Studies of the enhancement of natural cytotoxicity by the streptococcal immunopotentiator OK432

Inhibition by streptococcal immunopotentiator OK432 of lymph-node metastasis in hamster cheek-pouch carcinoma with enhancement of tumour necrosis factor-alpha and interleukin-6 in serum

A well-known metastic model of human oral cancer employs 9,10-dimethyl-1,2-benzanthracene (DMBA) to induce hamster cheek-pouch carcinoma. Streptococcal immunopotentiator OK432 was studied here for its inhibitory effect on lymph-node metastasis in that model. The intraperitoneal administration of OK432, after excision of cheek-pouch tumours induced by DMBA, resulted in a marked reduction in the incidence of cervical lymph-node metastasis to 7%, a significant decrease beneath the rates observed for control animals not receiving OK432 (40%). OK432 also caused an increased in serum levels of tumour necrosis factor-alpha and interleukin-6 in tumor-bearing hamsters. These results suggest that the immune response may play an important part in the antimetastatic effects of OK432.

Enhancement of natural killer cell activity in human immunodeficiency virus-infected subjects by in vitro treatment with biologic response modifier OK-432

A decrease in natural killer (NK) cell function has been related to the progression of human immunodeficiency virus (HIV) infection. In the present study, we assessed the ability of a streptococcus-derived biologic response modifier, OK-432, to augment NK lysis of uninfected K562 and U937 cells and HIV-infected U937 cells by peripheral blood mononuclear cells (PBMC) from HIV-seropositive homosexual men. Optimal two- to fourfold increases in lysis of the three targets were observed after pretreatment of PBMC from HIV-negative subjects for 4 h with 2 micrograms of OK-432 per ml. This effect was related primarily to gamma interferon (IFN-gamma) production induced by OK-432 and was not linked to production of tumor necrosis factors alpha and beta or to monocytes in the cultures. The enhancing effect of OK-432 on NK cell function was diminished but still evident in PBMC from subjects with relatively early-phase (< 3-year) HIV infection and high CD4+ cell counts and was lower in subjects with longer-term HIV infection (> 3 years), in association with reduced production of IFN-gamma. Augmentation of NK cell activity in HIV-infected men by OK-432 was comparable to that induced by treatment of cells with 1,000 U of IFN-alpha or interleukin 2 per ml. The data suggest that the NK cell-enhancing effects of OK-432 are at least in part mediated by IFN-gamma and that OK-432 may be effective in treatment of patients with early-phase HIV infection.

Enhancement of polymorphonuclear leukocyte (PMN) function by OK-432

The influence of OK-432, a streptococcal preparation, on human polymorphonuclear leukocytes (PMN) was examined. OK-432 increased O2- generation was also observed when PMN were cultured with 10(-2)KE/ml OK-432 for 1 h and then stimulated with phorbol myristate acetate or formyl-metionyl-leucil-phenylalanine (FMLP). In addition, PMN O2- generation was promoted by culture supernatants of peripheral blood mononuclear cells (PBMC) incubated with 10(-3) or 10(-2) KE/ml OK-432. Furthermore, OK-432 (10(-3)-10(-2) KE/ml) enhanced the chemiluminescence of FMLP- and PMA-stimulated PMN. However, nitroblue tetrazolium reduction and myeloperoxidase activity were only minimally enhanced. Not only the candidacidal activity of PMN but also antibody-dependent cell-mediated cytotoxicity against Candida and Raji cells were enhanced in correspondence with the increased generation of reactive oxygen species. Culture of PMN or PBMC for 24 h with OK-432 resulted in a concentration-dependent increase in the substantial production of interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha. OK-432 also enhanced granulocyte-macrophage colony stimulating factor and gamma-interferon generation by leukocytes in a dose-dependent manner. Our research indicates that OK-432 enhances PMN function directly as well as via the promotion of cytokine production, and suggests that these effects of OK-432 could be beneficial in immunosuppressed patients.

Local injection of OK-432/fibrinogen gel into head and neck carcinomas

Immunotherapy with biological response modifiers (BRM) is a possible strategy against head and neck solid tumours. However, the rapid disappearance of BRM from the tumour area is one of the reasons for its limited clinical application. In this pilot study, fibrinogen gel containing OK-432 (a compound composed of attenuated Streptococcus pyogenes), an inducer of natural killer cells and T-cell cytotoxity, was injected directly into head and neck solid tumours of 15 patients. A dose of 5 Klinische Einheiten (KE) of OK-432 was reconstituted in 1 ml aprotinin and mixed with fibrinogen, the latter to maintain the OK-432 locally. 3 patients showed tumour regression, and in addition, we observed histological changes in the injected tumour of all patients. These results suggest that OK-432/fibrinogen gel generates a local immune response, leading to tumour regression.

Comparison of OK-432 and mitomycin C pleurodesis for malignant pleural effusion caused by lung cancer. A randomized trial

A prospective randomized study to compare the effectiveness of pleurodesis by two new sclerosing agents: OK-432 and mitomycin C were conducted in 53 patients with malignant pleural effusion caused by lung cancer. None of the patients received concomitant systemic chemotherapy or radiation therapy during the study. After complete drainage of pleural fluid, the patients were allocated randomly to receive 10 Klinische Einheit units of OK-432 or 8 mg of mitomycin C by intrapleural injection at weekly intervals. The treatment was terminated if the pleural effusion disappeared or the patients had received four consecutive procedures. There were 26 patients who received pleurodesis with OK-432 and 27, with mitomycin C. Patient characteristics in the two treatment groups (age, sex, histologic type, performance status, and prior treatment before pleurodesis) were compatible. These results showed that pleurodesis with OK-432 achieved a higher complete response rate (73%) than that of mitomycin C (41%). The rates of objective treatment response (complete response plus partial response) were comparable in both groups (88% for OK-432 and 67% for mitomycin C). The average number of intrapleural injections needed to achieve complete response was fewer in the OK-432 group (1.9 +/- 0.9) than in mitomycin C group (2.8 +/- 0.9). There was no significant difference in the median survival of the patients who received pleurodesis with OK-432 (5.8 months) or mitomycin C (5.1 months). However, the effusion-free period in the OK-432 group was significantly longer than that in the mitomycin C group (7.0 months versus 1.5 months). Patients who underwent OK-432 pleurodesis had a higher complication rate (80%) than did those in the mitomycin C group (30%). Transient febrile reaction was the most common reaction encountered. The immunologic study in OK-432 group showed an increase in peripheral leukocyte count and decrease in the OKT4/OKT8 ratio. The mitomycin C group had a mild reduction in peripheral blood leukocyte count and no significant change in the OKT4/OKT8 ratio. It was concluded that pleurodesis with OK-432 is an effective alternative treatment for malignant effusion in patients with lung cancer.

Antitumor action of an acidic glycoprotein (SAGP) from Streptococcus pyogenes in mice

We have shown that an acidic glycoprotein (SAGP) isolated from a cell-free extract of Streptococcus pyogenes (Su strain) prolonged the life-span of Ehrlich ascites carcinoma (EAC)-bearing mice. The present study shows that the life-span prolonging effect of SAGP in EAC-bearing mice was reduced by whole body X-irradiation before EAC inoculation. SAGP (500 micrograms protein/mouse/day X 4, i.p.) also showed a life-span prolonging effect (T/C (%) = 169) on Meth A fibrosarcoma (Meth A)-bearing mice, but the effect of SAGP was abrogated by an i.p. pretreatment of the host with carrageenan, an antimacrophage agent. The spleen cells from the Meth A-inoculated and SAGP-treated mice were found to have a considerable cytostatic activity by a 3H-thymidine incorporation assay. But the activity disappeared in the presence of carrageenan. These results suggest that the in vivo antitumor effects of SAGP are mediated through its immunomodulating action.

Changes in immunological parameters in lung cancer patients undergoing immunotherapy with streptococcal preparation OK-432

We have studied the immunological status of patients treated with streptococcal preparation OK-432. Two KE of OK-432 was injected intramuscularly once every week for more than three years unless the patients died. The natural killer (NK) activity in those patients who underwent curative surgery for lung cancer and had no sign of recurrence was significantly increased (P less than 0.01) during the OK-432 treatment. However, the NK activity in the patients who had persistent disease (non-resected cases, incompletely resected cases or recurrent cases) was not significantly increased in comparison with that before the immunotherapy. Also, in the cases with no clinical symptoms of recurrence, both the lymphoblastogenetic reactions to the mitogens and the IL-2 production were significantly enhanced (P less than 0.01) during the administration of OK-432. Reactions in the SU-PS (polysaccharide taken from the cell-wall fraction of the Streptococcus pyogenes SU strain and containing 7.2% of protein) skin-test appeared to significantly correlate with the immunological status of the patients under OK-432 therapy, but the PHA and PPD skin reactions showed no definitive enhancement. The survival rate of the patients whose SU-PS skin tests were positive during the OK-432 immunotherapy was significantly higher (P less than 0.01) than that of the patients with negative reactions.

Proliferative responses of peripheral blood mononuclear cells from psoriatic patients to T lymphocyte-stimulating cytokines (IL-2, IL-3, IL-4, and granulocyte-macrophage colony-stimulating factor) and OK-432

We have examined the effects of four well-characterized cytokines with T lymphocyte-stimulatory activity, i.e., interleukin (IL)-2, IL-3, IL-4, and granulocyte-macrophage colony-stimulating factor (GM-CSF) on [3H]-thymidine incorporation in peripheral blood mononuclear cells (PBMs) obtained from patients with psoriasis. Under the influence of these cytokines, the incorporation of [3H]-thymidine into the PBMs was not different between psoriatic patients and healthy controls either in culture supplemented with pooled AB serum or with autologous serum. However, a potent immunopotentiator OK-432, which is a lyophilized preparation of penicillin-treated low virulence Su-strain of Streptococcus pyogenes group A3, induced significantly less incorporation of [3H]-thymidine into the PBMs from psoriatic patients than those from healthy controls [in both the culture supplemented with pooled AB serum (p less than 0.01) and that with autologous serum (p less than 0.01)]. This reduction in thymidine uptake was closely related to the disease activity as well as to the extent of skin lesions of the psoriatic patients. The defective immune response of PBMs from psoriatic patients to OK-432 probably reflects an abnormality at the level of interaction between monocytes and T cells or at the subsequent production and release of cytokines by them.

Clinical efficacy of endoscopic injections of OK-432 in the treatment of gastric cancer

A total of 48 patients with gastric cancer were randomly assigned to receive either endoscopic injections of OK-432 plus systemic treatment with intravenously administered 5-fluorouracil and intradermally injected OK-432 (group A) or systemic therapy alone (group B). Morphologic improvement occurred in 7 of the 22 patients in group A. In one patient the tumor mass disappeared completely. In group B morphologic improvement occurred in only 2 of the 26 patients. The survival rate throughout the 24-month period was significantly (P less than 0.01) higher in group A than in group B patients. Thus, local administration of OK-432 by endoscopic injection is effective and is recommended for the treatment of patients with advanced gastric cancer.

Cytokines produced by blood mononuclear cells stimulated with the streptococcal preparation OK-432: effect on production by supplementing the medium with xenogeneic serum

Human blood MNC were stimulated for 7 days with a streptococcal preparation, OK-432, in a medium supplemented with either 10% autologous serum (autoserum) or 10% FCS. Cytokines, including IL-2, IL-1, IFN, and TNF in the supernatants, and antitumor cytotoxicity of MNC were analyzed. None of the IL-2 was detectable during the culture in medium with autoserum, although significant enhancement of cytotoxicity was observed at day 1. On the other hand, production of IL-2 and higher cytotoxicity were induced in the medium with FCS. Even a control culture of MNC unstimulated with OK-432 in the medium with FCS, showed a slight but significant amount of IL-2 and considerable cytotoxicity. However, such a culture in the medium with autoserum showed no such IL-2 production or cytotoxicity. The cytotoxicity induced in the medium with FCS was significantly inhibited by the addition of anti-IL-2 antibody to the culture as well as by the addition of anti-IFN gamma antibody, whereas the cytotoxicity in the medium with autoserum was not inhibited at all by anti-IL-2 antibody. Therefore, the cytotoxicity induced in the medium with FCS included IL-2-induced killer activity, i.e., LAK activity. Similarly, the levels of IL-1, IFN, and TNF production in the supernatants were variable depending on the serum used to supplement the medium. The nonspecific production of IL-2 and the unexpected induction of cytotoxicity were consistently provoked in the medium using several different lots of FCS, but not in the medium with human allogeneic sera or pooled AB serum nor in that with autoserum. It was revealed that the source of sera used to supplement the medium is an important factor affecting the results of analysis of cytokine production and cytotoxicity of MNC induced by certain stimulants.