bluuebunny/crossref_metadata_2025_split huggingface dataset:
Canine Parvovirus (CPV) Vaccination: Comparison of Neutralizing Antibody Responses in Pups after Inoculation with CPV2 or CPV2b Modified Live Virus Vaccine
Authors: Pratelli Annamaria , Cavalli Alessandra , Martella Vito , Tempesta Maria , Decaro Nicola , Carmichael Leland Eugene , Buonavoglia Canio 
Published: July 2002

ABSTRACT
Canine parvovirus type 2 (CPV2) emerged in 1978 as causative agent of a new disease of dogs. New antigenic variants (biotypes), designated CPV2a and CPV2b, became widespread during 1979 to 1980 and 1984, respectively. At the present time the original CPV2 has disappeared in the dog population and has been replaced by the two new viruses. In the present study the comparison of neutralizing antibody titers in two groups of pups (18 pups in each group) inoculated with CPV2 and CPV2b modified live virus vaccines is reported. Using the hemagglutination inhibition (HI) test, relevant differences between antibody titers, against either the homologous or the heterologous virus, were not constantly observed. Using the neutralization (Nt) test, however, the pups inoculated with CPV2 had antibody titers which were approximately 30 times higher to the homologous virus (mean, 4,732) than to the heterologous virus (CPV2b) (mean, 162). The results of these experiments support two conclusions: (i) the HI test may not always accurately evaluate the true immune status of dogs with respect to CPV, and (ii) dogs inoculated with CPV2 vaccine develop relatively low Nt antibody titers against the heterologous virus (CPV2b). These data may suggest an advantage for new vaccines, considering that most presently licensed vaccines are produced with CPV2, which no longer exists in the dog population.
Seroprevalence of Canine Distemper Virus in Cats
Authors: Ikeda Yasuhiro , Nakamura Kazuya , Miyazawa Takayuki , Chen Ming-Chu , Kuo Tzong-Fu , Lin James A. , Mikami Takeshi , Kai Chieko , Takahashi Eiji 
Published: July 2002

ABSTRACT
A seroepidemiological survey of canine distemper virus (CDV) infection in Asian felids revealed that the prevalence of antibodies varied depending on region and, in some cases, exposure to dogs. The serologic pattern in cats with antibodies indicated that they had likely been exposed to field strains rather than typical CDV vaccine strains.
Enhancement of Splenic-Macrophage Fcγ Receptor Expression by Treatment with Estrogens
Authors: Gomez F. , Ruiz P. , Bernal J. A. , Escobar M. , Garcia-Egido A. , Lopez-Saez J. J. B. 
Published: July 2002

ABSTRACTSplenic-macrophage Fcγ receptors (FcγRs) participate in the pathophysiologies of immune-complex diseases and in host defense against infection. Modulation of macrophage FcγR expression is an immuno-therapeutic target. Glucocorticoids, sex steroids, and dopaminergic drugs modulate macrophage FcγR expression. Previous data indicate that estradiol increases macrophage FcγR expression. Nevertheless, the effects of clinically used estrogens upon macrophage FcγR expression are unknown. We assessed the effects of treatment with commonly used estrogens on the expression of macrophage FcγRs using a guinea pig experimental model. Six estrogens have been studied: ethynylestradiol (Et), mestranol (M), chlortianisene (Ct), promestriene, 17-epiestriol, and 17β-estradiol. Following in vivo treatment of guinea pigs, we determined the clearance of immunoglobulin G (IgG)-sensitized erythrocytes in vivo, the binding of IgG-sensitized erythrocytes by isolated splenic macrophages, and splenic-macrophage FcγR cell surface expression. Estrogens enhance the clearance of IgG-sensitized erythrocytes by increasing splenic-macrophage FcγR expression. Et, M, and Ct were more effective than the other estrogens. Flow cytometry and fluorescence microscopy with monoclonal antibodies demonstrated that estrogens increase the cell surface expression of FcγR1 and -2 more than that of FcγR2. These data indicate that treatment with commonly used estrogens enhances the clearance of IgG-sensitized cells by improving splenic-macrophage FcγR expression.
Passive Immunization with Milk Produced from an Immunized Cow Prevents Oral Recolonization by
Streptococcus mutans
Authors: Shimazaki Yoshihiro , Mitoma Morihide , Oho Takahiko , Nakano Yoshio , Yamashita Yoshihisa , Okano Kaoru , Nakano Yutaka , Fukuyama Masataka , Fujihara Noboru , Nada Youichi , Koga Toshihiko 
Published: July 2002

ABSTRACT

Cell surface protein antigen (PAc) and water-insoluble glucan-synthesizing enzyme (GTF-I) produced by cariogenic
Streptococcus mutans
are two major factors implicated in the colonization of the human oral cavity by this bacterium. We examined the effect of bovine milk, produced after immunization with a fusion protein of functional domains of these proteins, on the recolonization of
S. mutans
. To prepare immune milk, a pregnant Holstein cow was immunized with the fusion protein PAcA-GB, a fusion of the saliva-binding alanine-rich region (PAcA) of PAc and the glucan-binding (GB) domain of GTF-I. After eight adult subjects received cetylpyridinium chloride (CPC) treatment, one subgroup (
n
= 4) rinsed their mouths with immune milk and a control group (
n
= 4) rinsed with nonimmune milk.
S. mutans
levels in saliva and dental plaque decreased after CPC treatment in both groups. Mouth rinsing with immune milk significantly inhibited recolonization of
S. mutans
in saliva and plaque. On the other hand, the numbers of
S. mutans
cells in saliva and plaque in the control group increased immediately after the CPC treatment and surpassed the baseline level 42 and 28 days, respectively, after the CPC treatment. The ratios of
S. mutans
to total streptococci in saliva and plaque in the group that received immune milk were lower than those in the control group. These results suggest that milk produced from immunized cow may be useful for controlling
S. mutans
in the human oral cavity.
Analogs of Eap Protein Are Conserved and Prevalent in Clinical
Staphylococcus aureus
Isolates
Authors: Hussain Muzaffar , Becker Karsten , von Eiff Christof , Peters Georg , Herrmann Mathias 
Published: July 2002

ABSTRACT

Map and Eap are secreted
Staphylococcus aureus
proteins that interact with various extracellular matrix molecules. PCR analysis using
map
primers yielded positive reactions in 97.9% of
S. aureus
isolates but not in
Staphylococcus epidermidis
isolates. Cloning and sequencing of the conferring genes revealed a high degree of overall homology combined with size variability of the gene product due to various repeat numbers and early translation termination in a poly(A) region. Thus, Map and Eap may provide a potential novel tool for
S. aureus
identification and typing.
Bacterial Challenge Stimulates Formation of Arachidonic Acid Metabolites by Human Keratinocytes and Neutrophils In Vitro
Authors: Eberhard Jörg , Jepsen Søren , Pohl Lutz , Albers Hans Karl , Açil Yahya 
Published: July 2002

ABSTRACTAlthough the interactions of bacteria with keratinocytes induce the synthesis of various mediators, the capability of epithelial cells to form arachidonic acid mediators has not been studied, and therefore the first part of this study was initiated. The complex mixture of epithelium-derived mediators suggests that chemoattraction is not their only effect on neutrophils and that they may also affect neutrophil mediator synthesis. The effect of epithelium-derived mediators on neutrophil eicosanoide synthesis was evaluated in the second part of this study. We incubated human keratinocytes with human-pathogenic bacteria for 2 h and harvested the supernatants after 4, 6, 10, and 18 h of culture. Subsequently, the supernatants were coincubated for 5 min with human neutrophils with or without arachidonic acid. The formation of the arachidonic acid metabolites prostaglandin E2(PGE2), leukotriene B4(LTB4), 12-hydroxyeicosatetraenoic acid (12-HETE), and 15-HETE in keratinocytes and neutrophils was measured by reverse-phase high-pressure liquid chromatography. We demonstrated for the first time that keratinocytes produced significant amounts of LTB4and 12-HETE 4 to 6 h after bacterial challenge. Upon stimulation with epithelial supernatants, neutrophils produced significant amounts of PGE2, LTB4, 12-HETE, and 15-HETE throughout the observation period of 18 h, with a maximum synthesis by supernatants harvested 4 to 10 h after bacterial infection. The results of the study suggest that arachidonic acid mediator formation by epithelial cells following bacterial challenge may act as an early inflammatory signal for the initiation of the immune response. The epithelial supernatants were capable of inducing the formation of arachidonic acid mediators by neutrophils, which may have further regulatory effects on the immune response.
Infectious Disease Issues in Xenotransplantation
Authors: Boneva Roumiana S. , Folks Thomas M. , Chapman Louisa E. 
Published: July 2002

SUMMARYXenotransplantation, the transplantation of living organs, tissues, or cells from one species to another, is viewed as a potential solution to the existing shortage of human organs for transplantation. While whole-organ xenotransplantation is still in the preclinical stage, cellular xenotransplantation and extracorporeal perfusion applications are showing promise in early clinical trials. Advances in immunosuppressive therapy, gene engineering, and cloning of animals bring a broader array of xenotransplantation protocols closer to clinical trials. Despite several potential advantages over allotransplantation, xenotransplantation encompasses a number of problems. Immunologic rejection remains the primary hindrance. The potential to introduce infections across species barriers, another major concern, is the main focus of this review. Nonhuman primates are unlikely to be a main source for xenotransplantation products despite their phylogenetic proximity to humans. Genetically engineered pigs, bred under special conditions, are currently envisaged as the major source. Thus far, there has been no evidence for human infections caused by pig xenotransplantation products. However, the existence of xenotropic endogenous retroviruses and the clinical evidence of long-lasting porcine cell microchimerism indicate the potential for xenogeneic infections. Thus, further trials should continue under regulatory oversight, with close clinical and laboratory monitoring for potential xenogeneic infections.
Historical Perspective of Foamy Virus Epidemiology and Infection
Authors: Meiering Christopher D. , Maxine L. Linial  
Published: July 2002

SUMMARY
Foamy viruses (FV) are complex retroviruses which are widespread in many species. Despite being discovered over 40 years ago, FV are among the least well characterized retroviruses. The replication of these viruses is different in many interesting respects from that of all other retroviruses. Infection of natural hosts by FV leads to a lifelong persistent infection, without any evidence of pathology. A large number of studies have looked at the prevalence of primate foamy viruses in the human population. Many of these studies have suggested that FV infections are prevalent in some human populations and are associated with specific diseases. More recent data, using more rigorous criteria for the presence of viruses, have not confirmed these studies. Thus, while FV are ubiquitous in all nonhuman primates, they are only acquired as rare zoonotic infections in humans. In this communication, we briefly discuss the current status of FV research and review the history of FV epidemiology, as well as the lack of pathogenicity in natural, experimental, and zoonotic infections.
Salmonella enterica
Serovar Typhimurium Invasion Is Repressed in the Presence of Bile
Authors: Prouty A. M. , Gunn J. S. 
Published: July 2002

ABSTRACT

As enteric pathogens, the salmonellae have developed systems by which they can sense and adapt appropriately to deleterious intestinal components that include bile. Previously, growth in the presence of bile was shown to repress the transcription of
prgH
, a locus encoding components of the
Salmonella
pathogenicity island I (SPI-1) type III secretion system (TTSS) necessary for eukaryotic cell invasion. This result suggested an existing interaction between salmonellae, bile, and eukaryotic cell invasion. Transcription assays demonstrated that invasion gene regulators (e.g.,
sirC
and
invF
) are repressed by bile. However, bile does not interact with any of the invasion regulators directly but exerts its effect at or upstream of the two-component system at the apex of the invasion cascade, SirA-BarA. As suggested by the repression of invasion gene transcription in the presence of bile, Western blot analysis demonstrated that proteins secreted by the SPI-1 TTSS were markedly reduced in the presence of bile. Furthermore,
Salmonella enterica
serovar Typhimurium grown in the presence of bile was able to invade epithelial cells at only 4% of the level of serovar Typhimurium grown without bile. From these data, we propose a model whereby serovar Typhimurium uses bile as an environmental signal to repress its invasive capacity in the lumen of the intestine, but upon mucous layer penetration and association with intestinal epithelial cells, where the apparent bile concentration would be reduced, the system would become derepressed and invasion would be initiated.
Genetically Determined Disparate Innate and Adaptive Cell-Mediated Immune Responses to PulmonaryMycobacterium bovisBCG Infection in C57BL/6 and BALB/c Mice
Authors: Wakeham Julia , Wang Jun , Xing Zhou 
Published: July 2002

ABSTRACTThe current study was designed to investigate the impact of genetic heterogeneity on host immune responses to pulmonary intracellular infection by using two mouse strains of distinct genetic background, C57BL/6 and BALB/c mice, and a model intracellular pathogen,Mycobacterium bovisBCG. Upon infection, compared to C57BL/6 mice, BALB/c mice developed an earlier response of interleukin 12 (IL-12), gamma interferon (IFN-γ), tumor necrosis factor alpha, and macrophage chemoattractive protein 1, and greater neutrophilic influx to the lung by days 7 and 14. However, the level of these cytokines at days 27, 43, and 71 was much lower in BALB/c mice than in C57BL/6 mice. The magnitude of cellular responses was also much lower in the lung of BALB/c mice around day 27. Histologically, while C57BL/6 mice developed lymphocytic granulomas, BALB/c mice displayed atypical granulomas in the lung. Of importance, the level of type 2 cytokines IL-4 and IL-10 remained low and similar in the lung of both C57BL/6 and BALB/c mice throughout. Furthermore, lymphocytes isolated from systemic and local lymphoid tissues of infected BALB/c mice demonstrated a markedly lower antigen-specific IFN-γ recall response. While the number of mycobacterial bacilli recovered from both the lung and spleen of BALB/c mice was similar to that in C57BL/6 mice at day 14, it was higher than that in C57BL/6 mice at day 43. However, it was eventually leveled off to that in C57BL/6 counterparts later. These results suggest the following: (i) genetic heterogeneity can lead to differential innate and adaptive cell-mediated immune responses to primary pulmonary mycobacterial infection; (ii) it is the level of adaptive, but not innate, immune response that is critical to host resistance; and (iii) a lower type 1 immune response in BALB/c mice is not accompanied by a heightened type 2 response during pulmonary mycobacterial infection.
Construction of Urease-Negative Mutants of
Yersinia enterocolitica
Serotypes O:3 and O:8: Role of Urease in Virulence and Arthritogenicity
Authors: Gripenberg-Lerche Christel , Zhang Lijuan , Ahtonen Päivi , Toivanen Paavo , Skurnik Mikael 
Published: July 2002

ABSTRACT

Yersinia enterocolitica
serotype O:3 and O:8 urease-negative mutants unable to express the 19-kDa β subunit of urease were constructed and tested for virulence and arthritogenicity. Our results indicate that urease is needed for full virulence in oral infections and that it is not an arthritogenic factor in the rat model.
Malaria Infection Induces Rapid Elevation of the Soluble Fas Ligand Level in Serum and Subsequent T Lymphocytopenia: Possible Factors Responsible for the Differences in Susceptibility of Two Species ofMacacaMonkeys toPlasmodium coatneyiInfection
Authors: Matsumoto Jun , Kawai Satoru , Terao Keiji , Kirinoki Masashi , Yasutomi Yasuhiro , Aikawa Masamichi , Matsuda Hajime 
Published: July 2002

ABSTRACTThe intraerythrocytic stage of the simian malaria parasitePlasmodium coatneyi(CDC strain) was intravenously inoculated into two species of macaques with different susceptibilities to infection with this parasite, including four Japanese macaques (Macaca fuscata) and three cynomolgus macaques (M. fascicularis). The Japanese macaques infected withP. coatneyideveloped severe clinical manifestations similar to those of severe human malaria and eventually became moribund, while the infected cynomolgus macaques, natural hosts of the parasite, exhibited no severe manifestation of disease except anemia and finally recovered from the infection. In the infected Japanese macaques, peripheral CD4+and CD8+T-cell populations were markedly decreased and fragmentation of chromosomal DNA in peripheral blood mononuclear cells was detected during the terminal period of infection, suggesting that apoptotic cell death was responsible at least in part for the T lymphocytopenia. Furthermore, soluble Fas ligand levels in sera of the infected Japanese macaques increased gradually to a markedly high level of 28.83 ± 10.56 pg/ml (n= 4) when the animals became moribund. On the other hand, none of the infected cynomolgus monkeys exhibited either T lymphocytopenia or elevated soluble Fas ligand level. These findings suggest that differences in immune response between the two species of macaque tested accounted for the contrasting outcomes after infection with the same isolate of malarial parasite, and in particular that a profound T lymphocytopenia due to Fas-derived apoptosis played a role in the fatal course of malaria in the infected Japanese macaques.
Characterization of In Vitro DNA Binding Sites of the EUO Protein of
Chlamydia psittaci
Authors: Zhang Li , Howe Martha M. , Hatch Thomas P. 
Published: July 2002

ABSTRACT

The EUO gene of chlamydia is highly expressed early in the developmental cycle, relative to other genes, but continues to be expressed throughout the active growth phases. The precise function of EUO protein is not known, but it binds to DNA in vitro. In this study, we developed a selection and amplification scheme for identifying chlamydial genomic fragments to which EUO preferentially binds in vitro. The scheme involved mixing recombinant EUO with a
Chlamydia psittaci
genomic library in a pBluescript plasmid vector in vitro, trapping EUO-bound plasmid clones on filters, and amplifying the clones in
Escherichia coli
. After nine rounds of enrichment, the EUO binding sites of the three most highly enriched clones were identified by DNase I footprint analysis. All three clones had multiple binding sites of various sizes with no clear distinguishing feature other than they were AT-rich and were usually not located in putative promoter regions. We used limited site-specific mutagenesis to characterize the strongest binding site of the most-highly-enriched clone, which represented about 50% of the population after nine rounds. This mutagenesis identified a core binding site of 15 nucleotides (nt) whose sequence was used to find related sequences within each of the strong binding sites in the other two clones. Using the frequency of bases at specific positions within this group of sequences as a guide, we carried out trial-and-error searching with many related sequences, eliminating those which identified nonfootprinted sites. This process led us to the consensus 15-nt sequence AHGAAAWVTYTWDAY, which, when allowing two mismatches, picked out all of the strong binding sites and no nonfootprinting sites within the three enriched clones. This sequence may be useful for predicting additional possible EUO binding sites in the chlamydial genome.
Gamma Interferon Dominates the Murine Cytokine Response to the Agent of Human Granulocytic Ehrlichiosis and Helps To Control the Degree of Early Rickettsemia
Authors: Akkoyunlu Mustafa , Fikrig Erol 
Published: July 2002

ABSTRACTThe cytokine response to the agent of human granulocytic ehrlichiosis (HGE) was assessed in a murine infection model and the role of gamma interferon (IFN-γ), a cytokine that is crucial for host defenses against intracellular pathogens, was investigated by using IFN-γ-deficient mice. The agent of HGE (aoHGE) is an obligate intracellular bacterium that survives within neutrophils: morulae (vacuoles containing HGE organisms) are evident in polymorphonuclear leukocytes of experimentally infected immunocompetent mice for 1 to 2 weeks. We now show that IFN-γ levels increase during early infection of C3H/HeN or C57BL/6 mice with HGE bacteria. Moreover, in response to aoHGE extracts or concanavalin A, splenocytes from ehrlichia-infected mice produced more IFN-γ and less interleukin-4 than controls, suggesting that aoHGE partially skewed the immune response towards a Th1 phenotype. Absolute concentration of morulae containing neutrophils in blood was 122 ± 22 cells/μl on day 8. The bacterial DNA burden was also highest on day 8 and then declined after IFN-γ levels peaked. In contrast, IFN-γ-deficient mice had a markedly elevated HGE bacteria burden with morulae concentration of 282 ± 48 cells/μl on day 5 (P= 0.004) and 242 ± 63 cells/μl on day 8 (P= 0.005). Rickettsemia resolved in immunocompetent and IFN-γ deficient mice after 2 weeks, while both the immunocompetent and the IFN-γ-deficient mice had increased serum antibodies against aoHGE antigens at this time point. These data demonstrate that the HGE agent elicits a prominent IFN-γ response in mice and that IFN-γ is important in controlling the degree of rickettsemia during the early phase of infection, while IFN-γ independent mechanisms play a role at later time points.
Antibodies against the
Plasmodium falciparum
Receptor Binding Domain of EBA-175 Block Invasion Pathways That Do Not Involve Sialic Acids
Authors: Narum David L. , Haynes J. David , Fuhrmann Steven , Moch Kathy , Liang Hong , Hoffman Stephen L. , Sim B. Kim Lee 
Published: July 2002

ABSTRACT

The 175-kDa
Plasmodium falciparum
erythrocyte binding protein (EBA-175) binds to its receptor, sialic acids on glycophorin A. The binding region within EBA-175 is a cysteine-rich region identified as region II. Antibodies against region II block the binding of native EBA-175 to erythrocytes. We identified a
P. falciparum
strain, FVO, that could not invade erythrocytes devoid of sialic acids due to prior neuraminidase treatment, and in addition, we used a strain, 3D7, that could invade such sialic acid-depleted erythrocytes. We used these two strains to study the capacity of anti-region II antibodies to inhibit FVO and 3D7 parasite development in vitro. Analysis of growth-inhibitory effects of purified FVO anti-region II immunoglobulin G (IgG) with the FVO and 3D7 strains resulted in similar levels of growth inhibition. FVO and 3D7 strains were inhibited between 28 and 56% compared to control IgG. There appeared to be no intracellular growth retardation or killing of either isolate, suggesting that invasion was indeed inhibited. Incubation of recombinant region II with anti-region II IgG reversed the growth inhibition. These results suggest that antibodies against region II can also interfere with merozoite invasion pathways that do not involve sialic acids. The fact that EBA-175 has such a universal and yet susceptible role in erythrocyte invasion clearly supports its inclusion in a multivalent malaria vaccine.