Effects of PEG antibodies on in vivo performance of LNP-mRNA vaccines.

Polyethylene glycol (PEG) plays important roles in stabilizing and lengthening circulation time of lipid nanoparticle (LNP) vaccines. Nowadays various levels of PEG antibodies have been detected in human blood, but the impact and mechanism of PEG antibodies on the in vivo performance of LNP vaccines has not been clarified thoroughly. By illustrating the distribution characteristics of PEG antibodies in human, the present study focused on the influence of PEG antibodies on the safety and efficacy of LNP-mRNA vaccine against COVID-19 in animal models. It was found that PEG antibodies led to shortened blood circulation duration, elevated accumulation and mRNA expression in liver and spleen, enhanced expression in macrophage and dendritic cells, while without affecting the production of anti-Spike protein antibodies of COVID-19 LNP vaccine. Noteworthily, PEG antibodies binding on the LNP vaccine increased probability of complement activation in animal as well as in human serum and led to lethal side effect in large dosage via intravenous injection of mice. Our data suggested that PEG antibodies in human was a risky factor of LNP-based vaccines for biosafety concerns but not efficacy.

Metabolic Effects on Body Components After a Three-Month Physical Intervention in Overweight Medical Staff.

Purpose This study analyzes the metabolic effects on body components of short-term standard physical training interventions in the staff of a Chinese hospital. Methods and materials We analyzed annual medical examinations, including blood sampling, ultrasound examinations, etc., and selected 10 overweight voluntary participants to take part in formal physical training, and a body composition analyzer DBA-550 (Donghuayuan Medical Co., Ltd, Beijing, China) was used to analyze body components' change before physical training interventions and the first month and third month after the physical intervention. Results The intervention significantly decreased body mass index (BMI) (p<0.05). Plasma lipids, triglyceride, and waist/hip ratio in females, trunk circumference in males, and limb circumference in females changed significantly (p<0.05). The body composition analysis showed that alterations in lean mass, fat weight, and fat percentage were not significant. Moreover, the segmental skeletal weight stable and segmental edema indices changed significantly but were within the normal range. Conclusions Three months of short-term physical intervention effectively lower body weight and fat, but more significant changes in long-term intervention and larger groups can be expected. Besides, the body composition analyzer proved reliable and can modify more individualized treatment plans for overweight and obese individuals.