A Novel Peptide-Based Detection of SARS-CoV-2 Antibodies.

The need for rapidly developed diagnostic tests has gained significant attention after the recent pandemic. Production of neutralizing antibodies for vaccine development or antibodies to be used in diagnostic tests usually require the usage of recombinant proteins representing the infectious agent. However, peptides that can mimic these recombinant proteins may be rapidly utilized, especially in emergencies such as the recent outbreak. Here, we report two peptides that mimic the receptor binding domain of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and investigate their binding behavior against the corresponding human immunoglobulin G and immunoglobulin M (IgG and IgM) antibodies in a clinical sample using a quartz crystal microbalance (QCM) sensor. These peptides were immobilized on a QCM sensor surface, and their binding behavior was studied against a clinical serum sample that was previously determined to be IgG and IgM-positive. It was determined that designed peptides bind to SARS-CoV-2 antibodies in a clinical sample. These peptides might be useful for the detection of SARS-CoV-2 antibodies using different methods such as enzyme-linked immunosorbent assay (ELISA) or lateral flow assays. A similar platform might prove to be useful for the detection and development of antibodies in other infections.

Tau proteins in the cerebrospinal fluid of patients with subacute sclerosing panencephalitis.

Neurodegenerative diseases characterized by cytoskeletal deformation and neurofibrillary tangles are associated with altered levels of tau and related proteins in cerebrospinal fluid (CSF). Neuronal or glial fibrillary tangles have been shown in 20% of subacute sclerosing panencephalitis (SSPE) patients. We therefore investigated CSF samples from 60 newly diagnosed SSPE and 31 neurological control patients for total tau (t-tau), phosphorylated tau (p-tau), and S100-B levels by ELISA. There was no difference between patient and control groups in t-tau and S100-B levels. p-Tau was lower in the SSPE group (p=0.009). Past history of measles infection, measles immunization status, latent period between measles and onset of SSPE, duration of symptoms, frequency of myoclonia, neurological deficit index, stage and progression rate of the disease, CSF glucose levels and cell counts, CSF and serum measles IgG titer, distribution of lesions on brain magnetic resonance imaging were not related to t-tau, p-tau and S100-B levels. Mental status and age were negatively correlated with t-tau, and male gender and EEG abnormalities were associated with higher t-tau levels. The levels of tau proteins in our patients suggest there is no, or only scarce and immature, neurofibrillary tangle formation in SSPE. Autopsy studies showing neurofibrillary tangles might have examined older patients with longer disease and more parenchymal involvement.