AS03 adjuvant enhances the magnitude, persistence, and clonal breadth of memory B cell responses to a plant-based COVID-19 vaccine in humans.

Vaccine adjuvants increase the breadth of serum antibody responses, but whether this is due to the generation of antigen-specific B cell clones with distinct specificities or the maturation of memory B cell clones that produce broadly cross-reactive antibodies is unknown. Here, we longitudinally analyzed immune responses in healthy adults after two-dose vaccination with either a virus-like particle COVID-19 vaccine (CoVLP), CoVLP adjuvanted with AS03 (CoVLP+AS03), or a messenger RNA vaccination (mRNA-1273). CoVLP+AS03 enhanced the magnitude and durability of circulating antibodies and antigen-specific CD4+ T cell and memory B cell responses. Antigen-specific CD4+ T cells in the CoVLP+AS03 group at day 42 correlated with antigen-specific memory B cells at 6 months. CoVLP+AS03 induced memory B cell responses, which accumulated somatic hypermutations over 6 months, resulting in enhanced neutralization breadth of monoclonal antibodies. Furthermore, the fraction of broadly neutralizing antibodies encoded by memory B cells increased between day 42 and 6 months. These results indicate that AS03 enhances the antigenic breadth of B cell memory at the clonal level and induces progressive maturation of the B cell response.

Intralipid Vehicle Does Not Interfere with the Efficacy of Progesterone in Attenuating Edema following Traumatic Brain Injury.

The recent disappointing results of phase III trials for progesterone (PROG) in traumatic brain injury (TBI) have triggered speculation about reasons for the negative outcomes. One confounding factor may have been the vehicle used to administer PROG. Virtually all of the many pre-clinical experiments informing the clinical trials and reporting beneficial PROG effects used more soluble 2-hydroxypropyl-b-cyclodextrin as a vehicle given intraperitoneally or subcutaneously rather than a lipid formulation given intravenously (IV). The present investigation compared the effect of PROG infusion with that of lipid emulsion (Intralipid®) as a carrier/vehicle on edema following TBI in rats. Eight-mg/kg doses of PROG with 20% Intralipid were given IV via central venous catheter beginning 1 h post-injury over a 1 h duration (1.2 mL/h). Animals were killed and brains removed at 24 h post-injury. All the brain-injured groups showed more edema compared with the control group. However, PROG+Intralipid significantly attenuated cerebral swelling compared with Intralipid alone. No difference was observed between the TBI-alone and Intralipid groups. Although this study used much a smaller volume and shorter duration of Intralipid infusion than the clinical trials (up to 5 days of continuous infusion), our results suggest that the use of Intralipid in rats did not prevent or mask the beneficial effect of PROG.

Evaluating the neurotherapeutic potential of a water-soluble progesterone analog after traumatic brain injury in rats.

The poor aqueous solubility of progesterone (PROG) limits its potential use as a therapeutic agent. We designed and tested EIDD-1723, a novel water-soluble analog of PROG with >100-fold higher solubility than that of native PROG, as candidate for development as a field-ready treatment for traumatic brain injury (TBI). The pharmacokinetic effects of EIDD-1723 on morphological and functional outcomes in rats with bilateral cortical impact injury were evaluated. Following TBI, 10-mg/kg doses of EIDD-1723 or PROG were given intramuscularly (i.m.) at 1, 6 and 24 h post-injury, then daily for the next 6 days, with tapering of the last 2 treatments. Rats were tested pre-injury to establish baseline performance on grip strength and sensory neglect, and then retested at 4, 9 and 21 days post-TBI. Spatial learning was evaluated from days 11-17 post-TBI. At 22 days post-injury, rats were perfused and brains extracted and processed for lesion size. For the edema assay the animals were killed and brains removed at 24 h post-injury. EIDD-1723 significantly reduced cerebral edema and improved recovery from motor, sensory and spatial learning deficits as well as, or better than, native PROG. Pharmacokinetic investigation after a single i.m. injection in rats revealed that EIDD-1723 was rapidly converted to the active metabolite EIDD-036, demonstrating first-order elimination kinetics and ability to cross the blood-brain barrier. Our results suggest that EIDD-1723 represents a substantial advantage over current PROG formulations because it overcomes storage, formulation and delivery limitations of PROG and can thereby reduce the time between injury and treatment.