Vaccinomics: understanding tick-host-pathogen interactions for vaccine development

Resumen del trabajo presentado al Workshop on Ticks and Tick-borne Diseases celebrado en Berlin (Alemania) del 30 de septiembre al dos de octubre de 2014.Ticks and the pathogens that they transmit have co-evolved, resulting in a complex relationship complementary to both the tick host and pathogen. The infection and transmission cycle of tickborne pathogens is perfectly coordinated with the tick feeding cycle, and ticks can harbor high pathogen levels without impacting their biology. Tick-borne diseases continue to emerge and/or spread to new areas of the world posing increasing threat to human and animal health. The limitations of acaricide control have been realized, most notably by the selection of acaricide resistant ticks. New approaches for tick control are dependent on defining molecular interactions between hosts, ticks and pathogens to allow for discovery of key molecules that could be tested in vaccines for intervention of tick-pathogen cycles. Tick vaccines offer the important advantages of being a cost-effective and environmentally friendly alternative with a dual effect reducing tick infestations and preventing ticks from transmitting disease-causing pathogens. Tick antigens studied thus far have demonstrated multiple impacts when used in a vaccine including reductions in (a) tick infestations and fertility, (b) tick pathogen infection, (c) tick vector capacity for pathogen transmission and (d) tick response to pathogen infection. However, commercialization of tick vaccines has not advanced since the first BM86-based vaccines were registered in the early 1990s. The challenge of developing improved tick vaccines arises from the need to understand the complex molecular relationship between vertebrate hosts, ticks and pathogens which requires a systems biology approach that will allow for discovery of key molecules that mediate tick and pathogen success. A vaccinomics approach could then be used to identify and fully characterize candidate protective antigens and validate vaccine formulations, including development of effective screening platforms and algorithms for analysis and validation of data produced by the systems biology approach to tick research. New candidate protective antigens will most likely be identified by focusing on abundant proteins with relevant biological function in tick feeding, reproduction, development, immune response, subversion of host immunity and pathogen transmission. Tick vaccines that affect both tick infestations and pathogen transmission could then be developed and used to vaccinate human and animal populations at risk for disease prevention and also reservoir host species in order to reduce tick infections and their vector capacity for pathogens that affect human and animal health worldwide.Peer Reviewe