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The accumulation of polymorphonuclear leukocytes (PMN) in synovial fluid is a common feature of rheumatoid arthritis (RA). We studied the chemotactic response of PMN obtained from the synovial fluid and from the peripheral blood of patients with RA using a modified Boyden's method, in which interleukin-8 (IL-8) or N-formyl-methionyl-leucyl-phenylalanine (FMLP) was used as a chemotactic agent. The IL-8-induced response of peripheral blood PMN from 15 patients with RA did not differ from that of 15 healthy controls. A decreased chemotactic response to IL-8 was, however, observed in PMN from the synovial fluid of 12 patients with RA compared with peripheral blood cells of the same individual. This defective chemotactic ability of PMN was inversely correlated with the number of infiltrating cells in the synovial fluid. We also obtained similar results with FMLP. These results indicate that the chemotactic ability of PMN may be reduced after migrating to the synovial fluid.

Interleukin-2 (IL2) is the obligatory signal for both T cell mitogenesis and in vitro generation of alloreactive cytotoxic T lymphocytes (CTL). An investigation was made to determine whether an antibody directed against IL2 would suppress the rejection reaction of rat cardiac allografts. Rabbit anti-interleukin 2 (anti-IL2) antiserum was obtained by immunizing at 2 week intervals over a period of 8 weeks with 10(6) U of recombinant human IL2 along with complete Freund's adjuvant. The bioassay for inhibition of IL2 activity by anti-IL2 antiserum was carried out in conjunction with the IL2-dependent cytotoxic T cell (CTLL cell) assay. Cardiac allografts of F344 rats were heterotopically transplanted into ACI rats. Seven daily doses of 1 ml of anti-IL2 antiserum were administered intravenously following transplantation. IL2-driven [3H]thymidine incorporation in CTLL cells was significantly inhibited by rabbit anti-IL2 antiserum. Graft survival in the anti-IL2 serum-treated group was significantly prolonged in a dose-dependent fashion compared to control groups. In conclusion, these results indicate that rabbit anti-IL2 antiserum may prove to be of significant value as an immunosuppressive agent in clinical organ transplantation.

Mechanical stress plays a key role in the pathogenesis of cartilage destruction seen in osteoarthritis (OA). We investigated the effect of cyclic tensile stress (CTS) on the anabolic and catabolic gene expression of rat cultured normal chondrocytes using the Flexercell strain unit. The effects of interleukin (IL)-4, a chondroprotective cytokine, on the changes in gene expression induced by CTS were also investigated. CTS (7% elongation at 0.5 Hz) for 24 h did not affect the expression of aggrecan and type II collagen, whereas CTS significantly upregulated matrix metalloproteinase (MMP)-13 and cathepsin B mRNA expression by chondrocytes. IL-1beta expression was also signifi cantly upregulated by CTS up to 12 h. The upregulation of MMP-13 was observed at 3 h, which was earlier than that of IL-1beta. Furthermore, pre-treatment with IL-4 (10 ng/ml) suppressed both MMP-13 and cathepsin B induction by mechanical stress, as well as CTS-induced IL-1beta expression. Our results suggest that IL-4 might have a therapeutic value in the treatment of OA by downregulation of mechanical stress-induced MMP-13 and cathepsin B expression by chondrocytes.

Co-cultivation of thymus and spleen cells of Fisher and Lewis rats with lethally irradiated MT-2 cells harboring human T-cell leukemia virus type I (HTLV-I) resulted in the establishment of lymphoid cell lines, FIRT-1, FIRS-1, LERT-1, and LERS-1, respectively. Cells of these cell lines had rat T-cell characters as demonstrated by the positive reaction to monoclonal antibodies (MAbs) to rat T cell antigens (Thy 1 and pan T). They lacked surface immunoglobulins and strongly expressed rat interleukin-2 receptor antigen (Tac) and Ia antigen. Karyotypic analysis revealed that they had the normal rat karyotype in early cultures, but showed marked aneuploidy after long cultivation. None of them expressed HTLV gag proteins (p19 and p24) or virus particles, but they contained HTLV-I proviral DNA monoclonally and weakly expressed pX gene products (p40x). They were not transplantable into syngeneic newborn rats.

The inflamed synovial tissue (ST) of rheumatoid arthritis (RA) is characterized by the selective accumulation of interferon gamma-producing Th1-type CD4+ T cells. In this study, we investigated whether the predominance of Th1-type CD4+ cells in the ST lesion is mediated by their selective recruitment through Th1 cell-associated chemokine receptors CXCR3 and CCR5. The lymphocyte aggregates in the ST of RA contained a large number of CD4+ T cells, which mostly expressed both CXCR3 and CCR5, but not CCR4. In contrast, the frequencies of CD4+ and CD8+ T cells expressing CXCR3 and CCR5 in the blood were significantly decreased in RA patients, compared with healthy controls (HC), although there was no difference in the frequencies of CCR4-expressing CD4+ and CD8+ T cells between RA and HC. CXCR3, CCR5, and CCR4 expression in blood CD4 + T cells and CXCR3 expression in CD8+ T cells were increased after interleukin-15 (IL-15) stimulation. Therefore, the distribution of Th1-type CD4+ T cells into the ST from the blood in RA may be associated with the local expression of chemokines, both CXCR3 and CCR5 ligands, and IL-15 may play a role in enhancing these chemokine receptors on CD4+ T cell infiltrates.

This study was conducted to examine the effect of gamma-interferon (IFN-gamma) on experimental metastasis formation by murine colon 26 adenocarcinoma in BALB/c mice. We found that the number of experimental lung metastases was increased after colon 26 cells were pretreated for 1 h with as little as 1 OIU/ml of IFN-gamma. 5-[125I] iodo-2'-deoxyuridine-radiolabeled colon 26 cells pretreated with IFN-gamma remained at higher level in the lung at 24h after intravenous injection than when the cells were not pretreated. In vivo elimination of asialo GM1-positive cells increased the number of lung metastases and, in such mice, there was no longer a difference in metastatic ability between control and IFN-gamma-treated cells. Colon 26 cells were completely resistant to lysis by isolated splenocytes. Splenocytes incubated in vitro with interleukin 2 exhibited moderate cytotoxicity against colon 26 cells, but there were no significant differences between control and IFN-gamma-treated cells. Colon 26 cells pretreated with IFN-gamma demonstrated resistance to tumor necrosis factor alpha-mediated growth inhibition. The enhancement of metastases by IFN-gamma was dependent on de novo protein synthesis since the enhancement was abolished by cycloheximide. Taken together, the data suggest that the metastatic ability of colon 26 cells pretreated with IFN-gamma is significantly higher due to the resistance to asialo GM1-positive cells accompanied with de novo protein synthesis.

Circulating hepatitis C virus (HCV) particles can be fractionated by means of differential flotation centrifugation. It is reported that in the bottom fraction HCV is in the form immune complexes, whereas in the top, it is free of antibodies. We evaluated the significance of circulating complex and free HCV in chronic hepatitis C, and assessed the relationship in terms of the response to interferon (IFN) therapy. We examined sera before, just after, and 1 year after administering IFN to 18 patients with chronic hepatitis C, 10 of whom responded (group CR), and 8 did not (group NR). The amounts of virus were similar between both groups before therapy. After differential flotation centrifugation with 1.063 g/ml of NaCl, the top and bottom fractions were assayed for HCV RNA. Before therapy, HCV RNA was detected in the top fraction in 1 of 10 in group CR, and in 6 of 8 in group NR (P < 0.05, chi-square test). HCV RNA was positive in the bottom fraction of all samples. In a follow-up study of group NR, HCV RNA was detected in the top fraction in 3 of 8 just after IFN therapy, and in 7 of 8 after 1 year. This study suggests that the presence of HCV in the top fraction can predict a poor response to IFN therapy.

We studied the effect of endogenous prostaglandin E2 (PGE2) on interleukin 1 (IL-1) production by peripheral blood monocytes from patients with rheumatoid arthritis (RA). IL-1 production by RA monocytes was not different from that of monocytes from normal controls, when the cells were either unstimulated or stimulated with lipopolysaccharide (LPS, 20 micrograms/ml), as measured by two different bioassays (thymocyte or fibroblast proliferation assay) and enzyme-linked immunosorbent assay. However, IL-1 production by LPS-stimulated monocytes from RA patients cultured in medium containing indomethacin, an inhibitor of PGE2 synthesis, was significantly greater than that of monocytes from normal controls. In addition, the levels of PGE2 in culture supernatants of unstimulated or LPS-stimulated monocytes from RA patients were higher than in culture supernatants of monocytes from normal controls. Moreover, the increase of in vitro IL-2 production by RA T cells stimulated by phytohemagglutinin (PHA) was observed when monocytes were removed from peripheral blood mononuclear cells. These results indicated that peripheral blood monocytes from RA patients could produce IL-1 in excess in vitro, but that in vivo IL-1 production by RA monocytes and IL-2 induction by RA T cells might be negatively regulated by endogenous PGE2.

Twenty-four patients with rheumatoid arthritis (RA) and 20 normal controls were examined for the ability of their peripheral blood B cells to produce interleukin 1 (IL-1) with or without lipopolysaccharide (LPS). B cells were purified from peripheral blood by negative selection methods (i.e., removal of adherent cells and sheep red blood cell rosette-forming cells, followed by treatment with monoclonal antibodies (OKT3 and OKM1) and complement). The amount of IL-1 in B cell culture supernatants (SN) was measured by thymocyte and fibroblast proliferation assays and an enzyme-linked immunosorbent assay for IL-1 alpha and beta. As a group, cultured B cells from patients with RA, both spontaneously and when stimulated with LPS, produced higher levels of IL-1 than those from normal controls. IL-1 production by RA B cells with LPS had a weak but positive correlation with disease activity. Moreover, RA B cell culture SN with elevated levels of IL-1 had a synergistic effect on the growth of anti-human IgM (anti-mu) stimulated B cells. In separate experiments, the growth of RA B cells was significantly promoted by IL-1 beta both with and without anti-mu stimulation. These results suggest that B cell-derived IL-1 may be involved in the B cell clonal expansion of RA through its own activity as a B cell stimulatory factor.

The antitumor effects of indomethacin and interleukin 2 (IL-2) were studied in C3H/HeJ mice inoculated with MH134 hepatoma cells. Combined treatment with indomethacin and IL-2 augmented natural killer (NK) cells in mice with MH134-induced peritoneal carcinomatosis, and the survival of the treated mice was significantly longer than the non-treated mice. In animals with subcutaneous MH134 tumors, the combined therapy with indomethacin and IL-2 significantly suppressed tumor growth and induced complete regression of the tumor in three out of five mice. These results suggest that indomethacin and IL-2 therapy could be effective on human gastrointestinal cancer cells as well.

Spleen cells serially sampled from normal mice following partial hepatectomy were tested for antibody-dependent cellular cytotoxicity (ADCC) and natural killer (NK) activity. There was a marked augmentation of these activities of spleen cells from the hepatectomized animals, compared to cells from controls with a simple laparotomy. The augmentation of ADCC in the hepatectomized mice was largely attributable to the activity of T lymphocytes. When cultured with interleukin-2 (IL-2), the spleen cells from hepatectomized mice exhibited cytotoxicity to syngeneic lymphoblasts, which was found to be effected by T cells.