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At least 19 recordsLinked to original sources
PubMed1977

Skin penetration of infective hookworm larvae. III. Comparative studies on the path of migration of the hookworms Ancylostoma braziliense, Ancylostoma ceylanicum, and Ancylostoma caninum.

The lateral skin areas of nine hookworm-free puppies were exposed to infective larvae of Ancylostoma braziliense, Ancylostoma ceylanicum and Ancylostoma caninum. Serial sections, stained with Harris' haematoxylin and eosin, showed that many similarities exist in the migration patterns of the hookworm species used. However, striking differences were observed between Ancylostoma braziliense on the one hand and Ancylostoma ceylanicum and Ancylostoma caninum on the other hand with regard to the speed with which the penetration occurred. Larvae of Ancylostoma braziliense may travel directly from the epidermis into the dermis--apart from migration via hair follicle systems--a path of migration we did not observe in infections with the other species used. Larvae of Ancylostoma braziliense seem to pass the skin more rapidly than those of Ancylostoma ceylanicum and Ancylostoma caninum. Many larvae of Ancylostoma ceylanicum managed to penetrate the skin 2--6 h after the onset of the exposure.

Ancylostoma↗
PubMed2000

Hookworm burden reductions in BALB/c mice vaccinated with recombinant Ancylostoma secreted proteins (ASPs) from Ancylostoma duodenale, Ancylostoma caninum and Necator americanus.

Vaccination of mice with alum-precipitated recombinant Ancylostoma secreted protein-1 from the canine hookworm Ancylostoma caninum (Ac-ASP-1) results in protection against A. caninum larval challenge. Vaccine protection is manifested by host reductions in hookworm burden compared to control mice. The goal of this study was to determine whether ASP antigens cloned and expressed from different hookworm species will cross protect against A. caninum larval challenge. Cross-species protection against A. caninum challenge infections was observed with immunizations using recombinant ASP-1 from the human hookworms Ancylostoma duodenale and Necator americanus. However, the degree of protection was proportional to the extent of amino acid sequence homology between the ASP immunogen used for vaccination and the Ac-ASP-1 produced by the challenge larval strain. Vaccine protection was noted to decrease significantly as amino acid sequence homologies diverged 10% or more. It was also determined that Ac-ASP-2, a molecule cloned from A. caninum having 55% amino acid sequence homology to the C-terminus of Ac-ASP-1, did not elicit vaccine protection. These observations were partly reflected in the titer of antibodies that recognize Ac-ASP-1. The studies reported here will help to design immunogenic peptide vaccines based on the sequence divergence of hookworm ASPs.

Ancylostoma↗
PubMed2003

Molecular characterisation of the Ancylostoma-secreted protein family from the adult stage of Ancylostoma caninum.

The Ancylostoma-secreted proteins are a family of nematode-specific cysteine-rich secreted proteins belonging to the pathogenesis-related protein superfamily. Previously we reported that third stage infective larvae of Ancylostoma caninum produce two different Ancylostoma-secreted proteins, a single and double-domain Ancylostoma-secreted protein, designated as Ancylostoma-secreted protein-1 and Ancylostoma-secreted protein-2, respectively. Here we report that adult A. caninum hookworms produce and release four additional Ancylostoma-secreted proteins (Ancylostoma-secreted protein-3-6). Using antiserum against adult excretory/secretory products, Ancylostoma-secreted protein cDNAs were isolated from cDNA expression libraries. Immunolocalisation experiments using specific antisera indicated that the single-domain Ac-Ancylostoma-secreted protein-3 is located in the adult pharyngeal and oesophageal glands. Ac-Ancylostoma-secreted protein-4, Ancylostoma-secreted protein-5 and Ancylostoma-secreted protein-6 are composed of two pathogenesis-related protein domains linked in tandem as a heterodimorphic repeat. Ac-Ancylostoma-secreted protein-4 is localised to the cuticular surface of the adult hookworm, whereas Ac-Ancylostoma-secreted protein-5 was found in the intestinal brush border membrane, and Ancylostoma-secreted protein-6 in the cephalic and excretory glands. All of the adult Ancylostoma-secreted proteins were identified in excretory/secretory products of adult hookworms by Western blotting and are presumably released by the parasite. None of the adult Ancylostoma-secreted proteins were detected by immunoblotting in L3 extracts, although mRNAs of Ac-Ancylostoma-secreted protein-3 and Ac-Ancylostoma-secreted protein-4 were present in the larval stage. The functions of the adult Ancylostoma-secreted proteins are unknown, although the secretion of multiple family members by the adult suggests an important role in the establishment or maintenance of the parasitic relationship.

Ancylostoma↗
PubMed2004

Phosphoinositide-3-OH-kinase inhibitor LY294002 prevents activation of Ancylostoma caninum and Ancylostoma ceylanicum third-stage infective larvae.

The developmentally arrested hookworm infective larva resumes development only after encountering specific host-mediated cues during invasion. These cues activate a signaling pathway that culminates in the resumption of development. In Ancylostoma caninum, activation is characterised by the resumption of feeding and the release of excretory/secretory products required for infection. The dauer stage of the free-living nematode Caenorhabditis elegans is a developmentally arrested stage analogous to the hookworm infective larva. Dauer larvae exit developmental arrest in response to environmental cues that indicate favorable conditions for reproduction and growth. Because of the similarity between dauer recovery and activation, exit from dauer provides a model for hookworm larval activation. An insulin-signaling pathway has been implicated in controlling exit from developmental arrest in both C. elegans dauers and A. caninum larvae. To further investigate the role of insulin signaling in hookworm larval activation, the phosphatidylinositol-3-OH kinase inhibitor LY294002 was tested for its effect on in vitro activation using the resumption of feeding as a marker for activation. LY294002 prevented feeding in A. caninum infective larvae stimulated with host serum filtrate and a glutathione-analogue, the muscarinic agonist arecoline, or the cell permeable cGMP-analogue 8-bromo-cGMP. Similar results were seen with the congeneric hookworm Ancylostoma ceylanicum. These data suggest that an insulin-signaling pathway mediates activation in hookworm larvae, as in C. elegans, and that the phosphatidylinositol-3-OH kinase inhibitor acts downstream of the cGMP and muscarinic signaling steps in the pathway. In A. caninum, LY294002 had no effect on the release of excretory/secretory products associated with activation, suggesting that the secretory pathway diverges from the activation pathway upstream of the phosphatidylinositol-3-OH kinase step. These results provide additional support for the insulin-signaling pathway as the primarily pathway for activation to parasitism in hookworm larvae.

Ancylostoma↗
PubMed2004

Cloning, yeast expression, isolation, and vaccine testing of recombinant Ancylostoma-secreted protein (ASP)-1 and ASP-2 from Ancylostoma ceylanicum.

cDNAs encoding 2 Ancylostoma-secreted proteins (ASPs), Ancylostoma ceylanicum (Ay)-ASP-1 and Ay-ASP-2, were cloned from infective third-stage larvae (L3) of the hookworm A. ceylanicum and were expressed as soluble recombinant fusion proteins secreted by the yeast Pichia pastoris. The recombinant fusion proteins were purified, adjuvant formulated, and injected intramuscularly into hamsters. Hamsters vaccinated either by oral vaccination with irradiated L3 (irL3) or by injections of the adjuvants alone served as positive and negative controls, respectively. Anti-ASP-1 and anti-ASP-2 antibody titers exceeded 1 : 100000. Each vaccinated hamster was challenged orally with 100 L3. Two groups of vaccinated hamsters (i.e., those vaccinated with either irL3 or ASP-2 formulated with Quil A) exhibited significant reductions in adult hookworm burdens, compared with control hamsters. The hookworms recovered from the hamsters vaccinated with ASP-2 plus Quil A were reduced in length. Splenomegaly, which was observed in control hamsters, was not seen in hamsters vaccinated with either irL3 or ASP-2 formulated with Quil A. These results indicate that ASP-2 is a promising molecule for the development of a hookworm vaccine.

Amino Acid Sequence↗
PubMed1996

Vaccination with alum-precipitated recombinant Ancylostoma-secreted protein 1 protects mice against challenge infections with infective hookworm (Ancylostoma caninum) larvae.

Ancylostoma-secreted protein 1 (ASP-1) is the major protein secreted by infective hookworm larvae (Ancylostoma caninum). The Escherichia coli-expressed recombinant protein was evaluated as a vaccine antigen in a mouse model of ancylostomiasis. A. caninum larvae migrate through mouse lungs, with maximal migration occurring 48-54 h after oral infection. Quantitative larval recovery from the lungs at this time was used as an end point for vaccine evaluation. All mice developed antibodies to recombinant ASP-1 (rASP-1) after immunization and boosting with the alum-precipitated protein. The immunized mice had their worm burden reduced 79% (P < .0001) compared with controls. Immunization with rASP-1 in the presence of Corynebacterium parvum adjuvant also showed a vaccine effect (63% protection; P < .0001). The possibility that this protective effect resulted from delayed larval lung entry was excluded. rASP-1 offers promise as a hookworm vaccine antigen.

Adjuvants, Immunologic↗
PubMed2005

Effect of combining the larval antigens Ancylostoma secreted protein 2 (ASP-2) and metalloprotease 1 (MTP-1) in protecting hamsters against hookworm infection and disease caused by Ancylostoma ceylanicum.

Syrian Golden hamsters were vaccinated with the recombinant fusion proteins Ay-ASP-2 and Ay-MTP-1 from the infective larvae of the hookworm Ancylostoma ceylanicum. Vaccines comprised each antigen alone or the combination of the two proteins. All vaccinated group developed high antibody titers (>1:40,000); coadministration of a second antigen did not significantly affect the magnitude of the antibody response. Following challenge, hamsters vaccinated with each single antigen exhibited reductions in worm burden (32% and 28% to Ay-ASP-2 and Ay-MTP-1, respectively) and fecal egg counts (56% and 43%, respectively). A vaccine cocktail, containing both antigens further reduced worm burden (36%) and fecal egg counts (59%) (p<0.001). Moreover, vaccination with the antigen cocktail significantly improved hemoglobin values (p=0.01) and body weights (p=0.001) compared to what achieved with either each antigen or adjuvant alone. Taken together, these data suggest that combination of two or more antigens may present an effective vaccine development strategy to improve protection and/or disease symptoms in affected individuals.

Amino Acid Sequence↗
PubMed1999

Ancylostoma secreted protein 2: cloning and characterization of a second member of a family of nematode secreted proteins from Ancylostoma caninum.

Invading infective third-stage larvae (L3) of parasitic nematodes execute a series of programmed developmental events in response to a host-specific signal encountered during infection. One of these early events is the release of excretory/secretory products. Using an in vitro feeding assay that mimics these early events of infection, a protein released by in vitro activated larvae of the hookworm Ancylostoma caninum was identified. This protein, Ac-ASP-2, was partially sequenced, and the cDNA encoding it isolated by PCR and screening of an A. caninum L3 cDNA library. The Ac-asp-2 cDNA encodes a protein of 219 amino acids that is related to a previously identified protein, Ac-ASP-1, from hookworms. Both molecules are members of an evolutionarily diverse family of molecules that include the venom allergens of the Hymenoptera, and the testes specific proteins/sperm-coating glycoproteins of mammals. Homologues are present in nearly all nematodes tested, as demonstrated by PCR-hybridization and database searching. The Ac-asp-2 mRNA is synthesized in all life history stages, but the gene product is released only by L3 activated to feed in vitro. The wide distribution of the Ac-asp-2 in nematodes and its release in response to host specific signals suggests that Ac-ASP-2 serves an important function in nematode physiology and development, and possibly in the infective process of parasitic species.

Amino Acid Sequence↗
PubMed1992

Efficacy of a chewable formulation of ivermectin against a mixed infection of Ancylostoma braziliense and Ancylostoma tubaeforme in cats.

The efficacy of a beef-based, chewable formulation of ivermectin against a mixed infection of Ancylostoma braziliense and A tubaeforme was determined in cats. Ivermectin administered orally at approximately 24 micrograms/kg of body weight was 92.8% effective against adult A braziliense and 90.7% effective against adult A tubaeforme. The number of eggs per gram of feces had decreased 98.1% by 7 days after treatment. Clinical signs of hookworm disease also decreased after treatment. Location of adult parasites within the small intestine, percentage of infecting larvae that developed to the adult stage, and egg size in cats with infections of A braziliense and A tubaeforme were similar to those reported for cats with separate infections of either species.

Administration, Oral↗