Vaccine development remains an elusive and coveted breakthrough. Several strategies have been tried over the past 40 years, addressing all stages selleck chemical of the life cycle in both whole-organism and recombinant subunit models. The use of radiation-attenuated sporozoites 21 is the only model that has consistently generated reproducible sterilizing immunity in humans and describing it as the “gold standard” of malaria vaccines has become an oft-repeated and
tired but nonetheless accurate phrase in the literature. In this model, sporozoites are subjected to gamma-radiation to cause random genetic mutations, and when injected into mouse and man, accumulate in the host liver, causing resistance to subsequent infections with wild-type parasites; however, despite the similar outcomes of genetically-modified parasite lines, it is debatable whether such whole-organism vaccines can be conceivably manufactured en masse to the market or pass the rigors of safety regulators. Nonethless, people are trying, and Sanaria Inc’s endeavours are ongoing to produce sterile, purified
and cryopreserved radiation-attenuated sporozoites; however, doubts as to the viability of the whole-organism model have paved the way for recombinant subunit vaccines based on immunodominant malarial antigens. One example of this, RTS, S/AS02A, the vaccine based BMS-777607 nmr on the Plasmodium falciparum circumsporozoite protein, developed by GlaxoSmithKline, has elicited
efficacies ranging from 40 to 60% in Phase III clinical trials and, this is, by all accounts, the best we have so far. Thus in immunology the connection between Plasmodium as a science and malaria as a disease is most apparent, and in the field of vaccinology the link between malaria disease and its impact on the human condition are clearest of all. But can we as basic researchers reconcile the yearly million-fold deaths to the exciting data from our FACS stains and ELISPOTs that will surely ensure that the next paper O-methylated flavonoid is accepted by a high-ranking journal? Perhaps some can, some cannot, and for others it does not even matter. All I know is that these two worlds collided quite symbolically for me last December outside the lab, in the form of that unfortunate gentleman in the corridor. The explanation for his condition was that he was presenting himself to the Tropical Medicine clinic of the University Hospital, with whom the research staff share lab and corridor space. Having just returned from a business trip to the Sudan, he was feeling under the weather, feverish, weak and not himself, and decided the best option would be to return to the clinic that had originally given him advice before his travels. Some 15 minutes later, this man was being maneuvered onto a stretcher and treated immediately with intravenous administration of artesunate. We learned later that he had P. falciparum infection with a blood parasitemia of 16%.