Modulation of expression of MHC antigens in the kidneys of mice by murine interferon-alpha/beta

Antagonist peptides of human interferon-alpha2b isolated from phage display library inhibit interferon induced antiviral activity

AIM

To screen human interferon (IFN)-alpha2b antagonist peptides from a phage displayed heptapeptide library.

METHODS

WISH cells and polyclonal anti-IFN-alpha2b antibodies were used to select IFN receptor-binding peptides from a phage displayed heptapeptide library. The specific binding of phage clones was examined by phage ELISA and immunohistochemistry. The specific binding activities of synthetic peptides to WISH cells were detected by competition assay. Effects of synthetic peptides to IFN-induced antiviral activity were analyzed by evaluating the cytopathic effect (CPE) using the MTT method.

RESULTS

Twenty-three positive clones were obtained after seven rounds of selection. Ten clones were randomly picked from the positive clones and were sequenced. The corresponding amino acid sequences suggested 3 groups homologous to the 3 domains of IFN-alpha2b, defined by residues 24-41, 43-49, and 148-158 of IFN-alpha2b. As they presented as corresponding to IFN receptor-binding domains, AB loop and E helix, clone No 26 and 35 were chosen for further characterization and shown to bind to WISH cells. Two peptides corresponding to clone No 26 and 35, designated SP-7(SLSPGLP) and FY-7(FSAPVRY) were shown to compete with GFP-IFN-alpha2b for binding to its receptor and to inhibit the IFN-alpha2b-induced antiviral activity.

CONCLUSION

Both IFN-alpha2b antagonist peptides, SP-7 and FY-7, were able to inhibit the IFN-induced antiviral activity, and could be helpful in laying the foundation for the molecular mechanism of the interaction between IFN and its receptor.

Characterization and humanization of a monoclonal antibody that neutralizes human leukocyte interferon: a candidate therapeutic for IDDM and SLE

We have developed a panel of murine monoclonal antibodies that recognize human interferon alpha. One of these mononclonal antibodies binds and neutralizes, with high affinity, all of seven tested recombinant human interferon alphas. This mononclonal antibody also neutralizes the interferon activity present in two independent pools of interferon alphas prepared following stimulation of human peripheral blood leukocytes. The complementary determining regions from this murine mononclonal antibody were transferred to a human IgG2 heavy chain and to a human kappa1 light chain. In addition, six (heavy chain) and two (light chain) amino acids were transferred from the framework regions. This generated a humanized mononclonal antibody that retained the specificity of the mouse parent. The humanized anti-interferon alpha antibody is a candidate therapeutic for those diseases, such as insulin-dependent diabetes, systemic lupus erythematosis, psoriasis and Crohn's disease, which are all characterized by pathological expression of interferon alpha.

Exacerbation of glomerulonephritis in subjects with chronic hepatitis C virus infection after interferon therapy

We previously reported the glomerular deposition of hepatitis C virus (HCV) core antigen (Ag) in HCV-related nephropathy. In this study, we analyzed 23 HCV-positive subjects with exacerbation of proteinuria and/or hematuria during interferon (IFN) therapy and measured urinary protein selectivity. We also examined the involvement of HCV-related Ag using anti-HCV core (capside) Ag murine monoclonal antibody (Ab) and anti-core2 rabbit polyclonal Abs in nine subjects. Of 17 subjects, 13 (78%) showed low selective proteinuria. We found mesangial proliferative glomerulonephritis in 9 subjects, membranoproliferative glomerulonephritis in 1 subject, and nephrosclerosis in 1 subject. Immunofluorescence study showed the glomerular deposition of immunoglobulin G (IgG) or IgA and complements in all 9 subjects examined. Trace amounts only of HCV core Ag were detected along the glomerular capillary wall in 3 of 9 subjects (33%). Electron microscopy showed subendothelial or mesangial electron-dense deposits and also foot process effacement (20% to 72.5% of glomerular capillary walls) in all subjects and endothelial swelling in 4 subjects. In conclusion, IFN therapy for HCV may exacerbate the underlying glomerulopathies, unrelated to HCV Ags, through direct or indirect effects on glomerular endothelial and epithelial cells. Physicians should carefully distinguish HCV-related nephropathy from other glomerular diseases when they administer IFN therapy to HCV-positive subjects.

Cytokine receptor gene expression in peripheral blood mononuclear cells during graft-versus-host disease after allogeneic bone marrow transplantation

Interleukin-1 receptor type 1 (IL-1R), IL-2 receptor alpha subunit (IL-2R) and IL-6 receptor alpha subunit (IL-6R) mRNA expression in peripheral blood mononuclear cells (PBMC) in 17 patients who underwent allogeneic bone marrow transplantation (allo BMT) and 2 patients who underwent autologous transplantation were analyzed using a semiquantitative reverse-transcriptase polymerase chain reaction (RT-PCR). There were several exceptions in some cases and IL-1R expression was found to vary in a rather wide range, however, the expression of IL-2R and IL-6R mRNA tended to increase during the development of graft-versus-host disease (GVHD). In particular, IL-2R mRNA expression was increased in four patients with GVHD and graft failure. In contrast, IL-2R and IL-6R mRNA expression was not increased in autologous (auto) BMT and auto peripheral blood stem cell transplantation (PBSCT) patients. These findings suggest that IL-2R and maybe IL-6R mRNA expression in PBMC play an important role in the development of an allo response and GVHD. Therefore, the analysis of cytokine receptor mRNA expression in PBMC after allo BMT may provide important information concerning the immune response and the cytokine network system in marrow transplants.

Primary biliary cirrhosis induced by interferon-alpha therapy for hepatitis C virus infection

Interferon-alpha is known to exacerbate and in some cases induce a variety of autoimmune disorders. In this report we describe the onset of primary biliary cirrhosis in a 55-year-old woman without evidence of preexisting autoimmune diseases receiving recombinant interferon-alpha 2a for chronic active hepatitis C. Shortly after discontinuing interferon therapy, alkaline phosphatase levels started to rise up to three times the normal range. Anti-mitochondrial antibodies were found to be positive at a high titer, and liver biopsy showed a picture of chronic active hepatitis along with primary biliary cirrhosis features (overlap syndrome). Primary biliary cirrhosis should be considered in the differential diagnosis in any patient treated with interferon-alpha with unexplained elevation of serum alkaline phosphatase.

Transplantation-related complications predicted by cytokine gene expression in the mixed lymphocyte culture in allogeneic bone marrow transplants

In this study, we have investigated cytokine (IL-1 beta, IL-2, IL-5, IL-6, IFN-gamma, TNF-alpha) and T cell surface molecule (IL-2 receptor, CD28, CTLA-4) gene expression in two way mixed lymphocyte cultures (MLC) enhanced by concanavalin A (ConA) to assess whether this is a useful predictive method for severe graft-versus-host disease (GVHD) and graft failure in allogeneic bone marrow transplantation (allo BMT) patients. Our present study revealed increased mRNA expression of IL-2, IL-5 and IFN-gamma using this assay in patients with delayed engraftment followed by graft failure and patients who developed grade III acute GVHD. Elevated IL-2 and IFN-gamma levels in MLC medium were also observed in these patients. Concerning T cell surface molecule gene expression in our modified MLC, IL-2 receptor gene expression was not altered so much in allo BMT patients, however, CD28 and CTLA-4 gene expression were elevated in patients with graft failure and severe acute GVHD. The elevated expression of cytokines (IL-2, IL-5 and IFN-gamma) and T cell surface molecules (CD28 and CTLA-4) mRNA in our modified MLC, in patients who developed severe lethal transplantation-related complications may suggest an important role for these molecules in inducing a strong alloresponse. Therefore, the detection of increased gene expression of those molecules, in our modified MLC system, appeared to be useful for predicting transplantation-related complications in allo BMT patients. In addition, this modified MLC assay may also be useful for the selection of the most compatible related and unrelated donors.

Dendritic cell loss from nonlymphoid tissues after systemic administration of lipopolysaccharide, tumor necrosis factor, and interleukin 1

Dendritic cells (DC) in nonlymphoid organs can internalize and process foreign antigens before migrating to secondary lymphoid tissues to initiate primary immune responses. However, there is little information on which stimuli promote migration of DC from the tissues. Systemic administration of lipopolysaccharide (LPS), which induces in vivo production of cytokines, led to a reduction in the numbers of major histocompatibility complex class II-positive (Ia+) leukocytes in mouse hearts and kidneys: > 95% of DC were depleted 1-3 d after injection of 50 micrograms LPS. Several lines of evidence indicated that this response was due to migration of DC rather than loss of Ia expression or cytotoxic effects. In skin of treated mice, the number of Ia+ epidermal Langerhans' cells (LC) was reduced, and "cords" of Ia+ leukocytes became evident in the dermis. The latter cells expressed little NLDC145 and may have originated from recruited or resident DC progenitors. Systemic administration of recombinant tumor necrosis factor (rhTNF)-alpha resulted in a decrease in numbers of Ia+ cells in heart and kidney and of epidermal LC, and it also induced dermal cords. Administration of a rh-interleukin (IL)-1 resulted in a decrease in Ia+ cells only in renal medulla, appeared to activate a subset of epidermal LC, and induced dermal cords. Similar microgram doses of rhIL-2 had no obvious effect. Treatment with a neutralizing anti-TNF antiserum before LPS administration inhibited the depletion of LC from skin but not from heart or kidney. Therefore, TNF-alpha and IL-1 alpha may promote DC migration from nonlymphoid tissues and may have differential effects on different DC populations, but it is unclear whether they act on DC directly or indirectly (e.g., via other cytokines).

Cytokine gene expression after allogeneic bone marrow transplantation

Cytokines produced by T lymphocytes, monocytes/macrophages, and fibroblasts play a central role in the immune response and in the development of graft-versus-host disease (GVHD). Also, it has been reported that dysregulated production of cytokines maybe the primary mediator of clinical manifestation of acute GVHD. Regarding cytokine gene expression after human allogeneic bone marrow transplantation (allo BMT), we have demonstrated increased IL-1 beta, IL-6, and TNF-alpha mRNA expression in peripheral blood mononuclear cells during the development of acute and chronic GVHD and that the degree of the increase was dependent on the severity of the disease. Furthermore, overexpression of these cytokine mRNAs could be detected before the clinical manifestations of GVHD developed. In contrast, IL-2 mRNA expression was not detected in peripheral blood mononuclear cells in GVHD patients. On the other hand, we have reported that increased mRNA expression and protein product of IL-2 and IFN-gamma were evident in the mixed lymphocyte culture of the cases who developed severe lethal transplantation-related complications. Therefore, the detection of increased IL-2 and IFN-gamma gene expression in MLC appeared to be useful for predicting transplantation-related complications in BMT patients. Furthermore, we found increased IL-2 receptor alpha subunit mRNA expression in the peripheral blood mononuclear cells during GVHD. These findings may indicate the important role of inflammatory cytokines such as IL-1 beta, IL-6 and TNF-alpha in the development of the clinical manifestation of GVHD and also may be indicative of the important role of IL-2 and the IL-2 receptor in allo response perhaps mainly as an autocrine effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of crossmatching on outcome in organ transplantation

The complement-dependent cytotoxicity (CDC) crossmatch and the flow cytometry crossmatch (FCXM) are both used prospectively in renal transplantation, and their use is under evaluation in other types of major organ transplantation. The FCXM is the more sensitive method and better predicts outcome in second and subsequent renal allografts. Improved survival has unmasked the detrimental effect of a positive crossmatch on outcome in liver transplantation. Because of the urgent need of liver transplant candidates, it is unrealistic to defer transplantation until a crossmatch-negative donor is found; however, additional therapeutic measures may be taken to improve outcome for crossmatch-positive liver recipients. Some reports suggest that prospective crossmatching may improve outcome for sensitized heart recipients, and, additionally, recent studies have demonstrated that HLA compatibility between donor and recipient is an independent variable affecting survival after heart transplantation, prompting a reassessment of the current practice of transplanting hearts without consideration of the HLA match.

Podocyte expression of MHC class I and II and intercellular adhesion molecule-1 (ICAM-1) in experimental pauci-immune crescentic glomerulonephritis

We examined immunopathological changes of podocytes in vivo which, based on in vitro studies, are thought to be relevant for the pathogenesis of renal diseases. We investigated the alterations of podocytes in local inflammation in a recently developed model of pauci-immune necrotizing crescentic glomerulonephritis (NCGN) in the rat. Frozen and plastic embedded kidney sections at different time points of the disease were incubated with antibodies directed to MHC class I, MHC class II, ICAM-1 and to relevant cytokines. Strong glomerular expression of MHC class I, II and ICAM-1 was found within 4 days, and plastic embedded sections clearly demonstrated increased cell membrane staining of podocytes. Increased glomerular interferon-gamma (IFN-gamma) was detected within 24 h of induction of NCGN, and IL-1 beta and tumour necrosis factor-alpha (TNF-alpha) were found from day 4. The potency of these cytokines to induce adhesion molecules on podocytes was investigated on rat glomerular epithelial cells in vitro. By using FACS analysis and electron microscopical techniques, we found that the in vivo expression of MHC class I, II and ICAM-1 by podocytes could in vitro be simulated by IFN-gamma. IFN-alpha weakly induced MHC class I, while IL-1 beta and TNF-alpha were ineffective. We hypothesize that podocytes in this in vivo model are important to maintain the local inflammatory process in the glomerulus by expression of relevant adhesion molecules and MHC molecules upon stimulation with specific cytokines.

Cytokine gene expression in peripheral blood mononuclear cells during graft-versus-host disease after allogeneic bone marrow transplantation

Cytokine gene expression in peripheral blood mononuclear cells during the development of graft-versus-host disease (GVHD) in patients who underwent allogeneic bone marrow transplantation (allo BMT) was analysed using a semiquantitative reverse-transcriptase polymerase chain reaction (RT-PCR). The expression of interleukin (IL)-1 beta, IL-6, and tumour necrosis factor (TNF)-alpha mRNA was increased during the development of GVHD and the degree of this increment depended on the severity of the disease. IL-2 expression was not detected at all and interferon-gamma expression was not much changed during GVHD. In patients with hepatic veno-occlusive disease (VOD), another transplantation-related complication, the expression of IL-1 beta and TNF-alpha mRNA was increased but IL-6 mRNA expression showed little increase. These findings suggest that IL-1 beta, IL-6 and TNF-alpha produced by peripheral blood mononuclear cells play an important role in the development of GVHD. Furthermore, liver dysfunction due to GVHD or VOD may be distinguishable by this type of cytokine analysis. Analysis of cytokine mRNA expression in peripheral blood mononuclear cells after allogeneic bone marrow transplantation may provide important information concerning the immune response and the cytokine network system in marrow transplant patients.