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The Role of the CD28 Receptor During T Cell Responses to Antigen

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 ---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 phos­ phorylation of specific substrates, including phospholipase Cy" and trig­ gers both calcium-dependent and calcium-independent signals. The CD28 costimulatory receptor represents a novel target for immunosuppressive drugs. INTRODUCTION T lymphocytes require for activation distinct signals from the antigen presenting cell (APC) (1, 2). An antigen-specific signal is delivered through 1 91 0732-0582/93/04 1 0-0 1 91$02.00 LINSLEY & LEDBETTER the antigen receptor following its engagement with antigenic peptides presented in the context of major histocompatability http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Annual Review of Immunology Annual Reviews

The Role of the CD28 Receptor During T Cell Responses to Antigen

Linsley, P S; Ledbetter, J A
Annual Review of Immunology , Volume 11 (1) – Apr 1, 1993
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Publisher
Annual Reviews
Copyright
Copyright 1993 Annual Reviews. All rights reserved
Subject
Review Articles
ISSN
0732-0582
eISSN
1545-3278
DOI
10.1146/annurev.iy.11.040193.001203
pmid
8386518
Publisher site
See Article on Publisher Site

Abstract

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 ---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 phos­ phorylation of specific substrates, including phospholipase Cy" and trig­ gers both calcium-dependent and calcium-independent signals. The CD28 costimulatory receptor represents a novel target for immunosuppressive drugs. INTRODUCTION T lymphocytes require for activation distinct signals from the antigen presenting cell (APC) (1, 2). An antigen-specific signal is delivered through 1 91 0732-0582/93/04 1 0-0 1 91$02.00 LINSLEY & LEDBETTER the antigen receptor following its engagement with antigenic peptides presented in the context of major histocompatability

Journal

Annual Review of Immunology – Annual Reviews

Published: Apr 1, 1993

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