BINDING OF ACTIVATED PROPERDIN TO UNTREATED ERYTHROCYTES - NEW FUNCTION OF ACTIVATED PROPERDIN

  • 1 January 1978
    • journal article
    • research article
    • Vol. 34  (2) , 207-215
Abstract
Activated human properdin was capable of binding to rabbit and sheep erythrocytes to form new intermediate cells of the alternative pathway of the complement [C] system. The intermediate cells, termed E.hivin.P, can react with B, .hivin.D and C3 to form other intermediate cells, tentatively termed E.hivin.PB(.hivin.D)C3, which can be lysed by the subsequent action of 6 late-acting C components, C3 to C9. The possibility of participation of C3, B, .hivin.D or immunoglobulin [Ig] in the formation of E.hivin.P cells was neglected by the experiments in which the inhibition of the reactivities of .hivin.P or E.hivin.P by antisera to .hivin.P, C3, B, .hivin.D or Ig were investigated. The reduction in reactivities of .hivin.P to E, or of E.hivin.P to B, .hivin.D and C3 was observed only when pretreated with antiserum to .hivin.P. E.hivin.P cells were agglutinated only by anti-.hivin.P, not by antisera to C3 or IgG. The other possibility of participation of the classical C components such as antibody, C1, C4 and C2 in the formation of E.hivin.PB(.hivin.D)C3 was excluded by the non-reactivities of E.hivin.P with C4 and C2 and of EAC1 with B, .hivin.D and C3. Activated properdin is likely to function not only as modulator of performed enzyme such as .**GRAPHIC**. but also as 1 of early-acting components of the alternative pathway.