ABSTRACT
Some of the most significant medical achievements in recent history are the development of distinct and effective vaccines, and the improvement of the efficacy of previously existing ones, which have contributed to the eradication of many dangerous and life-threatening diseases. Immunization depends on the generation of a physiological memory response and protection against infection. It is therefore crucial that antigens are delivered in an efficient manner, to elicit a robust immune response. The recent approval of COVID-19 vaccines containing lipid nanoparticles encapsulating mRNA demonstrates the broad potential of lipid-based delivery systems. In light of this, the present review article summarizes currently synthesized lipid-based nanoparticles such as liposomes, lipid-nano particles, or cell-derived exosomes.
ABSTRACT
A small but significant proportion of COVID-19 patients develop life-threatening cytokine storm. We have developed a new anti-inflammatory drug, EXO-CD24, a combination of an immune checkpoint (CD24) and a delivery platform (exosomes). CD24 inhibits the NF-kB pathway and the production of cytokines/chemokines. EXO-CD24 discriminates damage-from pathogen-associated molecular patterns (DAMPs and PAMPs) therefore does not interfere with viral clearance. EXO-CD24 was produced and purified from CD24-expressing 293-TREx™ cells. Exosomes displaying murine CD24 (mCD24) were also created. EXO-CD24/mCD24 were characterized and examined, for safety and efficacy, in vitro and in vivo. In a phase Ib/IIa study, 35 patients with moderate-high severity COVID-19 were recruited and given escalating doses, 108 -1010 , of EXO-CD24 by inhalation, QD, for 5 days. No adverse events related to the drug were observed up to 443-575 days. EXO-CD24 effectively reduced inflammatory markers and cytokine/chemokine, although randomized studies are required. EXO-CD24 may be a treatment strategy to suppress the hyper-inflammatory response in the lungs of COVID-19 patients and further serve as a therapeutic platform for other pulmonary and systemic diseases characterized by cytokine storm.