Tailoring a Combination Preerythrocytic Malaria Vaccine

The leading malaria vaccine candidate, RTS,S, based on thePlasmodium falciparumcircumsporozoite protein (CSP), will likely be the first publicly adopted malaria vaccine. However, this and other subunit vaccines, such as virus-vectored thrombospondin-related adhesive protein (TRAP), provide only intermediate to low levels of protection. In this study, thePlasmodium bergheihomologues of antigens CSP and TRAP are combined. TRAP is delivered using adenovirus- and vaccinia virus-based vectors in a prime-boost regime. Initially, CSP is also delivered using these viral vectors; however, a reduction of anti-CSP antibodies is seen when combined with virus-vectored TRAP, and the combination is no more protective than either subunit vaccine alone. Using an adenovirus-CSP prime, protein-CSP boost regime, however, increases anti-CSP antibody titers by an order of magnitude, which is maintained when combined with virus-vectored TRAP. This combination regime using protein CSP provided 100% protection in C57BL/6 mice compared to no protection using virus-vectored TRAP alone and 40% protection using adenovirus-CSP prime and protein-CSP boost alone. This suggests that a combination of CSP and TRAP subunit vaccines could enhance protection against malaria.

A horizontally polarizing liquid trap enhances the tabanid-capturing efficiency of the classic canopy trap

Host-seeking female tabanid flies, that need mammalian blood for the development of their eggs, can be captured by the classic canopy trap with an elevated shiny black sphere as a luring visual target. The design of more efficient tabanid traps is important for stock-breeders to control tabanids, since these blood-sucking insects can cause severe problems for livestock, especially for horse- and cattle-keepers: reduced meat/milk production in cattle farms, horses cannot be ridden, decreased quality of hides due to biting scars. We show here that male and female tabanids can be caught by a novel, weather-proof liquid-filled black tray laid on the ground, because the strongly and horizontally polarized light reflected from the black liquid surface attracts water-seeking polarotactic tabanids. We performed field experiments to reveal the ideal elevation of the liquid trap and to compare the tabanid-capturing efficiency of three different traps: (1) the classic canopy trap, (2) the new polarization liquid trap, and (3) the combination of the two traps. In field tests, we showed that the combined trap captures 2.4–8.2 times more tabanids than the canopy trap alone. The reason for the larger efficiency of the combined trap is that it captures simultaneously the host-seeking female and the water-seeking male and female tabanids. We suggest supplementing the traditional canopy trap with the new liquid trap in order to enhance the tabanid-capturing efficiency.