title: Functional isotypes are not encoded by the constant region genes of the beta subunit of the T cell receptor for antigen/major histocompatibility complex.
abstract: Human T cell clones and a cDNA probe specific for constant regions of the beta subunit of the antigen/major histocompatibility complex (MHC) receptor, TiC beta 1 and TiC beta 2, were employed to determine whether these genes were differentially used by functional classes of T lymphocytes. DNA from 10 interleukin-2-dependent T cell clones including class I and class II MHC-specific cytotoxic T lymphocytes (n = 6), T4+ inducer T lymphocytes (n = 2), and T8+ suppressor T lymphocytes (n = 2) showed rearrangement of the TiC beta 1 gene on Southern blot analysis with or without deletion of the other TiC beta 1 allele. In contrast, TiC beta 2 always remained in germline configuration. Moreover, the finding that one additional suppressor clone deleted both TiC beta 1 alleles, maintained a germline TiC beta 2 configuration, and yet actively transcribed TiC beta 2 message suggested that TiC beta 2 is not a pseudogene. Rather, it appeared to be used less frequently than the TiC beta 1 gene and in the absence of detectable DNA rearrangements. Together, these results demonstrate that the functional repertoire (or isotype) of a given subclass of T cells is not encoded within the Ti beta genes.
mesh_terms: D002999:Clone Cells / Q000276:immunology; D004247:DNA / Q000235:genetics; D005802:Genes, MHC Class II; D005815:Genetic Code; D006680:HLA Antigens / Q000235:genetics*; D006801:Humans; D007126:Immunoglobulin Allotypes / Q000235:genetics*; D007127:Immunoglobulin Constant Regions / Q000235:genetics*; D007136:Immunoglobulins / Q000235:genetics*; D007376:Interleukin-2 / Q000502:physiology; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D013601:T-Lymphocytes / Q000145:classification
chemical_list: D006680:HLA Antigens; D007126:Immunoglobulin Allotypes; D007127:Immunoglobulin Constant Regions; D007136:Immunoglobulins; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D004247:DNA