title: Rapid identification of antigenic T-cell epitopes by extracellular acidification rate signals.
abstract: We used a silicon-based biosensor, a microphysiometer, to measure real-time extracellular acidification rate signals associated with T lymphocyte responses to peptide ligands interacting with the T-cell receptor (TCR). We compared these effector responses with those of interferon-gamma (IFN-gamma) production, and T-cell proliferation. Within minutes, major histocompatibility complex (MHC)-bound peptides on antigen-presenting cells (APCs) engaged the TCR to increase acidification rates of the extracellular media was measured by microphysiometer. We exposed two myelin peptide-specific human T-cell clones, MSF132E11 (DRB1*1501 restricted) and TOM3A6 (DRB5*0101 restricted), to truncated analogues of the parent MBP 84-102 peptide, in the presence of MHC restricted human antigen-presenting cells, and measured the extracellular acidification rate signal changes, IFN-gamma production and T-cell proliferation. The core epitopes recognized by these clones were identified by microphysiometer and found to be MBP 88-100 and MBP 91-100, respectively. These epitopes were identical to those identified by the IFN-gamma and proliferation assays. We conclude that measurement of real-time extracellular acidification rate signals by the microphysiometer may facilitate rapid identification of human T-cell epitopes involved in immune disorders and the development of specific T-cell antagonists.
authors.affiliation: Corixa Corporation, Redwood City, California 94063, USA.
authors.forename: S
authors.initials: S
authors.lastname: Arimilli
authors.forename: M C
authors.initials: MC
authors.lastname: Howard
authors.forename: C C
authors.initials: CC
authors.lastname: Nacy
authors.forename: S V
authors.initials: SV
authors.lastname: Deshpande
mesh_terms: D000409:Alanine / Q000378:metabolism; D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods*; D002455:Cell Division; D002478:Cells, Cultured; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry* / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D008024:Ligands; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D013997:Time Factors
chemical_list: D018984:Epitopes, T-Lymphocyte; D008024:Ligands; D010455:Peptides; D007371:Interferon-gamma; D000409:Alanine