|
||
Involvement of the TCR Cß FG Loop in Thymic Selection and T Cell Function
2 Department of Medicine, Harvard Medical School, Boston, MA 02115
3 Department of Pediatrics, Harvard Medical School, Boston, MA 02115
4 Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
Address correspondence to Dr. Ellis L. Reinherz, Dana-Farber Cancer Institute, 44 Binney St., Boston, MA 02115. Phone: 617-632-3412; Fax: 617-632-3351; E-mail: ellis_reinherz{at}dfci.harvard.edu
The asymmetric disposition of T cell receptor (TCR) Cß and C
ectodomains creates a cavity with a side-wall formed by the rigid Cß FG loop. To investigate the significance of this conserved structure, we generated loop deletion (ß
FG) and ßwt transgenic (tg) mice using the TCR ß subunit of the N15 CTL. N15ßwt and N15ß
FG H-2b animals have comparable numbers of thymocytes in S phase and manifest developmental progression through the CD4-CD8- double-negative (DN) compartment. N15ß
FG facilitates transition from DN to CD4+8+ double-positive (DP) thymocytes in recombinase activating gene (RAG)-2-/- mice, showing that pre-TCR function remains. N15ß
FG animals possess
twofold more CD8+ single-positive (SP) thymocytes and lymph node T cells, consistent with enhanced positive selection. As an altered V
repertoire observed in N15ß
FG mice may confound the deletion's effect, we crossed N15
ß TCR tg RAG-2-/- with N15ß
FG tg RAG-2-/- H-2b mice to generate N15
ß RAG-2-/- and N15
ß.ß
FG RAG-2-/- littermates. N15
ß.ß
FG RAG-2-/- mice show an 810-fold increase in DP thymocytes due to reduced negative selection, as evidenced by diminished constitutive and cognate peptide-induced apoptosis. Compared with N15
ß, N15
ß.ß
FG T cells respond poorly to cognate antigens and weak agonists. Thus, the Cß FG loop facilitates negative selection of thymocytes and activation of T cells.
Key Words: negative selection thymocyte development TCR structure Ig superfamily transgenic mice
![]()
CiteULike
Complore
Connotea
Del.icio.us
Digg
Facebook
Reddit
Technorati
Twitter What's this?
This article has been cited by other articles:
| TABLE OF CONTENTS |
|