bluuebunny/crossref_metadata_2025 huggingface dataset:
Appearance and Persistence of Antibodies Against Different Virus Components After Regular Measles Infections
Authors: Norrby Erling , Gollmar Ylva
Published: January 2020

Different measles virus-specific antibody activities in acute, early (11 to 40 days after rash) and late (4 to 20 years postinfection) convalescent sera and gamma globulin were determined. Early immunoglobulin G antibodies gave a poor neutralization, which was increased 10- to 60-fold by addition of anti-gamma globulin.

There was a high degree of correlation between titers of hemolysis-inhibiting (HLI) and hemagglutinating-inhibiting (HI) antibodies. However, in one out of fifteen late convalescent sera an HLI antibody titer of 640 in the presence of titer of only 20 in HI tests with Tween 80—either-treated antigen was found. Similar findings were made with sera from two patients with multiple sclerosis included in a parallel study. A somewhat higher titer of HI antibodies was demonstrable in these three sera when untreated material was used as antigen. These findings are interpreted in the following way. Antibodies against the hemagglutinin can block not only virus-specific agglutination but also lysis of red cells. In contrast, antibodies against the hemolysin, besides blocking the biological activity of this component, carry only a slight HI activity. This HI activity can be detected only by use of antigen preparations containing hemagglutinin-associated hemolysin.

Complement-fixation (CF) and immunodiffusion tests (the latter were carried out with antigen preparations treated with 0.25% sodium dodecyl sulfate) demonstrated that, in almost all cases, antibodies against nucleocapsid structures dominated quantitatively among antibodies appearing in connection with and persisting after regular measles infections. Generally, only low titers of antibodies reacting with purified small particle hemagglutinin (HA; 10 to 14
S
) or additional structural or nonstructural components were identified in CF and immunodiffusion tests.
Nasal Secretion Protein Responses in Patients with Wild-Type Adenovirus Disease
Authors: McCormick David P. , Wenzel Richard P. , Davies John A. , Beam Walter E.
Published: January 2020

Proteins were studied in nasal secretions obtained from Marine Corps trainees infected with wild adenovirus type 7 both during the acute phase of illness and after recovery. Illness was associated with a marked increase in the concentration of serum proteins in the secretions, and during inflammation there was no apparent barrier to the passage of large molecules (molecular weight 775,000) from the serum into the respiratory passages. At the time of virus isolation, trainees requiring hospitalization had less immunoglobulin A (IgA) in their secretions even though they had greater quantities of immunoglobin G (
P
< 0.05) and albumin than trainees followed in the field, whose secretions were also tested at the time of virus isolation. Base-line IgA and protein concentrations were lower (
P
< 0.05) in hospitalized trainees than in trainees followed prospectively in the field. The results suggest a nonspecific protective function for secretion protein, although we have not excluded the possibility that field study trainees were protected by specific neutralizing antibody present in the nasal secretion.
Stimulation of Rabies Vaccine in Mice by Low Doses of Polyadenylic: Polyuridylic Complex
Authors: Branche Robert , Renoux Gérard
Published: January 2020

Addition of 100 μg of polyadenylic: polyuridylic (poly A:U) complex to each dose of inactivated rabies vaccine increased immunity to rabies challenge in mice. Stimulation was also observed after addition of 10 μg of poly A:U to the vaccines. Mixtures of rabies vaccine and poly A:U lost their stimulatory properties after storage at 37 or 4 C for 1 month. However, these data are encouraging for practical use of poly A:U as an adjuvant to viral vaccines.
Transplacental Transmission of Venezuelan Equine Encephalomyelitis Virus in Mice
Authors: Spertzel R. O. , Crabbs C. L. , Vaughn R. E.
Published: January 2020

Transplacental infection of mouse fetuses with Venezuelan equine encephalomyelitis was produced by intraperitoneal injection of dams at various stages of gestation with 10
3
suckling mouse intracerebral median lethal doses of an attenuated strain (TC-83). Virus inoculation, at times ranging from 6 days prior to mating to 9 days after conception, had no effect on conception rate, litter size, or survival of the newborn. Inoculation of the dam from the 10th to 13th days of gestation resulted in decreased litter size, an increase in stillbirths, and a decrease in birth-to-weaning survival. Inoculation of the dams later in gestation only decreased the birth-to-weaning survival. No evidence of morphologic abnormality was noted in any of the newborn.
Identification of a Canine Adenovirus (Infectious Canine Hepatitis Virus) Inhibitor in Dog Liver Extracts as Arginase
Authors: Carmichael L. E.
Published: January 2020

Extracts of canine liver inhibited growth of infectious canine hepatitis (ICH) virus, a canine adenovirus. Purified extracts from mammalian, but not avian, liver tissue contained the inhibitor, and evidence is presented that the inhibitory factor is the enzyme arginase (arginine ureohydrolase). This study further emphasized the need for arginine in adenovirus growth and may explain some of the difficulties in isolating small amounts of ICH virus from suspensions of liver.
Protective Action of 2,2-Bis(Parachlorophenyl)-1,1,1-Trichloroethane Against Intoxication of Cells by Staphylococcal Enterotoxin B
Authors: Gabliks Janis
Published: January 2020

Chlorinated hydrocarbon 2,2-bis(parachlorophenyl)-1,1,1-trichloroethane (DDT) and its derivative 2,2-bis(parachlorophenyl)-1,1-dichloroethane (
o,p
′-DDD) protected the cells of human embryonic intestine, Henle strain, against the cytotoxic effects induced by staphylococcal enterotoxin B (SEB). The hydrocarbons were incorporated in the culture medium, and the cytotoxicity of SEB was measured by cell destruction and by inhibition of cell growth during incubation for 48 hr. When DDT at nontoxic levels (4 to 25 μg/ml) was added to cultures, 24 or 4 hr prior to or 7 hr after the administration of toxin (100 μg/ml), the cells did not show the characteristic cytotoxicity. A therapeutic effect was also observed with
o,p
′-DDD added to cultures 9 hr after SEB. Because the cells treated with DDT for a period of 24 hr remained resistant to the toxin when DDT was removed from the cultures, it appears that DDT acts upon the cells rather then upon enterotoxin B. The protective effect of DDT was also observed against the toxin-induced skin erythemas and necrosis in guinea pigs treated with DDT.
Degradation of Group A Streptococcal Cell Walls by Egg-White Lysozyme and Human Lysosomal Enzymes
Authors: Glick Alan D. , Ranhand Jon M. , Cole Roger M.
Published: January 2020

Group A streptococci and their isolated cell walls, normally resistant to egg-white lysozyme and the lysosomal enzymes of human phagocytes, were converted to lysozyme-sensitive forms by partial removal of cell wall carbohydrate, substitution of free amino groups, and by saponification of O-acyl groups. The resultant modified streptococcal cell walls showed rapid degradation when treated with leukocyte granule extract derived from human peripheral blood polymorphonuclear leukocytes and monocytes and when subjected to phagocytosis by living human leukocytes. These results indicate that the factors responsible for lysozyme resistance of the group A cell wall also influence its resistance to human leukocyte granule enzymes and suggest that the chemical composition of the cell wall, in addition to the presence of cell wall carbohydrate, determines this resistance.
Purification of Polysaccharide Antigen from
Leptospira biflexa
Strain Urawa
Authors: Taniyama Tadayoshi , Yanagihara Yasutake , Mifuchi Ichiji , Azuma Ichiro , Yamamura Yuichi
Published: January 2020

Serologically active polysaccharide was isolated from the cells of
Leptospira biflexa
strain Urawa and purified. The constituents of this polysaccharide were characterized, and its serological specificity was partially examined.
Characterization and Comparison of Mycobacterial Antigens by Two-Dimensional Immunoelectrophoresis
Authors: Roberts Dianna B. , Wright George L. , Affronti Lewis F. , Reich Melvin
Published: January 2020

Two-dimensional immunoelectrophoresis (2D-IEP), in which a complex of antigens is subjected to electrophoresis first through an agarose matrix in one direction and secondly through an antiserum-agarose matrix at right angles to the first direction, was evaluated as a tool for analysis of mycobacterial antigens. Cell extracts from four species of mycobacteria,
Mycobacterium tuberculosis
(four strains),
M. bovis
strain BCG,
M. scrofulaceum
, and
M. phlei
, were assayed by 2D-IEP with four anti-mycobacterial antisera. Besides displaying the precipitin curves in a more easily interpreted format than did conventional immunoelectrophoresis (IEP), 2D-IEP offered greater sensitivity in terms of numbers of precipitin curves when like reactions were compared with IEP patterns. As many as 60 immunoprecipitates were observed on 2D-IEP slides compared to 18 on comparable IEP plates. Technical reproducibility of patterns from run to run was excellent. Other parameters, such as the influence of using different batches of antigen on the pattern, are discussed. Each of the cell extract antigens gave a unique pattern of precipitin peaks which could be easily differentiated from the patterns given by the other mycobacterial cell extracts when reacted with any of the antisera in 2D-IEP. Since both the species and strains of mycobacteria could be easily and reproducibly differentiated solely on the basis of two-dimensional immunoelectrophoretic patterns obtained with any of the antisera employed in this study, it may be possible, by using IEP, to differentiate and identify all species and strains of mycobacteria with one standard, highly sensitive antiserum, rather than a battery of antisera.
Shared Antigens Between Heterologous Bacterial Species
Authors: Minden Percy , McClatchy J. Kenneth , Farr Richard S.
Published: January 2020

Sera from normal rabbits were shown to have antibodies that bound radiolabeled test antigens derived from many taxonomically unrelated bacteria. Sera from rabbits that had been immunized with sonically treated material of 12 different bacteria, including
M. bovis
strain BCG, had antibodies that bound not only radiolabeled homologous test antigens but also radiolabeled antigens from many unrelated bacteria. Binding by normal and immunized sera to radiolabeled test antigens was inhibited by homologous unlabeled test antigens but not by substances such as bovine serum albumin, polyvinylpyrrolidone, sheep erythrocytes, and endotoxin. The broad range of shared or cross-reactivity among antigens in bacteria may explain the presence of antibodies to many bacteria in sera from normal humans and previously unimmunized experimental animals. The presence of these antibodies raises the question whether resistance to many bacterial infections may be partly due to immune mechanisms, whether cellular or humoral, that have been stimulated by unrelated bacteria.
Enteric Bacteria Cross-Reactive with
Neisseria meningitidis
Groups A and C and
Diplococcus pneumoniae
Types I and III
Authors: Robbins John B. , Myerowitz Richard L. , Whisnant John K. , Argaman Meir , Schneerson Rachel , Handzel Zeev T. , Gotschlich Emil C.
Published: January 2020

Enteric bacteria of 1,335 individual strains were studied for serological cross-reactions with
Neisseria meningitidis
groups A and C and
Diplococcus pneumoniae
types I and III. Enterobacterial antigens cross-reactive with the capsular polysaccharides of these four bacteria were found. Bacteria cross-reactive with noncapsular antigens of meningococci and pneumococci were also observed. Since some enteric bacteria possess antigens with serological specificities similar to those of meningococci, the possibility that enteric bacteria cross-reactive with meningococcal antigens provide an antigenic stimulus for the observed age-related “natural” immunity to this pathogen is discussed.
Purification and Biochemical Properties of
Clostridium perfringens
Type A Enterotoxin
Authors: Stark Raymond L. , Duncan Charles L.
Published: January 2020

The sporulation-specific enterotoxin of
Clostridium perfringens
type A, which is the toxin active in human food poisoning, has been purified from extracts of sporulating cells. Highly purified enterotoxin was obtained by treatment of crude cell extract with ribonuclease for 30 min, followed by sequential chromatography on Sephadex G-100, Cellex T cellulose, and hydroxylapatite. Recovery was 65 to 75% of the initial activity. Enterotoxin purity was > 99% as indicated by sedimentation velocity, sedimentation equilibrium, disc electrophoresis, and serological methods. Purified enterotoxin focused at pH 4.3 during isoelectric focusing. Molecular weights of 34,000 and 35,000 were obtained by Sephadex G-100 chromatography and sedimentation equilibrium, respectively. An
S
20,w
of 3.08 was obtained for the purified enterotoxin. The enterotoxin precipitated heavily at its isoelectric point and at concentrations greater than 4 mg/ml.
Foot-and-Mouth Disease: Changes in Serum-Neutralizing Activity of Immunized Cattle Shortly After Virus Exposure
Authors: Sutmoller P. , McVicar J. W.
Published: January 2020

After infection of the upper respiratory tract with foot-and-mouth disease (FMD) virus in immunized cattle, a drop in specific serum-neutralizing antibody activity was observed. Vaccinated cattle with high preexposure serum antibody titers had a precipitous drop for the first 4 days after virus exposure, followed by a rise in titer. This drop was also seen in passively immunized cattle with high preexposure titers; however, their antibody titers decreased for 5 to 7 days after exposure to virus. Some vaccinated and passively immunized cattle with low preexposure antibody titers showed fluctuations in their titers shortly after exposure. These data suggest that the course of infection with FMD virus in immunized cattle depends on the rapidity of new antibody formation as well as on the level of neutralizing antibody titer at the time of exposure.
Study of Inhibition of Induction of Phosphoenolpyruvate Carboxykinase by Endotoxin with Radial Immunodiffusion
Authors: Rippe Delfin F. , Berry L. Joe
Published: January 2020

Phosphoenolpyruvate carboxykinase (PEPCK) was precipitated from supernatant fluids of whole mouse liver homogenates by specific antiserum but not by normal rabbit immunoglobulin G. The slopes of inactivation curves were similar for supernatant fluids of control and poisoned mice. It was demonstrated by radial immunodiffusion that PEPCK activity assayed enzymatically was proportional to the diameter of precipitin rings in all cases, except when the enzyme was activated by tryptophan, a process not requiring new enzyme synthesis. Hence, the assay can be used to distinguish between enhanced catalytic activity due to increased enzyme levels or as the result of activation of existing enzyme molecules. Immunological quantitation of PEPCK showed that endotoxin inhibits the induction of the enzyme due to fasting between 4 and 8 hr after administration of the bacterial poison. This result is almost identical to that seen when livers of mice poisoned with actinomycin D were assayed for PEPCK by the radial immunodiffusion technique.
Comparative Studies of Plaque Variants Derived From a Florida Strain of Venezuelan Equine Encephalomyelitis Virus
Authors: Pedersen Carl E. , Slocum Donald R. , Robinson David M.
Published: January 2020

Small- and large-plaque variants of a Florida strain (Fe 3-7c) of Venezuelan equine encephalomyelitis virus were studied in vivo and in vitro. The small-plaque variant was less virulent in mice, hamsters, and guinea pigs than the large-plaque variant. The variants could be distinguished by calcium phosphate chromatography. The implications of plaque variants within a mixed virus population are discussed.
Proportional Distribution and Relative Adherence of
Streptococcus miteor
(
mitis
) on Various Surfaces in the Human Oral Cavity
Authors: Liljemark W. F. , Gibbons R. J.
Published: January 2020

A group of streptococci possessing the characteristics of
Streptococcus miteor
(
S. mitis
) was found to predominate on nonkeratinized human oral mucosa. These organisms averaged from 76 to 89% of the total flora cultivable on anaerobically incubated blood agar plates from cheek, lip, and ventral tongue surfaces. They averaged 34, 40, and 18% of the streptococci in dental plaque, in saliva, and on the tongue dorsum, respectively. Their ability to adhere to oral surfaces was studied by introducing mixtures of streptomycin-resistant strains of
S. miteor, S. salivarius
, and
S. mutans
into the mouths of volunteers. Samples of oral surfaces taken 1 hr later indicated
S. miteor
adhered far better than the other streptococci to buccal mucosa and to teeth, but
S. salivarius
showed a higher affinity to the tongue dorsum. Glucose-grown cells of
S. mutans
adhered feebly to all oral surfaces studied and were rapidly cleared from the mouth. Cells of
S. miteor
and
S. salivarius
present naturally in saliva adhered to cleaned teeth comparable to in vitro cultivated strains. Electron microscopy of cells of
S. miteor
attached to buccal epithelial cells obtained from germfree rats indicated that the organisms possessed a fibrillar “fuzzy” coat which appeared to mediate their attachment to the epithelial cell membrane. This “fuzzy” coat was removed by treatment with trypsin, and it appears to be similar to that previously observed on cells of
S. pyogenes
and
S. salivarius.
Nucleotide sequences of two adjacent M or M-like protein genes of group A streptococci: different RNA transcript levels and identification of a unique immunoglobulin A-binding protein
Authors: Bessen D E , Fischetti V A
Published: January 2020

M protein is a key virulence factor present on the surface of group A streptococci. M protein is defined by its antiphagocytic function, whereas M-like proteins, while structurally related to M proteins, lack an established antiphagocytic function. Group A streptococci can be divided into two main groups (class I and II) on the basis of the presence or absence of certain antigenic epitopes within the M and M-like molecules, and importantly, the two classes correlate with the disease-causing potential of group A streptococci. In an effort to better understand this family of molecules, a 2.8-kb region containing the two M protein-like genes from a class II isolate (serotype 2) was cloned and sequenced. The two genes lie adjacent to one another on the chromosome, separated by 211 bp, and have many structural features in common. The emmL2.1-derived product (ML2.1 protein) is immunoreactive with type-specific antiserum, a property associated with M proteins. The cloned product of the downstream gene, emmL2.2 (ML2.2 protein), is an immunoglobulin A (IgA)-binding protein, binding human myeloma IgA. Interestingly, the RNA transcript levels of emmL2.1 exceed that of emmL2.2 by at least 32-fold. Northern (RNA) hybridization and primer extension studies suggest that the RNA transcripts of emmL2.1 and emmL2.2 are monocistronic. The ML2.1 and ML2.2 proteins exhibit 53% amino acid sequence identity and differ primarily in their amino termini and peptidoglycan-spanning domains and in a Glu-Gln-rich region present only in the ML2.1 protein. However, the previously described M-like, IgA-binding protein from a serotype 4 isolate (Arp4) displays a higher level of amino acid sequence homology with the ML2.1 molecule than with the IgA-binding ML2.2 protein. Amino acid sequence alignments between all M and M-like proteins characterized to date suggest the existence of two fundamental M or M-like gene subclasses within class II organisms, represented by emmL2.1 and emmL2.2. In addition, IgA-binding activity can be found within both types of molecules.
Spontaneous insertion of an IS1-like element into the virF gene is responsible for avirulence in opaque colonial variants of Shigella flexneri 2a
Authors: Mills J A , Venkatesan M M , Baron L S , Buysse J M
Published: January 2020

Colonial variation of Shigella flexneri serotype 2a from the translucent (2457T) to the opaque form (2457O) occurs spontaneously once in 10(4) cell divisions, with concomitant loss of ipa gene expression and virulence. The appearance of 2457O was associated with the insertional inactivation of virF, an invasion plasmid-encoded positive regulator of ipa gene expression. Plasmid pWR110, a Tn5-tagged invasion plasmid that restores the invasive phenotype to plasmid-cured Shigella derivatives, was conjugally transferred into 2457O. Synthesis of the invasion-associated IpaB and IpaC polypeptides, normally present on the surface of virulent shigellae, and the invasive phenotype were restored in 2457O(pWR110) transconjugants. Plasmid DNA restriction endonuclease patterns of 2457T and 2457O, along with hybridization analysis, showed that a SalI fragment carrying the virF gene in 2457O had increased in size relative to its counterpart in 2457T. Analysis of virF DNA sequences amplified by the polymerase chain reaction revealed that the virF sequence from 2457O was 780 bp larger than that amplified from 2457T. Moreover, the virF sequence amplified from 2457O hybridized to an IS1 DNA probe whereas the amplified 2457T virF sequence did not. DNA sequence analysis mapped the insertion element, designated IS1SFO, within an A.T-rich region of the virF open reading frame and identified a 9-bp virF target sequence that was duplicated at the insertion site of IS1SFO. The DNA sequence of IS1SFO was greater than 99% homologous to IS1F. Plasmid pWR600, carrying a 1,260-bp HpaII fragment encoding a wild-type virF gene, was able to restore the virulent phenotype and translucent colonial morphology to nine independently isolated 2457O hosts.
A quantitative model of intracellular growth of Legionella pneumophila in Acanthamoeba castellanii
Authors: Moffat J F , Tompkins L S
Published: January 2020

A model of intracellular growth for Legionella pneumophila in Acanthamoeba castellanii has been developed and provides a quantitative measure of survival and replication after entry. In this model, Acanthamoeba monolayers were incubated with bacteria in tissue culture plates under nutrient-limiting conditions. Gentamicin was used to kill extracellular bacteria following the period of incubation, and the number of intracellular bacteria was determined following lysis of amebae. Intracellular growth of virulent L. pneumophila and other wild-type Legionella species was observed when the assay was performed at 37 degrees C. At room temperature, none of the Legionella strains tested grew intracellularly, while an avirulent L. pneumophila strain was unable to replicate in this assay at either temperature. The effect of nutrient limitation on A. castellanii during the assay prevented multiplication of the amebae and increased the level of infection by Legionella spp. The level of infection of the amebae was directly proportional to the multiplicity of infection with bacteria; at an inoculum of 1.03 x 10(7) bacteria added to wells containing 1.10 x 10(5) amebae (multiplicity of infection of 100), approximately 4.4% of A. castellanii cells became infected. Cytochalasin D reduced the uptake of bacteria by the amebae primarily by causing amebae to lift off the culture dish, reducing the number of target hosts; methylamine also reduced the level of initial infection, yet neither inhibitor was able to prevent intracellular replication of Legionella spp. Consequently, once the bacteria entered the cell, only lowered temperature could restrict replication. This model of intracellular growth provides a one-step growth curve and should be useful to study the molecular basis of the host-parasite interaction.
Restoration of exocytosis occurs after inactivation of intracellular tetanus toxin
Authors: Bartels F , Bigalke H
Published: January 2020

Tetanus toxin blocks carbachol-stimulated release of noradrenaline from bovine adrenal chromaffin cells in culture, provided it can gain access to the cells. This can be achieved by electropermeabilization of the plasma membrane or by enriching the membrane with exogenous gangliosides which serve as carriers of the toxin. The inhibition of noradrenaline release persists for at least 6 days, even in the presence of specific anti-tetanus toxin antibodies in the culture medium. However, the block is preventable, for the most part, when antibodies enter chromaffin cells during electropermeabilization, before the uptake of the toxin is facilitated by inserting exogenous gangliosides into the plasma membrane 2 days later. This indicates that the antibodies pass into the cells through the physically induced pores and that these intracellular antibodies neutralize incoming tetanus toxin. If, on the other hand, exocytosis has been inhibited by tetanus toxin, it will recover within 3 days, provided specific anti-tetanus toxin antibodies are introduced into the cells by electropermeabilization. The recovery is not linked to a specific route of entry of the toxin. It is concluded that the restoration of noradrenaline release requires not only the intracellular neutralization of tetanus toxin but also the reconstitution of the as yet unknown target molecule of the toxin.
Production, purification, and characterization of botulinolysin, a thiol-activated hemolysin of Clostridium botulinum
Authors: Haque A , Sugimoto N , Horiguchi Y , Okabe T , Miyata T , Iwanaga S , Matsuda M
Published: January 2020

A hemolysin, botulinolysin, produced by Clostridium botulinum was purified to homogeneity and characterized. First, a strain of C. botulinum type C, strain C-203 Tox, which produced a large amount of hemolysin, was selected, and optimal culture medium and conditions for its production of hemolysin were determined. The hemolysin produced in the culture supernatant of this strain under optimal conditions was purified by a combination of ammonium sulfate precipitation, DEAE-Sepharose CL-6B column chromatography, Sephadex G-75 gel permeation chromatography, and SP-Toyopearl 650 M cation-exchange column chromatography, with a recovery of 12%. The purified hemolysin gave a single protein band in polyacrylamide gel electrophoresis (PAGE) with and without sodium dodecyl sulfate (SDS). The protein in this band in PAGE with SDS was estimated to have a molecular weight of 58,000 and was immunostained with a neutralizing monoclonal antibody. In PAGE without SDS, the hemolytic activity corresponded in position to the single protein band. The pI of the hemolysin was 8.4. Amino acid analysis of the purified hemolysin indicated the presence of four half-cystine residues per molecule. The purified hemolysin had a specific activity of 2,100 hemolytic units per microgram of protein on rabbit erythrocytes. It was activated by SH compounds, inhibited by cholesterol, and heat labile. The optimum pH for hemolysis was 6.0 to 7.0. Rabbit, human, and guinea pig erythrocytes were the most susceptible to the hemolysin, while sheep, mouse, rat, and chicken erythrocytes were much less susceptible. The purified hemolysin had a lethal effect in mice and was cytotoxic for some cultured cells: its 50% lethal dose in mice was 310 ng, and its 50% cytotoxic dose for Vero cells was 120 ng/ml.
Adhesion to and invasion of cultured human cells by Bartonella bacilliformis
Authors: Hill E M , Raji A , Valenzuela M S , Garcia F , Hoover R
Published: January 2020

Bartonella bacilliformis was tested for its ability to adhere to and invade tissue culture cell monolayers. The parasite was able to efficiently bind and penetrate human dermal fibroblasts, human laryngeal epithelium, and human umbilical vein endothelial cells. Exposure of the organism to immune serum prepared against a crude Bartonella extract containing cell wall and membranous material resulted in decreased ability of the parasite to invade host cells. There was also an overall reduction in the invasiveness of bartonellae and total host cell association when human laryngeal epithelial cells and human umbilical vein endothelial cells were preexposed to cytochalasin D, indicating an active involvement of host cells in the uptake of bartonellae. Transmission electron microscopy revealed the presence of bartonellae inside and outside intracellular vacuoles. These data suggest that a surface-associated factor is involved in the invasion process and that internalization of the parasite by host cells involves a microfilament-dependent process similar to phagocytosis.
Retrovirus-induced immunodeficiency in mice exacerbates gastrointestinal candidiasis
Authors: Cole G T , Saha K , Seshan K R , Lynn K T , Franco M , Wong P K
Published: January 2020

Dysfunction of neutrophils in patients infected with human immunodeficiency virus is at least partly responsible for secondary microbial diseases in these individuals, including invasive gastrointestinal (GI) candidiasis. Immunoregulatory disturbances associated with the development of AIDS in human immunodeficiency virus-infected patients exacerbates Candida albicans infection of the upper GI tract and frequently leads to oropharyngeal and esophageal candidiasis. In this article, we present the first report of a murine model of invasive GI candidiasis associated with an AIDS-related murine immunodeficiency syndrome that results from infection of C57BL/6 mice with a previously described retrovirus complex (LP-BM5). Mice of the inbred strain were infected with C. albicans by oral-intragastric inoculation as infants and with the retrovirus by the intraperitoneal route 30 days later. Control mice of the same strain were infected with C. albicans as above and subsequently infected with the avirulent, ecotropic helper virus (MBI-5). Animals were killed 90 days after retroviral challenge. Total and differential blood cell counts, CD4+ T-cell counts in the spleen, and the histopathology of the gastric mucosa of experimental and control animals were determined. The virulent LP-BM5-infected animals developed murine AIDS and showed eruptive and suppurative lesions, with associated C. albicans mainly in regions of the cardial-atrium fold of the stomach. Well-defined abscesses with entrapped C. albicans hyphae were observed in the region of the cardial-atrium fold of control mice. A significant increase in the number of C. albicans CFU in homogenized and plated segments of the GI tract was recognized in mice with murine AIDS versus the control animals. The murine model of GI candidiasis reported here permits examination of the nature of C. albicans interaction with the gastric mucosa both in the immunocompetent host under conditions in which the yeast exists predominantly as a commensal organism and in the immunosuppressed host during progressive stages of AIDS induced by a retroviral infection.
Immunocytological responses in porcine proliferative enteropathies
Authors: McOrist S , MacIntyre N , Stokes C R , Lawson G H
Published: January 2020

The ileum, colon, and mesenteric lymph nodes of pigs naturally affected by either of the two major forms of proliferative enteropathy, namely, intestinal adenomatosis or hemorrhagic enteropathy, were examined for immunocytological responses to infection by immunocytochemistry, using antibodies directed against elements of the porcine immune system. In both forms, there was mucosal proliferation of immature enterocytes which lacked substantial major histocompatibility complex class II expression and a marked accumulation of immunoglobulin A (IgA) at the apical cytoplasm of affected enterocytes in association with intracellular Campylobacter-like organisms. In intestinal adenomatosis, there was only a mild infiltration of CD8+ and CD25+ T cells in the intestinal lamina propria. In hemorrhagic enteropathy, there was a moderate infiltration of CD8+ and CD25+ T cells and IgM+ B cells in the lamina propria. In rats and humans, villous enterocytes are thought to act as antigen-presenting cells, with major histocompatibility complex class II molecules present on their surface, capable of initiating a T-cell response (particularly of CD8+ T cells) in response to bacterial antigens. Therefore, the selection of immature crypt cells by the intracellular Campylobacter-like organisms for entry and multiplication may represent a remarkable microbial adaptation associated with local immunomodulation and enhanced bacterial survival. The accumulation of IgA within affected enterocytes may represent a reduced capability of the cells to process nonspecific IgA or an accumulation of specific IgA.
Coiling phagocytosis is the preferential phagocytic mechanism for Borrelia burgdorferi
Authors: Rittig M G , Krause A , Häupl T , Schaible U E , Modolell M , Kramer M D , Lütjen-Drecoll E , Simon M M , Burmester G R
Published: January 2020

The uptake mechanism for the spirochete Borrelia burgdorferi, the causative agent of Lyme disease, was investigated by electron microscopy for human and murine phagocytes. Spirochetes of both a low- and a high-passage strain were preferentially internalized by coiling rather than by conventional phagocytosis. The spirochetes engulfed by coiling phagocytosis were found to disintegrate in an organelle exclusion zone without evident participation of lysosomes. Preincubation of B. burgdorferi with monoclonal antibody to the spirochetal OspA enhanced phagocytosis in general but did not consistently influence the uptake mechanism. Quantitative and kinetic differences concerning the phagocytic rate and mechanism were evident between cells from different lineages, different human individuals, and mice and humans. In general, when few phagocytes participated in spirochete uptake, the active cells displayed a high ratio of coiling versus conventional phagocytosis. These results suggest that coiling phagocytosis of B. burgdorferi plays a critical role in the control of spirochetal infection. More detailed studies on the molecular basis of this phagocytic mechanism may lead to new insights into the pathogenesis of Lyme borreliosis, a disease which is frequently characterized by the host's inability to eliminate the pathogenic spirochete.
Opportunistic infections and retrovirus-induced immunodeficiency: studies of acute and chronic infections with Toxoplasma gondii in mice infected with LP-BM5 murine leukemia viruses
Authors: Gazzinelli R T , Hartley J W , Fredrickson T N , Chattopadhyay S K , Sher A , Morse H C
Published: January 2020

Mice infected with LP-BM5 murine leukemia viruses develop a syndrome, termed mouse AIDS (MAIDS), characterized by increasingly severe immunodeficiency and progressive lymphoproliferation. Virus-infected mice were examined for the ability to resist acute infection and to control chronic infection with the protozoan Toxoplasma gondii, a major opportunistic pathogen of individuals infected with human immunodeficiency virus. Mice infected with the retroviruses for 2 or 4 weeks responded normally to challenge with the parasite, but mice inoculated with the protozoan 8 or 12 weeks after viral infection died with acute disease due to T. gondii. Increased sensitivity to acute infection was associated with a reduced ability to produce gamma interferon (IFN-gamma) and with established changes in CD4+ T-cell function. Mice latently infected with T. gondii and then inoculated with the retrovirus mixture were found to reactivate the parasite infection, with 30 to 40% of dually infected animals dying between 5 and 16 weeks after viral infection. Reactivation was associated with reduced proliferation and impaired production of IFN-gamma in response to stimulation with soluble T. gondii antigens or to concanavalin A. Continuing resistance to lethal reactivation in the remaining mice was shown to require CD8+ T cells and expression of IFN-gamma. In addition, it was found that chronic infection with T. gondii altered the course of MAIDS by inhibiting the progression of splenomegaly and immunodeficiency and reducing the expression of both the helper and etiologic defective viruses. These results support previous studies which indicate that infection with T. gondii is controlled by synergistic interactions between CD4+ and CD8+ T cells, the functions of which are progressively impaired during the course of MAIDS.
Effect of gamma interferon on resolution of murine chlamydial genital infection
Authors: Rank R G , Ramsey K H , Pack E A , Williams D M
Published: January 2020

Mice infected in the genital tract with the Chlamydia trachomatis agent of mouse pneumonitis were treated with monoclonal rat anti-gamma interferon (anti-IFN-gamma) antibody to determine whether IFN-gamma participated in the resolution of the infection. In two experiments, anti-IFN-gamma antibody treatment resulted in significantly prolonged infections. In support of these data, passive administration of recombinant IFN-gamma to chronically infected nu/nu mice was able to bring about resolution of the infection in some animals.
Safety and immunogenicity in North Americans of a single dose of live oral cholera vaccine CVD 103-HgR: results of a randomized, placebo-controlled, double-blind crossover trial
Authors: Kotloff K L , Wasserman S S , O'Donnell S , Losonsky G A , Cryz S J , Levine M M
Published: January 2020

We conducted a double-blind, placebo-controlled, randomized crossover study to evaluate the safety and immunogenicity of a single 5 x 10(8)-CFU dose of live oral recombinant cholera vaccine CVD 103-HgR in 94 North American adults. The vaccine was well tolerated without associated adverse reactions. Despite minimal fecal excretion of vaccine, 97% of subjects exhibited serum vibriocidal antibody and 72% had antitoxin responses.
Effect of ingested pentoxifylline on neutrophil superoxide anion production
Authors: Crouch S P , Fletcher J
Published: January 2020

Superoxide and other oxygen radicals produced by activated polymorphonuclear leukocytes (PMN) may be important causes of tissue damage in a number of inflammatory conditions. Therefore, a drug which suppresses PMN responses in vivo is potentially important. In vitro, pentoxifylline (PTOX) inhibits superoxide anion production when PMN are stimulated with an activated complement component (C5a Des Arg) or formyl peptides but only at concentrations not achieved in the circulation. The aim of this study was to determine whether PTOX has an effect on PMN responses in vivo. Superoxide anion production, monitored by lucigenin-enhanced chemiluminescence, was inhibited by 40.5% +/- 8.0% (n = 8, P < 0.009) for C5a Des Arg and 47.7% +/- 9.6% (n = 8, P < 0.009) for formyl-methionylleucylphenylalanine stimulation 1.5 h after ingestion of 400 mg of PTOX in a slow-release tablet, with some inhibitory effects persisting at 5 h. There was a strong correlation between reduced PMN response to activated complement and plasma concentrations of three PTOX metabolites (P < 0.05), but not with plasma concentrations of the parent drug. In vitro investigations with each of the four methylxanthines showed two of these metabolites to be most effective at reducing PMN respiratory burst activity, lactoferrin release, and the expression of CD11b and CD18 molecules. Furthermore, this in vitro inhibitory activity was achieved at concentrations of metabolites achievable in vivo. The results suggest that PTOX reduces oxygen radical production and protects against unwanted tissue damage in vivo by the action of its metabolites.
Limited T-cell receptor beta-chain diversity of a T-helper cell type 1-like response to Mycobacterium leprae
Authors: Uyemura K , Ohmen J D , Grisso C L , Sieling P A , Wyzykowski R , Reisinger D M , Rea T H , Modlin R L
Published: January 2020

Delayed-type hypersensitivity (DTH) is the standard measure of T-cell responsiveness to infectious organisms. For leprosy, the Mitsuda reaction, a local immune response to cutaneous challenge with Mycobacterium leprae, is considered to represent a measure of DTH against the pathogen. We analyzed the diversity of the T-cell receptor beta-chain repertoire in Mitsuda reactions to determine the breadth of the mycobacterial antigens involved. The polymerase chain reaction was used to compare V beta usage in the Mitsuda reaction T-cell lines established and unstimulated peripheral blood. These molecular analyses revealed a skewed T-cell receptor V beta gene usage in the Mitsuda reaction and in T-cell lines from lesions. To examine the reactivity of T cells from these lesions, T-cell lines were tested against the available native and recombinant antigens of M. leprae. T-cell lines derived from Mitsuda reactions responded more strongly to the 10-kDa M. leprae antigen, a homolog of GroES in Escherichia coli, than to other M. leprae proteins. T-cell lines were also shown to proliferate strongly in response to the 17- and 3-kDa proteins. The pattern of the lymphokine mRNA of these cells was reminiscent of the pattern of murine TH1 cells, positive for interleukin-2 and gamma interferon and weakly positive for interleukin-4. These data indicate that a limited array of T cells, perhaps recognizing stress proteins, secrete a type 1 lymphokine profile in the DTH response to mycobacteria.
Poly(I.C)-induced interferons enhance susceptibility of SCID mice to systemic candidiasis
Authors: Jensen J , Vazquez-Torres A , Balish E
Published: January 2020

In the absence of any demonstrable T- or B-cell responses, gnotobiotic CB-17 SCID (severe combined immunodeficient) mice not only show innate resistance to acute systemic (intravenous challenge) candidiasis but also manifest innate resistance to systemic candidiasis of endogenous (gastrointestinal tract) origin. Poly(I. C), a potent inducer of interferons (IFNs) in vivo, enhanced the susceptibility of CB-17 SCID mice to acute systemic candidiasis and to systemic candidiasis of endogenous origin, as demonstrated by increased numbers of viable Candida albicans in internal organs after poly(I. C) treatment. The poly(I. C)-enhanced susceptibility of mice to candidiasis was abrogated by in vivo treatment with antibodies to IFN-alpha, -beta, and -gamma. In vivo depletion of natural killer cells from SCID mice did not significantly enhance their susceptibility to systemic candidiasis or abrogate poly(I. C)-enhanced susceptibility. In vivo and in vitro, treatment with poly(I. C) impaired the candidacidal and phagocytic activity of thioglycollate-elicited macrophages from SCID mice. Antibody to IFN-alpha/beta or IFN-beta alone interfered with the ability of poly(I. C) to impair the candidacidal activity of macrophages from SCID mice in vitro. These data suggest that poly(I. C)-induced interferons can impair the candidacidal activity of macrophages in SCID mice and decrease their innate resistance to acute systemic candidiasis and to systemic candidiasis of endogenous origin.
Transfer of a dense granule protein of Plasmodium falciparum to the membrane of ring stages and isolation of dense granules
Authors: Trager W , Rozario C , Shio H , Williams J , Perkins M E
Published: January 2020

A 14-kDa protein was localized to the dense granules of Plasmodium falciparum by immunoelectron microscopy with monoclonal antibody 1H1. The protein was present in dense granules in late-stage schizonts and free merozoites. After invasion, the protein was localized exclusively on the membrane of the newly invaded ring. The protein is referred to as RIMA, for ring membrane antigen. The 14-kDa protein was synthesized late in schizogony as determined by immunofluorescence microscopy and immunoblotting. At the late schizont stage it was distributed diffusely throughout the intracellular schizont. Only at the segmenter stage was the protein localized in defined spots that correspond to dense granules. Dense granules were isolated from schizont-infected erythrocytes by subcellular fractionation on a sucrose gradient. Fractions containing the 14-kDa protein were detected by immunoblotting with monoclonal antibody 1H1. The 14-kDa protein was first detected in vesicles at the late (8-nucleus) schizont stage. Mature dense granules sedimented with a peak density of 1.17 g/ml, which is similar to the density of rhoptries isolated by the same procedure.
Complement activation by polyclonal immunoglobulin G1 and G2 antibodies against Staphylococcus aureus, Haemophilus influenzae type b, and tetanus toxoid
Authors: Bredius R G , Driedijk P C , Schouten M F , Weening R S , Out T A
Published: January 2020

To obtain information on effector functions of human immunoglobulin G2 (IgG2), we have measured the complement-activating properties of polyclonal IgG subclass antibodies against bacterial antigens. IgG1 and IgG2 were purified from serum samples from five healthy individuals, and complement activation was measured with different bacterial antigens. We used Staphylococcus aureus Wood 46 (STAW), which is a common antigen, Haemophilus influenzae type b (Hib), which is a common pathogenic microorganism in children, and formaldehyde-inactivated tetanus toxin (TT). Bacteria were incubated with antibodies and then incubated with sera from agammaglobulinemic patients as a complement source, and C3c deposition was measured by enzyme-linked immunosorbent assay. We found that anti-STAW IgG2 activated complement to a level similar to that of anti-STAW IgG1. Anti-Hib IgG1 complement activation was as much as seven times higher than that of anti-Hib IgG2 in four individuals. In one individual, anti-Hib IgG2 was more effective in complement activation than anti-Hib IgG1. Anti-TT antibodies showed patterns similar to those of anti-Hib. Our results indicate that IgG2 antibodies may contribute significantly to antibacterial defense. Also, individual differences in antibody effector functions should be taken into account when evaluating the immune status of patients and during early phase 1 studies of new vaccines.
Phagocytosis and killing of Actinobacillus pleuropneumoniae by alveolar macrophages and polymorphonuclear leukocytes isolated from pigs
Authors: Cruijsen T L , Van Leengoed L A , Dekker-Nooren T C , Schoevers E J , Verheijden J H
Published: January 2020

To study the cellular response of phagocytic cells to Actinobacillus pleuropneumoniae, we investigated whether porcine alveolar macrophages (AM) and polymorphonuclear leukocytes (PMN) are able to phagocytize and intracellularly kill A. pleuropneumoniae in vitro. Bacterial cultivation methods of A. pleuropneumoniae were used to assess in vitro phagocytosis and the ability to kill. A specific-pathogen-free pig was killed, blood was collected, and PMN were isolated and counted. The AM were isolated by lung lavage of the same animal and counted. In addition, convalescent-stage serum was collected from a specific-pathogen-free pig that was infected with A. pleuropneumoniae. Both porcine AM and porcine PMN effectively phagocytized A. pleuropneumoniae in the presence of convalescent-stage pig serum. PMN killed 90 to 99% of the bacteria intracellularly, whereas AM did not. Because A. pleuropneumoniae produces exotoxins that kill porcine AM and porcine PMN, we incubated equal amounts of bacteria and phagocytic cells and tested the viability of the cells 120 min later. In the presence of convalescent-stage pig serum, A. pleuropneumoniae was toxic to AM but not to PMN. Probably in porcine AM, intracellular released toxins of A. pleuropneumoniae lessen the ability of the cell to kill the bacterium. Consecutive lysis of AM and release of viable A. pleuropneumoniae may initiate the characteristic porcine pleuropneumonia.