Immuno-parasitological parameters in schistosomiasis--a perspective view of a vaccine-oriented immunochemist.

It has been almost 10 years since we became involved in research on schistosomiasis. With a background of many years of research on structure-function relationships in protein antigens and a wide experience in the development of peptide-based synthetic vaccines, I was intrigued by the complexity of the immunological aspects of host-parasite relation and the unique capacity of parasites to evade the immune response of their hosts. Being of very ancient lineage, schistosomes, which evolved from blood flukes during the Permian era, had two hundred million years of evolution to their advantage, to perfect their survival strategies. As a result, they are capable of circumventing the immunological machinery of the mammalian host and may consequently survive in it for decades. It seemed to us that an understanding, at least in part, of these processes, was a prerequisite for any attempt to enhance the capacity of the host to mount effective immunity, the long-range goal of such studies being the development of an efficient vaccine. In this review I have attempted to summarize the various approaches pursued in our laboratory towards this goal. This is definitely not a comprehensive review, and I had no intention of covering the vast literature in this field, except for that closely relevant to the discussed topics. This is rather a perspective review summarizing our own findings concerning different aspects of the biological, biochemical and immunological properties of Schistosoma mansoni, and their contribution toward the global effort of the research on schistosomiasis.