Expression, purification and characterization of a human single-chain Fv antibody fragment fused with the Fc of an IgG1 targeting a rabies antigen in Pichia pastoris.

Because the demand for rabies post exposure prophylaxis (PEP) treatment has increased exponentially in recent years, the limited supply of human and equine rabies immunoglobulin (HRIG and ERIG) has failed to provide an adequate amount of the required passive immune component in PEP in countries where canine rabies is endemic. The replacement of HRIG and ERIG with a potentially cheaper and efficacious alternative biological for the treatment of rabies in humans, therefore, remains a high priority. In this study, we set out to assess a human single-chain Fv antibody fragment fused with the Fc of an IgG1 targeting a rabies antigen to develop a product that can be used as a component of the PEP cocktail. We cloned the ScFv fragment from a human ScFv library that was established previously and inserted this fragment into the expression vector pPICZαC/Fc. An active recombinant ScFv-Fc fusion protein was successfully expressed in Pichia pastoris. The production of ScFv-Fc was optimized and scaled up in an 80L fermentor with yields exceeding 60mg/L. The ScFv-Fc protein was purified to more than 95% purity using a two-step scheme: ammonium sulfate fractionation and Protein A Sepharose CL-4B. The ScFv-Fc fusion protein neutralized rabies virus in a standard in vivo neutralization assay in which the virus was incubated with the ScFv-Fc molecules before intracranial inoculation in mice. Our results suggest that functional antibodies can be produced in P. pastoris and that ScFv-Fc fusion proteins have the potential to serve as therapeutic candidates.

Correlation between PTSD and sleep quality in community-dwelling elderly adults in Hunan province of China.

Background: To understand the occurrence of post-traumatic stress disorder (PTSD) and the current status of sleep quality among community-dwelling elderly adults in Hunan Province of China, to explore the correlation between the two, and to analyze the trend of sleep disorders in PTSD elderly adults. Methods: A simple random sample containing 1,173 community-dwelling elderly adults in Hunan Province was established between March and May 2022, and an on-site face-to-face survey was administered using the PTSD Checklist-Civilian Version (PCL-C) with good reliability and validity, the Pittsburgh Sleep Quality Index (PSQI) scale, and a self-designed general condition questionnaire. Results: The incidence of PTSD in the 1,173 participants was 14.3% (168/1,173). The total incidence of sleep disorders was 40.9% (480/1,173); more specifically, the incidence of sleep disorders in participants with no PTSD symptom, in participants with mild-to-moderate PTSD symptoms, and in participants with severe PTSD symptoms was 36.3, 69.8, and 66.7%, respectively. The Spearman's rank correlation analysis showed that the total PTSD score and the scores of each dimension (i.e., re-experiencing symptom cluster, avoidance symptom cluster and hypervigilance symptom cluster) were positively correlated with the total PSQI score and its dimension scores (i.e., sleep quality, time to fall asleep, sleep duration, sleep efficiency, sleep disturbance, hypnotic medication, and daytime function) (P < 0.05). The correlation coefficients ranged from 0.013 to 0.495. For all PSQI dimensions, the differences across participants with different degrees of PTSD were statistically significant (P < 0.05). Conclusions: The overall status of PTSD and sleep quality in community-dwelling elderly adults in Hunan Province was not optimistic. The elderly with PTSD were more prone to sleep disorders, and the more severe the symptoms of PTSD, the poorer the sleep quality was. However, differences were observed in the scores of each dimension of sleep across participants with different degrees of PTSD. Regardless of the degree of PTSD symptoms, the sleep quality of the elderly is severely affected, and the occurrence rate is not unlimited.

Inhibitory effect of ginsenoside Rg3 on ovarian cancer metastasis.

BACKGROUND: Ginsenosides are main components extracted from ginseng, and ginsenoside Rg3 is one of the most important parts. Ginsenoside Rg3 has been found to inhibit several kinds of tumor growth and metastasis. The present study was undertaken to investigate the effect of ginsenoside Rg3 on human ovarian cancer metastasis and the possible mechanism. METHODS: The experimental lung metastasis models of ovarian cancer SKOV-3 and the assay of tumor-induced angiogenesis were used to observe the inhibitory effects of Rg3 on tumor metastasis and angiogenesis. The effect of Rg3 on invasive ability of SKOV-3 cells in vitro was detected by Boyden chamber, and immunofluorescence staining was used to recognize the expression of matrix metalloproteinase 9 (MMP-9) in SKOV-3 cells. RESULTS: In the experimental lung metastasis models of ovarian cancer, the number of tumor colonies in the lung and vessels oriented toward the tumor mass in each ginsenoside Rg3 group, was lower than that of control group. The invasive ability and MMP-9 expression of SKOV-3 cells decreased significantly after treatment with ginsenoside Rg3. CONCLUSIONS: Ginsenoside Rg3 can significantly inhibit the metastasis of ovarian cancer. The inhibitory effect is partially due to inhibition of tumor-induced angiogenesis and decrease of invasive ability and MMP-9 expression of SKOV-3 cells.