Tumor cells injected into the immunologically privileged anterior chamber (AC) of the eye grow progressively and induce an abnormal immune response (ACAID) that allows immunogenic tumor cells to escape immune-mediated elimination. The following experiments were performed to determine if the expression of the costimulatory B7-1 molecule on P815 tumor cells prevents immune privilege and progressive tumor growth within the AC of BALB/c mice. To this end, P815 cells were transfected with the episomal vector pBMGNeo that contained murine B7-1 cDNA. Transfected P815 cells (P815-B7-1+) constitutively expressed B7-1 on the cell surface. Groups of BALB/c mice received AC inoculations of P815-B7-1+ cells, and tumor growth was determined quantitatively by slit-lamp examination. Two types of negative controls were used in these experiments: 1) untransfected P815 cells, and 2) P815 cells transfected with empty pBMGNeo vectors that did not contain B7-1 cDNA. The P815-B7-1+ tumor cells grew progressively, and filled 100% of the AC by day 10 post-inoculation. During this time, the growth of B7-1+ tumor cells was not significantly different from the growth of either untransfected P815 cells or P815 cells transfected with empty pBMGNeo vectors. By contrast, between days 10 and 21 post-inoculation, P815-B7-1+ cells were eliminated completely, while tumors in control mice continued to grow progressively. Elimination of B7-1+ tumor cells was dependent upon T and/or B cells, as demonstrated by the growth of B7-1+ tumors in the AC of SCID mice. We conclude from these experiments that the expression of B7-1+ on P815 tumor cells prevents tumor cells from enjoying immune privilege within the anterior chamber of the eye.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Dec 1 1994|
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