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Lipopolysaccharide (LPS) of Brucella abortus is an essential component for developing the subunit vaccine against brucellosis. B. abortus LPS was extracted by n-butanol, purified by ultracentrifugation and detoxified by alkaline treatment. Pyrogenicity and toxicity of B. abortus LPS and detoxified-LPS (D-LPS) were analyzed and compared with LPS of E. coli. Different groups of mice were immunized intraperitoneally with purified B. abortus LPS, D-LPS, a combination of LPS with human serum albumin (LPS-HSA) and B. abortus S19 bacteria; besides, control mice were inoculated with sterile saline. Two doses of vaccine were given 4 weeks apart. Mice were challenged intraperitoneally with virulent B. abortus 544 strain 4 weeks after the second dose of vaccine. Sera and spleens of mice were harvested 4 weeks after challenge. LPS-B. abortus was 10,000-fold less potent in LAL test and 100-fold less potent in eliciting fever in rabbits than in E. coli LPS. And D-LPS was very less potent in LAL test and eliciting fever in rabbits ordinary LPS. The antibody titer of anti-LPS immunoglobulin G (IgG) was higher than D-LPS. However, mice immunized with either LPS, D-LPS or LPS-HSA vaccines showed a significant protection against infection of the spleen (p

Background: Helicobacter pylori is a common cause of chronic infection in human beings. The infection has universal prevalence and contracts all age groups. Probably, these bacteria are the cause of the most common chronic bacterial infection in man and have infected approximately half of the world population. The urease of these bacteria degrades the urea in stomach's mucosa to ammoniac which results pH increment of the stomach lumen. This may allow the pathogenic intestinal protozoa to take the opportunity to cross through stomach's decreased pH situation and cause the disease. Objectives: The current study aimed to evaluate the prevalence of parasitic infections (such as giardiasis) in children with Helicobacter pylori infection in Ilam city. Patients and Methods: Following the sample collection during 12 months from children in Ilam (Ilam, Iran), Helicobacter pylori infection was determined based on stool antigen analysis (HPSA) by enzyme-linked immunosorbent assay (ELISA) method in children who had recurrent abdominal pain. Stool specimens were examined by the direct examination and spontaneous sedimentation method to detect both trophozoite and cyst of parasites. Results: In this study 37 children with H. pylori infection were evaluated, and the patients with positive results for Giardia lamblia, and Entamoebahistolytica/dispar were found 29.7%, and 10.8% respectively. Conclusions: The results of the current study suggest that H. pylori infection may provide favorable conditions for Giardiasis infection, but this presumption needs to be investigated further with more samples.