Parasitologic, Pathologic and Serologic Reactions to Schistosoma Mansoni in Monkeys Exposed to Irradiated Cercariae

Sadun, E. H.; Bruce, J. I.; Macomber, Peter B.

doi:10.4269/ajtmh.1964.13.548

Cited by 27 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the case of schistosomes, doses of 3-4 krad of X-or c-radiation were shown to prevent developing schistosome worms surviving to the adult pathogenic egg-laying stage while doses of 1-3 krad resulted in persistence of a small proportion of stunted and generally sterile adults (Smithers, 1962). There followed various protection studies against S. mansoni and S. japonicum in mice and repeatedly exposed rhesus monkeys using cercariae exposed to relatively low levels of radiation (Hsu et al 1962 ;Radke and Sadun, 1963 ;Sadun et al 1964 ;Smithers, 1962 ;Villella et al 1961) and most studies reported higher levels of partial protection to challenge with very low doses of radiation which allowed a small proportion of stunted worms to survive. These studies were carried out at a time when the prevailing notion, based on studies in rhesus monkeys harbouring unattenuated S. mansoni infections Terry, 1965, 1967), was that the adult worm is the prime stimulus to protection and that the schistosomula stages contribute little to the development of resistance.…”

Section: R R a D I A T E D V A C C I N E S -E S T A B L I S H M E Nmentioning

confidence: 99%

Radiation-attenuated schistosome vaccination – a brief historical perspective

Bickle

2009

Parasitology

View full text Add to dashboard Cite

The high level of protection which can be induced by vaccination of a range of hosts, from rodents to primates, with live radiation-attenuated schistosome larvae offers great promise for development of a human schistosome vaccine. Studies of the irradiated vaccine models benefitted from significant funding during the 1970-90s and much was learned concerning the inducers, targets and mechanisms of immunity. Less progress was made in definition of the protective antigens involved. The application of new techniques for identifying membrane and secreted antigens has recently provided new vaccine candidates and a new impetus for schistosome vaccine development. This article is intended as an overview of some of the main lessons learned from the studies of the irradiated vaccines as a backdrop to renewed interest in schistosome vaccine development.

show abstract

Section: R R a D I A T E D V A C C I N E S -E S T A B L I S H M E Nmentioning

confidence: 99%

Radiation-attenuated schistosome vaccination – a brief historical perspective

Bickle

2009

Parasitology

View full text Add to dashboard Cite

show abstract

“…Over the next two years the fundamental characteristics of this protection were established, including such things as its species and stage-specificity [40], the humoral component of its action [41-42] and the effects of radiation on sporozoites [43]. Parenthetically, I had obtained the original idea for sporozoite attenuation by X-irradiation from similar studies that were then being done on immunization against schistosomiasis with X-irradiated cercariae [44-45] by Elvio Sadun at the Walter Reed Army Institute of Research. It was only later that earlier studies on attenuation of avian malaria sporozoites by in vitro maintenance [46], or by drying or UV treatment of the sporozoites [rev in 47] came to our attention.…”

Section: Initiation Of Immunization Studies With Rodent Malariamentioning

confidence: 99%

Reflections on early malaria vaccine studies, the first successful human malaria vaccination, and beyond

Vanderberg

2009

Vaccine

View full text Add to dashboard Cite

Advances towards protective vaccines against malaria were made feasible by the development of a rodent model of mammalian malaria that allowed production of all stages of the malaria parasite for study. Investigations with sporozoites (the stage transmitted by mosquitoes in their saliva) demonstrated that immunization with radiation-attenuated sporozoites could produce a solid, sterile immunity, first shown in studies with mice and later with human volunteers. Protective immune mechanisms involve anti-sporozoite antibodies that immobilize sporozoites injected into the skin by mosquitoes, followed by CD4+ and CD8+ T-cells acting against liver stage parasites produced by sporozoites that have escaped antibody-based immunity and invaded hepatocytes. Two alternative approaches now being used in human trials are immunization with intact, attenuated sporozoites vs. immunization with "sub-unit" vaccines based on immunogenic components of sporozoites or liver stage parasites. In addition to immunization against these pre-erythrocytic stages, encouraging progress is being made on immunization against blood stage parasites and on immunization for production of transmission-blocking antibodies. There is reason to be optimistic that one or more of the approaches will work on a large scale, and that a multi-stage vaccine may be able to combine several of these approaches in a sequential immunological assault against the malaria parasite as it progresses through its stages.

show abstract

“…The relatively small number of normal cercariae required to induce a significant level of immunity when compared with the results involving irradiated cercariae is of interest. In the case of irradiated cercariae, Sadun et al (1964) have reported that even 25,000 cercariae irradiated at 400 rep (rad equivalent, physical) and given as a single exposure does not induce protective immunity. Since it is known that the irradiation of cercariae at this level does not prevent their invasion and migration to the liver, but does prevent their development to fully mature adults, it may be inferred that effective immunity requires contact with living adult worms.…”

Section: Blood Helminthsmentioning

confidence: 99%

Immunity to Parasites

Cheng

1986

General Parasitology

View full text Add to dashboard Cite

Parasitologic, Pathologic and Serologic Reactions to Schistosoma Mansoni in Monkeys Exposed to Irradiated Cercariae

Cited by 27 publications

References 0 publications

Radiation-attenuated schistosome vaccination – a brief historical perspective

Radiation-attenuated schistosome vaccination – a brief historical perspective

Reflections on early malaria vaccine studies, the first successful human malaria vaccination, and beyond

Immunity to Parasites

Contact Info

Product

Resources

About