The JI PBL Intereron Source
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     
 

The Journal of Immunology, 1979, 123: 2212-2219.
Copyright © 1979 by The American Association of Immunologists, Inc.
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Liberti, P. A.
Right arrow Articles by Bausch, D. M.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Liberti, P. A.
Right arrow Articles by Bausch, D. M.

On the Interaction of Rabbit C1q with Sheep and Rabbit Immune Complexes1

Paul A. Liberti2, Richard D. Baillie, Kathleen F. Milligan and Dulcie M. Bausch

From the Department of Biochemistry, Jefferson Medical College, Philadelphia, Pennsylvania 19107

Abstract

The reversibility of interaction between rabbit C1q and a calcium dependent antigen-antibody system [GAT-anti-GAT-Ca+2], as well as reaction parameters thereof, have been carefully examined. By utilizing the reversibility of the GAT-anti-GAT-Ca+2 reaction by the addition of EDTA, it has been found that 1) C1q-IgG interaction is totally reversed by the disruption of the immune complex, independent of antigen-antibody ratios, 2) the amount of C1q bound to immune complexes mirrors antibody precipitated in the precipitin reaction, 3) the amount of C1q bound to "pre-formed" immune complexes is almost identical to that amount bound when immune complexes are formed in the presence of C1q, i.e., "dynamic complexes," 4) C1q specifically bound to immune complexes can rebind as many as three times without loss of binding activity, and 5) C1q multiply reacted with immune complexes suffers no loss of hemolytic activity. Items 4 and 5 provide strong evidence that C1q remains native upon binding and that the labile nature of C1q is probably not related to its triggering actions in the complement phenomenon. From quantitative binding studies of C1q with pre-formed immune complexes formed at antibody excess, equivalence and antigen excess, the shapes of the binding curves and Scatchard plots are not suggestive of co-operative interactions between C1q and IgG. Association constants obtained with sheep or rabbit pre-formed immune complexes were significantly greater in antibody excess than at equivalence, as were amounts of C1q bound. For dynamic immune complexes formed in the presence of C1q, more C1q is bound at equivalence. Since more C1q was found to bind to these immune complexes at equivalence than in antibody excess, i.e., similar to an in vivo situation, it appears that quantities of C1q bound, rather than the energy of interaction, may be more related to the degree of complement fixation.

Footnotes

1 This work was supported by Grant A1 12365 from the National Institutes of Health, United States Public Health Service.

2 Recipient of Public Health Service Research Career Development Award IK4A170731 from the National Institute of Allergy and Infectious Diseases, and to whom reprint requests and other correspondence should be directed.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Website Copyright © 1979 by The American Association of Immunologists, Inc. All rights reserved.
All Contents Copyright © 1979 by The American Association of Immunologists, Inc. All rights reserved.