The Journal of Experimental Medicine
Torrey Pines Biolabs
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

This Article
Right arrow Full Text (PDF, 1035K)
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JEM
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ravichandran, K. S.
Right arrow Articles by Burakoff, S. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ravichandran, K. S.
Right arrow Articles by Burakoff, S. J.
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

Journal of Experimental Medicine, Vol 179, 727-732, Copyright © 1994 by Rockefeller University Press


ARTICLES

Evidence for differential intracellular signaling via CD4 and CD8 molecules

KS Ravichandran and SJ Burakoff
Division of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115.

Although both the CD4 and CD8 molecules enhance antigen responsiveness mediated by the T cell receptor (TCR), it is not known whether CD4 and CD8 initiate similar or different intracellular signals when they act as coreceptors. To characterize the early signals transmitted by CD4 and CD8, both CD4 and CD8 alpha were expressed in the same murine T cell hybridoma. In the double positive transfectants, CD4 and CD8 associated with equal amounts of p56lck (Lck), and both molecules enhanced interleukin 2 (IL-2) production equivalently when cross-linked with suboptimal levels of anti-TCR antibody. However, in an in vitro kinase assay, cross-linking CD4 initiated fourfold greater kinase activity compared with CD8 cross-linking. In the same assay, when CD4 or CD8 was cross-linked to the TCR, novel phosphorylated proteins were found associated with the TCR/CD4 complex but not with the TCR/CD8 complex. Consistent with this data, antiphosphotyrosine immunoblotting revealed greater tyrosine phosphorylation of intracellular substrates after TCR/CD4 cross-linking compared with TCR/CD8 cross-linking. Additionally, a specific protein kinase C inhibitor (RO318220) inhibited CD8-mediated enhancement of IL-2 production far more effectively than CD4-mediated enhancement. Thus, it appears that CD8 alpha may depend more on a protein kinase C-mediated signaling pathway, whereas CD4 may rely on greater tyrosine kinase activation. Such differential signaling via CD4 and CD8 has implications for thymic ontogeny and T cell activation.
Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search
TABLE OF CONTENTS