T and B cells that recognize the same antigen do not transcribe similar heavy chain variable region gene segments.
We have attempted to determine whether T cells and B cells that have the same antigenic specificity and whose receptors share idiotypic determinants in fact express similar VH gene segments. To do this, we have obtained and characterized a cDNA clone containing the entire coding sequence for the VH gene from a glutamic acid60/alanine30/tyrosine10 (GAT)-binding immunoglobulin that carries the CGAT idiotype. The GAT-VH clone was hybridized to Northern blots of GAT-specific T cell RNAs; there was no evidence of a T cell transcript that hybridized to the GAT-VH probe. The T cells analyzed included: (a) 10 GAT-binding suppressor T cell hybridomas, 6 of which secreted factors with CGAT idiotypic determinants, (b) one GAT-specific helper T cell hybridoma, and (c) two GAT-specific helper T cell lines grown in the absence of feeder cells. The detection limit of the Northern blot analysis was 1-2 copies of a particular mRNA species per cell for the hybridomas and 5-10 copies per cell for the T cell lines. Therefore, we conclude that T and B lymphocytes responding to GAT do not utilize similar VH gene segments. Furthermore, the presence of idiotypic determinants on T lymphocytes does not necessarily imply close structural similarity between T and B cell antigen receptors.
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001666:Binding Sites, Antibody / Q000235:genetics*; D002460:Cell Line; D004247:DNA; D004274:DNA, Recombinant; D000939:Epitopes / Q000276:immunology*; D006825:Hybridomas / Q000276:immunology; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D051379:Mice; D009693:Nucleic Acid Hybridization; D010455:Peptides / Q000276:immunology*; D011108:Polymers; D012333:RNA, Messenger / Q000235:genetics; D011946:Receptors, Antigen / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology*; D014158:Transcription, Genetic
D004274:DNA, Recombinant; D000939:Epitopes; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D010455:Peptides; D011108:Polymers; D012333:RNA, Messenger; D011946:Receptors, Antigen; C020749:GAT; D004247:DNA