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Memorias Do Instituto Oswaldo Cruz 1999Six hundred and eleven random-source dogs (338 male, 273 female) one year of age or older, from six sections of the city of Recife, Pernambuco, were examined antemortem...
Six hundred and eleven random-source dogs (338 male, 273 female) one year of age or older, from six sections of the city of Recife, Pernambuco, were examined antemortem for circulating microfilariae Dirofilaria immitis and Dipetalonema reconditum adult heartworm (D. immitis) antigen, and examined postmortem for adult heartworms. The prevalence of heartworm infection was 2.3% (14/611), as determined by necropsy for adult worms, and 1% (6/611) had circulating microfilariae of D. immitis; thus, 57.1% of the heartworm-infected dogs had occult infections. The results of serological testing indicated that 1.3% (8/611) of the dogs were positive for adult heartworm antigen. A total of 42 (6.9%) of the dogs had microfilariae of D. reconditum; 40 of these had only D. reconditum and two additional dogs had microfilariae of both species, D. immitis and D. reconditum.
Topics: Animals; Brazil; Dirofilaria immitis; Dirofilariasis; Dog Diseases; Dogs; Female; Male; Prevalence
PubMed: 10464398
DOI: 10.1590/s0074-02761999000500004 -
The Journal of Biological Chemistry Jul 1999N-Type glycans containing phosphorylcholine (PC-glycans), unusual structures found in the important human pathogens filarial nematodes, represent a novel target for...
N-Type glycans containing phosphorylcholine (PC-glycans), unusual structures found in the important human pathogens filarial nematodes, represent a novel target for chemotherapy. Previous work in our laboratories produced compositional information on the PC-glycan of ES-62, a secreted protein of the rodent parasite Acanthocheilonema viteae. In particular, we established using fast atom bombardment mass spectrometry (MS) analysis that PC was attached to a glycan with a trimannosyl core, with and without core fucosylation, carrying between one and four additional N-acetylglucosamine residues. In the present study, we demonstrate that this structure is conserved among filarial nematodes, including the parasite of humans, Onchocerca volvulus, for which new drugs are most urgently sought. Furthermore, by employing a variety of procedures, including collision-activated dissociation MS-MS analysis and matrix-assisted laser desorption MS analysis, we reveal that surprisingly, filarial nematodes also contain N-linked glycans, the antennae of which are composed of chito-oligomers. To our knowledge, this is the first report of such structures in a eukaryotic glycoprotein.
Topics: Animals; Dipetalonema; Gerbillinae; Humans; Mass Spectrometry; Onchocerca volvulus; Phosphorylcholine; Polysaccharides; Species Specificity
PubMed: 10409642
DOI: 10.1074/jbc.274.30.20953 -
Parasite Immunology Apr 1999The recombinant extracellular copper/zinc superoxide dismutase of the filarial parasite Acanthocheilonema viteae (AVSOD2) was cloned in an expression vector under...
Immunogenicity of the extracellular copper/zinc superoxide dismutase of the filarial parasite Acanthocheilonema viteae delivered by a two-phase vaccine strain of Salmonella typhimurium.
The recombinant extracellular copper/zinc superoxide dismutase of the filarial parasite Acanthocheilonema viteae (AVSOD2) was cloned in an expression vector under control of the bacteriophage T7 promoter and the resulting plasmid pLAT7 was introduced in tha aroA attenuated Salmonella typhimurium vaccine strain SL3261:pYZ84. This vaccine strain carries a chromosomally integrated two phase expression system containing inducible T7 RNA polymerase. The recombinant AVSOD2 was efficiently expressed, constituting up to 5% of the total bacterial protein. Furthermore, the plasmid vector containing the AVSOD2 cDNA was shown to be stable over a long period of time in the vaccine strain without antibiotic selection in vitro and in vivo. Jirds which were immunised orally with the recombinant vaccine strain expressing the A. viteae EC-SOD produced a strong humoral immune response.
Topics: Administration, Oral; Animals; Antibodies, Helminth; Antigens, Helminth; Bacterial Vaccines; Dipetalonema; Drug Carriers; Gerbillinae; Recombinant Proteins; Salmonella typhimurium; Superoxide Dismutase
PubMed: 10320619
DOI: 10.1046/j.1365-3024.1999.00207.x -
Parasite Immunology Nov 1998Filarial nematodes constitute major causes of morbidity in the Tropics. The worms have a life-span exceeding five years, a longevity which is considered to reflect at...
Filarial nematodes constitute major causes of morbidity in the Tropics. The worms have a life-span exceeding five years, a longevity which is considered to reflect at least in part, their ability to interfere with host lymphocyte responsiveness. To date the molecular mechanisms underlying this ability have not been defined but we now demonstrate that ES-62, a phosphorylcholine (PC)-containing glycoprotein released by the rodent filarial parasite Acanthocheilonema viteae, is able to render Jurkat T cells anergic to intracellular signalling via the antigen receptor (TCR). In particular, ES-62 acts by modulating activation of the tyrosine kinases Fyn, Lck and ZAP-70 leading to selective disruption of TCR coupling to the phospholipase D, protein kinase C, phosphoinositide-3-kinase and RasMAPkinase signalling cascades. These cascades are key elements in the transduction of transcriptional and proliferative signals following ligation of TCR. As PC-containing secreted products (PC-ES) are also released by human filarial parasites, our data suggest that PC-ES may play a role in the induction of T lymphocyte hyporesponsiveness observed during filarial infections.
Topics: Amino Acid Sequence; Animals; CD3 Complex; Calcium-Calmodulin-Dependent Protein Kinases; Dipetalonema; Enzyme Activation; Helminth Proteins; Humans; Inositol Phosphates; Jurkat Cells; Lymphocyte Activation; Molecular Sequence Data; Phosphatidylinositol 3-Kinases; Phospholipase D; Protein Kinase C; Protein-Tyrosine Kinases; Receptors, Antigen, T-Cell; Signal Transduction; T-Lymphocytes; ras Proteins
PubMed: 9988312
DOI: 10.1046/j.1365-3024.1998.00181.x -
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 -
Parasite (Paris, France) Mar 1998The development of the human filaria Loa loa (Dirofilariinae, Onchocercidae), previously studied in monkeys, was studied using the non permissive hosts-mice and jirds....
The development of the human filaria Loa loa (Dirofilariinae, Onchocercidae), previously studied in monkeys, was studied using the non permissive hosts-mice and jirds. The development proved to be rapid: moult 3 occurred on day 8 post-inoculation, the adult stage was reached on day 25 and measured at that time 3-3.5 mm in length. As in the other filarioids, the female genital apparatus developed during the fourth stage. A critical analysis of the studies on the development of Onchocercid species was made. The optimal duration of the stages (i.g. the shortest time) was chosen for the comparison. It appeared that the duration of the stage 3 was a constant character in a given species whatever the experimental conditions, whereas moult 4 might be retarded in a non susceptible host. Comparison between the 18 developmental cycles of Onchocercidae in the vertebrate host was made. Two biological types could be distinguished: either the moult 3 occurred on day 2-3 and was followed apparently by a late moult 4 (> or = 50 days), or the moult 3 occurred after about one week of development and it was associated with a less long stage 4 (20-40 days). The first group includes Dirofilaria and Onchocerca, the second group brings together mainly Loa and the Onchocercinae of the Dipetalonema line and related genera (Acanthocheilonema, Brugia, Litomosoides, etc.). The groups thus formed suggest real relationships as they fit with the morphology of the infective stage and the results of a recent molecular analysis of the 5S DNA.
Topics: Animals; Disease Models, Animal; Female; Gerbillinae; Humans; Larva; Loa; Loiasis; Male; Mice; Molting; Morphogenesis
PubMed: 9754295
DOI: 10.1051/parasite/1998051037 -
Clinical Microbiology Reviews Apr 1998Filariae of animals, especially those of mammals, often infect humans and typically produce cryptic infections. These "zoonotic" infections have been reported from... (Review)
Review
Filariae of animals, especially those of mammals, often infect humans and typically produce cryptic infections. These "zoonotic" infections have been reported from virtually all parts of the world including temperate zones. Infections may be symptomatic or not, and the parasites are found in surgical tissue biopsy specimens or, more rarely, are removed intact from superficial sites such as the orbit or conjuctivae. Typically, these worms tend to occupy tissue sites similar to those occupied in the natural animal host, with the exception of the eyes. Many kinds of filariae have been isolated from humans, including species of Dirofilaria, Brugia, Onchocerca, Dipetalonema, Loaina and Meningonema. Worms have been found in subcutaneous tissues, the heart and lungs, lymphatics, the eye, and the central nervous system. Specific identification of these filariae is based on their morphological features in histologic sections. Unfortunately, some of these worms cannot be identified even at the generic level. There are other species of filariae, presumed to be zoonotic, which produce patent infections in humans but are poorly and incompletely known. These include Microfilaria semiclarum and Microfilaria bolivarensis. It is probable that almost any filaria parasitizing animals can, under proper circumstances, infect humans and undergo some degree of development. Undoubtedly, additional species of filariae will continue to be isolated from humans in the future.
Topics: Animals; Filariasis; Filarioidea; Humans; Species Specificity; Zoonoses
PubMed: 9564568
DOI: 10.1128/CMR.11.2.366 -
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 -
Tropical Medicine & International... Jun 1997CDRI Compound 92/138, a synthetic analogue of aplysinopsin, was evaluated in experimental filarial infections, Litomosoides carinii in cotton rats (Sigmodon hispidus)...
CDRI Compound 92/138, a synthetic analogue of aplysinopsin, was evaluated in experimental filarial infections, Litomosoides carinii in cotton rats (Sigmodon hispidus) and Acanthocheilonema viteae in Mastomys coucha. The compound killed 63.8 and 90% of adult L. carinii and A. viteae at doses of 30 and 50 mg/kg (i.p.) respectively given for 5 days. By the oral route, at 100 mg/kg for 5 days the compound caused 50.9 and 57% mortality of adult L. carinii and A. viteae, respectively. At 200 mg/kg administered orally on days 0, 10 and 25 post-infection, it reduced establishment of adult A. viteae by 68.5%. We also found 43.7 and 37.8% effect in vivo respectively on L3 and L4 stages of A. viteae at a single dose of 250 mg/kg, p.o. The compound was active in vitro at 100 micrograms/ml concentration and caused a significant decline in MTT reduction and 14C-glucose uptake by adult filariids. Thus synthetic marine aplysinopsin could provide a new pharmacophore for the development of antifilarial agents.
Topics: Animals; Dipetalonema Infections; Drug Evaluation, Preclinical; Filariasis; Filaricides; Filarioidea; Imidazoles; Indoles; Male; Muridae; Sigmodontinae
PubMed: 9236820
DOI: 10.1046/j.1365-3156.1997.d01-321.x -
The Journal of Biological Chemistry Jan 1997We have recently shown that the immunomodulatory substance phosphorylcholine (PC) is covalently attached to ES-62, a major secreted protein of the filarial nematode...
We have recently shown that the immunomodulatory substance phosphorylcholine (PC) is covalently attached to ES-62, a major secreted protein of the filarial nematode parasite Acanthocheilonema viteae, via an N-linked glycan. Linkage of PC to N-glycans is previously unreported, and hence we have investigated the biochemical events underlying it. PC addition was found by pulse-chase experiments to be a fairly early event during intracellular transport, occurring within 40-60 min of protein synthesis. Biosynthetic labeling/immunoprecipitation experiments revealed that addition of PC to ES-62 was blocked by (i) brefeldin A, an inhibitor of trafficking of newly synthesized proteins from the endoplasmic reticulum (ER) to the Golgi, (ii) 1-deoxynorijirimycin, an inhibitor of glucosidase activity in the ER, and (iii) 1-deoxymannojirimycin, an inhibitor of mannosidase I in the cis Golgi. Swainsonine, an inhibitor of mannosidase II in the medial Golgi, did not affect PC addition. Taken together these data indicate that PC attachment is a post-ER event which is dependent on generation of an appropriate substrate during oligosaccharide processing. Furthermore, they strongly suggest that PC addition takes place in the medial Golgi and that the substrate for addition is the 3-linked branch of Man5GlcNAc3 or Man3GLcNAc3.
Topics: Animals; Binding Sites; Brefeldin A; Cyclopentanes; Dipetalonema; Gerbillinae; Glycoproteins; Oligosaccharides; Phosphorylcholine; Polysaccharides; Protein Binding
PubMed: 8999824
DOI: 10.1074/jbc.272.3.1527