Campylobacter jejuni is considered one of the major causes of gastroenteritis worldwide. C. jejuni is the major cause of bovine abortion as well. The development of anti-Campylobacter vaccines based on the capsular polysaccharide of C. jejuni conjugated to carrier protein has proved its effectiveness and efficacy. The current research includes the characterization of the CPS of C. jejuni serotypes HS:1, HS:1/8, and HS:8. The structure was confirmed to have the same backbone as HS:1 previously characterized with the addition of an MeOPN at the Gal-6 position which has not been reported before. HS:8 CPS showed the presence of extra heptoses in different conformations and still needs more extensive investigation. The research introduces the development of prototype vaccines against C. jejuni strain HS:2, and HS1/8. In addition, the research introduces a multi-agent vaccine against S. flexneri serotype 2a which is conjugated to ETEC, and BSA by TEMPO-mediated oxidation.