In the 1970s, scientists found capsules in Haemophilus type B (Hib), meningococci and Streptococcus pneumoniae ,and then made vaccine with capsular polysaccharides. It's been called a landmark moment in the history of human battle against bacterial infection.

In the 1980s, the concept of polysaccharide conjugate vaccine came into being，which is on basis of the theory ，proposed by John Robbins and David Smith in 1929，that combining bacterial capsular polysaccharides (CPSS) with carrier proteins can enhance immunogenicity.Experiments have proved polysaccharide conjugate vaccines can effectively improve infants' immunity. This invention has a far-reaching impact that Polysaccharide conjugate vaccines are still widely used today(Hib polysaccharide conjugate vaccines were launched in US in 1990, meningococcal polysaccharide conjugate vaccines were launched in UK in 1999, and Streptococcus pneumoniae polysaccharide conjugate vaccines were launched in US in 2000).

Moreover,genetically modified escherichia colis through metabolic engineering were used in Bioconjugates by scientists in order to synthesize the mixture of capsular polysaccharide and carrier protein，which greatly reduce the production time and cost of conjugate vaccines and is beneficial to these economically underdeveloped countries.

Great science has brought far-reaching benefits to the human beings. Polysaccharide conjugate vaccines are made by combining polysaccharides with carrier proteins.Now，this technology has been applied into many launched polysaccharide conjugate vaccines,but mainly 3 types of carrier proteins:tetanus toxoid (TT), diphtheria toxoid (DT) and Haemophilus influenzae outer membrane protein.Consino's Group A and Group C Serogroup Neisseria Meningitidis Vaccines (Meningococcal conjugate vaccine) ,approved in Sep 30,2021，take CRM197 (Non-toxic mutant protein of diphtheria toxin , formaldehyde detoxification is not required) as the carrier protein，so that both the safety and effectiveness of the vaccine have been improved.

There are wide variety of polysaccharides for combination.Medical R&D practitioners are welcomed to browse the latest hundreds of sugar combinations on www.accelachem.com.