title: 3A1 (CD7) expression precedes T beta gene rearrangements in precursor T (lymphoblastic) neoplasms.
abstract: The phenotypes of early stages of T cell maturation are reflected by precursor T (lymphoblastic) neoplasms. In the present study, a series of such neoplasms was analyzed to reveal the developmental association of the expression of stage-related cell surface markers and T cell receptor gene rearrangement. Rearrangements of the T cell receptor beta-chain (T beta) gene were found in most, but not all, cases (88%) of T cell lymphoblastic neoplasms. T beta gene rearrangement preceded surface expression of the T cell receptor-linked molecular complex T3. Of all monoclonal anti-T cell antibodies tested, only antibody 3A1 was capable of reacting with neoplastic cells from all cases irrespective of the occurrence of T cell receptor gene rearrangements. In contrast, markers T1 and T11, normally expressed by mature T cells, were absent from the neoplastic cells in many cases (73% and 60% positive cases, respectively). Thus, antibody 3A1 is a valuable probe for the identification of T lymphoblastic neoplasms since its target antigen is consistently expressed and does not require prior T beta gene rearrangement. Furthermore, expression of 3A1 prior to T beta gene rearrangement suggests that it may be a cell surface protein that participates in the triggering of T cell receptor gene rearrangement and expression. It is concluded that precursor T cell neoplasms display an early T cell development hierarchy that, in sequence, consists of 3A1 expression, T beta gene rearrangements, and surface T3 expression.
mesh_terms: D002454:Cell Differentiation; D004262:DNA Restriction Enzymes; D004587:Electrophoresis, Agar Gel; D005838:Genotype; D006801:Humans; D007938:Leukemia / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D008223:Lymphoma / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D013601:T-Lymphocytes / Q000473:pathology
chemical_list: D011948:Receptors, Antigen, T-Cell; D004262:DNA Restriction Enzymes