Generation and characterization of fully human monoclonal antibodies against human Orai1 for autoimmune disease

J Pharmacol Exp Ther. 2013 May;345(2):225-38. doi: 10.1124/jpet.112.202788. Epub 2013 Mar 8.


Calcium entry into T cells following antigen stimulation is crucial for nuclear factor of activated T cells (NFAT)-mediated T cell activation. The movement of calcium is mediated by calcium release-activated calcium (CRAC) channels. There are two key components of this channel: Orai1 is the pore-forming subunit located in the plasma membrane, and stromal interaction molecule 1 (STIM1) functions as a Ca(2+) sensor in the endoplasmic reticulum. A subset of human patients carry mutations in either STIM1 or Orai1 that affect protein function or expression, resulting in defective store-operated Ca(2+) influx and CRAC channel function, and impaired T cell activation. These patients suffer from a hereditary form of severe combined immune deficiency syndrome, highlighting the importance of the CRAC channel for T lymphocyte function in humans. Since autoreactive T cells play an important role in the development of autoimmune diseases such as rheumatoid arthritis, multiple sclerosis, and organ transplantation, Orai1 becomes an attractive therapeutic target for ameliorating autoimmune disease. We developed a novel approach to inhibiting CRAC function by generating high-affinity fully human monoclonal antibodies to human Orai1. These antibodies inhibited ICRAC current, store-operated Ca(2+) influx, NFAT transcription, and cytokine release. These fully human antibodies to human Orai1 may represent a novel therapeutic approach for the treatment of autoimmunity.

MeSH terms

  • Aequorin / pharmacology
  • Amino Acid Sequence
  • Animals
  • Antibodies, Blocking / biosynthesis
  • Antibodies, Blocking / therapeutic use*
  • Antibodies, Monoclonal / biosynthesis
  • Antibodies, Monoclonal / therapeutic use*
  • Autoimmune Diseases / drug therapy*
  • Blotting, Western
  • Calcium Channels / drug effects*
  • Calcium Channels / immunology*
  • Chimera
  • Cytokines / blood
  • Epitope Mapping
  • Epitopes / drug effects
  • Flow Cytometry
  • Genes, Reporter
  • HEK293 Cells
  • Humans
  • Jurkat Cells
  • Kinetics
  • Luciferases / genetics
  • Mice
  • Molecular Sequence Data
  • NFATC Transcription Factors / biosynthesis
  • NFATC Transcription Factors / genetics
  • ORAI1 Protein
  • Patch-Clamp Techniques
  • Polymorphism, Single Nucleotide
  • Rats


  • Antibodies, Blocking
  • Antibodies, Monoclonal
  • Calcium Channels
  • Cytokines
  • Epitopes
  • NFATC Transcription Factors
  • NFATC2 protein, human
  • ORAI1 Protein
  • ORAI1 protein, human
  • Aequorin
  • Luciferases