Enhancement of tumor cell susceptibility to tumor-infiltrating lymphocytes by cisplatin

Augmenting major histocompatibility complex class I expression by murine tumors in vivo enhances antitumor immunity induced by an active immunotherapy strategy

OBJECTIVE

Tumors down-regulate major histocompatibility complex class I expression, escaping recognition by the cellular immune response. We hypothesized that augmentation of tumor cell class I expression by interferon-gamma would enhance the cellular antitumor immune response and cure rate of an active immunotherapy strategy.

METHODS

B16.F10 tumor cells were exposed to interferon-gamma in culture, and class I expression was quantified using flow cytometry. Syngeneic mice bearing established tumors were injected with interferon-gamma (5000 U, intraperitoneal), and class I expression was assessed using immunohistochemistry. Tumor-specific cytotoxic T lymphocytes were induced in mice by an intratumoral injection of AdCD40L (5 x 10(10) particles), an adenovirus gene transfer vector-based immunotherapy strategy previously demonstrated to augment cellular antitumor immunity. A conjugate-formation assay and the enzyme-linked immunospot assay were used to evaluate the binding and activation of cytotoxic T lymphocytes, respectively. Interferon-gamma was administered to tumor-bearing mice concomitantly with intratumoral AdCD40L. End points measured included the frequencies of cytotoxic T lymphocytes using the enzyme-linked immunospot assay, tumor size, and mouse survival. The role of class I expression was further evaluated by monoclonal antibody blockade in both in vitro and in vivo experiments.

RESULTS

B16.F10 cells exposed to interferon-gamma expressed significantly more class I, both in vitro and in vivo, and were able to bind to and activate cytotoxic T lymphocytes more efficiently than untreated cells. Cytotoxic T-lymphocyte frequencies, tumor regression, and the cure rate induced by AdCD40L were augmented by the addition of a single dose of interferon-gamma in tumor-bearing mice. These in vitro and in vivo effects of interferon-gamma were attenuated by class I monoclonal antibody blockade.

CONCLUSIONS

Up-regulation of class I expression using interferon-gamma enhances the cellular antitumor immune response and cure rate of AdCD40L, an active immunotherapy strategy. This approach may be useful for human tumors that lack class I expression.

Potent activity of soluble B7RP-1-Fc in therapy of murine tumors in syngeneic hosts

We have characterized a receptor:ligand pair, ICOS:B7RP-1, that is structurally and functionally related to CD28:B7.1/2. We reported previously that B7RP-1 costimulates T cell proliferation and immune responses (Yoshinaga et al., Nature 1999;402:827-32; Guo et al., J Immunol 2001;166:5578-84; Yoshinaga et al., Int Immunol 2000;12:1439-47). We report that B7RP-1-Fc causes rejection or growth inhibition of Meth A, SA-1 and EMT6 tumors in syngeneic mice. Established Meth A tumors were rejected effectively with a single dose of B7RP-1-Fc, however, the treatment was less effective on larger tumors. Mice that rejected Meth A tumors previously by Day 30, also rejected a subsequent Meth A challenge on Day 60, without additional B7RP-1-Fc treatment, indicating a long-lived memory response. Tumor cells believed to be less immunogenic, such as P815 and EL-4 cells, were less responsive to this treatment. The EL-4 responsiveness to the B7RP-1-Fc treatment was enhanced, however, by pre-treatment of the mice with cyclophosphamide. As expected, T cells appeared to be targeted by B7RP-1-Fc treatment. Thus, the administration of soluble B7RP-1-Fc may have therapeutic value in generating or enhancing anti-tumor activity in a clinical setting.

Clinical effect of immunochemotherapy for a patient with advanced gallbladder cancer: report of a case

A 56-year-old woman was admitted presenting with a sensation of abdominal fullness. She was diagnosed to have advanced gallbladder cancer with carcinomatous peritonitis, as well as lymph node and liver metastases. We obtained highly purified tumor cells and tumor-infiltrating lymphocytes (TIL) from extirpated cervical lymph nodes and peritoneal effusion, and the chemosensitivity of these cells was tested with an MTT assay. Intensive chemotherapy with cisplatin (CDDP) and 5-fluorouracil (5-FU) was then performed according to the results of the MTT assay. Thereafter, cytotoxic T-lymphocytes (CTL) were induced in mixed cultures of autologous tumor cells and peripheral blood lymphocytes, and adoptive immunotherapy was performed with TIL and CTL. The malignant ascites and metastatic lesions disappeared after the intraperitoneal administration of CDDP and the transfer of TIL and CTL, and subsequently the patient's quality of life improved. This patient could return to work; however, liver metastasis was later observed, and she died 14 months after the initial diagnosis. Combination therapy with anticancer drugs and activated killer cells was thus found to be effective in a patient with advanced gallbladder cancer.