Cutting Edge: C3d Functions as a Molecular Adjuvant in the Absence of CD21/35 Expression

Karen M. Haas, Franklin R. Toapanta, Julie A. Oliver, Jonathan C. Poe, John H. Weis, David R. Karp, Joseph F. Bower, Ted M. Ross, Thomas F. Tedder

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


Complement component C3 covalently attaches to Ags following activation, where the C3d cleavage fragment can function as a molecular adjuvant to augment humoral immune responses. C3d is proposed to exert its adjuvant-like activities by targeting Ags to the C3d receptor (CD21/35) expressed by B cells and follicular dendritic cells. To directly assess the importance of CD21/35 in mediating the immunostimulatory effects of C3d, CD21/35-deficient (CD21/35 -/-) mice were immunized with streptavidin (SA), SA-C3dg tetramers, recombinant HIV gp120 (gp120), or gp120 fused with linear multimers of C3d. Remarkably, SA and gp 120-specific Ab responses were significantly augmented in CD21/35-/- mice when these Ags were complexed with C3d in comparison to Ag alone. In fact, primary and secondary Ab responses and Ab-forming cell responses of CD21/35-/- mice approached those of wild-type mice immunized with SA-C3dg and gp120-C3d. Thus, C3d can function as a molecular adjuvant in the absence of CD21/35 expression.

Original languageEnglish (US)
Pages (from-to)5833-5837
Number of pages5
JournalJournal of Immunology
Issue number10
StatePublished - May 15 2004

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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