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 language | English |
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Pages (from-to) | 213-220 |
Number of pages | 8 |
Journal | Immunology Letters |
Volume | 91 |
Issue number | 2-3 |
DOIs | |
Publication status | Published - 2004 Feb 15 |
Externally published | Yes |
Keywords
- CTLA4pB
- Cell surface molecules
- Costimulation
- HRP
- Horseradish peroxidase
- Human
- Ig,
- Immunoglobulin
- Molecular biology
- N′-CTGTSSGNQV-C′
- PBMC
- Peripheral blood mononuclear cell
- T lymphocytes
ASJC Scopus subject areas
- Immunology and Allergy
- Immunology