title: Assessment of human allospecific IL-2-secreting helper T lymphocytes in limiting dilution cultures using restimulation and split well analysis.
abstract: A limiting dilution (LD) culture was established which allows the detection of allospecific interleukin-2 (IL-2)-secreting helper T lymphocyte precursors (HTL-p) among human peripheral blood mononuclear cells (PBMNC). HTL-p stimulated with allogeneic Epstein-Barr virus-transformed B lymphoblastoid cell lines (EBV-LCL) in the presence of exogenous recombinant IL-2 (r-IL-2) clonally developed into IL-2 secreting effector cells when restimulated against the original stimulating alloantigen. Split well cultures were performed prior to restimulation to assess the antigen specificity of the response. Frequencies of alloreactive IL-2-secreting HTL-p ranged from 1/100 to 1/800. Allospecificity of effector T cells was determined by a strong decline of frequencies obtained after restimulation against third-party antigens. In (clonal) segregation analyses the vast majority of IL-2-secreting progenies (80%) were specific for the original stimulating alloantigen. Allele specificity was disclosed by using class II MHC related third-party restimulator cells. By comparison with LD short-term cultures it became evident that exogenous r-IL-2 in the initial culture period was required to reveal optimal precursor frequencies of IL-2-producing T cells. Furthermore, successful antigenic restimulation was strictly confined to these culture conditions.
authors.affiliation: Department of Internal Medicine III, University of Ulm, F.R.G.
authors.forename: M
authors.initials: M
authors.lastname: Theobald
authors.forename: T
authors.initials: T
authors.lastname: Hoffmann
authors.forename: W
authors.initials: W
authors.lastname: Heit
mesh_terms: D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D016827:CD8 Antigens; D002478:Cells, Cultured; D006412:Hematopoietic Stem Cells / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism* / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D016827:CD8 Antigens; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2; D011994:Recombinant Proteins