Two serological approaches for detection of antibodies to SARS-CoV-2 in different scenarios: a screening tool and a point-of-care test
DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE
Authors: Hoste, Alexis C. R.; Venteo, Angel; Fresco-Taboada, Alba; Tapia, Istar; Monedero, Alejandro; Lopez, Lissette; Jebbink, Maarten F.; Perez-Ramirez, Elisa; Jimenez-Clavero, Miguel Angel; Almonacid, Mercedes; Munoz, Patricia; Guinea, Jesus; Vela, Carmen; van der Hoek, Lia; Rueda, Paloma; Sastre, Patricia
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected more than 8 million people world-wide, becoming a pandemic. Detecting antibodies against SARS-CoV-2 is of utmost importance and a good indicator of exposure and circulation of the virus within the general population. Two serological tools based on a double recognition assay [enzyme-linked immunosorbent assay (DR-ELISA) and lateral flow assay (DR-LFA)] to detect total antibodies to SARS-CoV-2 have been developed based on the recombinant nucleocapsid protein. A total of 1065 serum samples, including positive for COVID-19 and negative samples from healthy donors or infected with other respiratory pathogens, were analyzed. The results showed values of sensitivity between 91.2% and 100%, and specificity of 100% and 98.2% for DR-LFA and DR-ELISA, respectively. No cross-reactivity against seasonal coronavirus (HCoV-NL63, HCoV-229E, HCoV-HKU1, HCoV-OC43) was found. These results demonstrate the importance of serology as a complementary tool to polymerase chain reaction for follow-up of recovered patients and identification of asymptomatic individuals. (c) 2020 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Beta2 glycoprotein I-derived therapeutic peptides induce sFlt-1 secretion to reduce melanoma vascularity and growth
Authors: Smalley, Haley; Rowe, Jennifer M.; Nieto, Fernando; Zeledon, Jazmin; Pollard, Kellyn; Tomich, John M.; Fleming, Sherry D.
Melanoma, a form of skin cancer, is one of the most common cancers in young men and women. Tumors require angiogenesis to provide oxygen and nutrients for growth. Pro-angiogenic molecules such as VEGF and antiangiogenic molecules such as sFlt-1 control angiogenesis. In addition, the serum protein, Beta2 Glycoprotein I (beta 2-GPI) induces or inhibits angiogenesis depending on conformation and concentration. beta 2-GPI binds to proteins and negatively charged phospholipids on hypoxic endothelial cells present in the tumor microenvironment. We hypothesized that peptides derived from the binding domain of beta 2-GPI would regulate angiogenesis and melanoma growth. In vitro analyses determined the peptides reduced endothelial cell migration and sFlt-1 secretion. In a syngeneic, immunocompetent mouse melanoma model, beta 2-GPI-derived peptides also reduced melanoma growth in a dose-dependent response with increased sFlt-1 and attenuated vascular markers compared to negative controls. Importantly, administration of peptide with sFlt-1 antibody resulted in tumor growth. These data demonstrate the therapeutic potential of novel beta 2-GPI-derived peptides to attenuate tumor growth and endothelial migration is sFlt-1 dependent.