Differential effects of CTLA-4 substitutions on the binding of human CD80 (B7-1) and CD86 (B7-2)

J Immunol. 1996 Feb 1;156(3):1047-54.


CTLA-4 expressed on activated T cells binds to CD80 (B7-1) and CD86 (B7-2) molecules present on APC with high avidity and appears to deliver a negative regulatory signal to the T cell. We have investigated the kinetics of CTLA-4 binding to CD80 and CD86, together with the effects of selected CTLA-4 mutations on binding activity. The dissociation constants (Kd) for binding of CTLA-4-Ig to CD80 and CD86 transfectants were 8.1 and 6.7 nM, respectively. Surface plasmon resonance was used to determine kinetic parameters of CTLA-4-Ig binding to CD80-Ig and CD86-Ig fusion proteins and revealed enhanced association (ka) and dissociation (kd) rate constants for CD86-Ig compared with CD80-Ig. Furthermore, CD80-Ig and CD86-Ig fusion molecules demonstrated variable abilities to cross-compete for binding to several modified forms of CTLA-4-Ig. Differential binding of CD80 and CD86 to CTLA-4 was further revealed by analysis of 10 discrete CTLA-4 mutants. Five single amino acid substitutions within the CTLA-4 MYPPPY domain exerted modest effects on CD80 binding, but each of these substitutions completely abrogated CD86 binding. In addition, substitutions just N-terminal of the MYPPPY region, and within the CDR1-like region of CTLA-4, eliminated both CD80 and CD86 binding. Hence, CD80 and CD86 bind with different association/dissociation kinetics to similar, but distinct, sites on CTLA-4.

MeSH terms

  • Abatacept
  • Amino Acid Sequence
  • Antigens, CD / chemistry*
  • Antigens, Differentiation / chemistry*
  • Antigens, Differentiation / genetics*
  • B7-1 Antigen / chemistry*
  • B7-2 Antigen
  • Biosensing Techniques
  • CTLA-4 Antigen
  • Cell Line
  • Humans
  • Immunoconjugates*
  • Kinetics
  • Lymphocyte Activation / genetics
  • Lymphocyte Activation / immunology
  • Membrane Glycoproteins / chemistry*
  • Molecular Sequence Data
  • Protein Binding / immunology
  • Radioligand Assay
  • Signal Transduction / immunology
  • T-Lymphocytes / immunology
  • Transfection


  • Antigens, CD
  • Antigens, Differentiation
  • B7-1 Antigen
  • B7-2 Antigen
  • CD86 protein, human
  • CTLA-4 Antigen
  • CTLA4 protein, human
  • Immunoconjugates
  • Membrane Glycoproteins
  • Abatacept