Effects Of Recombinant Human Interleukin-10 Research Articles

Effects of IL-10 on serum TNF-α and pancreatic tissue in rats with severe acute pancreatitis

Objective To investigate the effects of recombinant human interleukin-10 (IL-10) on serum tumor necrosis factor α (TNF-α) and histopathological changes of pancreas in rats with severe acute pancreatitis (SAP), and provide theorical basis for SAP clinical treatment. Methods 90 Sprague-Dawley (SD) rats were randomly divided into three groups: normal control group (group N, n=30), SAP group (group S, n=30) and IL-10 interference group (group I, n=30). 5% sodium taurocholate was retrogradely injected into the pancreatic duct in S group and I group to induce SAP model. Rats in N group whose pancreas was just flipped and stricken gently without injection. Group I was treated with 10 000 units of intrape-ritioneal recombinant human IL-10 at 1, 3 and 5 h. Group N and group S received three intraperitoneal injections of 0.9% normal saline at the same time points. Rats were killed at 6, 12 and 24 h. The level of TNF-α in serum was determined by enzyme-linked immunosorbent assay (ELISA), and the level of amylase was assayed by biochemical methods. The pancreas histological changes were observed by H-E staining. Results Compared with group N [serum amylase (1 025.3±326.9), (999.9±212.3), (962.3±128.9) IU/L; TNF-α (55.6±2.1), (56.1±2.2), (58.7±1.3)ng/L; pancreatic histopathological score 0.13±0.11, 0.15±0.12, 0.16±0.15], serum amylase (6 633.9±846.7), (9 421.4±1 031.8), (8 755.6±734.5) IU/L, TNF-α (87.6±3.3), (113.3±10.2), (100.2±2.3) ng/L and pancreatic histopathological score (8.58±0.63, 13.41±0.79, 16.78±0.87) in group S were increased significantly at 6, 12 and 24 h (P<0.05). The pancreatic damage at 24 h was the most severe, and the peak concentration of AMY and TNF-α reached at 12 h. Compared with group S, pancreatic histopathological scores 6.52±0.54, 9.37±0.35, 12.43±0.69, the level of serum amylase (6 032.8±534.9), (7 475.8±834.2), (6 903.4±377.1) IU/L and TNF-α (67.5±2.5), (93.0±4.9), (86.7±6.6) ng/L in group I were significantly decreased at corresponding time points (P<0.05). Conclusions Early application of recombinant human IL-10 can attenuate SAP inflammatory response and relieve the histopathological injury of pancreas by inhibiting the release of TNF-α. IL-10 can be used for the treatment of SAP. Key words: Severe acute pancreatitis; Interleukin-10; Tumor necrosis factor-α; Rat

Effects of recombinant human interleukin-10 on Treg cells, IL-10 and TGF-β in transplantation of rabbit skin

The current study aimed to investigate the rejection and survival time of grafted skin, and the changes of Treg cells, interleukin 10 (IL-10) and transforming growth factor-β (TGF-β) in peripheral blood following skin transplantation with recombinant human interleukin-10 (rhIL-10) or cyclosporin A (CsA), as well as the role of IL-10 in immunological rejection mechanisms. A total of 36 rabbits were divided into two groups. The skin of a donor rabbit was transplanted onto the back of one receptor rabbit. Receptors were randomly divided into six groups, including rhIL-10 low-dose (5 μg/kg/d), rhIL-10 high-dose (10 μg/kg/d), CsA low-dose (5 mg/kg/d), CsA high-dose (10 mg/kg/d), rhIL-10 (5 μg/kg/d) and CsA (5 mg/kg/d) and negative control normal saline (NS; 1 ml/d). All groups received intramuscular drug injection for ten days, beginning one day prior to skin transplantation surgery. Following transplantation, each rabbit’s peripheral blood was collected at different times. The changes of CD4+CD25+ regulatory T cells, IL-10 and TGF-β were determined by flow cytometry and enzyme-linked immunosorbent assay. When compared with the control group, the rejection and survival times of the experimental groups were longer following skin graft. Compared with the two CsA groups and the control group, the proportion of CD4+CD25+ regulatory T cells of rhIL-10 groups was significantly upregulated on the 4th and 7th days following surgery. However, TGF-β levels were not significantly different. Data suggested that the concentration of IL-10 was positively correlated with the proportion of CD4+CD25+ regulatory T cells. In addition, IL-10 may delay the rejection time of rabbit skin transplantation and prolong the survival time. Thus, the role of IL-10 in inhibited allograft rejection may be associated with CD4+CD25+ regulatory T cells and IL-10, and may be independent of TGF-β.

Dose-related effects of recombinant human interleukin-10 on hypoxia-induced skeletal muscle injury in immature rats

BackgroundThe role of cytokines in the pathogenesis of skeletal muscle injury in patients with hypoxia and inflammation remains unclear. The aim of the present study was to determine the dose-related effects of recombinant human interleukin-10 (rhIL-10) on hypoxia-induced skeletal muscle injury in immature rats. MethodsThe study was performed on 1-day-old Sprague- Dawley rat pups that were randomized to one of five groups: nonhypoxic controls (group 1; n=8); rats subjected to hy- poxia-reoxygenation (H/O) and returned to their mothers (group 2; n=11); rats subjected to H/O, returned to their mothers, and treated with rhIL-10 (10 |Ag/kg per day s.c.) for 3days (group 3; n=10); rats subjected to H/O, returned to their mothers, and treated with rhIL-10 (25 |Ag/kg per day s.c.) for 3days (group 4; n=10); or rats subjected to H/O, returned to their mothers, and treated with rhIL-10 (75 |Ag/kg per day s.c.) for 3days (group 5; n=10). All animals were killed on day 4, and skeletal muscle specimens were obtained to determine the tissue levels of malondialdehyde (MDA) and superoxide dismutase (SOD) and to check for any histological changes. ResultsThe polymorphonuclear leukocyte count, amount of interstitial edema, microvessel size, and area of myocyte necrosis was greater in groups 2, 3, 4, and 5 than in group 1, although the findings were significantly less prominent in groups 4 and 5 than in groups 2 and 3. MDA levels significantly increased in groups 2 and 3 compared to those in groups 1, 4, and 5. SOD values decreased significantly in groups 2 and 3 compared to those in groups 1, 4, and 5. ConclusionsAdministration of rhIL-10 reduced skeletal muscle injury produced by hypoxia in immature rats. Intermediate and high doses of rhIL-10 were associated with a significant reduction of skeletal muscle damage, whereas a low dose was not.

Protective effects of recombinant human interleukin-10 on intestines of hypoxia-induced necrotizing enterocolitis in immature rats

Background/Purpose: The role of cytokines in the pathogenesis of hemodynamic instability or tissue destruction in patients with necrotizing enterocolitis (NEC) remains undefined. The aim of this study was to determine the effects of recombinant human interleukin-102 (rhIL-10) on intestines of hypoxia-induced necrotizing enterocolitis in immature rats. Methods: The study was performed on 1-day-old Sprague Dawley rat pups. Group 1 (n = 8) served as nonhypoxic controls. Group 2 (untreated, n = 11) rats were subjected to hypoxia-reoxygenation (H/O) and then were returned to their mothers. Group 3 (rhIL-10 treated, n = 10) rats were subjected to H/O, were returned to their mothers, and were treated with rhIL-10 (75 μg/kg subcutaneously) for the next 3 days. All animals were killed on day 4, and intestine specimens were obtained to determine the tissue level of malondialdehyde (MDA) and histologic changes. Results: The microscopic lesions in the untreated rats were virtually the same as those seen in neonatal NEC, with destruction of villi and crypts, and in some cases extension to the muscularis. In contrast, in the rats treated with rhIL-10, lesions were limited essentially to the very tips of the villi. Intestinal injury score was significantly less in the rhIL-10–treated rats than in the untreated rats (P <.05). In the rhIL-10–treated group, Malondialdehyde (MDA) levels were not significant in comparison to the control group. In the untreated group, MDA levels were significantly increased when compared with the control and the rhIL-10–treated groups (P <.001 and P <.05, respectively). Conclusion: RhIL-10 has a protective effect on intestinal injury in NEC in an experimental model. J Pediatr Surg 37:1330-1333. Copyright 2002, Elsevier Science (USA). All rights reserved.

Interleukin-10 inhibits in vitro hematopoietic suppression and production of interferon-gamma and tumor necrosis factor-alpha by peripheral blood mononuclear cells from patients with aplastic anemia.

Mononuclear cells (MNC) from patients with aplastic anemia (AA) can inhibit hematopoietic colony formation from normal bone marrow (BM) cells. Interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) are considered as soluble mediators of BM suppression in AA. Because of its cytokine synthesis inhibiting action, interleukin-10 (IL-10) could be a potentially useful molecule to modulate the hematopoietic effects of MNC from patients with AA. Using coculture experiments we studied the effect of recombinant human IL-10 (rhIL-10) on the in vitro hematopoietic suppression by peripheral blood (PB) MNC from AA patients. PBMNC (5 x 10(5)/ml) from seven patients with AA caused a 40-100% reduction of normal burst-forming unit-erythroid (BFU-E) growth and a 38-91% reduction of colony-forming unit-granulocyte/macrophage (CFU-GM) growth, respectively, in semisolid cocultures. IL-10 was highly effective in reversing growth inhibition in these cocultures. Addition of 10 ng/ml IL-10 to cocultures significantly restored growth of BFU-E in all seven cases and growth of CFU-GM in five of seven cases, respectively. The effect was dose dependent and correlated with decreased IFN-gamma and TNF-alpha production in suspension cultures. Using intracellular cytokine staining it was found that increased TNF-alpha production in AA cells was derived from both CD4+ and CD8+ cells, whereas aberrant IFN-gamma synthesis was only detected in CD8+ cells. IL-10 is effective in reversing in vitro hematopoietic suppression by PBMNC from AA patients. These results suggest therapeutic evaluation of rhIL-10 in patients with AA.

Inhibition of microglial egress in excised ganglia by human interleukin 10: Implications for its activity in invertebrates

We studied the effects of recombinant human interleukin-10 (IL-10) on invertebrate immunocytes and microglia. The present report demonstrates that the spontaneous activation of invertebrate immunocytes can be specifically inhibited by recombinant human IL-10. Induced immunocyte activation by fMLP can also be significantly diminished by IL-10. This inhibition becomes apparent over hours and causes ameboid cells to become round and nonmobile. Furthermore, Mytilus edulis pedal ganglia maintained in culture, over the course of 24 hours, emit microglia. IL-10 significantly reduces this microglial egress, an action that can be diminished by concomitant exposure of the excised ganglia to an antibody specific to IL-10 as well as IL-10. The anti-IL-10 alone is without effect. Active-ameboid microglia that egress become round and inactive following IL-10 exposure, an action prevented by anti-IL-10. Lastly, a substance immunoreactively similar to human IL-10 can be detected in pedal ganglia homogenates. Taken together, and since the immunocytes and microglia are responding to IL-10, it implies that an IL-10-like substance could be present in invertebrates. In conclusion, the study demonstrates that both invertebrate immunocytes and microglia respond to IL-10, suggesting an early evolution of this generally inhibitory cytokine.

Interleukin-10 Inhibits Erythropoietin-Independent Growth of Erythroid Bursts in Patients With Polycythemia Vera

In polycythemia vera (PV) erythroid colonies that grow in vitro in the absence of exogenous erythropoietin (EPO) arise from the abnormal clone that is responsible for overproduction of red blood cells. Although the mechanism of autonomous formation of burst-forming units-erythroid (BFU-E) is not fully understood, a spontaneous release of growth regulatory molecules by PV cells and/or by accessory cells is likely to be involved. Because of its cytokine synthesis inhibiting action, interleukin-10 (IL-10) could be a potentially useful molecule to modulate abnormal erythropoiesis in PV. We studied the effect of recombinant human IL-10 on the EPO-independent growth of erythroid bursts derived from peripheral blood mononuclear cells (PBMNCs) of patients with PV. IL-10 showed a profound, dose-dependent, and specific inhibitory effect on autonomous BFU-E formation. Ten nanograms per milliliter of IL-10 significantly suppressed spontaneous growth of erythroid colonies in methylcellulose in five of five PV patients tested with a mean inhibition by 81% (range, 72-94). To elucidate the possible mechanism of the inhibitory action of IL-10 we further studied the effect of anticytokine antibodies on autonomous BFU-E growth and the ability of exogenous cytokines to restore IL-10–induced suppression of erythroid colony growth. Among a panel of growth regulatory factors tested (granulocyte-macrophage colony-stimulating factor [GM-CSF], IL-3, granulocyte colony-stimulating factor, stem cell factor, and insulin-like growth factor-1) GM-CSF was the only molecule for which both an inhibition of spontaneous BFU-E formation by its respective antibody as well as a significant restimulation of erythroid colonies in IL-10-treated cultures by exogenous addition was found. Moreover, inhibition of GM-CSF production by IL-10 was shown in PV PBMNCs at the mRNA level. Our data indicate that autonomous BFU-E growth in PV can be profoundly inhibited by IL-10 and that this inhibitory effect seems to be at least in part secondary to suppression of endogenous GM-CSF production.© 1998 by The American Society of Hematology.

Interleukin-10 Inhibits Erythropoietin-Independent Growth of Erythroid Bursts in Patients With Polycythemia Vera

In polycythemia vera (PV) erythroid colonies that grow in vitro in the absence of exogenous erythropoietin (EPO) arise from the abnormal clone that is responsible for overproduction of red blood cells. Although the mechanism of autonomous formation of burst-forming units-erythroid (BFU-E) is not fully understood, a spontaneous release of growth regulatory molecules by PV cells and/or by accessory cells is likely to be involved. Because of its cytokine synthesis inhibiting action, interleukin-10 (IL-10) could be a potentially useful molecule to modulate abnormal erythropoiesis in PV. We studied the effect of recombinant human IL-10 on the EPO-independent growth of erythroid bursts derived from peripheral blood mononuclear cells (PBMNCs) of patients with PV. IL-10 showed a profound, dose-dependent, and specific inhibitory effect on autonomous BFU-E formation. Ten nanograms per milliliter of IL-10 significantly suppressed spontaneous growth of erythroid colonies in methylcellulose in five of five PV patients tested with a mean inhibition by 81% (range, 72-94). To elucidate the possible mechanism of the inhibitory action of IL-10 we further studied the effect of anticytokine antibodies on autonomous BFU-E growth and the ability of exogenous cytokines to restore IL-10-induced suppression of erythroid colony growth. Among a panel of growth regulatory factors tested (granulocyte-macrophage colony-stimulating factor [GM-CSF], IL-3, granulocyte colony-stimulating factor, stem cell factor, and insulin-like growth factor-1) GM-CSF was the only molecule for which both an inhibition of spontaneous BFU-E formation by its respective antibody as well as a significant restimulation of erythroid colonies in IL-10-treated cultures by exogenous addition was found. Moreover, inhibition of GM-CSF production by IL-10 was shown in PV PBMNCs at the mRNA level. Our data indicate that autonomous BFU-E growth in PV can be profoundly inhibited by IL-10 and that this inhibitory effect seems to be at least in part secondary to suppression of endogenous GM-CSF production.

IL-10 Suppresses Experimental Autoimmune Neuritis and Down-regulates TH1-Type Immune Responses

Experimental autoimmune neuritis (EAN) is a CD4+T cell-mediated monophasic inflammatory disorder of the peripheral nervous system (PNS). Cellular mechanisms, including macrophage and T cell infiltration, and cytokines like IFN-γ and TNF-α are intimately involved in the pathogenesis of EAN. Interleukin 10 (IL-10) is a TH2-type cytokine that suppresses monocyte and TH1 cell functions. We examined the effect of recombinant human IL-10 (rHuIL-10) in EAN. When administered from the start of immunization with bovine peripheral myelin emulsified in Freund's complete adjuvant, IL-10 effectively suppressed and shortened clinical EAN. Even when given after Day 12 post immunization (pi) after clinical EAN had been established, IL-10 also effectively suppressed the severity of EAN. Pheripheral nerve myelin antigen-reactive IFN-γ-secreting TH1-like cells were decreased in lymph nodes from IL-10-treated compared to control EAN rats. PNS autoantigen-induced T cell proliferation and B cell responses were not affected. P2 protein-reactive IFN-γ, TNF-α, IL-1β, and IL-6 mRNA-expressing lymph node cells were also downregulated in IL-10-treated compared to control EAN rats at Day 14 and 26 pi, while P2-reactive IL-4 mRNA-expressing cells were upregulated throughout treatment. Also, in IL-10-treated EAN rats, upregulated anti-P2 IgG1 and downregulated IgG2a were observed. Our results clearly show that rHuIL-10 can suppress clinical EAN, and this suppression is associated with downregulation of TH1 responses and macrophage function and upregulated TH2 responses.

Interleukin-10 Inhibits Spontaneous Colony-Forming Unit–Granulocyte-Macrophage Growth From Human Peripheral Blood Mononuclear Cells by Suppression of Endogenous Granulocyte-Macrophage Colony-Stimulating Factor Release

AbstractSpontaneous growth of myeloid colonies (colony-forming unit–granulocyte-macrophage [CFU-GM]) can be observed in methylcellulose cultures containing peripheral blood mononuclear cells (PB-MNCs) and is supposedly caused by the release of colony-stimulating factors (CSF ) by accessory cells. Because of its cytokine synthesis-inhibiting effects on T lymphocytes and monocytes, interleukin-10 (IL-10) may be a potential candidate for indirect modulation of hematopoiesis. We studied the effect of recombinant human IL-10 (rhIL-10) on spontaneous growth of myeloid colonies derived from human PB-MNCs. A total of 10 ng/mL of IL-10 almost completely inhibited spontaneous CFU-GM proliferation (by 95.1%; P < .001, n = 7) in unseparated PB-MNCs. This effect was dose-dependent and specific, because a neutralizing anti–IL-10 antibody was able to prevent IL-10–induced suppression of CFU-GM growth. Spontaneous CFU-GM growth, which required the presence of both monocytes (CD14+ cells) and T lymphocytes (CD3+ cells), was also greatly suppressed by a neutralizing anti–granulocyte-macrophage CSF (GM-CSF ) antibody but was only slightly or not at all inhibited by antibodies against G-CSF or IL-3. Moreover, IL-10–suppressed colony growth could be completely restored by the addition of exogenous GM-CSF. Using semiquantitative polymerase chain reaction, we were able to show that GM-CSF transcripts that spontaneously increased in PB-MNCs within 48 hours of culture were markedly reduced by the addition of IL-10. Inhibiton of GM-CSF production in PB-MNCs by IL-10 was also confirmed at the protein level by measuring GM-CSF levels in suspension cultures. Our findings suggest that autonomous CFU-GM growth, resulting from an interaction of monocytes and T lymphocytes, is mainly caused by endogenous GM-CSF release and can be profoundly suppressed by the addition of exogenous IL-10. Considering the strong inhibitory action of IL-10 on GM-CSF production and spontaneous cell growth in vitro, this cytokine may be useful in myeloid malignancies in which autocrine and/or paracrine mechanisms involving GM-CSF are likely to play a pathogenetic role.

Interleukin 10 and interleukin 13 synergize to inhibit vascular permeability factor release by peripheral blood mononuclear cells from patients with lipoid nephrosis.

It has been proposed that a vascular permeability factor (VPF) is involved in the pathogenesis of lipoid nephrosis (LN). There is now increasing evidence that interleukin 10 (IL-10) and interleukin 13 (IL-13) have regulatory effects on cytokine production by activated macrophages. These results prompted us to study the effects of recombinant human IL-10 and IL-13 on VPF secretion in LN. In the present study, we demonstrate that the regulatory cytokines IL-10 and IL-13 are potent inhibitors of the VPF activity of activated peripheral blood mononuclear cells. Each cytokine was found to suppress VPF secretion in a dose-dependent fashion. More importantly, the combination of the cytokines was found to give a potent synergistic suppression of VPF by concanavalin A activated peripheral blood mononuclear cells from patients with LN. When both anti-IL-10 and anti-IL-13 antibodies were added together to the peripheral blood mononuclear cells, a further increase of concanavalin A enhanced secretion of VPF occurred. These data establish IL-10 and IL-13 as potent inhibitors of VPF activity and suggest their utility in controlling deleterious VPF-mediated responses such as occur in LN patients with nephrotic syndrome.

Interleukin 10 inhibits growth and granulocyte/macrophage colony-stimulating factor production in chronic myelomonocytic leukemia cells.

Autonomous release of hematopoietic growth factors may play a crucial role in the pathogenesis of certain hematological malignancies. Because of its cytokine synthesis-inhibiting action, interleukin 10 (IL-10) could be a potentially useful molecule to affect leukemic cell growth in such disorders. Chronic myelomonocytic leukemia (CMML) cells spontaneously form myeloid colonies (colony-forming units-granulocyte/macrophage) in methylcellulose, suggesting an autocrine growth factor-mediated mechanism. We studied the effect of recombinant human IL-10 (rhIL-10) on the in vitro growth of mononuclear cells obtained from peripheral blood or bone marrow of patients with CMML. IL-10 specifically binding to leukemic cells had a profound and dose-dependent inhibitory effect on autonomous in vitro growth of CMML cells. IL-10 significantly inhibited the spontaneous growth of myeloid colonies in methylcellulose in 10/11 patients, and autonomous CMML cell growth in suspension in 5/5 patients tested. Spontaneous colony growth from CMML cells was also markedly reduced by addition of antigranulocyte/macrophage colony-stimulating factor (GM-CSF) antibodies, but not by addition of antibodies against G-CSF, IL-3, or IL-6, IL-10-induced suppression of CMML cell growth was reversed by the addition of exogenous GM-CSF and correlated with a substantial decrease in GM-CSF production by leukemic cells, both at the mRNA and protein levels. Our data indicate that IL-10 profoundly inhibits the autonomous growth of CMML cells in vitro most likely through suppression of endogenous GM-CSF release. This observation suggests therapeutic evaluation of rhIL-10 in patients with CMML.

Interleukin‐10 functions as an antiinflammatory cytokine in rheumatoid synovium

Interleukin-10 (IL-10) is an antiinflammatory cytokine that has been shown to play a role in rheumatoid arthritis (RA). We therefore investigated the effects of IL-10 on the function and phenotype of synovial fluid mononuclear cells (SFMC) derived from patients with RA. In addition, we studied the production of IL-10 in rheumatoid joints, and the role of endogenous IL-10 in the regulation of SFMC function. The presence of IL-10 in rheumatoid joints was studied using IL-10-specific enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase- polymerase chain reaction (RT-PCR) techniques. The effects of recombinant human IL-10 or neutralizing anti-IL-10 monoclonal antibodies (MAbs) on both cytokine production and phenotype of SFMC were evaluated using cytokine-specific ELISAs and flow cytometry. The effect of IL-10 on proliferation of SFMC was determined by incorporation of tritiated thymidine. IL-10 was detected by ELISA in 22 of 23 SF samples, and was spontaneously produced by cultured SFMC. IL-10 messenger RNA was detectable in all 8 SFMC samples, as determined by RT-PCR. Neutralization of endogenously produced IL-10 by anti- IL-10 MAbs resulted in increased production of IL-1 beta, tumor necrosis factor alpha (TNF alpha), and granulocyte- macrophage colony-stimulating factor (GM-CSF) by SFMC, and in enhanced proliferation of SFMC. In particular, the production of TNFalpha was dramatically increased by anti-IL-10 MAbs. Moreover, the expression of HLA-DR molecules by SF macrophages was increased, and the expression of CD16 was decreased by anti-IL-10 MAbs. In contrast, addition of recombinant IL-10 significantly decreased the production of IL-1 beta, TNF alpha, and GM-CSF by SFMC, and decreased spontaneous and IL-2-induced proliferation of SFMC. Finally, IL-10 decreased HLA-DR expression and increased the expression of the Fc gamma receptors, CD16 and CD64, by SF macrophages. These data indicate that endogenously produced IL-10 functions as an immunoregulatory molecule in rheumatoid synovium. Importantly, exogenous IL-10 has potent antiinflammatory effects on SFMC, suggesting that IL-10 may be useful in the treatment of patients with RA.

Spontaneous and lipopolysaccharide-stimulated secretion of cytokines by peripheral blood monocytes in IgA nephropathy is inhibited by interleukin-10.

The effect of recombinant human interleukin-10 (IL-10) on the in vitro cytokine secretion of peripheral blood monocytes (PBM) was evaluated in patients with IgA nephropathy (IgAN). Significantly increased spontaneous and lipopolysaccharide (LPS)-stimulated secretion of tumor necrosis factor-alpha and interleukin-8 was determined in PBM cultures of IgAN patients compared to those of normal controls. In the present study IL-10 inhibited the spontaneous as well as the LPS-stimulated cytokine secretion of PBM in IgAN. A significant inhibitory effect of IL-10 was observed in cultures of PBM from IgAN patients as well as from normal controls. When both LPS and anti-IL-10 antibody were added together to the PBM, a further increase in LPS-enhanced secretion of cytokines occurred. This study provides some novel information showing the inhibitory effects of IL-10 on cytokine secretion by PBM derived from IgAN patients.

INHIBITORY EFFECTS OF RECOMBINANT HUMAN INTERLEUKIN 10 ON DISEASE MANIFESTATIONS IN A P→F1 MODEL OF ACUTE GRAFT VERSUS HOST DISEASE

Interleukin 10 (IL-10) is a cytokine with both antiinflammatory and immunosuppressive properties. In the present study, we have examined the effects of recombinant human IL-10 (rHuIL-10) on the development of acute graft-vs.-host disease (GVHD) in unirradiated (C57B1/6JxA/J) F1 recipients of parental A/J lymphocytes. rHuIL-10 (2.5 to 100 micrograms/mouse administered subcutaneously) caused a significant reduction in splenomegaly in GVH mice. GVH splenocytes exhibited an augmented capacity to produce IFN-gamma when stimulated in culture with Con A or LPS. The IFN gamma produced in response to LPS stimulation was found to be derived from CD4+ and CD8+ T cells with little or no contribution from the NK1.1+ subpopulation of the GVH spleen. Treatment with IL-10 in vivo was found to diminish the capacity of splenocytes to produce IFN gamma when stimulated with LPS but not with Con A. IL-10 did not protect GVH mice from a lethal dose of LPS but caused a marked reduction in the serum TNF alpha response triggered by the LPS challenge. We conclude that IL-10 may be useful in controlling those clinical manifestations of acute GVHD that arise as a result of the activities of proinflammatory cytokines such as IFN gamma and TNF alpha.