Table 2

When the tumor stroma does not present antigen, gp33-Hi tumors escape a CTL response as ALVs.

Cell line Stroma T cells Tumor outgrowth in experiment no.1 Total
1 2 3 4 Tumor growth Antigen retained2
gp33 C3H - - 1/1 1/1 - 2/2 2/23
+ 1/2 4/4 - - 5/6 0/54
B6 - 1/1 1/1 1/1 2/2 5/5 2/25
+ 0/2 0/2 - 0/3 0/7 N.A.6
B6 → C3H - - - - 1/1 1/1 N.D.
+ - - - 5/5 5/5 0/57
C3H → B6 - - - - 1/1 1/1 1/1
+ - - - 3/3 3/3 N.D.
B6 → B6 - - - - 1/1 1/1 N.D.
+ - - - 0/3 0/3 N.A.

1C3H Rag2(-/-) and C57BL/6 Rag1(-/-) were challenged with 1-3 x 106 cancer cells. 14-16 days after tumor challenge, mice were treated i.v. with in vitro activated P14 T cells. Tumor outgrowth was assessed after 30 d. 2Unless otherwise noted, averages are from two independent experiments. 360.6 ± 17.7% of the reisolated cells expressed antigen above background levels. The average fold increase in antigen expression was 41.4 ± 8.3. 40.47 ± 0.1% of the reisolated cells expressed antigen above background levels. The average fold increase in antigen expression was 4.4 ± 3.1. 561.6 ± 16.4% of the reisolated cells expressed antigen above background levels. The average fold increase in antigen expression was 38.9 ± 7.8. 6N.A. = Not applicable. 70.2 ± 0.1% of the reisolated cells expressed antigen above the secondary staining. The average fold increase in antigen expression was 1.1 ± 0.1. Averages are from one experiment.