Search PubMed⌕ Search

Biomedical subjects

G V Hillyer

Publications and source records attributed to G V Hillyer.

At least 91 records · Page 5Linked to original sources
PubMed1983

The antigens of Paragonimus westermani, Schistosoma mansoni, and Fasciola hepatica adult worms. Evidence for the presence of cross-reactive antigens and for cross-protection to Schistosoma mansoni infection using antigens of Paragonimus westermani.

The presence of cross-reacting antigens between Paragonimus westermani, Schistosoma mansoni, and Fasciola hepatica adult worms was demonstrated by Ouchterlony immunodiffusion and enzyme-linked immunosorbent assay (ELISA). A serum bank was developed against the three trematode genera to serve as probes to determine the presence of cross-reacting antibodies to P. westermani worm extracts. In this manner, it was possible to demonstrate that antigens common to F. hepatica and S. mansoni tegument were also present in P. westermani worm extracts. Likewise, it was possible to demonstrate that the F. hepatica antigens which bind to Concanavalin A, as well as the subfraction which in isoelectric focusing has a pI of 4.2, were also found in P. westermani worms. Also, a monospecific polyclonal serum to a Fasciola/Schistosoma cross-reacting antigen and the anti-P. westermani serum both reacted in Ouchterlony immunodiffusion with the P. westermani antigenic extract, each producing a line which linked with each other indicating common antigenic determinants and suggesting a common antigen among the digenetic trematodes. Finally, the P. westermani antigenic extracts induced in mice the production of antibodies which reacted with S. mansoni adult worm antigens by ELISA. As all of the Fasciola and Schistosoma sera were prepared against antigenic preparations which induced in mice protection to challenge infection with S. mansoni, this suggested that the P. westermani worms also contain protective antigens against S. mansoni. Immunity to Schistosoma mansoni infection was induced in mice by vaccination with Paragonimus westermani whole worm extracts (PwWWE). Immunized mice showed as high as a 67% worm burden reduction over controls. High doses of PwWWE did not confer protection to S. mansoni infection. Thus, in this study, immunity in heterologous systems was demonstrated and the existence of a common protective antigen shared by the digenetic trematodes was suggested.

Animals↗
PubMed1982

Cross protection in infections due to Schistosoma mansoni using tegument antigens of Fasciola hepatica.

Immunity to infection due to Schistosoma mansoni was induced in CBA/J mice by using a tegument antigen from Fasciola hepatica worms. Multiple immunizations resulted in up to 83% higher worm-burden reductions than did single immunizations. The vaccine also had an adverse effect on the fecundity of female schistosome worms, which resulted in a lower number of eggs per worm pair recovered from the livers of infected mice. Mice immunized once with tegument antigens of F. hepatica survived lethal doses of S. mansoni cercariae for longer periods than did control mice. These results--lowered worm-burden recoveries, lower egg burdens per worm pairs resulting in lesser numbers of granulomatous lesions, and longer survival times--in immunized mice suggest that protection against infection due to S. mansoni is possible using soluble antigens as vaccines.

Animals↗
PubMed1982

Circumoval precipitin antigens for the diagnosis of schistosomiasis. II. Isolation of functional antigens.

A serum was prepared by immunizing rabbits with circumoval precipitin (COP) immune complexes isolated by Protein A Sepharose affinity chromatography. This serum, positive in the COP test, was used to isolate by antibody affinity chromatography the COP antigens contained in crude schistosome egg antigens (SEA). The COP antigens were then applied to the enzyme-linked immunosorbent assay (ELISA) and compared to SEA. In a rabbit immunized repeatedly with the COP immune complexes the reactivity in the ELISA to both SEA and the COP antigens increased with time. In a primary infection of S. mansoni the reactivity to both antigen preparations rose in parallel; however, SEA showed higher reactivity. Interestingly, with the COP antigens a dramatic increase in antibody response was obtained in the serum of the 4th week in two separate groups of infected mice. This is probably a reflection of the common antigens between worms and eggs since two of the three major antibodies to the COP antigens identified previously are absorbable with lyophilized S. mansoni worms.

Animals↗
PubMed1982

Human fascioliasis in Corozal, Puerto Rico.

A limited survey for human infection with F. hepatica was conducted in the mountain region of Corozal, Puerto Rico. This region was selected because bovine fascioliasis was hyperendemic, watercress was grown locally for human consumption, and Lymnaea cubensis snails (an intermediate host for F. hepatica in Puerto Rico) were found in the watercress farms. Of 110 fecal samples examined 12 were positive for F. hepatica. Seven matched serum samples were also positive for F. hepatica antibodies by counterelectrophoresis. Eleven of the 12 infected individuals had a history of eating watercress. This is the first survey to demonstrate a relatively large proportion of asymptomatic. F. hepatica-infected humans in Puerto Rico. Other helminth parasites commonly found in the study population included Trichuris trichiura and hookworm.

Adult↗
PubMed1981

Immunoperoxidase localization by electron microscopy of soluble egg antigen and human IgG in circumoval precipitin reactions around Schistosoma mansoni eggs.

Soluble egg antigen and human IgG were localized by the unlabelled antibody enzyme technique for electron microscopy on Schistosoma mansoni eggs having circumoval precipitin reactions. Reaction products indicating the presence of soluble egg antigen were on portions of the circumoval precipitate outside the egg, between the eggshell and vitelline membrane, and between the vitelline membrane and miracidium inside the egg. Reaction products indicating human IgG were only found on portions of the circumoval precipitate external to the eggshell.

Animals↗
PubMed1980

Isolation of Fasciola hepatica tegument antigens.

Fasciola hepatica tegument antigens were isolated from intact worms in the cold by using Nonidet P-40. Proof of the tegumental nature of the antigens was shown by the peroxidase-antiperoxidase immunocytochemical technique at the light microscope level. The potential of F. hepatica tegument antigens for the immunodiagnosis of rabbit and human fascioliasis was shown by Ouchterlony immunodiffusion, although cross-reactivity was evident in one of six serum samples from patients infected with Schistosoma mansoni. A genus-specific Fasciola antigen was found in F. hepatica tegument. Finally, F. hepatica tegument contained antigens which protected mice from challenge infection with S. mansoni.

Animals↗
PubMed1980

The circumoval precipitin reaction on Schistosoma mansoni eggs as seen by scanning electron microscopy.

The circumoval precipitin reaction on Schistosoma mansoni eggs was examined for the first time by scanning electron microscopy. The precipitates appeared as layered segmenters, and apparent fusion of adjacent precipitates was observed. This suggests that the single precipitates seen by light microscopy may on occasion be a collection of several precipitates exuding from nearby pores. The precipitates appeared on all areas of the egg surface except the spine.

Animals↗