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Extraction, purification and detoxification of Brucella abortus lipopolysaccharide and biological activity evaluation

Abstract number: 1733_1257

Pakzad I., Rezaee A., Rasaee M., Hosseini A., Kasemnejad A., Bahman T., Saied R.

Lipopolysaccharide (LPS) of Brucella abortus is important in brucellosis diagnosis and as one of the components for developing a subunit vaccine against brucellosis. Biological evaluation of B. abortus LPS and it's protection have been considered as the goal of this research. Brucella abortus LPS was extracted by n-butanol, then it was purified by ultracentrifugation and it was detoxified by alkaline treatment. Toxicity of LPS and detoxified LPS (D-LPS) by LAL (Limulus Amoebocyte Lysate) method, and pyrogenicity in Rabbit was compared. Immunological evaluation in animal model was carried out.

Purified LPS from B. abortus by butanol extraction was shown to have <2% (wt/wt) contamination by protein and <1% (wt/wt) contamination by nucleic acids. Pyrogenicity test of B. abortus LPS (10 mg/mL) and E. coli LPS (0.5 mg/mL) was positive, but for D-LPS (10, 50 mg/mL) it was negative. In LAL test, 10 ng/mL of D-LPS was negative, but 0.04 ng/mL of B. abortus LPS was positive and endotoxin unit of B. abortus LPS was less than E. coli LPS. Antibody titer of LPS group was higher than that of D-LPS group. The difference of protection among LPS group, DLPS group comparing with negative control was significant (p≤0.05), In addition, the difference of protection ratio between LPS and D-LPS groups was not significant.

Results show that D-LPS toxicity is severely decreased; we can use several as many as B. abortus LPS for stimulating immune system. Besides, ability of B. abortus LPS is likely much less than the LPS from E. coli to evoke endotoxic shock, and it can be used directly as immunogen. In addition, protection of LPS and D-LPS probably is due to humoral important role in secondary infection of brucellosis.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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