Sunday, June 29, 2008

My picks from PLoS ONE: Malaria and tularemia – diagnostic markers and vaccine candidates

PLoS ONE published 54 new articles last week. I had a chance to thoroughly read two of them also because they were edited by me and that they have some real potential towards the development of diagnostics and vaccines for infection control.

The paper - Novel Peptide Marker Corresponding to Salivary Protein gSG6 Potentially Identifies Exposure to Anopheles Bites from Anne Poinsingnon’s group is highly relevant in the context of devising vector control strategies in malaria endemic regions. This study combined a bio-informatics approach with standard immunoepidemiological assays to identify an Anopheles specific salivary peptide that could be developed as a marker of exposure to Anopheles bites. Such an epidemiological tool would have direct application in identifying high risk areas for malaria transmission and areas where vector control strategies should be implemented. I really think that this work is of interest not only for those who work in malaria control and in the evaluation of vector control strategies but also in the field of the immune response to arthopod salivary components. If this approach proved to be succesful, it could be applied to the control of other vector-borne diseases.

Another study - A Francisella tularensis Schu S4 Purine Auxotroph Is Highly Attenuated in Mice but Offers Limited Protection against Homologous Intranasal Challenge from the group of Thomas Zahrt was another interesting article to recommend. It describes the use of type A and LVS-derived purine auxotroph mutants of Francisella as potential candidates for live attenuated vaccines against tularemia. The intranasal challenge approach taken by the investigators is new and is more representative of a real exposure than other studies, and was judged a major strength of the study. However, there are certain shortcomings of this study that would invite future research efforts by this and other groups working in the field of tularemia prophylaxis - the type A-derived mutant offered a little bit of protection of challenged animals in terms of lethality but the vaccinated animals still exhibited bacterial survival in the lungs, and many of them succumbed to infection. Nonetheless, the results clearly inform us that the development of next generation live attenuated vaccine for Francisella should be based on the use of less aggressive B type strains rather than the more reactogenic type A.