Ligand Binding Sites of Inducible Costimulator and High Avidity Mutants with Improved Function

نویسندگان

  • Shengdian Wang
  • Gefeng Zhu
  • Koji Tamada
  • Lieping Chen
  • Jürgen Bajorath
چکیده

Interaction between inducible costimulator (ICOS) and its ligand is implicated in the induction of cell-mediated and humoral immune responses. However, the molecular details of this interaction are unknown. We report here a mutagenesis analysis of residues in ICOS that are critical for ligand binding. A three-dimensional model of the extracellular immunoglobulin-like domain of ICOS was used to map the residues conserved within the CD28 family. This analysis identified a surface patch containing the characteristic "PPP" sequence and is conserved in human and mouse ICOS. Mutations in this region of human ICOS reduce or abolish ligand binding. Our results suggest that the ligand binding site in ICOS maps to a region overlapping yet distinct from the CD80/CD86 binding sites in CD28 and cytotoxic T lymphocyte antigen (CTLA)-4. Thus, the analysis suggests that differences in ligand binding specificity between these related costimulatory molecules have evolved by utilization of overlapping regions with different patterns of conserved and nonconserved residues. Two site-specific mutants generated in the course of our studies bound ICOS ligand with higher avidity than wild-type ICOS. An S76E mutant protein of ICOS blocked T cell costimulatory function of ICOS ligand and inhibited T cell response to allogeneic antigens superior to wild-type ICOS. Our studies thus identified critical residues involving in ICOS receptor-ligand interaction and provide new modulators for immune responses.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Interaction of Human Serum Albumin with Ethyl 2-[2-(dimethylamino)-4-(4-nitrophenyl)-1,3-thiazole-5-yl]-2-oxoacetate as a Synthesized Ligand

The interaction of human serum albumin with Ethyl 2-[2-(dimethylamino)-4-(4-nitrophenyl)- 1,3-thiazole-5-yl]-2-oxoacetate was investigated by using isothermal titration UV-visible spectrophotometry in tris-buffer, pH 7.4. According to these results, it was found that there are a set of 4 binding sites for this ligand on HSA with positive cooperativity in the binding process. This thiazole deriv...

متن کامل

P-30: The Effect of The T26248G Polymorphism on Putative MethyltransferaseNsun7 Protein Function and Its Role in Male Infertility

Background: Male infertility has many causes, including genetic infertility. The NOP2/Sun domain family, member7 (Nsun7) gene, which encodes putative methyltransferase Nsun7, has a role in sperm motility. The aim of the present study was to investigate the effect of the T26248G polymorphism on Nsun7 protein function and its role in male infertility. Materials and Methods: Semen samples were col...

متن کامل

P-31: The Alteration of SpermatogenesisHas A Correlation with Sertoli Cell Mitochondrial Abnormal Morphology in Cytotoxicity of Testicular Tissue Mediatedwith Monosodium

Background: Male infertility has many causes, including genetic infertility. The NOP2/Sun domain family, member7 (Nsun7) gene, which encodes putative methyltransferase Nsun7, has a role in sperm motility. The aim of the present study was to investigate the effect of the T26248G polymorphism on Nsun7 protein function and its role in male infertility. Materials and Methods: Semen samples were col...

متن کامل

Probing the phosphocholine-binding site of human C-reactive protein by site-directed mutagenesis.

Human C-reactive protein (CRP) can activate the classical pathway of complement and function as an opsonin only when it is complexed to an appropriate ligand. Most known CRP ligands bind to the phosphocholine (PCh)-binding site of the protein. In the present study, we used oligonucleotide-directed site-specific mutagenesis to investigate structural determinants of the PCh-binding site of CRP. E...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • The Journal of Experimental Medicine

دوره 195  شماره 

صفحات  -

تاریخ انتشار 2002