RT - Journal Article T1 - MOLECULAR CHARACTERIZATION AND OPTIMIZATION OF VI-CAPSULAR POLYSACCHARIDE OF SALMONELLA TYPHI TY6S PRODUCTION IN BIOREACTOR JF - MJIRI YR - 1999 JO - MJIRI VO - 13 IS - 1 UR - http://mjiri.iums.ac.ir/article-1-970-en.html SP - 37 EP - 42 K1 - Salmonella typhi. Vi-CPS K1 - Polysaccharide vaccine. AB - The role of Vi-capsular polysaccharide (Vi-CPS) in human immunity against infection caused by Salmonella typhi is well known. The downstream process of purification generally causes depolymerization of Vi-CPS to a nonimmunogenic low molecular weight form. In the present study, a standard strain of Sal. typhi Ty6s was grown under submerge cultural conditions in a pilot-plant scale of 90 Liter fermentor. At the late exponential growth phase, crude polysaccharide wa obtained from fermentation broth by detergent-phenol extraction method and purified by ultracentrifuge differentiation technique. Analytical data reveals that by optimization of fermentation parameters, not only was the yield of production increased from 1.6 mg/L to 4.9 mg/L, but also the polysaccharide retained its native molecular stability and immunogenicity. Therefore, purified Vi-CPS can be regarded as a reliable immunogen to control typhoid fever in man. LA eng UL http://mjiri.iums.ac.ir/article-1-970-en.html M3 ER -