Excretory-secretory antigens from adult Nematospiroides dubius

Adult Nematospiroides dubius excretory-secretory (ES) products were collected from worms cultured in vitro, radiolabelled and separated by sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE). The components were characterized and assessed for molecular weight (MW) after autoradiography and gel staining, for antigenicity in immunoblots, for sensitivity to protease enzymes, and for carbohydrate contents. ES contained at least 18 denatured components from MW < 20000 to 200000. At least one of the surface proteins of adults was found with the ES antigens recovered when adults were cultured in vitro. Molecules with MW 200000, 78000 and 60000 were glycoproteins and reacted with immune mouse serum in Western blots. The dominant ES=, MW 60000 component stained with periodic acid-Schiff (PAS), bound lectins with affinity for D-mannose, and was resistant to peptic and tryptic but not V8 protease digestion

Regulation of toxocariasis in mice selectively reared for high and low immune responses to Nematospiroides dubius

Test mice have been selectively reared for high (H) or low (L) immune responses to Nematospiroides dubius. After secondary infection with N. dubius, the L mice voided ten times as many eggs in their faeces as the H mice, and at necropsy, 71% versus 20% of the inoculum of N. dubius were recovered as adult worms from the L and H mice respectively. Furthermore, N. dubius were more fecund in the L than in H mice. High or low immune responsiveness was not restricted to N. dubius infection in these mice but was also observed during Toxocara canis infection. The migration of T. canis larvae from gut via the liver to skeletal muscle and CNS was inhibited in H versus L mice. Many more larvae were recovered from the livers of H compared with L mice which was indicative of greater immunity in the H mice. The protective immune response in H compared with L mice to both N. dubius and T. canis included pronounced cosinophilia and elevated antiparasitc antibody titres

Stage-specific antigens of Nematospiroides dubius Baylis, 1926 (Nematoda: Heligmosomides).

Antigens were identified from Nematospiroides dubius recovered from outbred Quackenbush mice between 4 and 10 days postinoculation (PI). Parasite surface proteins were radioiodinated and extracts of the whole worms were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and reacted with normal and immune mouse sera followed by an avidin-biotin-peroxidase assay. Antigens ranged between 250,000 and 20,000 molecular weight (MW). A major surface antigen, 60,000 MW, which appeared to be a complex of different antigens, and a 250,000-MW internal antigen were found on fourth-stage (L4) and fifth-stage (L5) larvae 5-10 days PI but not earlier. A group of minor surface antigens (24,000-30,000 MW) were also expressed as larvae molted from L4 to L5, 6 and 7 days PI, but they differed from antigens of similar MW expressed by adult worms. An antigen, 45,000 MW, was detected in worms 5-10 days PI, but it was only expressed on the surface of L5 worms 9 and 10 days PI. We suggest that the antigen(s) common to adults and larvae may account for protective immunity

Babesia bovis: Biosynthesis and localisation of the 12D3 antigen in bovine erythrocytes

The 12D3 antigen of Babesia bovis was found to be synthesised rapidly in cultured parasites, and localised to both the apical complex of the merozoite and the cytoplasm of the parasitised erythrocyte. Amino-terminal sequencing suggested that the nascent protein had been processed and differences between the predicted and measured molecular weights suggested post-translational modification. The major proportion of 12D3 appeared in the soluble compartment of the parasitised erythrocytes with a molecular weight consistent with no further processing. A significant proportion of the protein required extraction by sodium carbonate, suggesting association with membranous components. The timing of release of soluble 12D3 was coincident with haemoglobin release and this probably reflects a non-specific lysis of the erythrocyte. Synthesis of recombinant BV12D3 was achieved in baculovirus-infected SF9 insect epithelial cells. The product was of the same molecular weight as the native 12D3 and polyclonal antibodies raised against the recombinant protein reacted with both the recombinant and native forms of the antigen

Entrepreneurship in the Cook Islands

For more about the East-West Center, see http://www.eastwestcenter.org/</a

Amelioration of virulent Babesia bovis infection in calves by administration of the nitric oxide synthase inhibitor aminoguanidine

Calves undergoing initial infection with a virulent strain of the haemoprotozoan parasite Babesia bovis were treated with aminoguanidine (AG), an inhibitor of the inducible form of nitric oxide synthase (iNOS). The mean maximum parasitaemia of the AG treated calves was significantly lower than that of the control cattle. In addition, the febrile response and decrease in packed cell volume (PCV) observed during acute infection were significantly ameliorated in the AG treated cattle relative to the controls. However, AG had no effect on the multiplication of B. bovis in the microaerophilous stationary-phase (MASP) in-vitro culture system. These results provide evidence of a role for nitric oxide (NO) produced in response to acute infection in the pathology of bovine babesiosis