MIF contribution to progressive brain diseases.

Progressive brain diseases create a huge social and economic burden on modern societies as a major cause of disability and death. Incidence of brain diseases has a significantly increasing trend and merits new therapeutic strategies. At the base of many progressive brain malfunctions is a process of unresolved, chronic inflammation. Macrophage migration inhibitory factor, MIF, is an inflammatory mediator that recently gained interest of neuro-researchers due to its varied effects on the CNS such as participation of nervous system development, neuroendocrine functions, and modulation of neuroinflammation. MIF appears to be a candidate as a new biomarker and target of novel therapeutics against numerous neurologic diseases ranging from cancer, autoimmune diseases, vascular diseases, neurodegenerative pathology to psychiatric disorders. In this review, we will focus on MIF's crucial role in neurological diseases such as multiple sclerosis (MS), Alzheimer's disease (AD) and glioblastoma (GBM).

Microglia and astrocyte involvement in neurodegeneration and brain cancer.

The brain is unique and the most complex organ of the body, containing neurons and several types of glial cells of different origins and properties that protect and ensure normal brain structure and function. Neurological disorders are the result of a failure of the nervous system multifaceted cellular networks. Although great progress has been made in the understanding of glia involvement in neuropathology, therapeutic outcomes are still not satisfactory. Here, we discuss recent perspectives on the role of microglia and astrocytes in neurological disorders, including the two most common neurodegenerative conditions, Alzheimer disease and progranulin-related frontotemporal lobar dementia, as well as astrocytoma brain tumors. We emphasize key factors of microglia and astrocytic biology such as the highly heterogeneic glial nature strongly dependent on the environment, genetic factors that predispose to certain pathologies and glia senescence that inevitably changes the CNS landscape. Our understanding of diverse glial contributions to neurological diseases can lead advances in glial biology and their functional recovery after CNS malfunction.

Cross-Talk of the CNS With Immune Cells and Functions in Health and Disease.

The immune system's role is much more than merely recognizing self vs. non-self and involves maintaining homeostasis and integrity of the organism starting from early development to ensure proper organ function later in life. Unlike other systems, the central nervous system (CNS) is separated from the peripheral immune machinery that, for decades, has been envisioned almost entirely as detrimental to the nervous system. New research changes this view and shows that blood-borne immune cells (both adaptive and innate) can provide homeostatic support to the CNS via neuroimmune communication. Neurodegeneration is mostly viewed through the lens of the resident brain immune populations with little attention to peripheral circulation. For example, cognition declines with impairment of peripheral adaptive immunity but not with the removal of microglia. Therapeutic failures of agents targeting the neuroinflammation framework (inhibiting immune response), especially in neurodegenerative disorders, call for a reconsideration of immune response contributions. It is crucial to understand cross-talk between the CNS and the immune system in health and disease to decipher neurodestructive and neuroprotective immune mechanisms for more efficient therapeutic strategies.

Crosstalk Between Astrocytes and Microglia: An Overview.

Based on discoveries enabled by new technologies and analysis using novel computational tools, neuroscience can be re-conceived in terms of information exchange in dense networks of intercellular connections rather than in the context of individual populations, such as glia or neurons. Cross-talk between neurons and microglia or astrocytes has been addressed, however, the manner in which non-neuronal cells communicate and interact remains less well-understood. We review this intriguing crosstalk among CNS cells, focusing on astrocytes and microglia and how it contributes to brain development and neurodegenerative diseases. The goal of studying these intercellular communications is to promote our ability to combat incurable neurological disorders.

Skin Immunity.

Skin is the largest organ of the body with a complex network of multitude of cell types that perform plastic and dynamic cellular communication to maintain several vital processes such as inflammation, immune response including induction of tolerance and disease prevention, wound healing, and angiogenesis. Of paramount importance are immunological functions of the skin that protect from harmful exposure coming from external and internal environments. Awareness of skin immunity can provide a better comprehension of inflammation, autoimmunity, cancer, graft-versus-host disease, vaccination, and immunotherapy approaches. This paper will update on what we currently know about immune sentinels contributing to skin immunity.

[Uroplakins as markers of diseases of the urinary system]. / Uroplakiny jako markery chorób ukladu moczowego

An unique element of bladder urothelium is a multilayer membrane, which extends from the renal pelvis to the urethra. Urotelial membrane covers more than 90% of the inner portion of the bladder and is in direct contact with urine. Urothelium is composed of characteristic two-dimensional, asymmetric plaques, composed of uroplakins (UP), differentiated, hexagonally arranged proteins. The unique structure of the urothelial plaques determines the tightness, integrity and strength of the urothelium, prevent rupture of the walls of the bladder during the build-up of urine in the bladder and protects against the toxic ingredients. Uroplakins are tissue-specific, heterogeneous glycoproteins whose oligosaccharide part plays a specific role in the structure and function of urothelium. Disorders of normal expression of uroplakins are highly associated with the pathogenesis in infection and urinary tract malignancies, primary vesico-urinary reflux, hydronephrosis and renal impairment. The emergence of uroplakins in urine and / or plasma may have a potential role in the early detection of bladder tumors. In this paper, the structure and function of uroplakins types Ia, Ib, II, IIIa, their natural oligomerization into heterodimers, tetramers and hexamers, and the role in the construction of asymmetric and flexible urothelial epithelium is presented. We discuss the potential role of uroplakins in laboratory diagnosis of umbrella cell differentiation and in the screening analysis of urinary bladder disorders. The possibilities of using the knowledge of uroplakins in clinical settings as well as in modern strategies for treatment of infectious diseases and cancer of the urinary tract are highlighted.

Glycosylation of uroplakins. Implications for bladder physiopathology.

Urothelium, a specialized epithelium, covers the urinary tract and act not only as a barrier separating its light from the surrounding tissues, but fulfills an important role in maintaining the homeostasis of the urothelial tract and well-being of the whole organism. Proper function of urothelium is dependent on the precise assemble of highly specialized glycoproteins called uroplakins, the end products and differentiation markers of the urothelial cells. Glycosylation changes in uroplakins correlate with and might reflect progressive stages of pathological conditions of the urothelium such as cancer, urinary tract infections, interstitial cystitis and others. In this review we focus on sugar components of uroplakins, their emerging role in urothelial biology and disease implications. The advances in our understanding of uroplakins changes in glycan moieties composition, structure, assembly and expression of their glycovariants could potentially lead to the development of targeted therapies and discoveries of novel urine and plasma markers for the benefit of patients with urinary tract diseases.

Hypoxia-regulated overexpression of soluble VEGFR2 controls angiogenesis and inhibits tumor growth.

VEGFs are found at high levels in hypoxic tumors. As major components directing pathologic neovascularization, they regulate stromal reactions. Consequently, novel strategies targeting and inhibiting VEGF overproduction upon hypoxia offer considerable potential for modern anticancer therapies controlling rather than destroying tumor angiogenesis. Here, we report the design of a vector expressing the soluble form of VEGF receptor-2 (sVEGFR2) driven by a hypoxia-responsive element (HRE)-regulated promoter. To enable in vivo imaging by infrared visualization, mCherry and IFP1.4 coding sequences were built into the vector. Plasmid construction was validated through transfection into embryonic human kidney HEK293 and murine B16F10 melanoma cells. sVEGFR2 was expressed in hypoxic conditions only, confirming that the gene was regulated by the HRE promoter. sVEGFR2 was found to bind efficiently and specifically to murine and human VEGF-A, reducing the growth of tumor and endothelial cells as well as impacting angiogenesis in vitro. The hypoxia-conditioned sVEGFR2 expression was shown to be functional in vivo: Tumor angiogenesis was inhibited and, on stable transfection of B16F10 melanoma cells, tumor growth was reduced. Enhanced expression of sVEGFR2 was accompanied by a modulation in levels of VEGF-A. The resulting balance reflected the effect on tumor growth and on control of angiogenesis. A concomitant increase of intratumor oxygen tension also suggested an influence on vessel normalization. The possibility to express an angiogenesis regulator as sVEGFR2, in a hypoxia-conditioned manner, significantly opens new strategies for tumor vessel-controlled normalization and the design of adjuvants for combined cancer therapies.

MicroRNAs and tumor vasculature normalization: impact on anti-tumor immune response.

Inefficient immune response is a major glitch during tumor growth and progression. Chaotic and leaky blood vessels created in the process of angiogenesis allow tumor cells to escape and extricate anti-cancer immunity. Proangiogenic characteristics of hypoxic tumor microenvironment maintained by low oxygen tension attract endothelial progenitor cells, drive expansion of cancer stem cells, and deviantly differentiate monocyte descendants. Such cellular milieu further boosts immune tolerance and eventually appoint immunity for cancer advantage. Blood vessel normalization strategies that equilibrate oxygen levels within tumor and fix abnormal vasculature bring exciting promises to future anticancer therapies especially when combined with conventional chemotherapy. Recently, a new group of microRNAs (miRs) engaged in angiogenesis, called angiomiRs and hypoxamiRs, emerged as new therapeutic targets in cancer. Some of those miRs were found to efficiently regulate cancer immunity and their dysregulation efficiently programs aberrant angiogenesis and cancer metastasis. The present review highlights new findings in the field of miRs proficiency to normalize aberrant angiogenesis and to restore anti-tumor immune responses.

News on microenvironmental physioxia to revisit skin cell targeting approaches.

The skin is a multifunctional organ and a first line of defense actively protecting from environmental stress caused by injury, microbial treat, UV irradiation and environmental toxins. Diverse cutaneous cell types together with extracellular matrix elements and factors create a dynamic scene for cellular communication crucial in vital processes such as wound healing, inflammation, angiogenesis, immune response. Direct functional success of skin equilibrium depends on its microenvironment settings and particularly the local oxygen tension. Indeed, skin entire milieu is characterized by and highly dependent on its low oxygen tension called physioxia as emphasized in this review. In the context of skin physioxia, we review and propose here new approaches to minimize age-related changes in skin state and function. We particularly emphasize carbohydrate-mediated interactions and new 3D models of engineered skin substitutes. We highlight newly emerged tools and targets including stem cells, miRNAs, matrix metalloproteinases, mitochondria and natural antioxidants that are promising in prevention of skin ageing and disease restraint. In the era of advanced dermatology, new attempts are bringing us closer to 'well being' perception.

Hypoxia control to normalize pathologic angiogenesis: potential role for endothelial precursor cells and miRNAs regulation.

Tumor microenvironment is a complex and highly dynamic milieu that provides very important clues on tumor development and progression mechanisms. Tumor-associated endothelial cells play a key role in stroma organization. They achieve tumor angiogenesis, a formation of tumor-associated (angiogenic) vessels mainly through sprouting from locally preexisting vessels and/or recruitment of bone marrow-derived endothelial progenitor cells. This process participates to supply nutritional support and oxygen to the growing tumor. Endothelial cells constitute the interface between circulating blood cells, tumor cells and the extracellular matrix, thereby controlling leukocyte recruitment, tumor cell behavior and metastasis formation. Hypoxia, a critical parameter of the tumor microenvironment, controls endothelial/tumor cell interactions and is the key to tumor angiogenesis development. Under hypoxic stress, tumor cells produce factors that promote angiogenesis, vasculogenesis, tumor cell motility, metastasis and cancer stem cell selection. Targeting tumor vessels is a therapeutic strategy that has lately been fast evolving from antiangiogenesis to vessel normalization as discussed in this review. We shall focus on the pivotal role of endothelial cells within the tumor microenvironment, the specific features and the part played by circulating endothelial precursors cells. Attention is stressed on their recruitment to the tumor site and their role in tumor angiogenesis where they are submitted to miRNAs-mediated de/regulation. Here the compensation of the tumor deregulated angiogenic miRNAs - angiomiRs - is emphasized as a potential therapeutic approach. The strategy is to over express anti-angiomiRs in the tumor angiogenesis site upon selective delivery by precursor endothelial cells as miRs carriers.

Expression of natural autoantibodies in MRL-lpr mice protects from lupus nephritis and improves survival.

Natural autoantibodies (NAA) and their associated B cells constitute a substantial proportion of the normal Ab and B cell repertoire. They often have weak reactivity toward a variety of self-Ags such as DNA, nucleoproteins, and phospholipids. It remains controversial whether NAA contribute to or protect from autoimmune diseases. Using site-directed transgenic (sd-tg) mice expressing a prototypic NAA, we investigated the effect of NAA and NAA-producing B cells in disease development in the autoimmune-prone MRL/MpJ-Fas(lpr) (MRL-lpr) mice. We found that the expression of NAA in MRL-lpr mice prevented proteinuria and reduced kidney immune complex formation. The mice had significantly improved survival. Administration of the IgM NAA to MRL-lpr mice also delayed the onset of nephritis. The sd-tg MRL-lpr mice had decreased levels of anti-dsDNA Abs, anti-Hep2 nuclear Abs, and anti-Sm/ribonucleoprotein Abs. There is a shift in the IgG subclass profile from IgG2a and IgG3 to IgG1 in the sd-tg MRL-lpr mice. The CD4(+) T cells from the sd-tg MRL-lpr mice had increased expression of the negative costimulatory molecule CTLA-4 and increased production of IL-10 as compared with those from the wild-type mice. Furthermore, the NAA B cells produced large amounts of IL-10 upon TLR stimulation. These results indicate that NAA and NAA-producing B cells play an important role in protection from lupus nephritis and suggest that the NAA B cells may have an immune regulatory function via the provision of IL-10.

Vaccines targeting the neovasculature of tumors.

Angiogenesis has a critical role in physiologic and disease processes. For the growth of tumors, angiogenesis must occur to carry sufficient nutrients to the tumor. In addition to growth, development of new blood vessels is necessary for invasion and metastases of the tumor. A number of strategies have been developed to inhibit tumor angiogenesis and further understanding of the interplay between tumors and angiogenesis should allow new approaches and advances in angiogenic therapy. One such promising angiogenic approach is to target and inhibit angiogenesis with vaccines. This review will discuss recent advances and future prospects in vaccines targeting aberrant angiogenesis of tumors. The strategies utilized by investigators have included whole endothelial cell vaccines as well as vaccines with defined targets on endothelial cells and pericytes of the developing tumor endothelium. To date, several promising anti-angiogenic vaccine strategies have demonstrated marked inhibition of tumor growth in pre-clinical trials with some showing no observed interference with physiologic angiogenic processes such as wound healing and fertility.

Why is the partial oxygen pressure of human tissues a crucial parameter? Small molecules and hypoxia.

Oxygen supply and diffusion into tissues are necessary for survival. The oxygen partial pressure (pO(2)), which is a key component of the physiological state of an organ, results from the balance between oxygen delivery and its consumption. In mammals, oxygen is transported by red blood cells circulating in a well-organized vasculature. Oxygen delivery is dependent on the metabolic requirements and functional status of each organ. Consequently, in a physiological condition, organ and tissue are characterized by their own unique 'tissue normoxia' or 'physioxia' status. Tissue oxygenation is severely disturbed during pathological conditions such as cancer, diabetes, coronary heart disease, stroke, etc., which are associated with decrease in pO(2), i.e. 'hypoxia'. In this review, we present an array of methods currently used for assessing tissue oxygenation. We show that hypoxia is marked during tumour development and has strong consequences for oxygenation and its influence upon chemotherapy efficiency. Then we compare this to physiological pO(2) values of human organs. Finally we evaluate consequences of physioxia on cell activity and its molecular modulations. More importantly we emphasize the discrepancy between in vivo and in vitro tissue and cells oxygen status which can have detrimental effects on experimental outcome. It appears that the values corresponding to the physioxia are ranging between 11% and 1% O(2) whereas current in vitro experimentations are usually performed in 19.95% O(2), an artificial context as far as oxygen balance is concerned. It is important to realize that most of the experiments performed in so-called normoxia might be dangerously misleading.

Exclusion of natural autoantibody-producing B cells from IgG memory B cell compartment during T cell-dependent immune responses.

In healthy individuals, a substantial proportion of circulating Abs exhibit polyreactivity and self-reactivity. These Abs are referred to as natural autoantibodies (NAAs). As part of the innate immunity, NAAs play an important role in eliminating pathogens. However, inherent to their poly/autoreactivity is the potential for NAAs to differentiate to high-affinity autoantibodies during an immune response. We recently generated site-directed transgenic mice that express a prototypic NAA, ppc1-5, which binds a variety of self- and non-self-Ags including DNA and phosphocholine. We have shown previously that B cells expressing the ppc1-5 NAA are positively selected during their primary development. In this study, we demonstrate that following immunization with the T-dependent Ag, phosphocholine conjugated to keyhole limpet hemocyanin, ppc1-5 NAA B cells mounted a quick IgM Ab response and entered germinal centers, but they failed to differentiate to IgG-producing cells during late primary and memory responses. Hybridomas and cDNA clones derived from the immunized mice included many IgM NAA-producing cells, but IgG NAA clones were extremely rare. Instead, many of the IgG B cells replaced their IgH transgene with an endogenous V(H) gene and produced non-autoreactive Abs. These results indicate that although NAA B cells are positively selected in the preimmune repertoire and can participate in early IgM Ab response, they are subjected to regulatory mechanisms that prevent them from developing to high-affinity IgG autoantibody production. This would explain, at least in part, why NAAs do not cause autoimmunity in most individuals.

Association of CD45(dim)VLA-4 (+) cells with the NKT cell lineage and their selective expression of IL-13, IP-15, and CCR3 transcripts.

INTRODUCTION: Estrogen (E2) was shown to prevent experimental autoimmune encephalomyelitis (EAE) and to produce a novel population of regulatory CD45(dim)VLA-4(+) cells. Although their appearance was dependent upon an elevated hormonal level, E2 was not required for their production, as they also were induced by immunization with Mycobacterium tuberculosis as a component of complete Freund's adjuvant. MATERIALS AND METHODS: Molecular techniques, including ribonuclease protection assays and quantitative RT-PCR, were used to provide further characterization of CD45(dim)VLA-4(+) cells. Moreover, we determined the developmental requirements of the CD45(dim)VLA-4(+) cells using genetically modified mice and extensive flow cytometry analysis. RESULTS: Characterization of CD45(dim)VLA-4(+) mRNA profile revealed highly elevated levels of CD16, CD44, CCR3, IP-15, and IL-13 transcripts compared with their CD45(high)VLA-4(+) counterparts. Furthermore, we found up-regulation of anti-apoptotic bcl-w and bcl-xl genes and transcripts encoding the TCRalpha and CD8alpha homodimer. The production of CD45(dim)VLA-4(+) cells was evident in nude mice and in MHC class II- and beta2-microglobulin, but not in CD1-deficient mice, suggesting a crucial role for CD1 in their induction. CONCLUSIONS: These findings suggest that CD45(dim)VLA-4(+) cells might resemble natural killer T cells and imply possible roles for IL-13 and IP-15 in the protective function of CD45(dim)VLA-4(+) cells. A better understanding of how these cells, also occurring naturally during pregnancy, suppress the harmful immune response of EAE may lead to novel therapeutic approaches to combat multiple sclerosis and other autoimmune diseases.

Middle-age male mice have increased severity of experimental autoimmune encephalomyelitis and are unresponsive to testosterone therapy.

Treatment with sex hormones is known to protect against experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. However, little is known about how age affects the course of EAE or response to hormone treatment. This study demonstrates striking differences between middle-age vs young C57BL/6 male mice in the clinical course of EAE and response to both testosterone (T4) and estrogen (E2) hormone therapy. Unlike young males that developed an acute phase of EAE followed by a partial remission, middle-age males suffered severe chronic and unremitting EAE that was likely influenced by alterations in the distribution and function of splenic immunocytes and a significant reduction in suppressive activity of CD4+CD25+ regulatory T cells in the spleen and spinal cord. Middle-age males had reduced numbers of splenic CD4+ T cells that were generally hypoproliferative, but enhanced numbers of splenic macrophages and MHC class II-expressing cells, and increased secretion of the proinflammatory factors IFN-gamma and MCP-1. Surprisingly, middle-age males were unresponsive to the EAE-protective effects of T4 and had only a transient benefit from E2 treatment; young males were almost completely protected by both hormone treatments. T4 treatment of young males inhibited proliferation of myelin oligodendrocyte glycoprotein 35-55-specific T cells and secretion of TNF-alpha and IFN-gamma. The effects of T4 in vivo and in vitro were reversed by the androgen receptor antagonist, flutamide, indicating that the regulatory effects of T4 were mediated through the androgen receptor. These data are the first to define age-dependent differences in EAE expression and response to hormone therapy.

Estrogen treatment induces a novel population of regulatory cells, which suppresses experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is a debilitating neurological disease characterized by a progressive loss of motor and sensory function, eventually leading to paralysis and death. The primary cause of neurological impairment is demyelination of the central nervous system (CNS) caused by an inflammatory autoimmune response. Previous studies have shown that the severity of MS is reduced during pregnancy, suggesting that the increased level of sex hormones may reduce the autoimmune response. Recently, we have shown that estrogen treatment confers protection from experimental autoimmune encephalomyelitis (EAE), which is an animal model for MS. However, the cellular basis of estrogen's action remains unknown. In the current study, we demonstrate that estrogen treatment led to the induction of a novel subpopulation of regulatory cells in spleen and CNS, which also occurs naturally in pregnant mice. These previously uncharacterized cells display a low level expression of CD45 (CD45(dim)) and no detectable expression of many cell surface markers related to TCR signaling, including CD3 and TCR. However, these cells retained expression of VLA-4, an extracellular protein involved in cellular migration. Several lines of evidence suggest that these novel cells, defined as CD45(dim)VLA-4(+) cells, may play a role in the protective effects of estrogen in EAE. Injection of purified CD45(dim)VLA-4(+) cells conferred protection from spontaneous EAE (Sp-EAE). In contrast, injection of CD45(high)VLA-4(+) cells exacerbated the disease course. CD45(dim)VLA-4(+) cells also suppressed antigen-specific proliferation of primed lymphocytes in coculture. A better understanding of how CD45(dim)VLA-4(+) cells suppress the harmful immune response of EAE may help in explaining the induction of immune tolerance during pregnancy and lead to novel therapeutic approaches to combat MS and other autoimmune diseases.

Opposing roles for TGF-beta1 and TGF-beta3 isoforms in experimental autoimmune encephalomyelitis.

Hormones can exert significant protective effects on autoimmune diseases by activating immunoregulatory mechanisms. One of the possible mechanisms of hormonal protection might be through the anti-inflammatory effects of the TGF-beta molecule. The present study investigated the changes in expression of two TGF-beta isoforms, TGF-beta1 and TGF-beta3, in C57BL/6 and TCR transgenic (T/R+) B10.PL mice that manifested or were protected against clinical signs of experimental autoimmune encephalomyelitis (EAE) with 17beta-estradiol (E2) treatment. We here demonstrate an inverse relationship between expression of TGF-beta1 that is enhanced in mice with EAE, and TGF-beta3 that is enhanced in E2-protected mice. The differential expression of TGF-beta isoforms was observed in spinal cord tissue but not spleen. Additionally TGF-beta1 expression was evident both in whole spinal cord tissue and mononuclear cells isolated from inflamed tissue, in contrast to TGF-beta3 that was only detected in spinal cord tissue but not in mononuclear cells. Further studies revealed that CD3 and especially MAC-1 positive cells were the main source of TGF-beta1 in the mononuclear CNS population. Of crucial importance, the TGF-beta3 isoform displayed anti-proliferative properties towards encephalitogenic cells in vitro. We propose that the TGF-beta1 and TGF-beta3 isoforms play opposing roles in the expression of EAE.

Estradiol treatment redirects the isotype of the autoantibody response and prevents the development of autoimmune arthritis.

A number of clinical and experimental observations have been made relating elevated estrogen levels with the amelioration of autoimmune diseases, yet questions remain about the levels required for efficacy as well as the mechanism of disease inhibition. Using the collagen-induced arthritis (CIA) model, we have studied the effects of physiological, sustained levels of 17beta-estradiol in preventing the development of autoimmune arthritis and analyzed the changes in the autoimmune response. Using time-release pellets of 17beta-estradiol, arthritis development was significantly inhibited in three different strains of CIA-susceptible mice compared with the effect of placebo treatment, and serum estradiol levels similar to those of mice in estrus were found to be equally effective as higher estradiol concentrations. Analysis of the autoimmune response in the estradiol-treated mice indicated that T cell production of IFN-gamma was markedly decreased, and significant decreases were also observed in levels of IL-10 and GM-CSF produced by lymph nodes cells from estradiol-treated mice. Although the total IgG anti-CII response was only minimally affected by estrogen treatment, a significant reduction in the levels of IgG2a anti-CII Abs and an increase in the levels of IgG1 anti-CII Abs were observed in estradiol-treated mice. These data indicate that estradiol treatment altered the Th profile of the autoimmune T cell response, which, in turn, altered the production of IgG Abs to an isotype that is poor at fixing complement, an important component in the immunopathogenesis of CIA.