PLGA from PolySciTech investigated for use as adjuvant in Streptococcus vaccine development

Group A Strep is highly virulent and can be deadly without proper treatment. One means to reduce Strep infections is to apply nanoparticles presenting certain portions of the bacteria’s M-protein marker to elicit an immune response against Strep. Recently, researchers at The University of Queensland and Griffith University (Australia) utilized PolySciTech ( PLGA (PolyVivo AP041) to develop a nanoparticle vaccine against strep. They utilized PLGA as well as poly(lysine) and dextran to make these nanoparticles and found a substantially higher immune response against the PLGA likely due to its negative charge. This research holds promise for the development of an effective vaccine against Strep. Read more:  Marasini, Nirmal, Ashwini Kumar Giddam, Michael R. Batzloff, Michael F. Good, Mariusz Skwarczynski, and Istvan Toth. “Poly-L-lysine-coated nanoparticles are ineffective in inducing mucosal immunity against group a streptococcus.” (2017).

“Abstract Background: Group A Streptococcus (GAS) can cause a range of maladies, from simple throat infections to lethal complication, such as rheumatic heart disease. The M-protein, a bacterial cell surface protein, is the major virulence factor of GAS. Several attempts have been made over the past few decades to develop vaccines against GAS that employed peptides derived from the M-protein. One such approach used lipopeptides or lipid core peptide (LCP) systems that incorporated a B-cell epitope derived from the conserved region of the M-protein. Methods: In the present study, we prepared different biodegradable polymer [dextran, poly-(lactic- coglycolic-acid) (PLGA), and poly-L-lysine] nanoparticles (NPs)-based delivery systems for a lipopeptide vaccine candidate (LCP-1).The NPs were characterized by their size, charge, morphology, antigen-presenting cells (APCs) uptake and subsequent APCs maturations efficacy, followed by in vivo nasal immunization in mice. Results: All produced NPs ranged in size from 100-205 nm, and their charge varied depending upon the nature of polymer. A high APCs uptake efficacy for dextran and poly-L-lysine NPswere observed, compared to PLGA NPs. Despite the high uptake by APCs, dextran and poly-L-lysine NPs failed to improve APCs maturation that resulted in low antibody titres. In contrast, while LCP-1 encapsulated into PLGA showed low APCs uptake, it induced significant maturation of DCs and higher antibody titres compared to other NPs. Conclusions: Positively-charged poly-L-lysine NPs were non-immunogenic, while negatively charged PLGA NPs induced similar responses to antigens adjuvanted with cholera toxin B (CTB). Keywords: Mucosal delivery, lipopeptides, nanoparticles, nasal, vaccine, PLGA, Poly-L-lysine”

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