Antigenic Profile of Humoral Immune Response Against Pathogens of Interest in Public Health: Screening antigens from Rickettsia rickettsii by Phage Display Libraries

Abstract

Given the growing number of diseases caused by emerging or endemic pathogens in Brazil, like Brazilian spotted fever (BSF) is the most important and frequent rickettsia) disease in Brazil, original strategies are urgently required for pathogen characterization: (1) Better understanding of the immune proteome of pathogens, which has been limited because of a lack of detailed knowledge of the entire antigenic composition of strains circulating in Brazil (2) Identification of new biomarkers for diagnosis and epidemiological surveillance in Brazilian population to assure a rapid response to public health threats. In this context, characterization of immunological markers constitutes a promising area for disease detection, prevention and treatment. Identification and development of these markers require high-throughput screening of combinatorial libraries. Phage-display is a powerful technique for selecting unique molecules with selective affinity for a specific target from highly diverse combinatorial libraries. Phage Display technology will be applied initially in an adequate proteome expression of Ricketsia rickettsii to allow identification of specific antigens after screening with patients' sera from endemic are from Brazil. By high-throughput sequencing of the pool of recombinant phage clones following biopanning and validation by in vitro and in silico analyses, all categorized polypeptides will provide the antigenic profile of Ricketsia rickettsii containing the best candidates ranked. Thus, we hope to optimize the strong screening potential of this technique with complementary rational approaches based in deep sequencing for identification of the best target. By combining such approaches, it should be possible to maximize the selection of molecules with strong potential to improve epidemiological surveillance and diagnosis relevant to Brazilian spotted fever (BSF). This proposal attends the Institute Adolfo Lutz's primarily mission of surveillance, identification and a swift response to health threats, generating expertise and public awareness on major health issues. (AU)