Two different forms of human CTLA-4 proteins following peripheral T cell activation

Taehoon Chun, Hak Jong Choi, Yong Hoon Chung

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

To study expression of human CTLA-4 in peripheral T cells, we developed a new anti-peptide (anti-CTLA4pB) antibody. Both denatured and native forms of CTLA-4 can be recognized by anti-CTLA4pB antibody. After peripheral T cell activation, we observed that most of CTLA-4 is localized primarily to intracellular compartment rather than to the cell surface. Biochemical study using anti-CTLA4pB antibody was revealed two forms of CTLA-4 on activated peripheral T cells. The majority of CTLA-4 was detected as a 34kDa moiety in cytosolic fraction under reducing conditions. The presence of a 30kDa CTLA-4 moiety was observed simultaneously in membrane fraction under reducing condition. The post-induction ratio of cytosolic:membrane-bound forms of CTLA-4 was approximately 50:1. Further analysis was indicated that the 34kDa moiety in cytosolic fraction is part of a 250kDa multi-protein complex. Antibodies raised against this complex recognized 54 and 75kDa proteins together with a 34kDa form of CTLA-4. In contrast, membrane-bound forms of CTLA-4 were 60 and 120kDa under non-reducing condition. The molar ratio of 60 and 120kDa oligomers was approximately 1:1. These results may provide evidence for post-translational modification of human CTLA-4 after T cell activation.

Original languageEnglish
Pages (from-to)213-220
Number of pages8
JournalImmunology Letters
Volume91
Issue number2-3
DOIs
Publication statusPublished - 2004 Feb 15
Externally publishedYes

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Keywords

  • Cell surface molecules
  • Costimulation
  • CTLA4pB
  • Horseradish peroxidase
  • HRP
  • Human
  • Ig,
  • Immunoglobulin
  • Molecular biology
  • N′- CTGTSSGNQV -C′
  • PBMC
  • Peripheral blood mononuclear cell
  • T lymphocytes

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy

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