The anti-tumor effect of in vitro tumor-stimulated autologous peripheral blood lymphocytes measured by the subrenal capsule assay

Establishment of cytotoxic CD4+ T cell clones from cancer patients treated by local immunotherapy

We have previously reported that the antitumor effect of OK-432, a Streptococcal preparation, is markedly augmented when injected intratumorally together with fibrinogen (Cancer, 69: 636-642, 1992). In order to elucidate the mechanism of the antitumor effects, we established T cell clones from regional lymph nodes of colorectal cancer patients who received this local immunotherapy. By culture of lymph node lymphocytes, in the presence of IL-2 and OK-432, 4 clones of T cells were established from 4 patients treated by local immunotherapy. These clones had a helper T cell phenotype (CD3+, CD4+, CD8-, CD56-, WT31+) and were successfully maintained for several months. The cells strongly expressed CD25 when stimulated with OK-432 and exhibited a high level of cytotoxic activity in part explained by the increased expression of ICAM-1 and LFA-1, and the release of TNF beta. These results suggest that the CD4+ T cells play a role in the antitumor mechanism of local immunotherapy.

[Establishing three dimensional tumors in vitro and the reaction of the lymphokine-activated killer cells (LAK) to the three dimensional tumors]

In this study, we attempted to develop a technique, by which three-dimensional tumors were produced from two cultured head and neck tumor cell lines (Hep2, KB) and a colon adenocarcinoma cell line (HT29) using fibrinogen, thrombin, and double layered agar system. The three-dimensional tumor was large enough to perform the histologic study, which showed no significant histologic difference in comparison with the histologic findings of the xenografted tumor on nude mice. Furthermore, we applied this assay model to evaluate the antitumor effect of lymphokine activated killer (LAK) cells on the three-dimensional tumor produced by the technique. When tumor cells were cocultured with LAK cells, the damage of the three-dimensional structure due to the degeneration of tumor cells was observed. These findings suggest that the three-dimensional tumor may be useful to evaluate the antitumor effect of LAK cells in term of head and neck solid tumors.