Progression of rearrangements at T cell receptor beta and gamma gene loci during athymic differentiation of bone marrow cells in vitro.

A previously described in vitro system that supports T cell differentiation from bone marrow (BM) precursors was analyzed for T cell receptor gene rearrangement and expression. Cultured populations from days (d.) 0, 3, 6, and 12-13 were fused with BW5147. Only hybridomas from d.6 and d.12-13 bore BM-derived rearrangements. The rearrangement complexity was higher on d.12 than d.6 in that patterns consistent with D beta 1-J beta 1 and D beta 2-germ-line configurations decreased while V-D-J beta 2 and V gamma 2-J gamma 1 joining became dominant. Northern blots of d.13 BM cultures revealed gamma, alpha, and beta (1.0 and 1.3 kb) transcripts. Parallels between patterns in BM cultures and thymus ontogeny were recognized.