Entwicklung eines enzymatischen Testes zum Nachweis von Antikörpern gegen Lassavirus in menschlichen Seren unter Berücksichtigung verschiedener Lassavirus Serotypen

Abstract

Two highly sensitive and specific reverse enzyme- immunoassays were developed, to detect Lassa virus antibodies. IgG and IgM antibodies of the human sera were bound to microtiter plates coated either with Rheumatoid factor or with anti-human à µ-chain antibodies, respectively. For both tests a crude antigen extracted from Lassa virus infected tissue cultures cells was used. This antigen was in turn reacted with a labeled monoclonal antibody to Lassa virus nucleocapsid. The reverse Elisa turned out to detect IgG in serum samples of West African patients with recent Lassa fever and in 76 sera of healthy seropositive (IIF) West Africans with a sensitivity of 100. In 1031 controls samples of healthy Africans, who were negative for IgG and IgM antibodies by indirect immunofluorescence (IIF), also no IgM antibodies could by found by Elisa. Compared to IIF, the specificity of the reverse Elisa for IgG antibodies was only 95%. But upon retesting the 19 discrepant samples with three different Lassa virus antigens by IIF, 14 samples turned out to react positively (titer ≥20) with at least one antigen in IIF. When all 1107 West African serum samples were tested in the Elisa for IgG antibodies to the three different Lassa virus antigen, in about 30% strictly strain-specific reactions were seen.