unfortified TPB. The APF was neutralized specifically by sera from swine immune to streptococcic lymphadenitis (SLS), a disease caused by GES. It was hypothesized that the APF was associated with the pathogenicity of GES and that it was involved in the induction of protective immunity to SLS.
Classification of Mouse Thymic Virus as a Herpesvirus
Authors: Parker John C. , Vernon Mina L. , Cross Sue S.
Published: January 2020

Classical herpesvirus particles were observed by thin-section electron microscopy in thymus tissues from mice inoculated with mouse thymic virus. Intranuclear particles measured approximately 100 nm in diameter, and cytoplasmic and extracellular particles measured 135 nm in diameter. The morphology of mouse thymic virus particles together with its properties of heat and ether lability suggest that thymic virus should be classified as a member of the herpesvirus group.
Morphological and Biological Characteristics of the M-P Strain of Lymphocytic Choriomeningitis Virus
Authors: Ofodile Anselm , Padnos Morton , Molomut Norman , Duffy John L.
Published: January 2020

Based on present data, the M-P virus appears antigenically and morphologically to be a strain of the lymphocytic choriomeningitis virus, with some different biological properties.
Effect in Mice of Injection of Viable
Candida albicans
and a Cell-Free Sonic Extract on Circulating Platelets
Authors: Holder Ian A. , Nathan Paul
Published: January 2020

The ability of intravenously injected
Candida albicans
to cause thrombocytopenia and clotting disorders was tested. Mice injected in this manner showed a decrease in circulating platelets and a shortening of clotting time within hours after challenge. Treatment with heparin changed the death distribution pattern, but did not increase overall long-term survival. A cell-free sonic extract prepared from viable
C. albicans
cells was shown to cause aggregation of platelets in vitro, and injection of the cell-free extract into mice caused a decrease in circulating platelets similar to that observed when viable organisms were injected.
Immunosorbent for the Isolation of Specific Antibodies Against Mannan: Localization of Antigens in Yeast Cell Walls
Authors: Gerber H. , Horisberger M. , Bauer H.
Published: January 2020

A procedure is given for the insolubilization of yeast mannan by entrapment in a polyacrylamide gel. Specific anti-mannan antibodies were separated by immunosorption from all other antibodies of a rabbit antiserum against whole, Formalininactivated
Candida utilis
cells. Colloidal gold coated with the anti-mannan and anti-non-mannan antibody fractions was used for the ultrastructural visualization of cell wall antigens. A control was performed using normal rabbit serum. Inhibition of anti-mannan antibodies was obtained with mannan oligosaccharides, and none of the antibody fractions showed marking of
Saccharomyces cerevisiae
cell walls.
Macrophage Cytophilic Antibodies in Mice: Inability to Induce Ingestion of Sheep Erythrocytes by Mouse Peritoneal Macrophages
Authors: Tizard Ian R.
Published: January 2020

By using an in vitro test for phagocytosis, it was demonstrated that mouse antisheep erythrocyte macrophage-cytophilic antibodies did not significantly contribute to erythrocyte ingestion by mouse peritoneal macrophages.
Effect of Colon Flora and Short-Chain Fatty Acids on Growth In Vitro of
Pseudomonas aeruginosa
and
Enterobacteriaceae
Authors: Levison Matthew E.
Published: January 2020

Heat-stable antibacterial activity in the following suspensions was demonstrated against
Pseudomonas aeruginosa
at pH 6.5, 6.0, and 5.5: (i) pooled colon contents of normal mice; (ii) an anaerobic, 48-h culture of normal mouse feces; and (iii) anaerobic, 48-h cultures of different bacteria from human colon flora (
Escherichia coli, Bacteroides fragilis, Klebsiella pneumoniae
, and
Proteus mirabilis
). The lower the pH of the medium, the greater was the antibacterial activity of these suspensions. The antibacterial activity of five fatty acids (propionic, butyric, isobutyric, acetic, and formic acids) was greater against
P. aeruginosa
than against three
Enterobacteriaceae
(
E. coli, K. pneumoniae
, and
P. mirabilis
) at all fatty acid concentrations (0.16 M to 0.005 M) and at the 3 pH values studied (5.5, 6.0, and 6.5). As the pH value increased, the antibacterial activity decreased. Antibacterial activity was greater at higher fatty acid concentrations, and at each pH value it was greatest for the fatty acids having high pK
a
values. Lactic acid, with the lowest pK
a
, exhibited little or no antibacterial activity. Acetic and butyric acids, two of the three predominant volatile fatty acids determined by gas chromatography in the mouse colon contents and in the anaerobic culture of mouse feces, occurred in vivo in concentrations which inhibited growth of
P. aeruginosa
in vitro at the pH of the mouse cecum. These results suggest that undissociated short-chain fatty acids produced by the colon flora may be a mechanism of intestinal resistance to colonization by
P. aeruginosa.
Surface Antigens Produced by Herpesviruses: Varicella-Zoster Virus
Authors: Ito Michio , Barron Almen L.
Published: January 2020

Surface antigen(s) was demonstrated by the mixed agglutination technique on cell cultures infected with varicella-zoster virus (V-Z). The reactions appeared to be specific for V-Z, and no cross-reaction was obtained with herpes simplex virus (HSV). V-Z surface antigen had similar physicochemical properties to that of HSV. It was stable to heating at 56 C and treatment with 1% Formalin, 2,4-dinitrophenol, and periodate, whereas it was undetectable after exposure to acetone or ethanol. Antibodies detecting surface antigen were present in high titer in sera from varicella or herpes zoster patients and paralleled titers obtained by the complement fixation test.
Labile Inhibitor of Lymphocyte Transformation in Plasma from a Patient with Subacute Sclerosing Panencephalitis
Authors: Allen Jeffrey , Oppenheim Joost , Brody Jacob A. , Miller Joseph
Published: January 2020

A thermolabile inhibitory factor of mitogen-induced lymphocyte transformation was observed in the fresh plasma of one patient in stage 3 of subacute sclerosing panencephalitis (SSPE) and not in three other patients in various stages of the disease. Thus, its relevance to SSPE is not clear. The plasma factor was removed by adsorption onto human and animal cells and polystyrene beads, and it was found in the 7
S
globulin fraction of the effluent from gel permeation chromatography.
Ribosomes of Acid-Fast Bacilli: Immunogenicity, Serology, and In Vitro Correlates of Delayed Hypersensitivity
Authors: Baker R. E. , Hill W. E. , Larson C. L.
Published: January 2020

Ribosomal fractions obtained from
Mycobacterium bovis
(BCG) and
M. smegmatis
(strain
butyricum
) were studied to determine their antigenicity, their ability to stimulate the production of soluble mediators of delayed hypersensitivity (in vitro correlates) by sensitized peritoneal exudate cells, and the antigenic relations of ribosomal antigens of BCG to BCG protoplasm and H37Rv culture filtrates. The crude ribosomes and the 50-30S ribosomal subunit pool obtained from each of the organisms induced both delayed and immediate hypersensitivity when injected in incomplete Freund adjuvant into rabbits, and skin reactions could be elicited in sensitized rabbits with those antigens. The crude ribosomes and 50-30S ribosomal subunit pool of
M. smegmatis
stimulated lymphocytes of guinea pigs sensitized with viable organisms to produce macrophage migration inhibition factor. Comparable ribosomal fractions from BCG bacilli caused lymphocytes of guinea pigs sensitized with viable
M. bovis
(BCG) to produce skin reactive factor. Immunoelectrophoretic studies showed that H37Rv culture filtrate, protoplasm, crude ribosomes, and 50-30S ribosomal subunits of BCG contain multiple precipitinogens and that many of these were shared between the different antigen systems. Comparative electrophoresis revealed that BCG protoplasm and H37Rv culture filtrate shared a major portion of their components with each other and relatively few with ribosomal systems. The ribosomal systems shared the major portion of their components with each other and relatively few with the other antigen systems.
Studies on the Mechanism of the Priming Effect of Interferon on Interferon Production by Cell Cultures Exposed to Poly(rI) · Poly(rC)
Authors: De Clercq Erik , Stewart William E. , De Somer Pierre
Published: January 2020

Interferon induction by poly(rI)·poly(rC) in primary rabbit kidney and mouse L-929 cell cultures was markedly increased if the cells were previously treated with homologous interferon. This priming effect has been established with different times of exposure of the cells to poly(rI)·poly(rC), and was most pronounced for short pulses of contact of the polynucleotide with the cells (10 s, 1 min). Treatment of the cells with pancreatic ribonuclease immediately after their exposure to poly(rI)·poly(rC) brought about a relatively greater reduction of the interferon response in interferon-primed cells than it did in unprimed cell cultures. Priming of the cells with interferon did not increase cell-binding of poly(rI)·poly(rC), whether this cell-binding was measured quantitatively (by radioactivity, upon exposure of the cells to radiolabeled polymer) or qualitatively (by antiviral activity, by assaying the cell extract for virus plaque reduction). Similarly, interferon priming did not alter the sensitivity of cell-associated poly(rI)·poly(rC) to extraneous ribonuclease treatment. Finally, priming with interferon did not decrease the rate of degradation of cell-bound poly(rI)·poly(rC) by cellular nucleases nor did it increase the anti-nuclease potency of the cells. The exact mechanism by which previous exposure of the cells to interferon enhances subsequent interferon production, induced by either synthetic polynucleotides or viruses, has not yet been resolved.
In Vitro Correlates of Delayed Hypersensitivity in Man: Ambiguity of Polymorphonuclear Neutrophils as Indicator Cells in Leukocyte Migration Test
Authors: Senyk George , Hadley W. Keith
Published: January 2020

Delayed cutaneous hypersensitivity (DCH) of 12 normal adult subjects to purified protein derivative (PPD) of
Mycobacterium tuberculosis
, streptococcal streptokinase-streptodornase (SK-SD), and
Candida albicans
Dermatophytin O (DO) was assayed in vivo by skin testing and compared with such in vitro correlates of cellular immunity as lymphocyte transformation (LT) and inhibition of leukocyte migration (ILM) from microcapillary tubes or in agarose gel. LT was shown to be the best in vitro correlate of specific lymphocyte sensitization with all antigens. In the ILM assays, PPD showed good correlation with in vivo DCH and in vitro LT; SK-SD showed partial correlation; DO showed no correlation, not being active in any of the ILM tests. Cell distribution and morphology of stained migration patterns, ILM tests performed on separated populations of lymphocytes and polymorphonuclear leukocytes (PMN), as well as the ability of test antigens to stimulate PMN cells to reduce nitroblue-tetrazolium dye, indicated that in ILM tests mononuclear cells were not inhibited in their migration, whereas migration of PMN cells appeared to depend on their direct reaction with the test antigens.
Cytotoxic Factor in the Blood and Plasma of Animals During Leptospirosis
Authors: Knight Loren L. , Miller Norman G. , White Roberta J.
Published: January 2020

Whole blood and plasma from animals in the acute stage of leptospirosis contained a toxic factor which produced a cytopathic effect on fibroblastic L cell monolayers. Firm adsorption of cytotoxic factor (CTF) to L cells occurred within 1 h. The highest titer of CTF in plasma was reached at 24 h and declined after 48 h after the inoculation of leptospires. Toxic effects were also obtained with intracerebral inoculation of mice with plasma containing CTF. Mice showed signs of motor instability and muscular spasms shortly after inoculation with CTF. Death usually occurred within 1 h.
Immune Response to Vaccination with a Live Influenza Virus (H
3
N
2
) Vaccine (“Ann” Strain)
Authors: Prévost J. M. , Peetermans J. , Lamy F. , Huygelen C.
Published: January 2020

A live attenuated influenza virus (“Ann” strain) derived from A/England/878/69 was given intranasally to a group of volunteers, most of whom had already circulating antibodies against H
3
N
2
viruses at the time of inoculation. There was a fourfold or higher increase of circulating hemagglutination-inhibiting antibodies in those volunteers who had relatively low initial titers. The response was lower in those with initially higher serum titers. The pattern of the serum neutralizing antibody response was very similar. The geometric means of the antineuraminidase antibodies were 67 and 118 pre- and postvaccination, respectively. All subjects showed a rise in local neutralizing antibodies in their nasal secretions with geometric means of 4 and 17 pre- and postvaccination, respectively. The levels of local antineuraminidase antibodies also rose in most subjects. In addition to the response to the homologous virus type, the antibody formation to the recent A/England/42/72 was measured in the sera and nasal secretions of some subjects. There was a clearcut response in most of the sera and in all of the secretions examined. The stimulation of circulating lymphocytes was measured in 6 volunteers. All volunteers showed a temporary stimulation. The stimulation index ranged between 2.5 and 28.5.
Interferon Responsiveness of Rabbit Synovial Cells and Chondrocytes
Authors: Craig C. P. , Gordon S. L. , Greer R. B.
Published: January 2020

Rabbit synovial cells (SC), articular chondrocytes (AC), and epiphyseal (EC) chondrocytes were grown in vitro. A portion of the spectrum of human pathogenic viruses infective for the cells was determined. Responses of the cells to different viruses or a chemical inducer of interferon varied, with EC responding vigorously and with high titers, AC responding only to chemical inducer and influenza virus, and SC producing no detectable interferon. All cells supported prolonged growth of influenza virus without showing microscopic cytopathology.
Toxinogeny in
Corynebacterium diphtheriae
After Loss of Catalase, Cystinase, or Deoxyribonuclease Activity
Authors: Groman Neal B. , Dean Cynthia K.
Published: January 2020

The relationship of catalase, cystinase, and deoxyribonuclease activity to toxinogeny in
Corynebacterium diphtheriae
was examined. Mutants deficient in each activity were isolated after mutagenization of strain C4 with nitrosoguanidine. All mutants were converted to toxinogeny after lysogenization with beta-converting phage, thus establishing that there is no absolute link between toxin production and these enzymatic activities. No differences were observed in the rate of lysogenization of the mutants by beta-converting phage over that of the parental strain. However, the data suggest that catalase mutants lysogenic for beta phage are generally induced at a higher rate than the parental strain after irradiation with ultraviolet light. Cystinase mutants vary widely in their rate of induction whereas the deoxyribonuclease mutants are similar to the parental strain. The relationship of these results to the production of toxinogenic strains is discussed.
Immunization of Mice with Live Attenuated Encephalomyocarditis Virus: Local Immunity and Survival
Authors: Bogaerts W. J. C. , Durville-Van Der Oord B. J.
Published: January 2020

Mice were vaccinated with an attenuated encephalomyocarditis (EMC) virus strain by the intraperitoneal (i.p.) route and by various ways of respiratory administration: aerosol exposure and intratracheal (i.t.) and intranasal (i.n.) instillation. A linear relationship was found between vaccine dose and the resulting serum antibody titer. The effectiveness of the vaccine was determined by measuring the 50% protective doses (ED
50
values) after a lethal challenge with live virulent virus given by the i.p. route. For all three methods of respiratory immunization essentially the same ED
50
value was found, about 200 plaqueforming units (PFU), but i.p. immunization was less effective, the ED
50
value being about 600 PFU. To investigate the protective effect of local immunity, mice were vaccinated i.p. or i.n. and challenged by the i.n. route. The same ED
50
values were found as after i.p. challenge, indicating that the degree of protection afforded by the vaccine depends only on the route of vaccination and not on the route of challenge. This means that protection depends largely on systemic immunity and that local immunity plays only a minor role in this system. The results are discussed in relation to the feasibility of respiratory immunization against animal viruses.
Antibody to
Mycoplasma pneumoniae
in Nasal Secretions and Sputa of Experimentally Infected Human Volunteers
Authors: Brunner Helmut , Greenberg Harry B. , James Walter D. , Horswood Robert L. , Couch Robert B. , Chanock Robert M.
Published: January 2020

After experimental infection with
Mycoplasma pneumoniae
, 42% of 67 volunteers developed a threefold or greater rise in antibody in nasal secretions as measured by radioimmunoprecipitation. Development of an antibody increase in sputum was detected more often, i.e., in 73% of the volunteers. Each of the antibody increases involved immunoglobulin (Ig) A. Twelve rises in IgG antibody were detected in the specimens which exhibited a rise in IgA antibody. In almost every instance the rise in IgA antibody exceeded that seen with IgG antibody. Analysis of the response to experimental challenge with
M. pneumoniae
of volunteers with different levels of preexisting respiratory tract IgA antibody suggested that this secretory antibody was related to host resistance to
M. pneumoniae
disease. Further, respiratory tract IgA antibody appeared to be more directly related to host resistance than was antibody in serum.
Purification and Properties of a Toxin Isolated from
Mortierella wolfii
Authors: Davey G. , Smith J. M. B. , Kalmakoff J.
Published: January 2020

A substance toxic for mice has been extracted from the washed mycelia of
Mortierella wolfii.
This toxin could also be demonstrated in culture fluids after spontaneous autolysis of the fungal hyphae. Purification of the toxin was carried out using Sephadex chromatography (G-200, G-50) and resulted in a single band on sodium dodecyl sulfate polyacrylamide gels. Properties of the toxin included heat lability at 60 C, trypsin sensitivity, activity over a wide pH range, and a molecular weight of 23,600. The mean lethal dose for 16-week-old male mice was 3.3 μg of protein.
Mycoplasma hyorhinis
Swine Arthritis III. Modified Disease in Piney Woods Swine
Authors: Barden Jerri A. , Decker John L. , Dalgard Dan W. , Aptekar Robert G.
Published: January 2020

Piney Woods miniature swine, when injected with
Mycoplasma hyorhinis
, develop an acute arthritis. The disease in these animals is limited clinically, microbiologically, and pathologically to a mild acute illness without the more chronic and destructive features noted in a previous study of the experimental disease in Yorkshire swine.
Pathogenesis and Immunology of Experimental Gonococcal Infection: Virulence of Colony Types of
Neisseria gonorrhoeae
for Chicken Embryos
Authors: Bumgarner Linda R. , Finkelstein Richard A.
Published: January 2020

The virulence of gonococcal strains and colony types was evaluated in embryonated hen eggs of various ages inoculated by different routes. Striking differences in virulence of colony types were revealed by intravenous inoculation of 11-day embryos. T1 and T2 colony types were found to have high virulence for embryos, whereas T3 and T4 colony types were relatively avirulent. These observations are in accord with previous studies in volunteers. The differences in virulence were not related to differences in toxicity of killed gonococci, sonic lysates, or to the susceptibility of gonococci to cidal effects of chicken embryo blood. Rather, they appeared to involve differences in clearance of gonococci from the blood stream and subsequent multiplication of the virulent colony types. Infection with virulent colony types appears to be primarily bacteremic in this model. Preliminary experiments indicated that chicken embryos may be protected against the lethal infection by prior treatment of the inoculum with normal and immune rabbit serum. This protective effect was not associated with bactericidal activity. The chicken embryo model is potentially useful as a means of investigating attributes of virulence of gonococci and factors in immunity against gonorrhea.
Simian Model for the Evaluation of Immunity to Influenza
Authors: Berendt Richard F.
Published: January 2020

Rhesus monkeys (
Macaca mulatta
) exposed to small-particle aerosols of the Aichi strain of type A2 influenza virus responded by shedding virus from the nasopharynx for 7 to 9 days and by seroconversion (hemagglutination inhibition) 8 or 9 days after exposure. After rechallenge with the homologous virus, no replication of the organism was observed, and a serological anamnestic reaction occurred. The data indicate that the rhesus monkey is a useful primate model for evaluating induced immunity to influenza virus infection.
Isolation of a Specific Enhancer for Echovirus 6 from Uninfected Permissive Host Cells
Authors: Righthand V. Fay , Hughes Patricia F.
Published: January 2020

A specific enhancer for the
m
+ variant of echovirus 6 was isolated from uninfected, permissive host cells. The enhancer transferred the susceptibility to virus infection from permissive cells to less susceptible cells. Enhancer activity in cultured, human cells (WISH) was released by these cells into extracellular fluids at a linear rate. Maximal enhancer activity was recovered from cell monolayers that were extracted with buffered salt solutions (pH 6.6) for 5 h at 37 C. Crude enhancer preparations contained substances that reduced virus titers in permissive host cells and suppressed some of the enhancer activity. Viral inhibitory activity was removed from cellular extracts by either differential centrifugation or ion exchange chromatography. The enhancer, in contrast to inhibitory substances, remained in supernatant fractions after centrifugation at 110,000 ×
g
for 4 h and adsorbed to diethylaminoethyl-Sephadex columns. Enhancer preparations that were devoid of inhibitory activity increased the virus titers in less susceptible simian cell cultures (approximately 100-fold) to the titers attained by fully permissive human cell cultures. A direct relationship between protein concentration and enhancer activity in cellular extracts was demonstrated. Partial purification of the enhancer by differential centrifugation and ammonium sulfate precipitation increased the specific activity of enhancer (units/mg of protein) by 13-fold.
Isolation and Biochemical Activities of Trehalose-6-Monomycolate of
Mycobacterium tuberculosis
Authors: Kato Masahiko , Maeda Jiro
Published: January 2020

A monoester of trehalose linked at the 6-position with mycolic acids (trehalose-6-monomycolate) was isolated from the wax D fraction of virulent human
Mycobacterium tuberculosis
, and its biochemical action on host-cell mitochondria was studied. Trehalose-6-monomycolate showed a delayed toxicity for mice. The 50% lethal dose at 2 weeks was 452 μg. It induced in vitro a swelling of mouse liver mitochondria and uncoupled respiration and phosphorylation in the nicotinamide adenine dinucleotide pathway of the electron transport chain. The site of functional damage was located specifically at coupling site II. Mitochondrial adenosine triphosphatase was slightly stimulated by trehalose-6-monomycolate. These findings indicate that trehalose-6-monomycolate affects mitochondrial oxidative phosphorylation in a similar manner to, but to a lesser extent than, trehalose-6, 6′-dimycolate (cord factor) of
M. tuberculosis.
Characterization of Anti-
Aeromonas salmonicida
Antibodies from Coho Salmon
Authors: Cisar J. O. , Fryer J. L.
Published: January 2020

Coho salmon (
Oncorhynchus kisutch
) anti-
Aeromonas salmonicida
agglutinins were excluded from Sephadex G-200 and their activity was lost after partial reduction and alkylation followed by exposure to 2 M urea. Immunoelectrophoretic analysis of coho antiserum revealed anodic and cathodic populations of immunoglobulin (Ig), and the anti-
A. salmonicida
antibodies present 12 weeks after parenteral immunization were primarily anodic Ig. Antibodies were specifically purified by dissociation of
A. salmonicida
cell wall agglutinates with 15% NaCl. The purified Ig was a 17
S
macroglobulin, and electron microscopy and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that it was composed of four IgM-like subunits. The minimum coho antibody concentration required for visible agglutination of
A. salmonicida
cells was approximately 0.006 μg of Ig nitrogen/ml.
Immunological Nature of Antimycobacterial Phenomenon in Macrophages
Authors: Kochan Ivan , Golden Carole A.
Published: January 2020

Heptane-extractable fractions (HEF) prepared from immune-activated macrophages (IA-M) of tubercle bacilli or bovine gamma globulin-sensitized and -challenged guinea pigs inhibited the growth of tubercle bacilli whereas HEF of normal macrophages exerted no antibacterial activity. In distinction to the strong antibacterial activity of HEF of IA-M, HEF of immune macrophages exerted weak or no antimycobacterial activity. HEF of alveolar macrophages exerted stronger antibacterial activity than HEF of peritoneal macrophages. The degree of the antibacterial activity of HEF was determined primarily by the time of macrophage collection from antigenically stimulated animals. The antibacterial activity gradually increased and peaked at 2 weeks after the antigenic stimulation of sensitized animals; subsequently, the activity declined and disappeared in about 5 weeks. Similar to other immunological reactions, the stimulation of sensitive animals with specific antigen induced an anamnestic reaction which was characterized by a rapid recall of the macrophage antimycobacterial phenomenon (MAP). The antibacterial strength of the recalled phenomenon in sensitized animals was dependent upon the intensity of the sensitizing regimen; the phenomenon was much stronger in three times-sensitized animals than in once- and twice-sensitized animals. The time of appearance and the specificity of induction and of recall of the MAP indicate that the phenomenon is associated with the activated state in macrophages and, as a consequence of this association, it has a well-defined immunological nature.
Eperythrozoon coccoides
II. Effect on Interferon Production and Role of Humoral Antibody in Host Resistance
Authors: Glasgow L. A. , Murrer A. T. , Lombardi P. S.
Published: January 2020

Eperythrozoon coccoides
was shown to inhibit the interferon response in mice only during the first 3 weeks after acute infection. By 6 weeks the production of interferon in response to Newcastle disease virus returned to a normal level. Antibody to
E. coccoides
could be demonstrated by three methods: (i) neutralization, (ii) indirect fluorescent antibody, and (iii) gel diffusion. The clearance of the parasitemia could be correlated with the appearance of circulating antibody. The critical role of humoral antibody was confirmed by evidence that immunosuppressive therapy prevented, in an infected animal, clearing of
E. coccoides
from the blood and converted a nonlethal infection to one with a 100% mortality. Administration of immune serum to the
E. coccoides
-infected, immunosuppressed animal, however, resulted in clearing of the parasitemia and prevention of death. Finally, a series of immunosuppressive regimens failed to exacerbate
E. coccoides
in animals after recovery from the acute phase of infection.
E. coccoides
may not be as important a laboratory contaminant as postulated originally.
Development of a Purified Cholera Toxoid I. Purification of Toxin
Authors: Rappaport Ruth S. , Rubin Benjamin A. , Tint Howard
Published: January 2020

The enterotoxin from
Vibrio cholerae
is selectively concentrated from cell-free culture supernatant by co-precipitation with hexametaphosphate and is further purified by adsorption on aluminum hydroxide powder. The bulk of residual somatic antigen becomes insoluble upon lyophilization of the toxin preparation and is removed by centrifugation of the rehydrated material. Other contaminants are eliminated by treatment with activated carbon. Preparations of toxin, purified by this method, have been characterized by: (i) a single immunoprecipitin line against polyvalent antisera; (ii) homogeneity on acrylamide gels; (iii) specific activities on the order of 22 limit-of-bluing doses/μg; (iv) ultraviolet spectra characteristic of pure protein; and (v) overall yields on the order of 50%, irrespective of purification scale. Such preparations, however, have been shown to contain trace amounts of somatic antigen when they are intensively tested either for their ability to elevate serum vibriocidal antibody titers in immunized rabbits or for their ability to increase resistance of immunized mice to live vibrio challenge. In the latter test system, the level of residual somatic antigen per 50 μg of toxin (toxoid) antigen generally did not exceed 0.025% of the Division of Biological Standards reference vaccine,
V. cholerae
Inaba IN-12. Methods for elimination of this small amount of somatic antigen have been investigated and are discussed. The particular combination of purification steps which are presently described have been easily and reproducibly applied on a production scale to prepare gram amounts of toxin with a high degree of purity, even under a variety of initial conditions.