Cloning and expression of Rift Valley fever virus nucleocapsid (N) protein and evaluation of a N-protein based indirect ELISA for the detection of specific IgG and IgM antibodies in domestic ruminants
Veterinary Faculty, Eduardo Mondlane University, C. Postal 257, Maputo, Mozambique; Division of Immunology, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Yalelaan I, 3584 CL Utrecht, Netherlands; National Institute for Communicable Diseases, Special Pathogens Unit, Private Bag X4, Sandringham, 2131, South Africa; Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa; Division of Virology, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, 3584 CL Utrecht, Netherlands
Serodiagnosis of Rift Valley fever (RVF) currently relies on the use of live or inactivated whole virus as antigens. The recombinant nucleocapsid (N) protein of RVF virus was tested for diagnostic applicability in an indirect enzyme-linked immunosorbent assay (I-ELISA), using sera from experimentally infected sheep (n = 128), vaccinated sheep (n = 240), and field-collected sera from sheep (n = 251), goats (n = 362) and cattle (n = 100). The N-protein based I-ELISA performed at least as good as VN and HI tests. In goat the diagnostic sensitivity (D-Sn) and specificity (D-Sp) of the I-ELISA was 100% when using the anti-species IgG conjugate. Using protein G as a detection system, the D-Sn and D-Sp in goats were 99.4% and 99.5%, in sheep field sera both 100%, in cattle 100% and 98.3%, respectively. The I-ELISA based on recombinant N-protein has the potential to complement the traditional assays for serodiagnosis of RVF. Advantages of the N-protein are its safety, stability and cost-effectiveness in use and production. © 2006 Elsevier B.V. All rights reserved.
immunoglobulin G; immunoglobulin M; nucleocapsid protein; protein G; recombinant protein; animal experiment; animal model; antibody detection; article; bovids; cattle; controlled study; cost effectiveness analysis; diagnostic accuracy; domestic species; enzyme linked immunosorbent assay; goat; hemagglutination inhibition; hemorrhagic fever; molecular clock; nonhuman; protein analysis; protein expression; protein stability; Rift Valley fever bunyavirus; sensitivity and specificity; serodiagnosis; sheep; vaccination; virus inactivation; virus neutralization; virus nucleocapsid; Animal Diseases; Animals; Antibodies, Viral; Antibody Specificity; Cattle; Cattle Diseases; Cloning, Molecular; DNA, Viral; Enzyme-Linked Immunosorbent Assay; Goat Diseases; Goats; Hemagglutination Inhibition Tests; Immunoglobulin G; Immunoglobulin M; Neutralization Tests; Nucleocapsid Proteins; Polymerase Chain Reaction; Recombinant Proteins; Rift Valley Fever; Rift Valley fever virus; Sheep; Sheep Diseases; Bos; Capra hircus; Ovis aries; Rift Valley fever virus