Cellular mechanism for tumor rejection mediated by cell surface targeting of gp96. (A) Cellular requirement for eliciting effective primary anti-tumor immune responses by Meth A-96tm. Wild type syngeneic BALB/c mice were depleted of CD4+, CD8+ cells or phagocytes on day -1 and then injected with 5 x 10⁵ Meth A-96tm cells on day 0. The average growth kinetics of 5 mice per group is plotted. The numbers in parenthesis indicate the number of tumor-free mice in each group at the end of the experiment. (B) Cellular requirement for eliciting anti-tumor memory immune responses by cell surface gp96. Mice were immunized with 5 x 10⁵ live Meth A-96tm cells on day -30, depleted of various subsets of cells on day -1, and re-challenged with 5 x 10⁵ wild type Meth A cells on day 0. These results were replicated three times.