CD3-associated alpha/beta and gamma/delta heterodimeric receptors are expressed by distinct populations of CD4- CD8- thymocytes.
Immature double negative (DN) CD4-8- thymocytes expressing the CD3 molecular complex can be subdivided into two distinct subsets based on expression of the B2A2 antigen. Thus, B2A2+ CD3+ DN thymocytes express CD3-associated 35 kDa and 45 kDa polypeptide chains characteristic of a gamma/delta T cell receptor, whereas B2A2- DN thymocytes express predominantly 38 to 43 kDa CD3-associated structures typical of alpha/beta TCR. At the mRNA level, B2A2+ DN thymocytes express full length gamma and delta transcripts but no alpha message and only short (1 kb) B transcripts. In contrast, the B2A2- DN subset expresses full length alpha and beta transcripts and minimal levels of delta transcripts. Interestingly, B2A2- DN thymocytes, unlike mature T cells, also express abundant levels of full length TCR gamma mRNA, perhaps suggesting that these cells represent an early stage after divergence of the gamma/delta and alpha/beta T cell lineages.
Miescher
G C
GC
Ludwig Institute for Cancer Research, Lausanne Branch, Epalinges, Switzerland.
Howe
R C
RC
Lees
R K
RK
MacDonald
H R
HR
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D017252:CD3 Complex; D005260:Female; D005786:Gene Expression Regulation; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000032:analysis; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis* / Q000235:genetics; D013601:T-Lymphocytes / Q000032:analysis* / Q000145:classification
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D012333:RNA, Messenger; D011948:Receptors, Antigen, T-Cell