Immunogenicity And Structural Properties Of Polysaccharide Conjugated Vaccine Based On Chemical Modification

Streptococcus pneumoniae easily lead to pneumonia,bronchitis,bronchitis and sepsis non-invasive disease,which caused by the elderly,infants,young people and the low incidence of the main cause of the disease,although antibiotics play a role in the clinical treatment.But the patient still has a high risk of mortality.Therefore,there is an urgent need to find a way to prevent the infection of Streptococcus pneumoniae.The subunit vaccine has a new direction for the development of new bacterial vaccines because of its clear chemical composition,good safety and ease of production.It aims to solve the problem of human health through the prevention of disease.The way of immunization subunit vaccine is a large extent to solve this medical problems.By chemically modifying the combined vaccine,polysaccharides（Ps）can be converted from T cell-independent antigens to T cell-dependent antigens,thereby increasing the immunogenicity of the conjugate vaccine,while the adjuvant is chemically coupled with the conjugated vaccine.Under certain conditions to combine,it can significantly improve the immunogenicity of the vaccine,the specific research content is as follows:In this paper,capsular polysaccharides（Ps）were oxidized by sodium periodate and then treated with N-2-aminoethylmaleimide（AM）under the condition of reducing agent sodium cyanoborohydride（NaCNBH₃）.Chemically coupled with a sulfonated carrier protein（TT）via an iminothiohydrochloride（IT）,followed by reaction of hexadecane（HDA）with polyethylene glycol（PEG）in DMF And then combined with Ps-TT conjugates.The binding properties of the samples were separated and purified by Superdex 200 gel purification column.The binding properties of the samples were determined by SDS-PAGE gel electrophoresis,and the samples were separated and purified.The magnetic resonance spectra,Structuralanalysis of color spectra.Animals were tested for 8-week-old female Balb / c mice.The titer of anti-polysaccharide IgG,IgM,IgG1,IgG2 a in the body,including mice,was measured in vivo,and the levels of cytokine proliferation in cell immunization were evaluated,including TNF-α,γ-IFN And IL-5.In the experiment,the humoral immunity and cellular immunity of the conjugate（Ps-TT-PEG-HDA）prepared by HDA as the adjuvant of the pneumonia polysaccharide combination vaccine were significantly improved,and the results were significantly higher than those in the control group（Ps）and carrier protein（TT）can be reduced by the chemical coupling of the carrier protein（TT）to the polysaccharide（Ps）by the chemical method.The effect of the carrier protein（TT）on the polysaccharide（Ps）Polyethylene glycol（PEG）is a hydrophilic polymer that is widely used in pharmaceutical research and development.Studies have found that polyethylene glycol（PEG）can inhibit the carrier protein（TT）immunogenicity,and can improve the immune efficiency of the combined vaccine.At the same time,hexadecane（HDA）is a kind of hydrophobic chain alkane.In this paper,hexadecane（HDA）was successfully synthesized and chemically coupled with polyethylene glycol（PEG）as a bridging bridge.The results showed that PEG as a combination of vaccine adjuvants,which antibody titers and cell proliferation levels were significantly higher than PEG single vaccine adjuvants,and the results showed that HDA as an adjuvant significantly increased the probability of binding to the vaccine in vivo,thereby increasing the binding of the vaccine in vivo Immunogenicity,at the same time in the future development of vaccine there is a huge potential value.