A prospective study of the protective effect of SARS-CoV-2-specific antibodies and T cells in Moscow residents

Rapid spread of COVID-19 pandemic made a substantial share of the world population immunised by SARS-CoV-2 antigens. Infection induces the development of virus-specific antibodies and T cells. Ample evidence on the antibody-mediated protection is contrasted by the elusive role of T cells in preventing infection. To explore the impact of T cells and to quantify the protective levels of the immune responses we conducted a large prospective study: 5,340 Moscow residents were evaluated for the antibody and cellular immune responses to SARS-CoV-2 and monitored for COVID-19 up to 300 days. The antibody and cellular responses were tightly interconnected, their magnitude inversely correlated with infection probability. Similar maximal level of protection was reached by individuals positive for both types of responses and by individuals with antibodies alone. Meanwhile, T cells in the absence of antibodies provided an intermediate level of protection. The real-world data on the protective effects of T cells have important implications for T cell immunology and development of the strategies to fight the pandemic.

Cytotoxicity of Chitosan Ultrafine Nanoshuttles on the MCF-7 Cell Line as a Surrogate Model for Breast Cancer.

AIM: This study aimed to explore an affordable technique for the fabrication of Chitosan Nanoshuttles (CSNS) at the ultrafine nanoscale less than 100 nm with improved physicochemical properties, and cytotoxicity on the MCF-7 cell line. BACKGROUND: Despite several studies reported that the antitumor effect of CS and CSNS could achieve intracellular compartment target ability, no enough information is available about this issue and further studies are required to address this assumption. OBJECTIVES: The objective of the current study was to investigate the potential processing variables for the production of ultrafine CSNS (less than; 100 nm) using Box-Behnken Design factorial design (BBD). This was achieved through a study of the effects of processing factors, such as CS concentration, CS/TPP ratio, and pH of the CS solution, on PS, PDI, and ZP. Moreover, the obtained CSNS was evaluated for physicochemical characteristics, morphology. In addition, hemocompatibility and cytotoxicity using Red Blood Cells (RBCs) and MCF-7 cell lines were investigated. METHODS: Box-Behnken Design factorial design (BBD) was used in the analysis of different selected variables. The effects of CS concentration, sodium tripolyphosphate (TPP) ratio, and pH on particle size, Polydispersity Index (PDI), and Zeta Potential (ZP) were measured. Subsequently, the prepared CS nanoshuttles were exposed to stability studies, physicochemical characterization, hemocompatibility, and cytotoxicity using red blood cells and MCF-7 cell lines as surrogate models for in vivo study. RESULT: The present results revealed that the optimized CSNS has ultrafine nanosize, (78.3 ± 0.22 nm), homogenous with PDI (0.131 ± 0.11), and ZP (31.9 ± 0.25 mV). Moreover, CSNS has a spherical shape, amorphous in structure, and physically stable. Moreover, CSNS has biological safety as indicated by a gentle effect on red blood cell hemolysis, besides, the obtained nanoshuttles decrease MCF-7 viability. CONCLUSION: The present findings concluded that the developed ultrafine CSNS has unique properties with enhanced cytotoxicity, thus promising for use in intracellular organelles drug delivery.

Molecular docking analysis of an isoflavone derivative with the protein phosphatase 1 from Leishmania donovani.

Leishmaniasis is one of the most neglected diseases with high morbidity and mortality rate. Severe side effects with existing drug and lack of proper vaccine encouraged us to design alternative models to combat the disease. We showed that PP1 of Leishmania donovani mediates immunomodulation in host macrophages needed for parasite survival. Therefore, it is of interest to report the molecular docking analysis of 512 isoflavone derivatives with the phosphatase 1 protein from Leishmania donovani to highlight compound 362 (5-hydroxy-5-{9-[2-methoxy-2-(2-methylfuran-3-yl) ethyl]-1H, 3H, 4H, 10bH-pyrano[4,3-c]chromen-3-yl}pentanoic acid) having good binding features and acceptable ADMET properties for further consideration.