GROUP B STREPTOCOCCAL PEPTIDE MIMETIC VACCINE

Group B streptococcus (GBS) causes invasive infections of newborns, pregnant women and adults with underlying medical conditions, such as diabetes or cancer. Despite antibiotic treatment, estimated case fatality rates of 5-20% in neonates and 15-32% in adults establish the prevention of GBS infections as a public health priority. Peptide immunogens that mimic the structure of GBS capsular polysacharide (CPS) antigens would provide an alternate vaccine strategy, compared to currently tested CPS-conjugates for induction of maternal antibodies to prevent neonatal infection. The long-term goal of the proposed research is to develop a multi-valent peptide mimotope vaccine for prevention of GBS infections caused by the predominant serotypes Ia, Ib, II, III, and V. The proposed work is a direct extension of research identifying peptides that mimic type III CPS. Phase I use anti-CPS antibodies to select phage libraries to identify peptides that bind uniquely to the antibodies; and to determine whether the selected peptides are true mimotopes of the CPS. Phase II innovative vaccine approaches utilizing peptide mimotopes of microbial polysaccharides offer the design and development of T-dependent immune responses and better immunologic memory for prevention of disease.