Histologic analysis of inflamed F9 tumors after injection of Id-specific T cells. SCID mice with barely palpable subcutaneous F9 or F55 tumors were injected intravenously with purified Id-specific CD4+ T cells (1 × 106) and analyzed 4 to 5 days later. (A) Hematoxylin and eosin–stained section of paraffin-embedded acutely inflamed F9 (15 mm diameter) tumor. V indicates vessel; and T, tumor. Arrows mark some of the neutrophils infiltrating the perivascular edematous connective tissue. (B-C) Immunohistochemistry on cryosections of tumor tissue. Ly-6G (Gr-1) is shown in red, IgG in green, and nuclei (DAPI) in blue. Lymphoma cells express surface IgG2a and are therefore stained green. (B) F9 tumor in mice injected with T cells. (C) F9 tumor in mice not injected with T cells. (D) F55 tumor in mice injected with T cells. (E) Same tumor as in panel B, but stained for detection of Id-specific T cells (GB113, clonotype-specific, red) and IgG+ F9 cells. Original magnification, × 60.
