The role of the CD28 receptor during T cell responses to antigen.
The CD28 receptor is stimulated during the contact of T cells with antigen-presenting cells. A counter-receptor for CD28 is the B7 molecule expressed on activated B cells, dendritic cells, and macrophages. B7 also binds to CTLA-4, a receptor that is structurally related to CD28. CTLA-4 is expressed in low copy number by T cells only after activation, but it binds B7 with approximately 20-fold higher affinity than CD28. Inhibition of B7-CD28 interactions blocks immune responses in vitro and in vivo. Therefore, CD28 receptor stimulation is required for T cell responses to antigens and for B cell responses to T-dependent antigens. During T cell responses to antigens, CD28 receptor stimulation may be required to prevent clonal inactivation or anergy. CD28 receptor ligation induces tyrosine phosphorylation of specific substrates, including phospholipase C gamma 1, and triggers both calcium-dependent and calcium-independent signals. The CD28 costimulatory receptor represents a novel target for immunosuppressive drugs.[1]References
- The role of the CD28 receptor during T cell responses to antigen. Linsley, P.S., Ledbetter, J.A. Annu. Rev. Immunol. (1993) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Use
The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.








