Fact or hypothesis: Taenia crassiceps as a model for Taenia solium, and the S3Pvac vaccine

Research undertaken over the past 40 years has established many of the general principals concerning immunity to taeniid cestodes. Although much is well understood about the host-protective mechanisms against taeniids and this knowledge has been exploited in studies on vaccine development, many aspects require further investigation or confirmation. Some phenomena have come to be regarded as being well established, while careful analysis of the published data would suggest that they may be better regarded as hypotheses rather than established facts. This review considers one selected issue pertaining to immunity to cestode infections and examines carefully the nature of the evidence that is available to support conclusions that have been made in this area. The issue examined is the use of Taenia crassiceps as a model for cysticercosis in pigs caused by Taenia solium, together with the S3Pvac vaccine, which has been developed based on this model. Strong evidence is found to support the conclusion that defined T. crassiceps antigens can limit intraperitoneal proliferation of the ORF strain of T. crassiceps in mice; however, the potential for these antigens to affect T. solium infection in pigs requires further confirmation.