Expression of T-cell receptor beta-chain mRNA and protein in gamma/delta T-cells from euthymic and athymic rats: implications for T-cell lineage divergence.
The relationship between alpha/beta and gamma/delta T-cell lineages was studied in rats using RT-PCR analysis of TCRbeta transcripts in gamma/delta T-cell hybridomas and an intracellular staining technique to detect TCRbeta protein in primary gamma/delta T-cells. We report the presence of functional TCRbeta transcripts in 2/9 gamma/delta T-cell hybridomas. About 15% of peripheral gamma/delta T-cells and thymocytes also express TCRbeta protein, giving a minimum estimate for successful Tcrb rearrangement based on ex vivo single cell analysis. In athymic rats, gamma/delta T-cells expressing intracellular beta protein are present but at a lower frequency than in euthymic controls, suggesting that in the thymus, more gamma/delta T-cell precursors pass through a stage where functional beta rearrangement has occurred than in extrathymic sites. Analysis of TCR expression in purified transitory immature CD4-8+ (iCD8SP) thymocytes and their spontaneously developing CD4+8+ (DP) progeny showed that TCRy mRNA is expressed in iCD8SP cells but not in their immediate DP progeny that reinitiate RAG-I transcription and commence alpha/betaTCR expression. We conclude that rat gamma/delta T cells can separate from the alpha/beta lineage after TCRbeta expression, but not after entry into the DP compartment.
Bischof
A
A
Institute for Virology and Immunobiology, Würzburg, Germany.
Park
J H
JH
Hünig
T
T
D000818:Animals; D002454:Cell Differentiation; D019070:Cell Lineage; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D018398:Homeodomain Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011917:Rats, Inbred Lew; D011923:Rats, Nude; 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 / Q000166:cytology / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D018398:Homeodomain Proteins; D012333:RNA, Messenger; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; C064658:RAG-1 protein