title: Rapid polarization of Th2 cells during induction of antigen-specific IgE antibodies in vitro.
abstract: BACKGROUND
  Type 2 T-helper cells (Th2) are involved in the regulation of the humoral immune response against antigens and allergens and directly affect which isotype will be produced. The mechanism that regulates antigen-specific IgE secretion and immune deviation is still not known.
  
  
  OBJECTIVE
  To delineate mechanisms behind antigen-specific IgE secretion we have used in vitro immunization and focused on T-cell phenotype and the activation status of the transcription factor NFkappaB.
  
  
  METHODS
  Peripheral blood lymphocytes (PBMC) from seronegative donors were immunized in vitro with a peptide consisting of both a T-cell and a B-cell epitope.
  
  
  RESULTS
  Antigen-specific IgE antibodies could be detected after a primary immunization, during which T-helper cells secreted type 2 cytokines. Specific IgE was also detected in the secondary immunization, but due to a rapid polarization from Th2 to Th1 phenotype, exogenous IL-4 was required for the specific IgE secretion. Analysis of NFkappaB activation in B and T cells during primary and secondary immunization showed that NFkappaB could be detected in both B and T cells during primary immunization, but was dependent on exogenous IL-4 in the secondary immunization.
  
  
  CONCLUSIONS
  This is the first evidence of antigen-specific IgE induction in vitro using naive B cells, demonstrating the involvement of T-helper cell phenotype and NFkappaB and demonstrates the usefulness of in vitro cultures to study the effect of antigens on human immunocytes.
authors.affiliation: Department of Immunotechnology, Lund University, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Akesson
authors.forename: S
authors.initials: S
authors.lastname: Ingvarsson
authors.forename: K
authors.initials: K
authors.lastname: Brady
authors.forename: P
authors.initials: P
authors.lastname: Moynagh
authors.forename: C A
authors.initials: CA
authors.lastname: Borrebaeck
mesh_terms: D000595:Amino Acid Sequence; D000941:Antigens / Q000737:chemistry / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D016764:Cell Polarity; D002478:Cells, Cultured; D000939:Epitopes; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D006801:Humans; D007114:Immunization; D007117:Immunization, Secondary; D007073:Immunoglobulin E / Q000096:biosynthesis* / Q000097:blood; D015847:Interleukin-4 / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D013745:Tetanus Toxoid / Q000737:chemistry / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology*
chemical_list: D000941:Antigens; D000939:Epitopes; D015699:HIV Envelope Protein gp120; D016328:NF-kappa B; D010455:Peptides; D013745:Tetanus Toxoid; D015847:Interleukin-4; D007073:Immunoglobulin E