Induction of antitumor humoral and cellular responses by 4TOO and FC/4TOO fusion cell immunization.
(A) Balb/c mice (6 per group) were immunized twice subcutaneously with 1 × 106 irradiated 4TOO plasmacytoma cells (■), FC/4TOO cells (●), or DCs (□). PBS (○) was used as a control. Serum was collected on day 7 after the last immunization and was examined for reactivity with 4TOO cell lysates by enzyme-linked immunosorbent assay. (B) Balb/c mice (3 per group) were twice immunized with FC/4TOO. The sera were collected and added to plates coated with lysates from 4TOO (●), MPC-11 (▴), or SKO-007 (□) cells. (C) Splenocytes were isolated 7 days after vaccinating twice with 1 × 106 irradiated 4TOO cells (■), FC/4TOO cells (●), DCs (□), or PBS (○). The T cells were purified by nylon wool columns and incubated with 4TOO targets at the indicated ratios. (D) CTLs isolated from mice twice immunized with FC/4TOO were analyzed: CTL activity against 4TOO (●), MPC-11 (▴), or SKO-007 (□) targets. CTL activity was determined by the 51Cr release assay. The CTL results are expressed as the mean ± SD of 3 replicates.
