• COVID-19 Subunit Vaccine: A novel microparticulate microneedle vaccine using spike S1 protein

      Patil, Smital Rajan; Vijayanand, Sharon; Joshi, Devyani; Gomes, Keegan Braz; Menon, Ipshita, J; D'Souza, Martin J. (2021)
      COVID-19 has affected around 118 million people and caused more than 2 million deaths worldwide. Currently, the Food Drug Administration (FDA) authorized vaccines such as Pfizer for COVID-19 require cold chain storage, thus their availability in developing countries is challenging. Microparticles (MPs) are suitable delivery vehicles for vaccine antigens as they are better taken up by antigen-presenting cells, and they eliminate the need for cold chain storage. The spike S1 protein is a suitable antigen candidate due to its ability to produce a robust immune response. For this study, the spike protein was loaded into poly (lactic-co-glycolic acid) (PLGA) MPs and then incorporated into dissolving microneedles, a promising delivery system for large molecules such as proteins. The microparticles were characterized and assessed for innate and adaptive immune response in vitro. The vaccine particles induced a significantly higher nitrite production in mammalian cells compared to control groups. They also exhibited significantly higher expression of antigen-presenting molecules: major histocompatibility complex (MHC) I, CD80, MHC II, and CD40 on the surface of the dendritic cells. This formulated vaccine thus shows high immunogenicity in vitro and has the potential to produce a robust immune response in a murine model, conferring long-lasting protection against coronavirus. This has the potential to be a promising vaccine in the ongoing COVID-19 pandemic the world is facing currently.