Kupffer cell activation and hematopoiesis in the liver of autoimmune MRL-lpr/lpr mice

Hematopoiesis can be induced in the adult murine liver by the administration of macrophage activators. The proliferation of macrophages and extrathymic T cells is spontaneously induced in the liver of autoimmune MRL-lpr/lpr mice, and deeply involved in the development of disease. To study the role of Kupffer cell activation in the induction of hematopoiesis and lymphocyte proliferation in the liver, we histologically analysed the kinetic and spatial relationship between Kupffer cells and hematopoietic cells or lymphocytes. At 5 weeks of age before the onset of disease, there were no appreciable histological changes in the liver. At 7 weeks, Kupffer cells had slightly increased in number, while hematopoietic islands were not yet detected. When disease had fully developed at 14 weeks, Kupffer cells were considerably increased in number and size, and exhibited numerous lysosomes. Hematopoietic cells of erythroid and myeloid series frequently appeared in the sinusoid, and lay in close apposition to Kupffer cells. Promyelocytes further migrated into the space of Disse to cluster there, being surrounded by the stellate cells (or fat-storing cells) and hepatocytes. After maturation, metamyelocytes and mature granulocytes were released into the sinusoidal circulation. Mitotic figures were detected in the cells of both erythroid and myeloid series. Lymphocytes proliferated in various sites such as in the sinusoid lumen, the space of Disse, and interlobular connective tissue, whether associated or not with Kupffer cells. The present results indicate that erythropoiesis, granulopoiesis, and lymphocyte proliferation are induced in the liver of MRL-lpr/lpr mice and are closely associated with Kupffer cell activation.

Effect of splenectomy on hepatic metastasis of colon carcinoma and natural killer activity in the liver

We have previously demonstrated that administration of killed streptococcal preparation (OK432), a biological modifier, increased the number of asialo GM1-positive cells in the liver, enhanced NK activity of hepatic mononuclear cells, and reduced the number of hepatic metastases of colon 38 adenocarcinoma that were inoculated into the superior mesenteric vein of C57BL/6 strain mice. In the present study, to clarify the role of the spleen in immune surveillance of the liver, the effect of splenectomy on hepatic metastasis of colon carcinoma and on hepatic NK activity has been examined. The number of hepatic metastasis increased in the splenectomized mice, compared with that in sham-operated mice. Administration of OK432 increased the number of asialo GM1-positive cells in the liver and enhanced NK activity of hepatic mononuclear cells in both groups, but NK activity of hepatic mononuclear cells in the splenectomized mice was less than that of the sham-operated mice. An enhanced NK activity of these cells was abolished by treatment with anti-asialo-GM1 antibody plus complement in vitro. Interleukin-2 mRNA expression was increased in the spleen 2 hr after OK432 administration and persisted until 8 hr, but was scarcely noted in the liver. On the other hand, NK activity of hepatic mononuclear cells in the asialo GM1-positive cell-depleted (previous administration of antiserum against asialo GM1) mice was enhanced after OK432 administration in the sham operated and splenectomized mice, but an enhanced NK activity in these mice was only partially or not at all abolished by treatment with anti-asialo GM1 antibody plus complement in vitro, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative analysis of rod-cored vesicles and dense granules of large granular lymphocytes in the liver, spleen, and peripheral blood of rats

Large granular lymphocytes (LGL) comprise a natural defense system in the liver and exert an inhibitory effect on tumor cell metastasis. In order to demonstrate the maturation of LGL in the liver from the morphological aspect, we evaluated electron-microscopically the frequency of 0.2 micron vesicles (rod-cored and "empty" vesicles) and dense granules in LGL from the liver, spleen, and peripheral blood of the rat. Both of these cell organelles are characteristic to LGL and may relate to natural killer-mediated cytolysis. On the average, there were 12.7 of the 0.2 micron vesicles and 4.3 rod-cored vesicles (RCV) per cell section in the liver, 6.6 0.2 micron vesicles and 1.6 RCV in the spleen, and 8.6 0.2 micron vesicles and 0.9 RCV in the peripheral blood. The number of 0.2 micron vesicles per cell section ranged from 0 to 19 with the exception of a few higher instances. Therefore, LGL were divided into vesicle-rich (> 9 0.2 micron vesicles per cell section) and vesicle-poor (< 8 per cell section) populations. Hepatic LGL consisted mainly of a vesicle-rich population while splenic LGL consisted mainly of a vesicle-poor population, and peripheral blood contained equal proportions of both populations. In addition to diversity with regard to the number of 0.2 micron vesicles, LGL obtained from various organs also displayed heterogeneity in the number and size of dense granules.(ABSTRACT TRUNCATED AT 250 WORDS)

Augmented local immunity in the liver by a streptococcal preparation, OK432, related to antitumor activity of hepatic macrophages

The aim of this study was to investigate the augmentative effect of a streptococcal preparation, OK432, on the immunological competence of hepatic macrophages. We found that OK432 was distributed predominantly to hepatic macrophages after intravenous injection, and Northern blot analysis revealed that OK432 induced the gene expression of IL-1 alpha, beta, and TNF alpha in the liver. The induction of mRNAs was evident 1 h after the intravenous injection of OK432 and their accumulation reached a maximal level at 3 h. TNF production of hepatic macrophages was also increased by the intravenous injection of OK432. Furthermore, OK432 significantly increased the proportion of IL-2 receptor-positive hepatic macrophages. As for antitumor activity in the liver being augmented by OK432, the cytotoxic and cytostatic activity of hepatic macrophages from OK432-treated rats against tumor cells was significantly increased and OK432 markedly reduced the number of tumor nodules in the liver after the inoculation of tumor cells via the portal vein. These findings, which indicate that OK432 has various immuno-stimulating actions on hepatic macrophages, leading to the augmentation of antitumor activity in the liver, suggest that OK432 may be of some benefit in helping to prevent hepatic metastasis, at least in part, via its activation of hepatic macrophages.

Inhibition of hepatic metastasis of colon carcinoma by asialo GM1--positive cells in the liver

This study investigates the role of hepatic asialo GM1-positive cells in inhibiting hepatic metastasis of colon carcinoma (colon adenocarcinoma 38) in mice after administration of a biological response modifier, streptococcal derivative (OK432). Administration of OK432 increased the number of asialo GM1-positive cells in the liver, enhanced natural killer activity of hepatic mononuclear cells and reduced the number of hepatic metastases of colon carcinoma inoculated into the superior mesenteric vein. Administration of antiserum against asialo GM1 reduced the number of hepatic asialo GM1-positive cells, abolished natural killer activity of hepatic mononuclear cells and increased the number of hepatic metastases. In addition, administration of antiserum against asialo GM1 even after OK432 treatment also decreased the number of asialo GM1-positive cells, reduced natural killer activity of hepatic mononuclear cells and increased the number of hepatic metastases of colon carcinoma. However, administration of gadolinium chloride, which suppresses phagocytic function of Kupffer cells, did not influence the natural killer activity of hepatic mononuclear cells or the number of hepatic metastases. In vivo tumor-neutralization assay revealed that tumor growth was inhibited by the hepatic mononuclear asialo GM1-positive cells, but not by T lymphocytes or Kupffer cells after OK432 administration. These results suggest that an increased number of hepatic asialo GM1-positive cells after administration of OK432 plays an important role in protecting against metastasis of colon carcinoma in the liver.

Establishment of animal liver metastatic model for C-1300 murine neuroblastoma and immunotherapy for it using OK-432, streptococcus preparation

Intrasplenic administration of 1 x 10(6) C-1300 murine neuroblastoma cells induced spleen tumor in 78.6% of mice and liver metastasis in 64.3%. When mice were pretreated with carrageenan, an antimacrophage agent, the incidence of spleen and liver tumors in this system was lower, possibly due to the rebound increase in macrophage activity following the disappearance of the carrageenan effect. Continuous daily intraabdominal injection of 1 KE of OK-432 streptococcus preparation markedly reduced the appearance of liver metastasis (P less than 0.01), whereas the spleen mass was not reduced to such an extent. However, the survival rate of the OK-432-treated group did not differ greatly from that of the nontreated group. These results demonstrate the usefulness of the model of liver metastasis induced by intrasplenic administration of tumor cells and the effectiveness of OK-432 against liver metastasis formation.

Enhancement of rat hepatic macrophages by treatment with interleukin-2 and streptococcal preparation OK432, with reference to antitumor activity, soluble factor production and Ia expression

The effect of biological response modifiers, such as interleukin-2 (IL-2) and streptococcal preparation OK432, on the functions of hepatic macrophages was investigated. The macrophages, even with no exogenous stimulation, produced superoxide anion (O2-) and tumor necrosis factor (TNF), displayed cytotoxicity against K562 cells and cytostasis against P815 cells and expressed immune-region-associated antigen (Ia). IL-2 administered in vitro or in vivo enhanced O2- production by hepatic macrophages and the intravenous injection of OK432 also enhanced O2 production. Furthermore, IL-2 added to the culture medium of hepatic macrophages isolated from OK432-injected rats augmented O2- production even more. The TNF production and Ia expression of the macrophages were also increased by the intravenous injection of OK432. As with O2- production, the cytotoxicity of the cells was enhanced by OK432 injection or by IL-2 added to the culture medium and the combination of OK432 and IL-2 augmented their cytotoxicity even more. Thus, the present study suggested that IL-2 and OK432 induce the augmentation of the antitumor activity of hepatic macrophages, partly as a result of the increase in production of O2- and TNF and Ia expression.

Localization and ultrastructure of the Kupffer cells in orthotopically transplanted liver grafts in the rat

Kupffer cells play an important role in the acceptance or rejection of liver grafts. We examined the ultrastructure of the Kupffer cells in transplanted rat livers, from an early to a late stage where the graft is accepted, using a DA-to-PVG combination. Two days after surgery, endocytic activity of the Kupffer cells had increased, as evidenced by worm-like structures and many endocytic vacuoles. There was often close apposition to the monocytes or lymphocytes. By day 4, infiltration of mononuclear cells into the sinusoids was readily noticeable. By day 7, several Kupffer cells had migrated into the space of Disse through the openings in endothelial linings. The number of Kupffer cells reached a maximum at 14 days. They were located mostly outside the sinusoid, adhering to the hepatocytes. At this point in time, however, the Kupffer cells contained few endocytic vacuoles and phagolysosomes, in contrast to those at 2 days. The number and location of Kupffer cells became almost normal at 2 months. The present results indicate that Kupffer cells are highly activated before mononuclear cell infiltration becomes manifest in the sinusoid, and that when a rejecting reaction reaches a peak, they are usually located extrasinusoidally and show a morphologically immature profile.