Fetal calf serum-injected F1 mice spontaneously generate specific anti-parental cytotoxic T lymphocytes in in vitro culture

Effective induction of human NK cells with OK-432 and further augmentation of their cytolytic function by rIL-2

Low concentrations of exogenously added recombinant interleukin 2 (rIL-2) were able to augment OK-432-induced natural killer (NK) cell activity. This kind of augmenting effect depended on the dose of rIL-2 and manifested itself only in PBMC stimulated with OK-432 (OK-MC) followed by rIL-2; augmentation did not happen in the reverse order. The existence of CD16+/CD25+ (IL-2 receptor positive; IL-2R+) and CD57+/CD25+ double positive cells which possess NK cell surface markers in OK-MC markedly increased in a long-term culture (12 days). A strong positive correlation was observed between the IL-2-dependent augmentation of NK activity and the quantitative changes in cell populations that possessed NK cell phenotypes. Treatment of the day-12-OK-MC with monoclonal anti-CD56 antibody plus complement could almost completely abrogate the augmented NK cytotoxicity. Furthermore, this augmenting effect was detectable within 4 hr after addition of rIL-2 at single cell level, suggesting that the effect did not require NK cell's DNA synthesis. Thus it was suggested that OK-432 could promote and upregulate the expression of IL-2 receptor (CD25) on CD56+ NK cell populations. Moreover, it was considered that the interaction of low concentration rIL-2 with IL-2 receptors on OK-432-activated NK cells could augment their lytic function.

Tumoricidal effect of human PBMC following stimulation with OK-432 and its application for locoregional immunotherapy in head and neck cancer patients

Both cell-mediated and cytokine-mediated antitumor activities were induced in peripheral blood mononuclear cells (PBMC) in short-term culture with streptococcal preparation, OK-432. Kinetic analysis of OK-432-activated killer activity (OKAK) showed that it reached a plateau level much faster (by 48 h of culture) than that detected in PBMC stimulated with recombinant interleukin 2 (rIL-2) (lymphokine-activated killer: LAK). We also found that the tumor growth inhibitory factor (TGIF) activity was produced in the culture supernatant (CSN) of the OK-432-activated PBMC (OK-MC) and the activity synchronously increased with augmentation of OKAK activity. The TGIF activity was rarely found in the CSN of rIL-2-stimulated PBMC. The TGIF activity detected in CSN of OK-MC was further characterized as derived from a cytokine different from interferon gamma (IFN gamma), tumor necrosis factor (TNF), or lymphotoxin (LT) by a neutralization test using monoclonal antibodies to these cytokines. These 48-h-cultured-OK-MC were adoptively transferred (adoptive immunotherapy: AIT) into 19 head and neck cancer patients either alone or in combination with chemotherapy and/or radiation therapy, and their therapeutic effects were examined. AIT was performed by intra-arterial or intratumoral administration of OK-MC. There were no significant side effects observed in this treatment. In these patients, approximately 1-10 x 10(7) cells were transferred into the tumor burden. Of the 19 patients, 17 had primary cancer, and in 6 (6/17;35%) of them complete remission (CR) of the tumor was obtained. Partial remission (PR) was attained in 9 of the 17 patients (9/17; 53%), giving the overall response rate of 88%.(ABSTRACT TRUNCATED AT 250 WORDS)