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Biochemical analysis of CTLA-4 immunoreactive material from human blood.
- Source :
-
BMC immunology [BMC Immunol] 2009 Sep 22; Vol. 10, pp. 51. Date of Electronic Publication: 2009 Sep 22. - Publication Year :
- 2009
-
Abstract
- Background: CTLA-4 was initially described as a membrane-bound molecule that inhibited lymphocyte activation by interacting with B7.1 and B7.2 molecules on antigen presenting cells. Alternative splicing of mRNA encoding the CTLA-4 receptor leads to the production of a molecule (sCTLA-4) that lacks a membrane anchor and is therefore secreted into the extracellular space. Despite studies finding that people with autoimmune disease more frequently express high levels of sCTLA-4 in their blood than apparently healthy people, the significance of these findings is unclear.<br />Methods: Molecules isolated from blood using CTLA-4 specific antibodies were analyzed with ligand binding assays, mass spectroscopy, and biochemical fractionation in an effort to increase our understanding of CTLA-4 immunoreactive material.<br />Results: Mass spectroscopy analysis of the molecules recognized by multiple CTLA-4-specific antibodies failed to identify any CTLA-4 protein. Even though these molecules bind to the CTLA-4 receptors B7.1 and B7.2, they also exhibit properties common to immunoglobulins.<br />Conclusion: We have identified molecules in blood that are recognized by CTLA-4 specific antibodies but also exhibit properties of immunoglobulins. Our data indicates that what has been called sCTLA-4 is not a direct product of the CTLA-4 gene, and that the CTLA-4 protein is not part of this molecule. These results may explain why the relationship of sCTLA-4 to immune system activity has been difficult to elucidate.
- Subjects :
- Antibodies, Monoclonal immunology
Antigen-Antibody Complex blood
Antigen-Antibody Complex chemistry
Antigens, CD blood
Antigens, CD chemistry
Antigens, CD immunology
B7-1 Antigen immunology
B7-1 Antigen metabolism
B7-2 Antigen immunology
B7-2 Antigen metabolism
Blood Proteins chemistry
Blood Proteins immunology
CTLA-4 Antigen
Chemical Fractionation
Humans
Immunomodulation
Mass Spectrometry
Myasthenia Gravis blood
Protein Binding
Antigen-Antibody Complex immunology
Antigens, CD metabolism
Blood Proteins metabolism
Myasthenia Gravis immunology
Subjects
Details
- Language :
- English
- ISSN :
- 1471-2172
- Volume :
- 10
- Database :
- MEDLINE
- Journal :
- BMC immunology
- Publication Type :
- Academic Journal
- Accession number :
- 19772653
- Full Text :
- https://doi.org/10.1186/1471-2172-10-51