SUBOPTIMAL C3B/C3BI DEPOSITION AND DEFECTIVE YEAST OPSONIZATION .1. EVIDENCE FOR THE ABSENCE OF ESSENTIAL COFACTOR ACTIVITY

  • 1 January 1985
    • journal article
    • research article
    • Vol. 62  (2) , 427-434
Abstract
Defective yeast opsonization in sera with no demonstrable abnormality of known complement components is associated with the absence of inactivity of a co-factor which enhances the deposition of C3 fragments (C3b C3bi) derived from both classical and alternative pathways of complement activation. The factor binds strongly to zymosan at 4.degree. C and loses its biological activity completely when heated for 30 min at 56.degree. C but not when similarly heated at 50.degree. C. Sera with defective deposition of C3 fragments may be readily corrected with small quantities of sera having normal function. Sera with the defect do not correct other similar sera.