In this renewal application we propose to continue our multidisciplinary approach to the study of Bacillus anthracis infections in humans. We view B. anthracis as one of the most significant threats to our society as a bioterrorist agent, distinct from its use as a biological weapon. B. anthracis is alarming as a weapon of terror for several reasons: 1) the spore is long-lived and stable in harsh environments;2) the vaccine is poor, of questionable efficacy, has a cumbersome injection schedule, and is not provided to civilians;3) there are no effective treatments for the disease;4) a small number of deaths from a rare and thus exotic disease is sufficient to cause terror in our population. Indeed, this is exactly what happened after the US Postal Service Center attacks in 2001. Our application builds on a previously funded U19 to study the human and non-human primate response to B. anthracis infections and immunizations. During the first grant period, we built an organization with remarkable physical and intellectual assets and a superb infrastructure. The group we assembled is productive, highly interactive and has a formidable background in immunology. Our group includes faculty, fellows, technicians, veterinary staff and other support staff at four different institutions: The Oklahoma Medical Research Foundation, The University of Oklahoma, and now The University of Chicago, and Boston University. The application contains five Scientific Projects, three Technical Projects and two Core Facilities (along with Administrative and Educational cores). We attack the problem from every direction: powerful experimental models largely developed in house, a novel approach to vaccine genetics and vaccine efficacy, several host-response issues, studies of the exotoxins, and two novel and exciting therapeutic approaches. Overall, we are confident that the four years of funding puts us in a competitive position to exploit the findings of our first cycle to make substantive advances in the next five years. RELEVANCE (See instructions): B. anthracis is highly relevant and important agent of bioterrorism. Although a vaccine is provided to military personnel, it is not given to private citizens and is of highly questionable efficacy. There is very little understood of B. anthracis infections in humans, largely because anthrax is only a weapon of terror and natural human infections occur rarely. PROJECT 1: Edema Toxin Suppression of Immune Responses During Anthrax Disease (Ballard, J) PROJECT 1 DESCRIPTION (provided by applicant): Anthrax disease progresses from initial infection to serious systemic illness due to the ability of Bacillus anthracis to avoid clearance by the host immune system. Anthrax toxin, composed of protective antigen (PA), edema factor (EF), and lethal factor (LF), is a major contributing factor to disease as the toxin suppresses immune cell function. Thus, insights into the mechanism of action for anthrax toxin provides critical information necessary for understanding the pathogenesis of B. anthracis. In the current project experiments are designed to elucidate the effects of edema toxin (ET: PA plus EF) on innate immune responses, and determine how ET combines with lethal toxin (LT: PA plus LF) to accomplish this process. After translocation into the cell by PA, EF functions as an adenylate cyclase and generates high levels of cAMP. In recent studies we have discovered that ET activates glycogen synthase kinase-3|3 (GSK- 3(3) leading to inactivation p-catenin and loss in (3-catenin cotranscriptional regulation. The goal of these studies are now to elucidate the impact ET-mediated disruption immune cell function and the effects of this process on human alveolar macrophages and peripheral blood mononuclear cells, as well as determine the combined effects of ET and LT on these cells. The specific aims of this project are: Specific Aim 1: We will characterize the ET-induced changes in inflammatory responses and intracellular signaling that account for critical immunosuppression during early stages of inhalational anthrax Specific Aim 2: We will characterize the ET-induced changes in inflammatory responses and intracel signaling that account for critical immunosuppression during late stages of inhalational anthrax Specific Aim 3: We will characterize the combined effects of ET and LT on immunosuppression during both early and late stages of anthrax disease. RELEVANCE (See instructions): Anthrax is a major threat to the health of US population, because of the potential nefarious use of B. anthracis by bioterrorist. Anthrax has a high mortality rate, despite various treatment options. Thus it continues to be essential to understand the basic mechanisms of B. anthracis virulence. For this reason the proposed studies are highly relevant as findings from this work will help better understand immune suppression during disease and identify new avenues for prophylactic and therapeutic treatments.