Figure 1.

APC purified from MOPC315 tumors are spontaneously primed with Id and stimulate T cells. (A) Transiently (APC I) and permanently (APC II) plastic-adherent cells were isolated from tumors and spleens of BALB/c mice with large s.c. MOPC315 (1.4–2.5 cm, serum M315 140–420 μg/ml) or J558 tumors, irradiated, cultured with LN cells from either N-TG or TCR-TG mice, and IL-2 in supernatants determined. As a positive control, 91-101 (λ2³¹⁵) synthetic peptide was added to cultures. (B) APC I, isolated from intermediate (0.5–1.5 cm) and large (1.5–2.5 cm) size MOPC315 tumors established in TCR-TG mice, were tested for their ability to stimulate Th1-polarized TCR-TG SCID LN cells. Isolated APC II gave similar results.