Development of an ostrich-derived single-chain variable fragment (scFv) against PTPRN extracellular domain.

In type 1 diabetes, the immune system destroys pancreatic beta cells in an autoimmune condition. To overcome this disease, a specific monoclonal antibody that binds to pancreatic beta cells could be used for targeted immunotherapy. Protein tyrosine phosphatase receptor N (PTPRN) is one of the important surface antigen candidates. Due to its high sequence homology among mammals, so far, no single-chain monoclonal antibody has been produced against this receptor. In this study, we developed a novel single-chain variable fragment (scFv) against the PTPRN extracellular domain. To this aim, ostrich species was used as a host is far phylogenetically birds from mammals to construct a phage display library for the first time. An ostrich-derived scfv phage display library was prepared and biopanning steps were done to enrich and screen for isolating the best anti-PTPRN binders. An scFv with appropriate affinity and specificity to the PTPRN extracellular domain was selected and characterized by ELISA, western blotting, and flow cytometry. The anti-PTPRN scFv developed in this study could be introduced as an effective tool that can pave the way for the creation of antibody-based targeting systems in cooperation with the detection and therapy of type I diabetes.

Aspirin Use is Associated with Decreased Mortality in Patients with COVID-19: A Systematic Review and Meta-analysis

BackgroundNovel Corona Virus Disease 2019 (COVID-19) has resulted in more than three and half million deaths worldwide as of June 6, 2021. The role of aspirin in prevention of COVID-19 mortality has not been much studied. We aimed to study the relationship between aspirin use and covid-19 mortality. MethodsWe searched PubMed, MEDLINE, EMBASE, and Cochrane database for studies from January 2019 till June 6, 2021 with inclusion criteria of RCT, Cohort study, studies reporting mortality, and comparison studies on aspirin versus non-aspirin. Statistical analysis was done with Review Manager 5.4 statistical software using the inverse variance method. We assessed the pooled hazard ratio (HR), and 95% confidence interval using the random effect model and I-squared test was used to determine statistical heterogeneity. ResultsWe included five retrospective cohort studies which met our inclusion criteria with total of 14065 participants in both groups. There were 6797 participants in the aspirin group and 7268 participants in the non-aspirin group. Our results show that the use of aspirin was associated with 53% decrease in mortality compared to non-aspirin in patients with COVID-19 (adjusted HR 0.47, 95% CI 0.35-0.63, P< 0.001, I2= 47%). In the analysis restricted to patients hospitalized for COVID-19, the use of aspirin was associated with a 49% reduction in the risk for in-hospital mortality (adjusted HR 0.51, 95% CI 0.33-0.80, P = 0.004, I2= 39%). ConclusionsOur results show that aspirin is associated with decrease in both overall mortality and in-hospital mortality in patients with COVID-19.