HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ziegler, J. B. Articles by Lepow, I. H. Search for Related Content PubMed Articles by Ziegler, J. B. Articles by Lepow, I. H.

Complement Activation in Semi-Solid Medium: Insolubilization of Properdin and the Third Component of Complement (C3) in Agar Gels

From the Immunology Division, Children's Hospital Medical Center, Boston, Massachusetts 02115; The Center for Blood Research, Boston, Massachusetts 02115; the Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115; and the Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut 06032

Abstract

Although the role of properdin in the alternative pathway of complement activation remains unclear, evidence has recently been obtained for the formation of complexes between properdin and other components, including C3. In this study such complexes have apparently been directly visualized. When normal human serum and properdin were allowed to diffuse toward each other in agar gel for 16 hr, a line of precipitation could be seen when stained with Coomassie brilliant blue. The reaction occurred at pH 8.6 in 0.05 M Veronal buffer at room temperature but not under physiologic conditions of pH or tonicity. Like the alternative pathway, the reaction was Me⁺⁺ dependent, occurred with C2- or C5-deficient or hypogammaglobulinemic serum, and did not occur with aged, 52°C-inactivated, C3b inactivator-deficient, or C3-deficient serum. ¹²⁵I-labeled C3 and properdin but not Factor B were incorporated in the precipitate. Eleven sera containing the C3 nephritic factor failed to produce a precipitate with properdin, but a line of precipitation occurred between seven of these sera and normal serum. This line showed identity with the line occurring between properdin and normal serum. The phenomenon appears to result from formation of insoluble complexes between proteins of the alternative pathway and agar.

Footnotes

¹ Deceased.