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Cadernos de Saude Publica 2001A survey on the prevalence of Dirofilaria immitis and Dipetalonema reconditum was conducted in 1,519 dogs from Maceió and two coastal areas in the State of Alagoas,...
A survey on the prevalence of Dirofilaria immitis and Dipetalonema reconditum was conducted in 1,519 dogs from Maceió and two coastal areas in the State of Alagoas, Northeast Brazil, from 1995 to 1999, by testing for microfilariae in blood. All blood samples were from exclusively domiciled dogs with a known history, showing that the infections were autochthonous, confirming transmission of canine filariasis in these areas. In Greater Metropolitan Maceió, 15 (1.3%) microfilaremic dogs were detected with D. immitis and 15 (1,3%) with D. reconditum. In the southern coastal area there was an estimated prevalence of 12.7% for D. immitis. D. immitis and D. reconditum microfilaria were 298.1 micrometer and 249.2 micrometer long and 7.3 micrometer and 4.4 micrometer wide, respectively. A Witness immunotest that detects D. immitis antigen was used to confirm parasitological results and reveal occult dirofilariasis cases. Of the total 6,579 females examined, 8 (0.1%) Culex quinquefasciatus were observed to be naturally infected with D. immitis larvae. These results proved dirofilariasis transmission in Maceió and demonstrated D. reconditum in the same geographic area.
Topics: Animals; Antigens, Helminth; Brazil; Dipetalonema; Dipetalonema Infections; Dirofilaria immitis; Dirofilariasis; Dog Diseases; Dogs; Female; Male; Prevalence
PubMed: 11784911
DOI: 10.1590/s0102-311x2001000600021 -
The Journal of Clinical Investigation Jan 1999Intracellular bacteria have been described in several species of filarial nematodes, but their relationships with, and effects on, their nematode hosts have not...
Intracellular bacteria have been described in several species of filarial nematodes, but their relationships with, and effects on, their nematode hosts have not previously been elucidated. In this study, intracellular bacteria were observed in tissues of the rodent parasite Litomosoides sigmodontis by transmission electron microscopy and by immunohistochemistry using antiendobacterial heat shock protein-60 antisera. Molecular phylogenetic analysis of the bacterial 16S ribosomal RNA gene, isolated by PCR, showed a close relationship to the rickettsial Wolbachia endobacteria of arthropods and to other filarial intracellular bacteria. The impact of tetracycline therapy of infected rodents on L. sigmodontis development was analyzed in order to understand the role(s) these bacteria might play in filarial biology. Tetracycline therapy, when initiated with L. sigmodontis infection, eliminated the bacteria and resulted in filarial growth retardation and infertility. If initiated after microfilarial development, treatment reduced filarial fertility. Treatment with antibiotics not affecting rickettsial bacteria did not inhibit filarial development. Acanthocheilonema viteae filariae were shown to lack intracellular bacteria and to be insensitive to tetracycline. These results suggest a mutualistic interaction between the intracellular bacteria and the filarial nematode. Investigation of such a mutualism in endobacteria-containing human filariae is warranted for a potential chemotherapeutic exploitation.
Topics: Animals; Bacterial Proteins; Dipetalonema; Filariasis; Filarioidea; Immunohistochemistry; Infertility; Mice; Mice, Inbred BALB C; Microscopy, Electron; Phylogeny; RNA, Ribosomal, 16S; Rats; Rickettsia; Tetracycline
PubMed: 9884329
DOI: 10.1172/JCI4768 -
Bulletin of the World Health... 1969
[Evaluation of 2 immunological tests (skin test and complement fixation test) for the detection of filariasis in populations of Upper Volta where Wuchereria bancrofti, Onchocercă volvulus and Dipetalonema perstans occur together].
Topics: Antigens; Burkina Faso; Complement Fixation Tests; Dipetalonema; Filariasis; Humans; Onchocerca; Skin Tests; World Health Organization; Wuchereria
PubMed: 5307597
DOI: No ID Found -
The Canadian Veterinary Journal = La... Aug 1969
Topics: Animals; Caniformia; Female; Filariasis; Heart Diseases; Lung Diseases, Parasitic; Pseudomonas Infections
PubMed: 5388277
DOI: No ID Found -
Experimental Parasitology Sep 2012ES-62 is an immunomodulatory phosphorylcholine (PC)-containing glycoprotein secreted by the rodent filarial nematode Acanthocheilonema viteae. Previously, the use of...
ES-62 is an immunomodulatory phosphorylcholine (PC)-containing glycoprotein secreted by the rodent filarial nematode Acanthocheilonema viteae. Previously, the use of knockout mice has revealed the effects of ES-62 on macrophages and dendritic cells to be dependent on TLR4. However, it is possible that ES-62 may interact with additional proteins on the surfaces of target cells and hence that cells may vary with respect to receptor usage. In this study, we identified by molecular weight, proteins that interact with ES-62 and found differences amongst the immune system cells studied. Thus, whereas lymphocytes appear to have two major interacting proteins of ∼135 and ∼82 kDa, U937 monocytes only contain an ES-62-binding protein of the latter molecular weight. Binding to the proteins on B cells and U937 cells was blocked by PC, suggesting a critical role for this ES-62 moiety in facilitating interaction. Finally, ES-62 binding is followed by internalization in both macrophages and B cells but only in the former was absence of TLR4 found to block internalization. These findings are consistent with differences in receptor usage by ES-62 amongst different cell-types.
Topics: Animals; B-Lymphocytes; Biosensing Techniques; Blotting, Western; Cell Membrane; Dipetalonema; Helminth Proteins; Humans; Jurkat Cells; Macrophages; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Molecular Weight; Monocytes; Receptors, Cell Surface; T-Lymphocytes; Toll-Like Receptor 4; U937 Cells
PubMed: 21925176
DOI: 10.1016/j.exppara.2011.09.001 -
The FEBS Journal Jul 2009Parasitic nematodes can downregulate the immune response of their hosts through the induction of immunoregulatory cytokines such as interleukin-10 (IL-10). To define the...
Parasitic nematodes can downregulate the immune response of their hosts through the induction of immunoregulatory cytokines such as interleukin-10 (IL-10). To define the underlying mechanisms, we measured in vitro the production of IL-10 in macrophages in response to cystatin from Acanthocheilonema viteae, an immunomodulatory protein of filarial nematodes, and developed mathematical models of IL-10 regulation. IL-10 expression requires stimulation of the mitogen-activated protein kinases extracellular signal-regulated kinase (ERK) and p38, and we propose that a negative feedback mechanism, acting at the signalling level, is responsible for transient IL-10 production that can be followed by a sustained plateau. Specifically, a model with negative feedback on the ERK pathway via secreted IL-10 accounts for the experimental data. Accordingly, the model predicts sustained phospho-p38 dynamics, whereas ERK activation changes from transient to sustained when the concentration of immunomodulatory protein of Acanthocheilonema viteae increases. We show that IL-10 can regulate its own production in an autocrine fashion, and that ERK and p38 control IL-10 amplitude, duration and steady state. We also show that p38 affects ERK via secreted IL-10 (autocrine crosstalk). These findings demonstrate how convergent signalling pathways may differentially control kinetic properties of the IL-10 signal.
Topics: Animals; Autocrine Communication; Cystatins; Cysteine Proteinase Inhibitors; Dipetalonema; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation; Helminth Proteins; Interleukin-10; MAP Kinase Signaling System; Macrophages; Male; Mice; Mice, Inbred BALB C; Models, Theoretical; Phosphorylation; p38 Mitogen-Activated Protein Kinases
PubMed: 19456864
DOI: 10.1111/j.1742-4658.2009.07068.x -
Tropical Medicine & International... Feb 1998To determine mitogenic and antigen-specific cellular immune responses of two species of rodents, viz. Meriones unguiculatus and Mastomys coucha to assess the usefulness...
OBJECTIVE
To determine mitogenic and antigen-specific cellular immune responses of two species of rodents, viz. Meriones unguiculatus and Mastomys coucha to assess the usefulness of the A. viteae/Mastomys model for cellular immune studies in experimental filariasis.
METHODS
Lymphocyte blast transformation test (LTT) using spleen cells of normal and A. viteae infected animals.
RESULTS
The proliferative response of gerbils was much higher than that of Mastomys to both ConA and filarial antigens. Cells of both species of rodents did not respond to microfilarial (mf) antigen, however, their mitogenic response differed during infection. Some degree of nonspecific suppression was observed in gerbils during prepatent and patent stages of infection, while Mastomys revealed highest proliferation during patent microfilaraemia. Mastomys cells did not respond to adult or mf antigen, while adult-specific proliferation was detected in the case of gerbils.
CONCLUSION
The A. viteae/gerbil model shows more similarity to human filarial infection regarding cellular immune response. Markedly low responsiveness of a high percentage of Mastomys and wide variations in the cellular response to nonspecific mitogen limit the usefulness of Mastomys coucha in immunological studies, especially cellular immunity.
Topics: Animals; Antigens, Helminth; Dipetalonema; Dipetalonema Infections; Disease Models, Animal; Gerbillinae; Humans; Immune Tolerance; Immunity, Cellular; Lymphocyte Activation; Male; Microfilariae; Muridae
PubMed: 9537274
DOI: 10.1046/j.1365-3156.1998.00161.x -
Biophysical Journal Jan 2003ES-62, a protein secreted by filarial nematodes, parasites of vertebrates including humans, has an unusual posttranslational covalent addition of phosphorylcholine to an... (Comparative Study)
Comparative Study
ES-62, a protein secreted by filarial nematodes, parasites of vertebrates including humans, has an unusual posttranslational covalent addition of phosphorylcholine to an N-type glycan. Studies on ES-62 from the rodent parasite Acanthocheilonema viteae ascribe it a dominant role in ensuring parasite survival by modulating the host immune system. Understanding this immunomodulation at the molecular level awaits full elucidation but distinct components of ES-62 may participate: the protein contributes aminopeptidase-like activity whereas the phosphorylcholine is thought to act as a signal transducer. We have used biophysical and bioinformatics-based structure prediction methods to define a low-resolution model of ES-62. Sedimentation equilibrium showed that ES-62 is a tightly bound tetramer. The sedimentation coefficient is consistent with this oligomer and the overall molecular shape revealed by small angle x-ray scattering. A 19 A model for ES-62 was restored from the small-angle x-ray scattering data using the program DAMMIN which uses simulated annealing to find a configuration of densely packed scattering elements consistent with the experimental scattering curve. Analysis of the primary sequence with the position-specific iterated basic local alignment search tool, PSI-BLAST, identified six closely homologous proteins, five of which are peptidases, consistent with observed aminopeptidase activity in ES-62. Differences between the secondary structure content of ES-62 predicted using the consensus output from the secondary structure prediction server JPRED and measured using circular dichroism are discussed in relation to multimeric glycosylated proteins. This study represents the first attempt to understand the multifunctional properties of this important parasite-derived molecule by studying its structure.
Topics: Amino Acid Sequence; Animals; Circular Dichroism; Dipetalonema; Helminth Proteins; Models, Molecular; Molecular Sequence Data; Protein Conformation; Protein Structure, Quaternary; Protein Structure, Secondary; Protein Structure, Tertiary; Sequence Alignment; Sequence Analysis, Protein; Sequence Homology, Amino Acid; Solutions
PubMed: 12524301
DOI: 10.1016/S0006-3495(03)74868-1 -
Infection and Immunity Jan 2008Chitinases of pathogens have been proposed as potential targets of vaccines or specific inhibitors. We studied the genomic organization, transcript levels, developmental...
Chitinases of pathogens have been proposed as potential targets of vaccines or specific inhibitors. We studied the genomic organization, transcript levels, developmental expression, and biological function of chitinases in the rodent filarial nematode Acanthocheilonema viteae, a model organism for human-pathogenic filarial worms. Characterization of nine genomic clones from an A. viteae phage library and Southern blot experiments revealed the existence of three different chitinase genes, two of which could theoretically yield functional transcripts. The deduced proteins of these genes had the common modular organization of family 18 chitinases. Northern blot experiments and rapid amplification of cDNA ends-PCR with adult worms and larval stages showed that only one gene is expressed, with high variation in transcript levels, as determined by real-time PCR. Chitinase transcript levels were lowest in the late male stage 4 larva (L4) and peaked in the stage 3 larva (L3), which was corroborated by Western blotting. RNA interference (RNAi) experiments showed that treatment of L3 and adult female worms with double-stranded RNA of chitinase inhibited molting of L3 worms and hatching of microfilariae. RNAi also led to the death of 50% of female worms, revealing the essential role of chitinase in the life cycle of filarial nematodes.
Topics: Animals; Chitinases; Dipetalonema; Female; Gene Expression Regulation; Genes, Helminth; Genome, Helminth; Helminth Proteins; Life Cycle Stages; Male; Molecular Sequence Data; RNA Interference
PubMed: 17938220
DOI: 10.1128/IAI.00701-07 -
Parasite Immunology May 2002Cystatins of two filarial nematodes were studied with regard to their capacity to up-regulate the production of nitric oxide (NO) in vitro, and the effects were...
Cystatins of two filarial nematodes were studied with regard to their capacity to up-regulate the production of nitric oxide (NO) in vitro, and the effects were analysed. Recombinant cystatin of the human pathogenic filaria Onchocerca volvulus and of the rodent filaria Acanthocheilonema viteae significantly enhanced the NO production of interferon (IFN)-gamma-activated macrophages of BALB/c and C3H/HeJ mice. Truncated cystatins lacking the N-terminal protease inhibitory active site, and showing marginal protease inhibitory activity, up-regulated the NO production to the same extent as the full-length proteins, indicating that the effect on the NO production is independent of cysteine protease inhibition. NO did not contribute to the suppression of proliferative T cell responses exerted by filarial cystatins, as shown in other studies, since NO synthase inhibitors did not restore proliferative responses. The up-regulation of NO production induced by filarial cystatins was partly dependent on the production of interleukin-10 and tumour necrosis factor-alpha, since depletion of both cytokines by antibodies led to a diminution of the enhanced NO production by 22-48%. Our data suggest that filarial cystatins are potent triggers of the production of NO, a mediator which was shown to have a role as an effector molecule against filarial worms in vitro and in vivo.
Topics: Adjuvants, Immunologic; Animals; Cystatins; Dipetalonema; Filariasis; Interferon-gamma; Interleukin-10; Life Cycle Stages; Macrophage Activation; Mice; Nitric Oxide; Onchocerca volvulus; Polysaccharides, Bacterial; T-Lymphocytes; Tumor Necrosis Factor-alpha; Up-Regulation
PubMed: 12060319
DOI: 10.1046/j.1365-3024.2002.00459.x