FIG. 4.
CTB-conjugated antigens induce enhanced IFN-γ secretion in vitro. (A through C) IFN-γ production by HA-specific TCR-transgenic T cells following incubation with HA peptide or HA-CTB-treated APC. Data are expressed as the concentrations of IFN-γ in 48-h culture supernatants obtained with different concentrations of HA peptide (□), chemical CTB-HA peptide (■), and genetic CTB-HA peptide (●) using DC (A), B cells (B), or Mφ (C) as APC. (D through F) IFN-γ production by OVA-specific TCR-transgenic T cells following incubation with antigen-pulsed DC (D), B cells (E), or Mφ (F). Data are expressed as the concentrations of IFN-γ in 48-h culture supernatants using different concentrations of OVA (◊), CTB-OVA (⧫), OVA peptide (▿), and CTB-OVA peptide (▾). Data represent one of two experiments using 105 purified T cells with 105 APC.