Oral administration of a streptococcal agent OK-432 activates alveolar macrophages in mice

Antimetastatic effect of an immunomodulatory arabinomannan extracted from Mycobacterium tuberculosis strain Aoyama B, Z-100, through the production of interleukin-12

In this study, the role of interleukin (IL)-12 on the antimetastatic effect of Z-100 was investigated using wild-type C57BL/6 mice or IL-12p40 knockout (IL-12p40 KO) mice inoculated with highly metastatic B16F10 melanoma. When C57BL/6 mice were inoculated with B16F10 melanoma (2x10(5) cells/mouse i.v.), Z-100 (10 mg/kg i.p.) significantly suppressed the pulmonary metastasis of B16F10 melanoma 14 d after tumor inoculation. On the other hand, the antimetastatic effect of Z-100 was not observed in IL-12p40 KO mice inoculated with B16F10 melanoma. These results indicate that IL-12 is essentially required for the appearance of the antimetastatic effect of Z-100. Since helper T (Th) 2 cell responses have been reported to have a role in tumor metastasis, the regulatory effect of Z-100 on the immune balance of Th1/Th2 cell responses was investigated. In both C57BL/6 mice and IL-12p40 KO mice bearing B16F10 melanoma, Th1 cytokine production (IL-2, interferon-gamma) was significantly suppressed as compared with those in normal mice. On the other hand, Th2 cytokine production (IL-4, IL-10) in these mice was increased. The administration of Z-100 (10 mg/kg i.p.) in C57BL/6 mice bearing B16F10 melanoma improved the balance of Th1/Th2 cell responses from the Th2-dominant state to the normal state. However, the improvement of Th1/Th2 cell responses by Z-100 was not observed in IL-12p40 KO mice bearing the same tumors. In addition, Z-100 significantly increased IL-12 production by macrophages in a concentration-dependent manner, while Z-100 significantly decreased IL-10 production by these cells in vitro. These results suggested that up-regulation of IL-12 production and down-regulation of IL-10 production by Z-100 are related to the improvement of Th1/Th2 cell responses from the Th2-dominant state to the normal state, which resulted in suppression of tumor metastasis.

OK-432 develops CTL and LAK activity in mononuclear cells from regional lymph nodes of lung cancer patients

We examined the effect of OK-432 on induction of cytotoxic T lymphocytes (CTL) directed against autologous tumor cells (ATC) and lymphokine-activated killer (LAK) cells from mononuclear cells separated from regional lymph node cells (RLMNCs) of 49 lung cancer patients. We also examined the phenotypic changes of RLMNCs during incubation with or without OK-432. Significant CTL activity and LAK activity against ATC developed from RLMNCs after stimulation with OK-432 or IL-2. Sequential treatment with OK-432 plus IL-2 or IL-2 plus OK-432 also developed significant CTL activity and LAK activity from RLMNCs. The CTL activity produced by OK-432 alone was as high as the CTL activity developed by IL-2 alone, OK-432 plus IL-2, or IL-2 plus OK-432. There was no significant difference in the CTL activities achieved by these four treatments. The proportion of CD25+ cells in RLMNCs after incubation with OK-432 was twice that before incubation. Although OK-432 increased IL-2 receptor expression on RLMNCs, it showed no synergistic effect with IL-2 in developing CTL and LAK activity. After incubation with OK-432, the proportion of HLA-DR + cells was also increased significantly. Moreover, the proportions of HLA-ABC+ and HLA-DR+ (class I and class II major histocompatibility complex antigens) cells in ATC were significantly larger than in Daudi cells. OK-432 alone could develop CTL activity against ATC from the RLMNCs of lung cancer patients that was as high as that developed by IL-2 alone or by sequential treatment with OK-432 plus IL-2 or IL-2 plus OK-432. The CTL developed from the RLMNCs of lung cancer patients may recognize class I and/or II antigens on the surface of ATC. These results indicated that treatment with OK-432 might be therapeutically useful for lung cancer patients as a CTL inducer rather than a LAK inducer.

Enhancement of murine alveolar macrophage functions by orally administered beta-glucan

The effect of orally administered SSG, a beta-1,3-glucan obtained from the culture filtrate of the fungus Sclerotinia sclerotiorum IFO 9395, on alveolar macrophage (AM) functions of CDF1 mice was examined. SSG administered orally (20, 40, 80 or 160 mg/kg) for 10 consecutive days enhanced the lysosomal enzyme activity of AM. The greatest enhancing effect was observed at 80 mg/kg of SSG. Multiple oral administrations of SSG (10 consecutive days) were needed to induce significant enhancing effects. Phagocytic activity and interleukin-1 (IL-1) production of AM were also augmented by oral administration of SSG, and the kinetics of the activated state differed depending on the kind of activity. However, H2O2 production of AM was not affected by SSG. Orally administered SSG also (40 or 80 mg/kg, 10 consecutive days) increased the number of AM and the greatest increment was observed 14 days after the first administration. On the other hand, the supernatant of Peyer's patch (PP) cells from mice administered SSG (80 mg/kg) orally stimulated the lysosomal enzyme activity of AM in vitro, and enhanced colony stimulating activity (CSA) was detected from this supernatant. These results demonstrate that SSG given by the oral route can activate murine AM both qualitatively and quantitatively, and it would mediated, at least in part, by the activation of PP cells in the intestine.