Selective elimination of B7⁺ tumor cells by P1CTL from a mixture of B7⁺ and B7⁻ tumor cells: flow cytometric analysis of the composition of B7⁺ and B7⁻ tumors in the presence or absence of P1CTL.

Single viable cell suspensions were prepared from freshly isolated tumors and were stained with anti–B7-1 mAb hybridoma supernatants (bold lines) or medium as control (thin lines). (A) J558-B7 or J558 tumor cells in separate mice. (B) J558-Neo and J558-B7 cells were mixed before injection. Tumors in panels i-ii were from mice that received no T cells; those in panels iii-iv received 5 × 10⁶ of CD28^+/− T cells, and those in panels v-vi received 5 × 10⁶ of CD28^−/− T cells.