Commitment and maintenance of the alpha beta and gamma delta T cell lineages.
We have generated transgenic mice using a rearranged, functional TCR-gamma gene that lacks the C gamma 1 3' silencer element, together with a TCR-delta cDNA construct designed for expression in lymphoid cells. All transgenic mice that descended from nine founders expressed alpha beta T cells and elevated levels of gamma delta T cells at various ratios. This observation does not support the proposal that alpha beta T cells are generated from T precursors in which C gamma 1 genes have been repressed via the cis-acting 3' silencer element, but it supports the idea that lineage commitment occurs independently of TCR gene expression. In seven transgenic lines, despite the absence of the 3' C gamma 1 silencer on the gamma transgene, the transgenic TCR is expressed only in gamma delta and not in alpha beta T cells. In the other two lines, in addition to T cells that express either the alpha beta or gamma delta TCR, a substantial fraction of T cells expresses both alpha beta and gamma delta TCR. These two lines also carry the highest number of copies of TCR-gamma transgene. However, in general, there is no correlation between the copy number of the gamma transgene and the fraction of T cells expressing the gamma delta TCR. The implications of these data are discussed.
Sim
G K
GK
Basel Institute for Immunology, Switzerland.
Olsson
C
C
Augustin
A
A
D000375:Aging / Q000276:immunology; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D005314:Embryonic and Fetal Development / Q000276:immunology; D005434:Flow Cytometry; D051379:Mice; D008822:Mice, Transgenic; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis / Q000235:genetics*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000096:biosynthesis / Q000235:genetics*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000196:embryology*
D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta