ABSTRACT
Humoral immunity to the Severe Adult Respiratory Syndrome (SARS) Coronavirus (CoV)-2 is not fully understood yet but is a crucial factor of immune protection. The possibility of antibody cross-reactivity between SARS-CoV-2 and other human coronaviruses (HCoVs) would have important implications for immune protection but also for the development of specific diagnostic ELISA tests. Using peptide microarrays, n = 24 patient samples and n = 12 control samples were screened for antibodies against the entire SARS-CoV-2 proteome as well as the Spike (S), Nucleocapsid (N), VME1 (V), R1ab, and Protein 3a (AP3A) of the HCoV strains SARS, MERS, OC43, and 229E. While widespread cross-reactivity was revealed across several immunodominant regions of S and N, IgG binding to several SARS-CoV-2-derived peptides provided statistically significant discrimination between COVID-19 patients and controls. Selected target peptides may serve as capture antigens for future, highly COVID-19-specific diagnostic antibody tests.
Subject(s)
Antibodies, Viral/blood , COVID-19/diagnosis , Protein Array Analysis/methods , SARS-CoV-2/immunology , Viral Proteins/immunology , Adult , Aged , Amino Acid Sequence/genetics , Antibodies, Viral/immunology , Coronavirus 229E, Human/immunology , Coronavirus Nucleocapsid Proteins/immunology , Coronavirus OC43, Human/immunology , Cross Reactions/immunology , Diagnostic Tests, Routine , Female , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Male , Middle Aged , Middle East Respiratory Syndrome Coronavirus/immunology , Phosphoproteins/immunology , Proteome/immunology , Severe acute respiratory syndrome-related coronavirus/immunology , Spike Glycoprotein, Coronavirus/immunology , Young AdultABSTRACT
The fast and simple detection of increased protein concentrations in cerebrospinal liquids is preferable in the emergency medicine and it can help to avoid unnecessary laboratory work by an early classification of neurological diseases. Here a test system is developed which is based on the electrostatic interaction between negatively charged gold nanoparticles and proteins at pH values around 5. The test system can be adjusted in such a way that protein/nanoparticles aggregates are formed leading to a red-shift in the absorption spectrum of the nanoparticles suspension. At concentrations above 500 mg/l the color of the suspension changes from red via violet toward blue in a rather small concentration range from 500 to 1000 mg/l. Furthermore the influence of various parameters such as gold nanoparticle concentration, pH value and varying ion concentration in the sample on the test system is examined. Finally cerebrospinal liquids of a larger number of patients have been analyzed.
