Figure 8.

Single-dose cyclophosphamide induces concomitant immunity when administered 4 d before primary tumor inoculation. (A) Mice (10/group) were treated with cyclophosphamide on day −4, inoculated with B16 cells in the right flank on day 0, and reinoculated with B16 in the left flank on day 6. The left graph represents growth of primary tumors, the middle graph depicts growth of challenge tumors, and the right graph shows growth of the challenge tumor inoculum in naive mice that were treated with cyclophosphamide according to the same schedule. (B) Incidence of B16 secondary tumors (left flank) was measured in mice bearing day-6 primary tumors and receiving the following: no treatment or cyclophosphamide treatment on days −4, −2, or 0 relative to primary tumor inoculation. The difference between challenge tumor incidence in untreated mice and those that received cyclophosphamide on day −4 was statistically significant (P = 0.002) as determined by log rank analysis.