Journal of Vaccines & Vaccination

Lipid core peptide nanoparticles as effective delivery system to trigger humoral immune responses against Group A streptococcus (GAS)

5^th Asia Pacific Global Summit and Expo on Vaccines & Vaccination

July 27-29, 2015 Brisbane, Australia

Saranya Chandrudu

Posters-Accepted Abstracts: J Vaccines Vaccin

Abstract:

Group A streptococcus (GAS) infections result in a number of human diseases, including pharyngitis, rheumatic fever and rheumatic heart disease. There is no vaccine available on the market to prevent GAS. We designed and synthesized a self-adjuvanting lipopeptide (LP) GAS vaccine constructs. Each lipopeptide was composed of GAS B-cell epitopes (J14, 88-30 or their combination), an universal CD4+ T-cell helper epitope (P25) and an immunostimulant lipid moiety. The lipopeptides were synthesized using Bocsolid phase peptide synthesis (SPPS) and formulated into nanoparticles. The immunogenicity of the nanoparticles was tested in mice and antibody titres were analyzed using ELISA. Systemic IgG antibody response was elicited in outbred Swiss mice after intranasal immunization. 88/30 specific IgG response was higher in the construct containing both 88/30 and J14 epitope (LP-88/30-J14) than LP containing only 88/30 epitope (LP-88/30). All the compounds (and their formulation) were characterized with the help of dynamic light scattering (DLS), circular dichroism (CD) and transmission electron microscopy (TEM). LP-88/30-J14 formed nanoparticles of smaller size (9 nm) than LP-88/30 (50-100 nm) while LP-J14 particle size was 5 nm. The immune responses against vaccine candidates were size dependent, with the smaller particles eliciting higher antibody titers. Thus, this study showed that the choice of epitopes influenced both the particle size and the immune response against LPs.