Phosphatidylserine-mediated oral tolerance.

Phosphatidylserine (PS) is an anionic phospholipid exposed on the surface of apoptotic cells. The exposure of PS typically recruits and signals phagocytes to engulf and silently clear these dying cells to maintain tolerance via immunological ignorance. However, recent and emerging evidence has demonstrated that PS converts an "immunogen" into a "tolerogen", and PS exposure on the surface of cells or vesicles actively promotes a tolerogenic environment.

Biophysical Characterization of Tolerogenic Lipid-Based Nanoparticles Containing Phosphatidylcholine and Lysophosphatidylserine.

Autoimmune conditions, allergies, and immunogenicity against therapeutic proteins are initiated by the unwanted immune response against self and non-self proteins. The development of tolerance induction approaches can offer an effective treatment modality for these clinical conditions. We recently showed that oral administration of lipidic nanoparticles containing phosphatidylcholine (PC) and lysophosphatidylserine (Lyso-PS) converted an immunogen to a tolerogen and induced immunological tolerance towards several antigens.

Pharmaceutical Aspects and Clinical Evaluation of COVID-19 Vaccines.

COVID-19, the disease caused by the novel severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2), was first detected in December 2019 and has since morphed into a global pandemic claiming over 2.4 million human lives and severely impacting global economy. The race for a safe and efficacious vaccine was thus initiated with government agencies as well as major pharmaceutical companies as frontrunners.