Infants and young children typically do not mount effective immune responses against T cell-independent antigens, such as Haemophilus influenzae type b (HIB) and Neisseria meningitidis. These encapsulated bacteria are responsible for a majority of severe infections in this age group. Although administering antibodies against the HIB capsular polysaccharide passively appeared to offer protection, attempts to immunize infants with pure polysaccharide vaccines proved unsuccessful.
To enhance immunogenicity, polysaccharides can be coupled to protein carrier molecules, leading to the activation of Th cells that recognize the carrier epitopes. One commonly used carrier for polysaccharide vaccines is OMPC derived from N. meningitidis serogroup B. By conjugating polysaccharide antigens to OMPC, a preferred solution to the aforementioned challenges can be achieved.
Fig.1 Schematic representation of the immune response to polysaccharides (A) and glycoconjugates (B). (Stefanetti, et al., 2022)
As a carrier protein, OMPC can be used in the development of HIB and pneumococcal vaccines. Taking the development of OMPC-pneumococcal conjugates as an example, CD BioGlyco provides a series of conjugate development services, mainly including the following steps:
OMPC-pneumococcal conjugates are prepared by chemistry-based polysaccharide conjugate technology or physical crosslinking-based polysaccharide conjugate technology.
Establish animal models that meet the experimental requirements. Experimental animals are divided into groups, and different groups are given different interventions (injection or no injection). For the experimental group, the experimental animals are injected with a certain dose and concentration of the OMPC-pneumococcus vaccine within a specified time. After one or more injections, the immune effect is verified in the laboratory.
Blood is drawn and stored refrigerated until processed in the laboratory (within 16 hours). Afterward, the serum is separated and stored frozen for antibody testing in an analytical laboratory. ELISA method is used to detect the IgG antibody level of S. pneumoniae.
Nasopharyngeal samples are collected using swabs and placed in appropriate culture media for processing (within 4 hours) in the microbiology laboratory. Pharyngeal swabs are immediately spread on trypsin agar medium containing sheep blood and then incubated aerobically. Pneumococci are identified by the presence or absence of hemolysis and optochin inhibition.
Significance analysis is performed according to statistical principles.
Fig.2 Process of OMPC-pneumococcal conjugate vaccine development. (CD BioGlyco)
CD BioGlyco has established a high-quality Glyco™ Vaccine Development Platform for glycobiology research. At CD BioGlyco, we pay attention to every detail in the Development of Carbohydrate-based vaccines and strive for perfection in every process. If you are interested in our services, please contact us for more details without any hesitation.
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