Helicobacter pylori (Hp) gastric infection is a common and serious infectious disease of humans. Current therapeutic regimens, while successful in 80 percent of the instances of infection, are complicated by expense, duration of treatment, emergence of resistant strains of Hp and lack of patient compliance. An ideal alternative to antimicrobial therapy is prophylactic or therapeutic vaccination for Hp. In this phase I SBIR, we will test the hypothesis that proteolytic digests of Hp incorporated into a novel adjuvant formulation will prevent manifestations of bacterial gastritis and promote gastric bacterial clearance in Hp-infected gnotobiotic piglets, an established animal model of this disease. Piglets will be parenterally immunized with Hp digests prior to and after established gastric infection. Evidence for protection (reduced/absent bacterial cfu, local and systemic immunity, etc) will be sought. Protection will be correlated to patterns of Western blot immunoreactivity of convalescent immune sera and isolated leukocyte in vitro responses to putative bacterial antigen(s). Reactive peptides will be isolated by HPLC, sequenced and identified. From these data, the feasibility of parenteral vaccination for Hp will be determined in this nonrodent model of bacterial gastritis and a phase II SBIR will be prepared if the protection data are positive.
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