Electron beam fragmentation of bacterial polysaccharides as a method of producing oligosaccharides for the preparation of conjugate vaccines

Abstract

End-group mediated conjugation of bacterial polysaccharides (PSs) to carrier proteins containing T-helper cell epitopes renders such polysaccharides immunogenic also in young infants. Optimal construction of such conjugate vaccines requires fragmentation of the PS prior to the coupling reaction. In the present study a general simple and inexpensive method for the fragmentation of PSs is presented. It is based on the irradiation of isolated PSs in an electron beam accelerator. Exposure of isolated pneumococcal capsular polysaccharides (PnPSs) to ionizing radiation resulted in their partial depolymerization in a radiation dose-dependent manner. Radiation, unlike sonication, generated PnPS fragments of molecular size lower than 50 kDa and as small as 1.5 kDa when high radiation doses were used. These PnPS fragments have terminal reducing groups that can be easily used for chemical activation and subsequent coupling to any chosen carrier protein. The radiation-produced PnPS fragments retained their antigenic epitopes, when compared to native, full-size PnPSs as determined by enzyme-linked immunoassay. z

Efficacy of a Conjugate Vaccine Containing Polymannuronic Acid and Flagellin against Experimental Pseudomonas aeruginosa Lung Infection in Mice

“…Polymannuronic acid was depolymerized by using a sonicator (60 sonic dismembrator; Fisher Scientific) as previously described (32). Briefly, PMA was dissolved in deionized water at a concentration of 1 mg/ml and placed on ice.…”

Reduction of the biogenic amine contents in low salt-fermented soybean paste by gamma irradiation

“…Recently, irradiation technology has been applied in new fields beside the sanitation of foods, such as the destruction or reduction of pesticides or anti-nutrients in foods (Lepine, 1991;Villavicencio, Mancini-Filho, Delincee, & Greiner, 2000), production of oligosaccharide for the preparation of conjugate vaccines (Pawlowski & Svenson, 1999), chlorophyll breakdown in oil and other purposes (Aliste, Vieira, & Del Mastro, 2000). Furthermore, besides the sanitary purpose, irradiation technology is applied to reduce carcinogenic nitrosamine and nitrite in model systems and meat products or allergenicity in foods Byun et al, 2000).…”

Reduction of Carcinogenic N‐Nitrosamines and Residual Nitrite in Model System Sausage by Irradiation

“…Recently, irradiation technology has been applied in new fields besides the sanitation of foods, such as destruction or reduction of pesticides or antinutrients in foods (Lepine 1991;Villavicencio and others 2000), production of oligosaccharide for the preparation of conjugate vaccines (Pawlowski and Svenson 1999), chlorophyll breakdown in oil ( Jo and others 2001), and others (Aliste and others 2000;Byun and others 2000). Irradiation was effective in breaking down the volatile N-nitrosamines in an aqueous model system, and the nitrosamine reformation from breakdown products was not observed in in vitro stomach conditions (Ahn and others 2002).…”