International Immunology, Vol. 11, No. 2, 169-177,
February 1999
© 1999 Japanese Society for Immunology
Differential effects of manipulating signaling in early T cell development in intestinal intraepithelial lymphocytes and thymocytes
1 Howard Hughes Medical Institute, and
2 Departments of Immunology, and
3 Biochemistry and Medicine (Medical Genetics), University of Washington, Seattle, WA 98195, USA
4 Centre d'Immunolgie, INSERM-CNRS de Marseille-Luminy, Case 906, 13288 Marseilles Cedex 9, France
Correspondence to: A. M. Pullen, Department of Pathology and Microbiology, School of Medical Sciences, Bristol University, University Walk, Bristol BS8 1TD, UK
A pre-TCR–CD3 signal is required for the efficient maturation of CD4–CD8– thymocytes to the CD4+CD8+ stage. This study addressed whether a similar signal is required for maturation of intestinal intraepithelial lymphocytes (IEL) that may develop extrathymically. We have shown previously that IEL from mice deficient for CD3-associated 
chains include an immature population of CD3–CD8
+ cells expressing cytoplasmic TCR ß chains but lacking detectable surface TCRß, CD16 and B220. Here we stimulated the appearance of such IEL in 
+/––/– mice by expression of an activated Lck transgene or in vivo treatment with anti-CD3. Anti-CD3 treatment of RAG-deficient animals also yielded CD16–B220– IEL. In contrast, expression of a TCRß transgene in rag-1–/– mice did not stimulate the appearance of CD3–CD8+CD16–B220– cells. Taken together these data indicate that although anti-CD3 treatment and LckF505 assist in catalyzing a CD16+B220+ 
CD16–B220– transition, these manipulations are not equivalent to a pre-TCR signal in IEL lymphocytes.
Keywords: CD3
, development, Fyn, intraepithelial lymphocyte, Lck, thymocyte
5 Present address: Merck Research Laboratories, PO Box 2000, RY80-A1, 126 East Lincoln Avenue, Rahway, NJ 07065, USA
6 Present address: Department of Pathology and Microbiology, School of Medical Sciences, Bristol University, University Walk, Bristol BS8 1TD, UK