COMPLEMENT RECEPTORS ON RAJI CELLS - THE PRESENCE OF A NEW TYPE OF C-3 RECEPTOR

  • 1 January 1980
    • journal article
    • research article
    • Vol. 41  (1) , 159-166
Abstract
Raji cells did not form rosettes with EAC43hu [sheep erythrocyte-rabbit IgM antibody-human complement C3 and C4 complex]. When EAC43hu are treated with .beta.1H, the treated EAC43hu forms heavy rosettes with Raji cells. These rosettes resulted from a new type of C3 receptor which is different from either CR1 (C3b receptor), CR2 (C3d receptor) or CR3 (C3bi receptor). Three lines of evidence clearly showed that C3 is implicated in the new rosette formation. C3 receptors isolated from human erythrocytes inhibited the new rosette formation, while they did not inhibit the rosette formation of Daudi cells via CR2, indicating that the new rosette-forming receptor is different from CR2. Anti-Raji cells antiserum inhibited the new rosette formation while it did not inhibit the reaction between human erythrocytes and EAC43 via CR1. This indicates that the new rosette-forming receptor is different from CR1 in accordance with the lack of rosette formation of Raji cells with EAC43. The evidence to differentiate the receptor from CR3 comes from no participation of C3b inactivator in the generation of rosette-forming activity of EAC43. Both the mode of action of anti-.beta.1H and the effect of modification of bound C3b by N-bromosuccinimide suggest that EAC43 reacts with .beta.1H, which in turn results in a conformational change of C3b. Raji cells might have receptors for the .beta.1H altered C3b.