Therapy Of Immune Disorders Research Articles

Cloning and high level expression of the biologically active extracellular domain of Macaca mulatta CD40 in Pichia pastoris

The CD40-mediated immune response contributes to a wide variety of chronic inflammatory diseases. CD40 antagonists have potential as novel therapies for immune disorders. However, the CD40 pathway has not been well characterized in the rhesus monkey Macaca mulatta, which is a valuable animal model for human immune disease. An 834 bp transcript was cloned from peripheral blood mononuclear cells (PBMCs) of rhesus monkey using specific primers designed according to the predicted sequence of M. mulatta CD40 (mmCD40) in GenBank. Sequence analysis demonstrated that mmCD40 is highly homologous to human CD40 (hCD40), with an amino acid sequence identity of 94%. Genes encoding the extracellular domain of mmCD40 and the Fc fragment of the hIgG1 were inserted into a pPIC9K plasmid to produce mmCD40Ig by Pichia pastoris. Approximately 15–20 mg of the mmCD40Ig protein with ∼90% purity could be recovered from 1 L of culture. The purified mmCD40Ig protein can form dimers and can specifically bind CD40L-positive cells. Additionally, the mmCD40Ig protein can bind hCD40L protein in phosphate buffered saline and form a stable combination in a size-exclusion chromatography assay using a Superdex 200 column. Moreover, mmCD40Ig is as efficient as M. mulatta CTLA4Ig (mmCTLA4Ig) to suppress Con A-stimulated lymphocyte proliferation. Additionally, mmCD40Ig only showed mild immunosuppressive activity in a one-way mixed lymphocyte reaction (MLR) system. These results suggest that mmCD40Ig secreted by P. pastoris was productive and functional, and it could be used as a tool for pathogenesis and therapies for chronic inflammatory diseases in a M. mulatta model.

The SCHOOL of nature: IV. Learning from viruses.

During the co-evolution of viruses and their hosts, the latter have equipped themselves with an elaborate immune system to defend themselves from the invading viruses. In order to establish a successful infection, replicate and persist in the host, viruses have evolved numerous strategies to counter and evade host antiviral immune responses as well as exploit them for productive viral replication. These strategies include those that modulate signaling mediated by cell surface receptors. Despite tremendous advancement in recent years, the exact molecular mechanisms underlying these critical points in viral pathogenesis remain unknown. In this work, based on a novel platform of receptor signaling, the Signaling Chain HOmoOLigomerization (SCHOOL) platform, I suggest specific mechanisms used by different viruses such as human immunodeficiency virus (HIV), cytomegalovirus (CMV), severe acute respiratory syndrome coronavirus, human herpesvirus 6 and others, to modulate receptor signaling. I also use the example of HIV and CMV to illustrate how two unrelated enveloped viruses use a similar SCHOOL mechanism to modulate the host immune response mediated by two functionally different receptors: T cell antigen receptor and natural killer cell receptor, NKp30. This suggests that it is very likely that similar general mechanisms can be or are used by other viral and possibly non-viral pathogens. Learning from viruses how to target cell surface receptors not only helps us understand viral strategies to escape from the host immune surveillance, but also provides novel avenues in rational drug design and the development of new therapies for immune disorders.

Novel Mechanistic Insights into Viral Modulation of Immune Receptor Signaling

To successfully infect, replicate, and persist in the host, viruses have evolved numerous strategies to take control of multiple cellular processes, including those that target transmembrane (TM) signal transduction mediated by immune receptors. Despite tremendous advancement in recent years, the exact molecular mechanisms underlying these critical points in viral pathogenesis remain unknown. In this Opinion, based on a novel model of immune signaling, the Signaling Chain HOmoOLigomerization (SCHOOL) model, I suggest specific mechanisms used by different viruses such as human immunodeficiency virus (HIV), cytomegalovirus (CMV), severe acute respiratory syndrome coronavirus (SARS-CoV), herpesvirus saimiri (HVS), human herpesvirus 6 (HHV-6), etc., to modulate the host immune response mediated by members of the family of multichain immune recognition receptors (MIRRs). I also demonstrate how the SCHOOL model, together with the lessons learned from viral pathogenesis, can be used practically for rational drug design and the development of new therapies for immune disorders.

The influence of type I interferons on immune cells can be mediated through regulation of estrogen receptor alpha level

Autoimmune disorders are connected with the actions of sex hormones. Clinical observations have shown that especially estrogens are involved in these phenomena. In some cases the administration of estrogens can increase the pathological symptoms of a disorder, while in others they can cause disease remission. In multiple autoimmune diseases, type I interferons, a family of cytokines acting through the common receptor IFNAR1/IFNAR2, seem to have action convergent with that of estrogens. We hypothesize that this coincidence is not accidental and type I interferons can regulate the level of estrogen receptor alpha (ERα) and consequently change the sensitivity of immune cells to estrogen's action. There is evidence that ERα is responsible for the effects exerted by estrogens and that this phenomenon mainly involves antigen-presenting cells. On the other hand, research on IFN-tau, a type I interferon family members, showed that this cytokine can modulate ERα levels in ovine endometrium. Because of the common receptor for these interferons, we suspect that other type I interferons can act in this way not only in endometrial cells, but also in immune cells. If there is such a mechanism, it can be exploited in the therapy of immune disorders, especially autoimmune disease, for example through simultaneous administration of less toxic interferons and estrogens.

“Spicing Up” of the Immune System by Curcumin

Curcumin (diferuloylmethane) is an orange-yellow component of turmeric (Curcuma longa), a spice often found in curry powder. Traditionally known for its an antiinflammatory effects, curcumin has been shown in the last two decades to be a potent immunomodulatory agent that can modulate the activation of T cells, B cells, macrophages, neutrophils, natural killer cells, and dendritic cells. Curcumin can also downregulate the expression of various proinflammatory cytokines including TNF, IL-1, IL-2, IL-6, IL-8, IL-12, and chemokines, most likely through inactivation of the transcription factor NF-kappaB. Interestingly, however, curcumin at low doses can also enhance antibody responses. This suggests that curcumin's reported beneficial effects in arthritis, allergy, asthma, atherosclerosis, heart disease, Alzheimer's disease, diabetes, and cancer might be due in part to its ability to modulate the immune system. Together, these findings warrant further consideration of curcumin as a therapy for immune disorders.

Closing in on Toll-like receptors and NOD-LRR proteins in inflammatory disorders

Our immune system faces the intricate task of eliminating pathogenic microorganisms, while autoimmunity against self-components or intestinal flora must be prevented. This complex task demands an exceptional level of regulation and specificity. Hereto, immune cells are equipped with a myriad of surface receptors, including cytokine-receptors and pathogen recognition receptors. In this review we describe two important PRR families, Toll-like receptors and nucleotide-binding oligomerization domain leucine-rich repeat proteins, and their crucial role in instruction of the immune response. Interestingly, these key immune-receptors have recently been identified as major players in several immune disorders, such as systemic lupus erythematosus, Crohn’s disease, auto-inflammatory diseases and rheumatoid arthritis. These findings, and their implications for future research and therapy of immune disorders, will be discussed.

In vitro investigations on the differential pro-oxidant and/or antioxidant properties of cyclosporin A and tacrolimus in human and rat liver microsomes

The use of cyclosporin A (CSA) and tacrolimus (TAC) in organ transplantation and in the therapy of immune disorders is often hampered by adverse effects, mainly nephro-, hepato- and neurotoxicity. For the development of these side effects, among others, an increased formation of reactive oxygen species, probably generated by the cytochrome P450 (CYP) system, has been accused. Since in this respect literature data are inconsistent, in the present study possible pro- and/or antioxidant effects of CSA and TAC and the involvement of the CYP system were re-evaluated in vitro. Effects of CSA and TAC were examined on CYP mediated oxidase functions by stimulated lipid peroxidation (LPO), H2O2 production, and lucigenin (LC) or luminol (LM) amplified chemiluminescence (CL) in liver microsomes of either untreated rats or of rats treated with beta-naphthoflavone (BNF), phenobarbital (PB) or dexamethasone (DEX) and in human liver microsomes. In rat liver microsomes, CSA displayed pro-oxidant properties (though only very slightly), whereas in human liver microsomes small antioxidant effects were seen. With TAC in both species the antioxidant capacity prevailed. Treatment of rats with BNF or DEX caused an increase in the pro-oxidant effects of CSA with respect to LPO or LM-CL, whereas in liver microsomes of DEX-treated rats H2O2 production and LC-CL were diminished. CSA seems to have both pro-oxidant and antioxidant properties, whereas with TAC mainly an antioxidant capacity was seen. The CYP system seems to be involved in the pro-oxidant influence of CSA. Whether pro-oxidant or antioxidant effects predominate may depend on the antioxidant capacity of a tissue and on the CYP isoforms mainly present.

Gene therapy for immune disorders: Good news tempered by bad news

After a dozen years of human gene therapy trials characterized by minimal gene correction and disappointing clinical impact, the field of gene therapy received some good news in 2000. Infants with X-linked severe combined immunodeficiency who received retroviral gene addition to cells from their bone marrow developed impressive immune reconstitution. During the following 2 years, additional patients were treated and the news was even better-babies receiving gene therapy had sustained T-cell production and in several cases developed better cell function than most patients treated with standard bone marrow transplants. Unfortunately, bad news followed. Three of the patients experienced leukemic T-cell expansions, found to be associated with retroviral insertions into genomic DNA. Where does the field stand today?

Profound toxicity of deoxyadenosine and 2-chlorodeoxyadenosine toward human monocytes in vitro and in vivo.

Deoxyadenosine is known to be toxic to both proliferating and resting lymphocytes that lack adenosine deaminase (ADA) activity. We now show that human monocytes are also highly sensitive in vitro to nanomolar concentrations of deoxyadenosine plus the ADA inhibitor deoxycoformycin, and to the ADA-resistant analogue 2-chlorodeoxyadenosine (CdA). Monocytes exposed to deoxyadenosine or to CdA in vitro accumulate massive DNA damage detectable within 1 hour. The DNA damage in monocytes exposed to CdA is associated with a decrease in protein synthesis and with inhibitions of phagocytosis and IL-6 secretion. However, unlike lymphocytes with similar DNA damage, the monocytes show no significant NAD or ATP depletion until cell viability declines. The selective toxicity of CdA to monocytes was confirmed by in vivo studies. In almost all patients receiving CdA infusion chemotherapy for cutaneous lymphoma, the blood monocytes counts fell to near 0 during one week of therapy. Our results suggest that CdA and related compounds may have potential clinical use in the therapy of immune disorders associated with monocyte/macrophage activation.

Homœopathic therapy for immune disorders

Homeopathic therapy for immune disorders M. JENAER (Brussels) The author's very innovative method of using drugs derives from recent discoveries in the field of immunology, opening an original way of using hom0eopathy. The distinction is made between cancer and viral diseases on the one hand (associated with an insufficient immune response) and autoimmune diseases on the other hand (associated with an exaggerated immune response ) . He also notes that cases with dys-immunity exist i.e. a mixture of insufficient and exaggerated responses related to the syphilis miasm. The following potentized drugs are used: RNA, DNA: Cancer: used in ascending potencies in cases with an identifiable cancer mass. Treatment in this way is stopped when cancer regresses because of fear of pathogenic effect of RNA and DNA, but is continued in a 9c to enhance a new equilibrium between host and tumour. Auto-immune diseases: used in a 15c.