bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathogenesis of Herpetic Neuritis and Ganglionitis in Mice: Evidence for Intra-Axonal Transport of Infection
Authors: Cook Margery L. , Stevens Jack G.
Published: January 2020

The pathogenesis of acute herpetic infection in the nervous system has been studied following rear footpad inoculation of mice. Viral assays performed on appropriate tissues at various time intervals indicated that the infection progressed sequentially from peripheral to the central nervous system, with infectious virus reaching the sacrosciatic spinal ganglia in 20 to 24 hr. The infection also progressed to ganglia in mice given high levels of anti-viral antibody. Immunofluorescent techniques demonstrated that both neurons and supporting cells produced virus-specific antigens. By electron microscopy, neurons were found to produce morphologically complete virions, but supporting cells replicated principally nucleocapsids. These results are discussed in the context of possible mechanisms by which herpes simplex virus might travel in nerve trunks. They are considered to offer strong support for centripetal transport in axons.
Isolation and Characterization of the β Antigen of
Neisseria gonorrhoeae
Authors: Apicella Michael A. , Allen James C.
Published: January 2020

The β antigen of
Neisseria gonorrhoeae
has been isolated from the alkaline-extracted gonococcal endotoxin by ion exchange, molecular sieve, and powder block electrophoretic chromatography. Hemagglutination inhibition studies indicate that the preparation is essentially free of common enterobacterial and gonococcal α antigen. Analysis of the isolated antigen by immunodiffusion and acrylamide gel electrophoresis reveal only one detectable component. Chemical studies indicate that the antigen is an acidic glycoprotein composed primarily of four major amino acids: alanine, glutamic acid, glycine, and proline. The antigen has an
s
0,w
of 8.55, and spectral analysis in the ultraviolet and visible range reveals a single absorption peak at 217 nm.
Transmissible Mink Encephalopathy: Studies on the Peripheral Lymphocyte
Authors: Marsh R. F. , Miller Janice M. , Hanson R. P.
Published: January 2020

Circulating lymphocytes from mink with transmissible mink encephalopathy were studied for the presence of virus particles and for infectivity. Electron microscope examination of phytohemagglutinin-stimulated lymphocyte cultures revealed no evidence of virus-like particles. Circulating lymphocytes were also found to be noninfectious when the transmissible agent could be demonstrated in intact lymphoid organs in infected mink. A lymphopenia was detected in affected mink during the late clinical stage of disease, but this was most likely a secondary effect due to a terminal stress factor.
A Simplified Method for Immunological Typing of Trachoma-Inclusion Conjunctivitis-Lymphogranuloma Venereum Organisms
Authors: Wang San-Pin , Kuo Cho-Chou , Grayston J. Thomas
Published: January 2020

Responding to the pressure of large numbers of trachoma-inclusion conjunctivitis (TRIC)-lymphogranuloma venereum (LGV) isolates from field studies requiring serotyping, we have developed a simplified, less-precise method that utilizes cell culture-grown organisms to produce mouse antisera which is tested agaist prototype TRIC-LGV antigens in the micro-immunofluorescence test. Cell cultures with as few as 5 to 15% of cells showing inclusions produced adequate antibody in mice 4 days after single injection. Knowledge of the reaction of prototype antisera with the antigens has allowed typing of most isolates tested from the pattern of cross-reaction of their antiserum.
Fate of Intravenously Injected
Mycoplasma arthridis
in Rodents and Effect of Vaccines
Authors: Cole B. C. , Ward J. R.
Published: January 2020

Virulent
Mycoplasma arthritidis
strain 158 P10 was rapidly eliminated from the peripheral circulation of rats and mice during the first 2 h after intravenous injection of the organisms. Characteristically after this time, the numbers of viable organisms remained remarkably constant through 48 to 72 h. The inability to clear the remaining mycoplasmas was not due to reticuloendothelial blockade but appeared to indicate the presence of a certain number of cells which were resistant to the clearance mechanism. Rat blood was usually devoid of mycoplasmas at 6 days and mouse blood was sterile by 14 days. An occasional transient mycoplasmemia occurred after these times. Avirulent
M. arthritidis
strain H606 was cleared more rapidly from rats in which it is non-arthritogenic. Different, but characteristic, clearance curves were obtained in mice using
M. hominis, M. bovirhinis
, and
M. pulmonis
. Active immunization procedures resulted in enhanced clearance of virulent
M. arthritidis
from rats. These procedures were less successful in mice. The results of passive immunization of normal rats and mice using convalescent serum indicated the presence of a serum factor which greatly enhanced clearance from rats but had only minimal effects in mice. This serum factor could not be correlated with metabolic-inhibiting antibody. Lymphocytes taken from convalescent rats enhanced the clearance rates of recipient rats. Mouse convalescent lymphocytes were without effect. The results indicated that mice are less able to control long-term infection by
M. arthritidis
than are rats.
Interaction of Lymphoid and Nonlymphoid Cells with the Lymphocytosis-Promoting Factor of
Bordetella pertussis
Authors: Adler Andy , Morse Stephen I.
Published: January 2020

The activity of soluble lymphocytosis-promoting factor (LPF) from
Bordetella pertussis
decreased after brief in vitro incubation with lymphoid cells or erythrocytes. The LPF activity was found to be associated with the cells used, and injection of the cells produced a leukocytosis and lymphocytosis which completely accounted for the loss of soluble activity. Attachment of LPF to cells was found to be reversible in vitro. It is suggested that reversible binding occurs in vivo.
Absence of an Immune Response after Oral Administration of Attenuated Feline Panleukopenia Virus
Authors: Schultz Ronald D. , Scott Fredric W.
Published: January 2020

Cats were orally vaccinated with attenuated feline panleukopenia virus to compare this route with parenteral immunization. Cats receiving vaccine virus by mouth did not produce a systemic or local antibody response to the virus. Intranasal and subcutaneous vaccination produced high levels of neutralizing antibodies and provided protection from challenge with virulent virus. The results suggest that virus does not initially infect the tissue of the oral pharynx or gastrointestinal tract as previously suspected.
Serotypes in
Saccharomyces telluris:
Their Relation to Source of Isolation
Authors: Hasenclever H. F. , Kocan R. M.
Published: January 2020

Three serotypes have been characterized with three reference strains of
Saccharomyces telluris
and designated as A, B, and C. One reference strain of
Torpulopsis bovina
, the imperfect form of
S. telluris
, belonged to serotype B.

Strains (141) of
S. telluris
isolated from four columbid species were serotyped. All 98 strains of this yeast isolated from
Columba livia
(feral pigeon) belonged to serotype B. Three other columbid species,
C. leucocephala
(white-crowned pigeon),
C. fasciata
(band-tailed pigeon), and
Zenaidura macroura
(mourning dove) harbored strains of serotype C only. Serotype A was not isolated from any of the avian species.
Isolation and Characterization of an Equine Adenovirus
Authors: Ardans Alexander A. , Pritchett Randall F. , Zee Yuan Chung
Published: January 2020

A viral agent was isolated from lung tissue obtained upon necropsy of an Arabian foal which had exhibited clinical signs of pneumonia. The virus is 75 nm in diameter, cubic in symmetry, and resistant to chloroform and low pH (3.0). It contains deoxyribonucleic acid and has a buoyant density of 1.31 g/cm
3
in cesium chloride. These findings indicate that the virus is a member of the adenovirus group.
Antigens of
Streptococcus mutans
I. Characterization of a Serotype-Specific Determinant from
Streptococcus mutans
Authors: Van De Rijn Ivo , Bleiweis A. S.
Published: January 2020

A membrane-associated glycerol teichoic acid antigen has been isolated from
Streptococcus mutans
AHT and a similar antigen has been demonstrated to be present in each of the other Bratthall serotype
a
organisms studied. Trichloroacetic acid-extracted material was resolved into two phosphorus-containing antigenic fractions (B and C) by agarose chromatography. Fraction B was preliminarily identified as a phospholipid moiety with a glycerol-to-phosphorus ratio of 2:1, and fraction C showed a ratio of 1:1 indicative of a glycerol teichoic acid. This latter fraction also was associated with glucose, galactose, alanine, and fatty acids. Diglycerol triphosphate, the compound characteristically released from 1-3 phosphodiester-linked glycerol teichoic acids by alkaline hydrolysis, was isolated and characterized. Alanine was identified as its alkaline-labile, ester-linked D-isomer. A glyceride was isolated containing a disaccharide of glucose and galactose attached to the 2-hydroxyl group of glycerol. Hapten inhibition analysis demonstrated that β-galactosides were the greatest inhibitors of the precipitin reaction (>75%), whereas glucose and its derivatives inhibited to a much lesser extent (<30%). Comparative immunodiffusion and immuno-electrophoresis analyses demonstrated that all six Bratthall serotype
a
organisms tested contained this antigenic determinant and that it was absent in serotypes
b, c
, and
d
. It is suggested that the common antigenic determinant of this serotype within
S. mutans
may be a β-galactoside associated with a glycerol teichoic acid and possibly other polymers.
Cytological Localization of Dengue-2 Antigens: an Immunological Study with Ultrastructural Correlation
Authors: Cardiff R. D. , Russ S. B. , Brandt W. E. , Russell P. K.
Published: January 2020

Immunofluorescence and electron microscopy were used to study the development and cytological distribution of dengue-2 virion and nonvirion antigens in monkey kidney cells. The type and combination of fixatives were found to affect the intensity of fluorescence. Paraformaldehyde fixation alone resulted in a low level of fluorescence, but an additional fixation step with ethanol or acetone resulted in maximum staining. No fluorescence was obtained after fixation with glutaraldehyde alone or in combination with other solvents. Methanol caused selective ablation of fluorescence by antibody to purified virions. Dengue-specific fluorescence that was most intense in the perinuclear area radiated in a granular pattern of decreasing intensity into the cytoplasm. The perinuclear fluorescence was associated with nonvirion antigens and the cytoplasmic fluorescence was associated with virion antigens. Electron micrographs of infected cells revealed vesicular bodies with reticular electron-dense centers, clusters of structurally complete virions deep within the endoplasmic reticulum, and single virus particles in vacuoles near the periphery of the cell.
Antigenic Relationships Among Four Herpesviruses
Authors: Blue W. T. , Plummer G.
Published: January 2020

Common viral antigens were detected, by fluorescent-antibody studies, in cells infected with herpes simplex virus 1, squirrel monkey herpesvirus 1, bovine rhinotracheitis, and equine abortion viruses. The two primate viruses showed slight cross-neutralization.
Factors Affecting the Regulation of Staphylococcal Enterotoxin B
Authors: Morse Stephen A. , Baldwin Jack N.
Published: January 2020

Several factors which regulate the synthesis of enterotoxin B were examined in
Staphylococcus aureus
S-6 and in its heme-requiring mutant S-6H2. The kinetics of enterotoxin B synthesis during anaerobic growth were identical to those observed under aerobic conditions; extracellular enterotoxin accumulated in the medium during the transition between exponential and stationary phase growth. Strain S-6H2 lacked a functional electron transport system unless the medium was supplemented with heme. In a casein hydrolysate medium, the presence or absence of a functional electron transport system had no effect upon the differential rate of toxin synthesis. The repression of toxin synthesis by glucose at either pH 6.0 or 7.7 or by pyruvate at pH 7.7 occurred in the absence of a functional electron transport system, but was enhanced significantly in its presence. Thus, a functional electron transport system appears to be involved in regulating the degree of glucose and pyruvate repression of enterotoxin B synthesis.
Homogeneity of Venezuelan Encephalitis Virion Populations of Hamster-Virulent and Benign Strains, Including the Attenuated TC83 Vaccine
Authors: Jahrling Peter B. , Scherer William F.
Published: January 2020

A hamster-virulent strain of Venezuelan encephalitis virus (BeAn8, subtype III) and a benign strain (BeAr35645, subtype IV) each yielded 100 clones with virulence properties like those of the parental virion population. Another hamster-virulent strain (63U2, subtype I, variety E) was heterogeneous since 2 out of 100 clones were less virulent for hamsters than the other 98 clones or the parental virus population. The attenuated TC83 vaccine strain, (a derivative of subtype I, variety A), although over 99% homogeneous with respect to hamster virulence, was unstable since virulent virions could be selected from the parental population by passage through hamsters.
Extracellular Factor Synthesized by
Bacillus cereus
Which Evokes a Dermal Reaction in Guinea Pigs
Authors: Glatz Bonita A. , Goepfert J. M.
Published: January 2020

A guinea pig skin assay was developed as a measure of ileal loop fluid-inducing factor in the rabbit and possibly of the causative principle of
Bacillus cereus
food poisoning. A green or bloody necrotic reaction was produced in the guinea pig skin by injection of culture filtrates from 21 of 24
B. cereus
strains tested, and by no other
Bacillus
species tested except for the closely related
B. thuringiensis.
The skin factor was synthesized and excreted by logarithmically growing cells, inactivated by heating at 56 C for 5 min, precipitable by ammonium sulfate, and was nondialyzable. The skin activity was not related to the lecithinolytic or hemolytic activities of
B. cereus.
Production of the skin factor depended on the medium in which the culture was growing. The factor was an antigenically active substance. There are indications that at least two antigenically distinct species of skin factors exist.
Induction of Viral Interference: Effects of Poly rI·rC and Diethylaminoethyl-Dextran on the Activity of the Antiviral Protein
Authors: Kalmakoff J. , Austin F. J.
Published: January 2020

The activity of the antiviral protein induced by various ratios of poly rI·rC and diethylaminoethyl (DEAE)-dextran was studied. It was found that, when large doses of poly rI·rC were used, very little viral interference was observed. This effect was initially attributed to the cells being refractory for production of antiviral protein. Subsequent experiments offered alternative explanations suggesting that, at any given dosage of poly rI·rC, an excess of DEAE-dextran is necessary for the production of viral interference. It is suggested that DEAE-dextran acts by exposing a cell receptor site for poly rI·rC.
Histamine Release Induced by Human Leukocyte Lysates: Implication of a Specific, Complement-Independent, Noncytotoxic Reaction
Authors: Kelly Michael T. , White Arthur
Published: January 2020

The characteristics of histamine release induced by human leukocyte lysates were determined. Intact human leukocytes released histamine during incubation with leukocyte lysates. Maximal release occurred under physiological conditions of temperature and pH, and both Ca
2+
and Mg
2+
were required. The addition of ethylenediaminetetraacetic acid abruptly inhibited release. Complement was not required, and serum actually inhibited release. Histamine release was maximal at lysate concentrations of 0.25 to 1.0 μg of protein per ml, and it was reduced at either higher or lower concentrations. Leukocytes continued to exclude trypan blue and maintained chemotactic activity after histamine release. Leukocytes released histamine independently of cellular protein or enzymes. Histamine release induced by leukocyte lysates was interrupted by subsequent removal of the lysate. The data suggest that this histamine release occurs by a specific, complement-independent, noncytotoxic process which resembles, but is not identical with, antigen-induced histamine release. The system has several unique characteristics which suggest that it is a novel form of inflammatory histamine release. This system should provide a useful in vitro model for studies of cellular processes in human inflammation.
Comparative Immunology: Sipunculid Bactericidal Responses
Authors: Evans E. Edward , Cushing John E. , Evans Marjorie L.
Published: January 2020

This report continues comparative studies of inducible bactericidins of invertebrates. The bactericidin of the sipunculid worm
Dendrostomum zostericolum
Chamberlain was induced by intracoelomic injections of killed bacteria. With the assay system used, optimal results were obtained with 90 min of incubation at 20 to 35 C. Bactericidal titers in coelomic fluids from noninjected worms were either low or nonexistent. After injections of gram-negative bacteria, bactericidal titers of up to 1:1280 were reached within 7 days. Considerable individual variations were noted. Optimal stimulation was achieved with 4 × 10
8
bacteria per injection. The response was relatively nonspecific as measured by cross-immunization and absorption experiments. Injections of sterile sea water produced no response. Coelomic fluids could be inactivated by heating at 50 or 56 C for 20 min. Activity was not restored by a pool of unheated coelomic fluid from nonimmunized worms. The significance of these observations was discussed with reference to immunity of sipunculids and to comparative immunology.
Granulocyte-Macrophage Precursor Cell and Colony-Stimulating Factor Responses of Mice Infected with
Salmonella typhimurium
Authors: Trudgett A. , McNeill T. A. , Killen M.
Published: January 2020

The response of granulocyte-macrophage progenitor cells (in vitro colony-forming cells) and of colony-stimulating (CS) factor in serum were studied in mice infected intraperitoneally with 10
3
viable
Salmonella typhimurium
. Increases in the number of colony-forming cells in marrow and spleen and increases in the serum level of CS factor occurred during the infection. There was no evidence to suggest that progressive infection was associated with failure of macrophage production. Medium rich in CS factor increased the bactericidal activity of macrophages in vitro and it was suggested that CS factor could be involved in macrophage activation.
Susceptibility of Guinea Pig Cell Cultures to Infection with Cell-Bound and Cell-Free Herpesvirus of Turkeys
Authors: Bedigian H. G. , Sevoian Martin
Published: January 2020

Cell-bound and cell-free herpesvirus of turkeys infected and replicated in guinea pig cell cultures as evidenced by cytopathic effects, intranuclear inclusions, and the presence of herpesvirus particles as seen by electron microscopy were studied in this investigation. Further evidence for the replication of herpesvirus of turkeys in cell cultures was determined by serum neutralization, complement fixation, and the fluorescent antibody tests.
Inhibition by Oxisuran of Cell-Mediated Hypersensitivity by Decrease in Numbers of Specifically Sensitized Cells
Authors: Fox Alfred E. , Gingold James L. , Freedman Henry H.
Published: January 2020

Oxisuran, 2-([methylsulfinyl]acetyl)pyridine, has previously been shown to selectively suppress cell-mediated immunity, as measured by prolongation of allograft survival, without inhibition of humoral immunity. In the present investigation, the influence of this compound on lymphoid cell transfer of delayed hypersensitivity was studied. In actively sensitized animals, including endotoxin-sensitized mice and rabbits, ovalbumin-, dinitrochlorobenzene-, and dinitrofluorobenzene-sensitive guinea pigs, or tuberculin-sensitive rats, daily treatment during the interval just preceding the elicitation and expression of the hypersensitivity was most inhibitory. In both endotoxin-sensitive mice and ovalbumin-sensitive guinea pigs, treatment of the sensitized cell donor just prior to lymphoid cell harvest and transfer resulted in inhibition of the expression of the hypersensitivity in untreated recipients. Approximately 10
4
fewer specifically sensitized lymphoid cells, but not fewer viable cells, were present in passively transferred cell preparations. In contrast, treatment of the lymphoid cell recipient in the same experimental model did not influence the expression of the transferred hypersensitivity. The results suggest that oxisuran may influence an as yet undefined event prior to the expression of a cell-mediated hypersensitivity response in sensitized animals.
Mechanism of Adherence of
Streptococcus mutans
to Smooth Surfaces I. Roles of Insoluble Dextran-Levan Synthetase Enzymes and Cell Wall Polysaccharide Antigen in Plaque Formation
Authors: Mukasa Hidehiko , Slade Hutton D.
Published: January 2020

The mechanism of adherence of
Streptococcus mutans
to smooth glass surfaces has been studied. The results with both viable and heat-killed cells showed that the process required (i) the synthesis of a water-insoluble dextran-levan polymer by cell-bound enzymes and (ii) the participation of a binding site on the surface of the
S. mutans
cell. Synthesis of the polymer from sucrose in the presence of the cells was required for adherence, and indicates that an “active” form of the polymer was required. Polymer synthesized by cell-free
S. mutans
enzymes when added to
S. mutans
cells did not produce adherence. Purified antibody globulin, specific for the a-d site in the polysaccharide
S. mutans
group a antigen, completely inhibited adherence. Antibody to the second antigen present in the polysaccharide molecule, the a antigen, did not inhibit adherence. The evidence indicates that adherence did not require an antigenic binding site which might be common to all
S. mutans
strains. The orientation of the synthetase enzyme(s), antigenic binding site, and dextran-levan polymer on the cell surface is under study.
Equine Herpesviruses: Antigenic Relationships and Deoxyribonucleic Acid Densities
Authors: Plummer G. , Goodheart C. R. , Studdert M. J.
Published: January 2020

Equine herpesviruses with a deoxyribonucleic acid density of 1.716 to 1.717 g/cm
3
were compared with one another by the plaque-reduction test and by the rate of development of cytopathic effect as indicated by plaque size in rabbit kidney cultures. Of the 19 isolates studied, the 9 which had already been tentatively labeled equine abortion viruses were serologically similar to one another; each of them grew more quickly than did any of the other 10 isolates although the mean plaque sizes formed a series of gradations with no clear hiatus which would permit the unequivocal delineation of the abortion viruses from the slowly growing strains. The 10 slowly growing isolates showed antigenic heterogeneity even though complement was present; the neutralizing capacity of an antiserum against the heterologous strains was, in most instances, markedly less than against the homologous strains, the range of the 50% endpoints being much greater than that observed among the equine abortion viruses, or among isolates of herpes simplex type 1. There was no cross neutralization between the equine abortion viruses and any of the 10 slowly growing isolates. An extra band of deoxyribonucleic acid, at 1.723 to 1.725 g/cm
3
, was present in two of the slowly growing strains when originally grown in rabbit cells, but was no longer present after passage in cat cells. This band occupied the same position as one reported in the hamster-passaged strain of equine abortion virus, and had a density similar to that of the equine genital herpesvirus. Although the taxonomic demarcation of the equine abortion viruses and the slowly growing herpesviruses from one another is still open to question, they can be conveniently labeled equine herpesviruses 1 and 2, respectively; the genital virus would be termed equine herpesvirus 3.
Persistent Newcastle Disease Virus Infection in Embryonic Chicken Tracheal Organ Cultures
Authors: Cummiskey J. F. , Hallum J. V. , Skinner M. S. , Leslie G. A.
Published: January 2020

The persistent infection of embryonic chicken tracheal organ cultures with Newcastle disease virus (NDV) is described. Tracheal explants remained morphologically intact and were able to support the replication of NDV for 6 months. Peak titers of released virus occurred at 1 week postinfection, whereas maximal immunofluorescence was not observed until 30 days postinfection. The inoculum titer was not critical, and viral persistence resulted with either of two strains of NDV tested. Serum was not required in the medium for explant viability or to maintain the persistent infection. The presence of a contaminating virus morphologically resembling a leukovirus neither altered the course of infection nor affected the survivability of explants. Although interferon was not detected in the culture medium, persistently infected explants were resistant to heterologous viral challenge, and a similar resistant state could be induced in uninfected explants with exogenous interferon or ultraviolet light-inactivated NDV. No evidence was found to implicate antibody as a regulatory factor in the establishment or maintenance of persistence. The results from electron microscopy and immunofluorescence suggest the cells of the subepithelial connective tissue as the site of NDV persistence.
Infection at the Subcellular Level II. Distribution and Fate of Intravenously Injected Brucellae Within Phagocytic Cells of Guinea Pigs
Authors: Guerra Humberto , Deter Russell L. , Williams Robert P.
Published: January 2020

Cells of
Brucella melitensis
strain 16 M were labeled with
32
P. When injected into normal guinea pigs, labeled, viable bacteria were taken up and inactivated in liver and spleen during the 60 min after infection. Both uptake and inactivation increased if brucellae were coated with antibrucella antibody. Neither viability nor radioactivity were lost when labeled brucellae were incubated for 60 min in vitro with normal guinea pig blood, liver homogenates, or in defined medium. Incubation for 12 h with antibrucella rabbit immunoglobulin G similarly was innocuous. Livers were removed from infected animals at various times up to 60 min after injection and were separated into subcellular fractions. The numbers of total (determined by radioactivity measurements) and viable brucellae as well as the acid phosphatase activity in the various fractions were determined. Total bacteria and acid phosphatase activity were progressively transferred from the mitochondrial plus light mitochondrial (M + L) fraction to the nuclear (N) fraction. Viability of brucellae declined more rapidly in the N fraction than in other fractions. Examination of M + L fractions by isopycnic centrifugation showed a decrease in viability of both free brucellae and those in particles. The results indicated the formation of bacteria-containing heterolysosomes which progressively increased in size and in which brucellae were inactivated. The antibrucella activity of phagocytes of guinea pig liver in vivo appeared to be greater than that of peritoneal macrophages from immune rabbits or of bovine leukocytes studied in vitro.
Production of Vascular Permeability Factor by Enterotoxigenic
Escherichia coli
Isolated from Man
Authors: Evans Doyle J. , Evans Dolores G. , Gorbach Sherwood L.
Published: January 2020

Enterotoxin preparations derived from
Escherichia coli
strain H-10407 were shown to contain vascular permeability factor (PF) activity as well as diarrheagenic activity. Intradermal injection of
E. coli
enterotoxin (ECT) caused localized induration and permeability of small blood vessels of the skin to intravenously administered Evans blue dye. The PF assay described here demonstrated a linear dose response and was at least as sensitive as the adult rabbit ileal loop assay for detecting ECT.
E. coli
PF activity was heat labile and was neutralized by homologous antiserum. PF production was enhanced by the addition of yeast extract (up to 0.6%) to a Casamino Acids-salts medium. PF activity was detectable as early as 6 h in aerated (shake) cultures in the Casamino Acids-yeast extract-salts medium, pH 8.5, maximal at 18 h and essentially unchanged at 48 h. The skin test (PF) assay for ECT has numerous advantages over current assay methods which involve gastrointestinal challenge of experimental animals.
Suppression of
Candida albicans
by Human Oral Streptococci in Gnotobiotic Mice
Authors: Liljemark W. F. , Gibbons R. J.
Published: January 2020

Mixed human salivary bacteria and strains of
Streptococcus salivarius
and
S. miteor
suppressed colonization of
Candida albicans
in gnotobiotic mice.
C. albicans
attached in lower numbers to epithelial cells from conventional rats than from germ-free rats, and attachment inhibition by indigenous flora may explain in part the suppression of
Candida
colonization.
Pathogenicity and Immunogenic Efficacy of a Live Attenuated Plague Vaccine in Vervet Monkeys
Authors: Hallett A. F. , Isaäcson Margaretha , Meyer K. F.
Published: January 2020

A live attenuated
Yersinia pestis (Pasteurella pestis)
vaccine strain designated EV51f, which had been passaged through guinea pigs previously treated with ferrous sulfate, was shown to be pathogenic for African green vervet monkeys (
Cercopithecus aethips pygerythrus
), but not for guinea pigs. The bacilli multiplied in the monkeys, as shown by positive blood cultures, caused an elevation of white cell counts and rectal temperatures, and resulted in death of 26% (13/50) of animals. Postmortem findings of these animals were typical of bubonic-septicemic plague. This vaccine did not cause deaths in 50 guinea pigs even in doses up to 100 million viable bacilli inoculated subcutaneously. It is suggested that the virulence of an attenuated
Y. pestis
strain which does not produce pigment on a defined medium containing hemin, but possesses all other known virulence determinants, is dependent on the availability of iron in vivo. The serological response of the monkeys as determined by the hemagglutinating and mouse protective antibodies was high one month after vaccination and also in guinea pigs, as shown by virulent challenge. This antibody level declined in monkeys over a period of nearly 6 months, and a decline in immunity was confirmed by virulent challenge which resulted in the death of 30% of vaccinated monkeys. The level of immunity in monkeys did not appear to be related to the dose of vaccine.
Group B Arbovirus Structural and Nonstructural Antigens III. Serological Specificity of Solubilized Intracellular Viral Proteins
Authors: Qureshi Ateef A. , Trent Dennis W.
Published: January 2020

Solubilized nonstructural antigen III from Saint Louis encephalitis (SLE)-Japanese B encephalitis (JBE)-West Nile (WN) and dengue-2 arbovirus-infected pig kidney cells was purified by employing Brij-58 solubilization, organic solvent extraction, and column chromatography. Diethylaminoethyl-cellulose column peak C eluate contained only intracellular viral envelope protein designated antigen I. Antigen I of SLE virus absorbed homologous neutralizing antibody; however, the intracellular nonstructural protein designated antigen III did not. The antigenic relationships of solubilized antigens I and III prepared from SLE, JBE, and WN virus-infected cells were determined by complement-fixation (CF) and immunodiffusion analyses. Solubilized antigen I of each virus cross-reacted broadly with both homologous and heterologous antibody at high antigen concentrations in the CF test. Antigen III of each virus reacted with only homologous antibody by both CF and immunoprecipitation. This study demonstrates that during SLE, JBE, WN, and dengue-2 infections, virus-specific proteins containing both type-specific and group-reactive determinants are synthesized. Antigen III, a nonstructural protein, is serologically virus type specific and may be useful as a type-specific diagnostic reagent.
Role of Mycobactin in the Growth and Virulence of Tubercle Bacilli
Authors: Golden Carole A. , Kochan Ivan , Spriggs Dale R.
Published: January 2020

Tubercle bacilli failed to grow in iron-void media enriched with solutions of iron-containing transferrin (Tr) or ferritin (F) because these substances do not provide the bacilli with iron, which is essential for their growth. Animal serum and macrophages possessed no iron carrier with an ability to satisfy the need of the bacteria for the metal. Mycobactin (M), the growth-product of tubercle bacilli, removed iron from Tr and F and supplied the metal for bacillary utilization. The role of M in the growth of tubercle bacilli was influenced by nonionic surfactants which inhibited bacillary growth by removing M from the bacillary cells and interfering with the absorption of M-iron complexes. Experiments with Tween 80, Triton WR-1339, and lecithin showed that avirulent bacilli lose M at lower concentrations of the surfactants than virulent bacilli. Since avirulent and virulent bacilli possess the same amount of M, these findings indicate that M is bound more firmly to lipid-rich virulent than lipid-poor avirulent cells. These findings indicate that the resistance of virulent bacilli to the M-removing activity of the surfactants is an indicator of their ability to multiply in the infected host and may be used as a measure of bacillary virulence.
Pathogenesis of Temperature-Sensitive Mutants of Sindbis Virus in the Embryonated Egg II. Control of the Infectious Process
Authors: Schluter Bonnie , Brown Arthur
Published: January 2020

Viral infection in the embryonated egg was controlled through appropriate temperature shifts. Through such control of the infection, certain groups of key tissues were implicated in the pathogenic processes that lead to death of the embryo, whereas other tissues were eliminated as relatively unimportant. Temperature shift-down experiments suggested that some mutants could resume the infectious process after relatively long periods (ribonucleic acid-negative mutants, Sts-4 and Sts-17) at the nonpermissive temperature, whereas others (RNA-positive mutants, Sts-2 and Sts-10) could not resume infection, even after a relatively short period at the nonpermissive temperature.
Parameters Affecting the Adherence and Tissue Tropisms of
Streptococcus pyogenes
Authors: Ellen Richard P. , Gibbons Ronald J.
Published: January 2020

Virulent M protein-containing strains of
Streptococcus pyogenes
were found to adhere well to human pharyngeal cells in vitro. In contrast, an avirulent M - strain and an enteropathogenic
Escherichia coli
strain adhered feebly. When various rat tissues were exposed to mixtures of a virulent
S. pyogenes
strain and an enteropathogenic
E. coli
strain, the relative proportions of the two pathogenic strains recovered from mucosal surfaces differed among the sites studied.
S. pyogenes
cells were found to adhere in higher proportions than enteropathogenic
E. coli
cells to the mucosal surfaces of rat tongues, whereas on surfaces of the urinary bladder, their affinities were reversed. The data indicate that bacterial adherence is influenced by the specificity of both the bacterial and epithelial surfaces, and they suggest that adherence may influence the tissue tropisms of pathogens. Early stationary-phase cells of
S. pyogenes
attached better to epithelial cells than did bacteria in other growth phases. The adherence of
S. pyogenes
cells was impaired by pretreatment with trypsin, wheat germ lipase, Tween 80, Triton X-100, sodium lauryl sulfate, heat at 56 C, anti-group A antiserum, the presence of phospholipids, and preincubation of the epithelial cells with
Streptococcus salivarius
cell walls. Altering the pH or treatment with ethylenediaminetetraacetic acid had no effect on the ability of
S. pyogenes
cells to adhere.
CAMP Factor of Group B Streptococci: Production, Assay, and Neutralization by Sera from Immunized Rabbits and Experimentally Infected Cows
Authors: Brown J. , Farnsworth R. , Wannamaker L. W. , Johnson D. W.
Published: January 2020

Quantitative assay methods for CAMP factor activity of group B streptococci and for neutralization of this activity by animal sera are described. The course of the CAMP reaction is influenced by preincubation of red cells with staphylococcal beta-hemolysin and the rate of the reaction by the concentration of CAMP factor. The production of CAMP factor is enhanced by substitution of maltose for glucose in culture broth. Rising inhibitory titers to CAMP activity in sera of rabbits injected with sterile culture supernates of group B streptococci suggest that CAMP factor is an antigen in the rabbit. Cows with experimentally induced group B streptococcal mastitis also demonstrated significant rises in neutralizing titers for CAMP activity.
Feline Immunoglobulins
Authors: Schultz R. D. , Scott F. W. , Duncan J. R. , Gillespie J. H.
Published: January 2020

Immunoglobulins (Ig) in feline sera and secretions were identified by immuno-electrophoresis and immunodiffusion with rabbit antisera prepared to feline IgG, IgA, IgM, and whole serum. Adult cat sera, colostral whey, postcolostral sera, tears, and nasal secretions contained IgG, IgA, and IgM. IgG was the only Ig identified in precolostral sera and cerebrospinal fluid. Milk, intestinal contents, pooled allantoic and amniotic fluids, and saliva from adult cats and urine from suckling kittens contained IgG and IgA. Ig were not detected in urine from adult cats. Bile was unique in that IgA and IgM were the predominant Ig.
Electron Microscopy of the Suckling Mouse Cataract Agent: a Noncultivable Animal Pathogen Possibly Related to Mycoplasma
Authors: Zeigel R. F. , Clark H F.
Published: January 2020

The suckling mouse cataract agent (SMCA) is a filtrable (<220 nm), noncultivable agent isolated from ticks in Georgia in 1961. It grows to high titer in the eyes and brains of intracerebrally inoculated mice in which it induces cataract, uveitis, and chronic brain infection. SMCA in high titer may also be recovered from the tissues of embryonated hen eggs in which the infection is lethal within 4 to 9 days. Fine-structural studies of ultrathin sections of pellets obtained by ultracentrifugation of SMCA-infected egg allantoic fluids have revealed pleomorphic structures with morphological characteristics typical of mycoplasma. Similar organisms have been observed in egg allantoic fluids infected with an SMCA-related tick isolate, GT-48, but not in fluids from uninoculated control eggs. Mycoplasma-like entities were also observed in high concentration within retinal tissues of rats and mice studied at the time of maximal retinitis and uveitis after SMCA inoculation. Comparable tissues from normal mouse eyes were free of microorganisms. These fine-structural observations are in agreement with those reported by other investigators and suggest that SMCA-induced pathology is associated with an agent that resembles mycoplasma in size and morphology but differs from typical mycoplasma in its apparent non-cultivability on artificial media and its resistance to inactivation by broad-spectrum antibiotics.
Protection of Chicken Embryos by Viridans Streptococci Against the Lethal Effect of
Staphylococcus aureus
Authors: Aly Raza , Maibach Howard I. , Shinefield Henry R. , Mandel Adrian D.
Published: January 2020

Chicken embryos were used to investigate the mechanism by which viridans streptococci inhibit the growth of pathogenic staphylococci. Ten-day-old embryonated eggs were infected allantoically. At a concentration of 1.8 × 10
2
colony-forming units (CFU) of viridans streptococci, the percentage of fatalities was less than 10%. There was 80% fatality with 8 × 10
1
CFU of
Staphylococcus aureus
strain 502A and 100% when a 100-fold increase in concentration was used. An inoculum size of 10
2
to 10
3
CFU of viridans streptococci was chosen to protect the embryos against the lethal effect of strain 502A when challenged 24 h later. The survival after challenging at 4 days was 93% in protected eggs and 37% in unprotected eggs. Chicken embryos receiving heat-killed viridans and challenged with strain 502A when examined after 4 days did not demonstrate a protective effect. This protection of embryonated eggs could not be transferred by administration of sterile filtrate of allantoic fluid in which protecting strain was grown. The experimental infection of embryonated eggs has demonstrated that prior allantoic infection with viridans streptococci affords significant protection against subsequent challenge with virulent staphylococci.
Respiratory Immune Response to Aerosolized Keyhole Limpet Hemocyanin in Primate Lungs
Authors: Mattson James R. , Roberts Mary , Patterson Roy
Published: January 2020

Methodology for delivery of antigen to the lower respiratory tract of rhesus monkeys and the recovery of respiratory secretions (RS) by bronchial lavage has been evaluated and has been done on repeated occasions without apparent risk to animals. Rhesus immunoglobulin (Ig)G, IgM, and IgA were identified in RS by their cross-reactivity with human IgG, IgA, and IgM, and relative concentrations of rhesus IgA and IgG could be evaluated in sequential samples of RS and serum (S) by radial immunodiffusion analysis using antiserum specific for human γ and α chains. Administration of keyhole limpet hemocyanin (KLH) by aerosol was compared with intravenous administration of KLH. The aerosol route of administration resulted in IgG, IgM, and IgA antibodies detectable by radio-immunodiffusion in RS but only IgG antibodies in serum. After separate sequences of exposure to KLH delivered to the lung, a secondary type of immune response in the lung appeared as indicated by time of appearance and height of antibody titers. Antibody titers against KLH were estimated by passive hemagglutination of tanned sheep red cells coated with KLH, and anti-KLH titers were comparatively higher in RS of animals immunized by the respiratory route. Treatment of RS and S with 2-mercaptoethanol resulted in reduction of hemagglutination titers of both S and RS, but the degree of reduction varied in different samples and was independent of whether or not the S and RS were collected simultaneously. These results indicate that at least part of the antibody response to aerosolized KLH in rhesus monkeys occurs in the lung and that antibodies may appear in all three immunoglobulin classes in this response.
Nonspecific Resistance to Intraocular Infection I. Elicitation of Resistance by
Neisseria meningitidis
Authors: Pribnow James F. , Hall Joan M. , Besemer Diana J. , Vedros Neylan A.
Published: January 2020

Both eyes of rabbits whose right eyes had previously been injected with
Neisseria meningitidis
were injected with
Diplococcus pneumoniae
. The pneumococci failed to grow in the right eye of most rabbits challenged 2 and 4 days after the injection of the meningococci, but grew well in all left eyes. The “protective” effect was less pronounced in the rabbits challenged on days 6 and 9 and virtually absent when the interval between the two injections was 14 or 22 days. Pneumococci grew equally well in both eyes of rabbits that had received nitrogen mustard treatment prior to the intravitreal injection of meningococci, indicating a possible role for the polymorphonuclear leukocyte in the protective effect.
Biogenesis of Marek's Disease (Type II Leukosis) Virus In Vitro: Electron Microscopy and Immunological Study
Authors: Hamdy Farouk , Sevoian Martin , Holt Stanley C.
Published: January 2020

The kinetic events involved in Marek's disease herpesvirus infection of avian cell culture were investigated by assaying viral infectivity and antigenicity as well as by electron microscopy during the infectious cycle. The levels of viral infectivity and complement-fixing (CF) antigens revealed that the rates of appearance of infectious particles and CF antigens were not synchronous. Viral specific CF antigen could be detected 5 h after infection, whereas viral infectivity or the appearance of viral particles could be demonstrated only after 10 h of infection. High proportions of the recovered CF antigens during the various stages of the infectious cycle were found to be soluble and did not sediment with the virus particles. Cytological analysis of the developmental stages of the JM virus-infected cells by thin sectioning and electron microscopy revealed that at 8 h small particles approximately 35 nm in diameter appeared in the cell nuclei. The appearance of nucleocapsids occurred at 10 h, and these were of varying shapes; however, all were approximately 100 nm in diameter. At approximately 18 h postinfection, mature virus particles were observed. Viral maturation of the immature particles occurred by the acquisition of envelope from the inner leaflet of the nuclear membrane or from the cytoplasmic membrane of the cell.
Glycolysis During Early Infection of Feline and Human Cells with Feline Leukemia Virus
Authors: Bardell D. , Essex M.
Published: January 2020

A 30 to 40% increase in glucose uptake and lactic acid production was observed during a 48-h period immediately following inoculation of feline fibroblasts and HEp-2 cells with feline leukemia virus. There was no evidence of morphological alterations in either cell type. Immunofluorescent procedures to detect feline leukemia virus group-specific antigen revealed that the feline and HEp-2 cells were infected, whereas the antigen was not found in parallel cultures of uninoculated cells. Increased glycolysis depends upon the physiological state of the host cell and was not observed with infected stationary-phase cells.
Characteristics of Streptolysin O Hemolysis: Kinetics of Hemoglobin and
86
Rubidium Release
Authors: Duncan James L.
Published: January 2020

The characteristics of hemolysis produced by streptolysin O (SLO) were investigated in rabbit, human, and rat erythrocytes. Kinetic studies of hemoglobin (Hb) release showed that rabbit and human erythrocytes exhibited typical “multi-hit” survival curves. Extrapolation of these curves to the ordinate indicated that approximately two molecules of SLO may be sufficient to produce lysis of a single cell. In contrast, exponential (“single-hit”) survival curves were observed when rat erythrocytes were treated with SLO. At 0 C, high concentrations of SLO rapidly lysed rabbit erythrocytes; low concentrations had no effect on the cells at this temperature. The release of intracellular
86
rubidium (
86
Rb
+
) and Hb in rabbit erythrocytes exposed to SLO was investigated. In the presence of phosphate-buffered saline, rubidium and Hb were lost at the same rate from toxin-treated cells. The addition of bovine serum albumin to the suspending medium did not retard the escape of Hb, and the efflux of
86
Rb
+
only slightly preceded Hb loss. Addition of sucrose to the cells delayed both Hb and rubidium release. These results are interpreted as indicating that the “colloid-osmotic” lytic process is not involved in the hemolysis of erythrocytes by streptolysin O.