Peptide-Integrated Superparamagnetic Nanoparticles for the Identification of Epitopes from SARS-CoV-2 Spike and Nucleocapsid Proteins

Abstract Background Recent studies indicate that, in addition to antibody production, lymphocyte responses to SARS-CoV-2 may play an important role in protective immunity to COVID-19 and a percentage of the general population may exhibit lymphocyte memory due to unknown/asymptomatic exposure to SARS-CoV-2 or cross-reactivity to other more common coronaviruses pre-vaccination. Total joint replacement (TJR) candidates returning to elective surgeries (median age 68 years) may exhibit similar lymphocyte and/or antibody protection to COVID-19 prior to vaccination Methods In this retrospective study, we analyzed antibody titters, lymphocyte memory, and inflammatory biomarkers specific for the Spike and Nucleocapsid proteins of the SARS-CoV-2 virus in a cohort of n=73 returning TJR candidates (knees and/or hips) pre-operatively. Results Peripheral blood serum of TJR candidate patients exhibited a positivity rate of 18.4% and 4% for IgG antibodies specific for SARS-CoV-2 nucleocapsid and spike proteins, respectively. 13.5% of TJR candidates exhibited positive lymphocyte reactivity (SI > 2) to the SARS-CoV-2 nucleocapsid protein and 38% to the spike protein. SARS-CoV-2 reactive lymphocytes exhibited a higher production of inflammatory biomarkers (i.e., IL-1β, IL-6, TNFα, and IL-1RA) compared to non-reactive lymphocytes. Conclusions A percentage of TJR candidates returning for elective surgeries exhibit pre-vaccination positive SARS-CoV-2 antibodies and T cell memory responses with associated pro-inflammatory biomarkers. This is an important parameter for understanding immunity, risk profiles, and may aid pre-operative planning. Trial registration Retrospectively registered.

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IgG and IgM antibody formation to spike and nucleocapsid proteins in COVID-19 characterized by multiplex immunoblot assays

BMC Infectious Diseases ◽

10.1186/s12879-021-06031-9 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Jyotsna Shah ◽

Song Liu ◽

Hari-Hara Potula ◽

Prerna Bhargava ◽

Iris Cruz ◽

...

Keyword(s):

Viral Infections ◽

Antibody Responses ◽

Nucleocapsid Proteins ◽

Igm Antibodies ◽

Igm Antibody ◽

Specificity And Sensitivity ◽

The Us ◽

Autoimmune Conditions ◽

Antibody Positivity ◽

Recombinant Nucleocapsid Protein

Abstract Background Rapid and simple serological assays for characterizing antibody responses are important in the current COVID-19 pandemic caused by SARS-CoV-2. Multiplex immunoblot (IB) assays termed COVID-19 IB assays were developed for detecting IgG and IgM antibodies to SARS-CoV-2 virus proteins in COVID-19 patients. Methods Recombinant nucleocapsid protein and the S1, S2 and receptor binding domain (RBD) of the spike protein of SARS-CoV-2 were used as target antigens in the COVID-19 IBs. Specificity of the IB assay was established with 231 sera from persons with allergy, unrelated viral infections, autoimmune conditions and suspected tick-borne diseases, and 32 goat antisera to human influenza proteins. IgG and IgM COVID-19 IBs assays were performed on 84 sera obtained at different times after a positive RT-qPCR test from 37 COVID-19 patients with mild symptoms. Results Criteria for determining overall IgG and IgM antibody positivity using the four SARS-CoV-2 proteins were developed by optimizing specificity and sensitivity in the COVID-19 IgG and IgM IB assays. The estimated sensitivities and specificities of the COVID-19 IgG and IgM IBs for IgG and IgM antibodies individually or for either IgG or IgM antibodies meet the US recommendations for laboratory serological diagnostic tests. The proportion of IgM-positive sera from the COVID-19 patients following an RT-qPCR positive test was maximal at 83% before 10 days and decreased to 0% after 100 days, while the proportions of IgG-positive sera tended to plateau between days 11 and 65 at 78–100% and fall to 44% after 100 days. Detection of either IgG or IgM antibodies was better than IgG or IgM alone for assessing seroconversion in COVID-19. Both IgG and IgM antibodies detected RBD less frequently than S1, S2 and N proteins. Conclusions The multiplex COVID-19 IB assays offer many advantages for simultaneously evaluating antibody responses to different SARS-CoV-2 proteins in COVID-19 patients.

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The thermodynamic properties of soft magnetic materials containing superparamagnetic nanoparticles frozen in the nodes of the regular cubic lattice

Journal of Nanoparticle Research ◽

10.1007/s11051-021-05268-4 ◽

2021 ◽

Vol 23 (7) ◽

Author(s):

Anna Solovyova ◽

Sergey Sokolsky ◽

Ekaterina Elfimova ◽

Alexey Ivanov

Keyword(s):

Thermodynamic Properties ◽

Magnetic Materials ◽

Superparamagnetic Nanoparticles ◽

Soft Magnetic Materials ◽

Soft Magnetic ◽

Cubic Lattice

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Concentration-dependent oscillation of specific loss power in magnetic nanofluid hyperthermia

Scientific Reports ◽

10.1038/s41598-020-79871-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ji-wook Kim ◽

Jie Wang ◽

Hyungsub Kim ◽

Seongtae Bae

Keyword(s):

Magnetic Dipole ◽

Critical Role ◽

Dipole Interaction ◽

Superparamagnetic Nanoparticles ◽

Physical Reason ◽

Strong Concentration ◽

Magnetic Nanofluid ◽

Specific Loss ◽

Specific Loss Power ◽

Magnetic Nanofluid Hyperthermia

AbstractMagnetic dipole coupling between the colloidal superparamagnetic nanoparticles (SPNPs) depending on the concentration has been paid significant attention due to its critical role in characterizing the Specific Loss Power (SLP) in magnetic nanofluid hyperthermia (MNFH). However, despite immense efforts, the physical mechanism of concentration-dependent SLP change behavior is still poorly understood and some contradictory results have been recently reported. Here, we first report that the SLP of SPNP MNFH agent shows strong concentration-dependent oscillation behavior. According to the experimentally and theoretically analyzed results, the energy competition among the magnetic dipole interaction energy, magnetic potential energy, and exchange energy, was revealed as the main physical reason for the oscillation behavior. Empirically demonstrated new finding and physically established model on the concentration-dependent SLP oscillation behavior is expected to provide biomedically crucial information in determining the critical dose of an agent for clinically safe and highly efficient MNFH in cancer clinics.

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SARS-CoV-2 reinfection with a virus harboring mutation in the Spike and the Nucleocapsid proteins in Panama

International Journal of Infectious Diseases ◽

10.1016/j.ijid.2021.06.004 ◽

2021 ◽

Author(s):

Yamilka Díaz ◽

Anyuri Ortiz ◽

Adriana Weeden ◽

Daniel Castillo ◽

Claudia González ◽

...

Keyword(s):

Nucleocapsid Proteins

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