INTERPRETATION OF THE RAJI CELL ASSAY IN SERA CONTAINING ANTI-NUCLEAR ANTIBODIES AND IMMUNE-COMPLEXES

  • 1 January 1981
    • journal article
    • research article
    • Vol. 44  (2) , 405-415
Abstract
The Raji [Burkitt lymphoma] cell assay is regarded as a test for the detection and quantitation of immune complexes [IC]. It is frequently positive in sera from patients with systemic lupus erythematosus. A relationship between Raji cell binding and antibodies to DNA and soluble cellular antigens was demonstrated. In 5 sera containing high titers of antibodies of known single specificity, most of the Raji cell binding occurred in the 7S IgG fraction where the majority of anti-nuclear antibody was also found. When each of these sera was incubated with its specific antigen, Raji cell binding increased. Subsequent fractionation showed that this binding was in the high MW fraction (> 200,000 daltons) and that Raji cell binding and antibody activity were abolished in the 7S fraction. Evidently Raji cells bind IC but also indicate that 7S anti-nuclear antibodies may interact directly with Raji cells by an unknown mechanism. In sera of patients with anti-nuclear antibodies, binding to Raji cells does not necessarily imply the presence of IC alone.