Covalent conjugate vaccines

Haemophilus influenzae type b (Hib) vaccines currently in use are conjugate products, consisting of either a polysaccharide or oligosaccharide of polyribosylribitol phosphate (PRP) covalently linked to a protein carrier. Hib conjugate vaccines are indicated for routine use in aU infants and children less than 5 years of age. 

Bioconjugates play an important role in several fields of biomolecular and biomedicinal sciences. Protein/polypeptide-based conjugates with covalently attached epitope peptides are considered as potential synthetic vaccine candidates and/or target antigens in affinity-based bioassays (e.g., ELISA, BIACORE) (1,2). Drugs such as daunomycin, methotrexate, and a GnRH analog coupled either to monoclonal antibodies or to synthetic linear or branched polypeptides... 

We examined HPMA copolymer-peptide conjugates as potential oral vaccines (138). A human rhinovirus peptide VP2 (VKAETRLNPDLQPTETSQDVANAIVC) was covalently linked to an HPMA-Gly-Gly-ONp polymeric precursor. Conjugation improved peptide stability during incubation with brush border membrane and luminal peptidases transport but studies on GI transport and oral immunization failed to show conjugate advantage. 

Conjugated Hib vaccine (Hib capsular antigen polyribosylphosphate covalently linked to the non-toxic diphtheria toxin variant CRM197) HBV Hepatitis B virus Hib Haemophilus influenzae type b HPV Human papilloma virus... 

The over-expression of MUCl, a human tumor-associated epithelial mucin, is correlated with the progression of breast, ovarian, and colon cancer. Based on these observations and the promising biological properties of the unimolecular pentavalent vaccine, Danishefslty s group prepared a hybrid vaccine construct containing a unimolecular pentavalent glycopeptide domain covalently linked to the MUCl peptide (Fig. 2). ° The preparation of the KLH conjugate of this construct is currently underway. 

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