T-cell helper activity promoting anti–GPIIb-IIIa antibody production from B cells in GPIIb-IIIa–reactive CD4⁺ T-cell lines.

(A) GPIIb-IIIa–reactive T-cell lines were cultured with autologous peripheral blood B cells in the presence or absence of GST or individual recombinant GPIIb-IIIa fragments for 10 days. (B) GPIIb-IIIa–reactive T-cell lines were cultured with autologous peripheral blood B cells and the antigenic GPIIb-IIIa fragment in the presence or absence of anti–IL-6 (1, 5, 25, and 50 μg/mL), anti–IFN-γ (25 μg/mL), anti–IL-4 (25 μg/mL), or isotype-control (25 μg/mL) mAbs for 10 days. The level of anti–GPIIb-IIIa antibodies in culture supernatants was measured by ELISA.