Expression of gp96 on the surface of tumor cells leads to increased infiltration by both CD4+ and CD8+ T cells. A total of 5 x 10⁵ Meth A-96tm or Meth A-neo cells were injected intradermally into BALB/c mice, followed by surgical excision of the palpable tumors which were snap-frozen in liquid nitrogen on day +6. Ten-micron cryostat sections were fixed in acetone and immunostained with antibodies against CD4, CD8, sequentially incubated with biotinylated secondary antibody and streptavidin-HRP, and developed with H₂O₂ and diaminobenzidine. An image of a representative section, taken at 100x magnification, is shown.