title: Potential cross-reactivity of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) nucleocapsid (N)-based IgG ELISA assay for plasma samples from HIV-1 positive intravenous drug users (IDUs).
abstract: OBJECTIVE
  to evaluate the specificity of the SARS-CoV N protein-based IgG ELISA assay for detection of immunoglobulin G (IgG) in plasma samples obtained from HIV-1 positive and HIV-1 negative intravenous drug users (IDUs).
  
  
  METHODS
  the SARS-CoV N gene was cloned into pQE-80L vector, and the constructs were transformed into Escherichia coli BL21. The 6x His-tagged N protein was expressed by inducing the bacterial cells with isopropyl-1-thio-D-galactopyranoside (IPTG) and purified by Ni-NTA affinity resin. The 6x His-tagged N protein was used as antigen for ELISA assay and evaluated for the serum samples from patients with SARS positive and the plasma samples from the HIV-1 positive and negative IDUs.
  
  
  RESULTS
  all sera samples from patients with SARS positive were the ELISA positive (100% sensitivity). The ELISA assay yielded no positive results of the total 61 HIV-1 negative IDU samples (100% specificity) and two positive results of the total 68 HIV-1 positive IDU samples (97.06% specificity).
  
  
  CONCLUSIONS
  the specificity of the SARS-CoV N protein-based IgG ELISA assay for the detection of the SARS-CoV N specific IgG in plasma samples from IDUs with HIV-1 positive is, therefore, questionable.
authors.affiliation: Department of Microbiology, Faculty of Medicine, University of Indonesia, Jakarta Pusat, Indonesia. andi.yasmon@ui.ac.id
authors.forename: Andi
authors.initials: A
authors.lastname: Yasmon
authors.forename: Fera
authors.initials: F
authors.lastname: Ibrahim
authors.forename: Budiman
authors.initials: B
authors.lastname: Bela
authors.forename: Agus
authors.initials: A
authors.lastname: Sjahrurachman
mesh_terms: D000328:Adult; D000086462:Coronavirus Nucleocapsid Proteins; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D018023:HIV Seronegativity; D006679:HIV Seropositivity / Q000276:immunology* / Q000821:virology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D019590:Nucleocapsid Proteins / Q000276:immunology*; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology*; D012680:Sensitivity and Specificity; D012698:Serologic Tests; D045169:Severe Acute Respiratory Syndrome / Q000175:diagnosis / Q000821:virology; D015819:Substance Abuse, Intravenous / Q000097:blood; D055815:Young Adult
chemical_list: D000086462:Coronavirus Nucleocapsid Proteins; D007074:Immunoglobulin G; D019590:Nucleocapsid Proteins