Mindfulness and Care Experience in Family Caregivers of Persons Living with Dementia

Background

Greater mindfulness, the practice of awareness and living in the moment without judgement, has been linked to positive caregiving outcomes in dementia caregivers and its impact attributed to greater decentering and emotion regulation abilities. Whether the impact of these mindfulness-based processes varies across caregiver subgroups is unclear.

Objective

Analyze cross-sectional associations between mindfulness and caregiver psychosocial outcomes, considering different caregiver and patient characteristics.

Methods

A total of 128 family caregivers of persons living with Alzheimer's disease and related disorders were assessed on several mindfulness measures (i.e., global; decentering, positive emotion regulation, negative emotion regulation) and provided self-reported appraisals of caregiving experience; care preparedness; confidence, burden, and depression/anxiety. Bivariate relationships between mindfulness and caregiver outcomes were assessed with Pearson's correlations and stratified by caregiver (women versus men; spouse versus adult child) and patient (mild cognitive impairment (MCI) versus Dementia; AD versus dementia with Lewy bodies; low versus high symptom severity) characteristics.

Results

Greater mindfulness was associated with positive outcomes and inversely associated with negative outcomes. Stratification identified specific patterns of associations across caregiver groups. Significant correlations were found between all mindfulness measures and caregiving outcomes in male and MCI caregivers while the individual mindfulness component of positive emotion regulation was significantly correlated to outcomes in most caregiver groups.

Conclusion

Our findings support a link between caregiver mindfulness and improved caregiving outcomes and suggest directions of inquiry into whether the effectiveness of dementia caregiver-support interventions may be improved by targeting specific mindfulness processes or offering a more inclusive all-scope approach depending on individual caregiver or patient characteristics.

Association of Sphingosine-1-phosphate (S1P)/S1P Receptor-1 Pathway with Cell Proliferation and Survival in Canine Hemangiosarcoma

Background

Sphingosine‐1‐phosphate (S1P) is a key biolipid signaling molecule that regulates cell growth and survival, but it has not been studied in tumors from dogs.

Hypothesis/Objectives

S1P/S1P₁ signaling will contribute to the progression of hemangiosarcoma (HSA).

Animals

Thirteen spontaneous HSA tissues, 9 HSA cell lines, 8 nonmalignant tissues, including 6 splenic hematomas and 2 livers with vacuolar degeneration, and 1 endothelial cell line derived from a dog with splenic hematoma were used.

Methods

This was a retrospective case series and in vitro study. Samples were obtained as part of medically necessary diagnostic procedures. Microarray, qRT‐PCR, immunohistochemistry, and immunoblotting were performed to examine S1P₁ expression. S1P concentrations were measured by high‐performance liquid chromatography/mass spectrometry. S1P signaling was evaluated by intracellular Ca²⁺ mobilization; proliferation and survival were evaluated using the MTS assay and Annexin V staining.

Results

Canine HSA cells expressed higher levels of S1P₁mRNA than nonmalignant endothelial cells. S1P₁ protein was present in HSA tissues and cell lines. HSA cells appeared to produce low levels of S1P, but they selectively consumed S1P from the culture media. Exogenous S1P induced an increase in intracellular calcium as well as increased proliferation and viability of HSA cells. Prolonged treatment with FTY720, an inhibitor of S1P₁, decreased S1P₁ protein expression and induced apoptosis of HSA cells.

Conclusions and clinical importance

S1P/S1P₁ signaling pathway functions to maintain HSA cell viability and proliferation. The data suggest that S1P₁ or the S1P pathway in general could be targets for therapeutic intervention for dogs with HSA.

Antigen microarrays identify CNS-produced autoantibodies in RRMS

OBJECTIVE

Multiple sclerosis (MS) is characterized by the local production of antibodies in the CNS and the presence of oligoclonal bands in the CSF. Antigen arrays allow the study of antibody reactivity against a large number of antigens using small volumes of fluid with greater sensitivity than ELISA. We investigated whether there were unique autoantibodies in the CSF of patients with MS as measured by antigen arrays and whether these antibodies differed from those in serum.

METHODS

We used antigen arrays to analyze the reactivity of antibodies in matched serum and CSF samples of 20 patients with untreated relapsing-remitting MS (RRMS), 26 methylprednisolone-treated patients with RRMS, and 20 control patients with other noninflammatory neurologic conditions (ONDs) against 334 different antigens including heat shock proteins, lipids, and myelin antigens.

RESULTS

We found different antibody signatures in matched CSF and serum samples The targets of these antibodies included epitopes of the myelin antigens CNP, MBP, MOBP, MOG, and PLP (59%), HSP60 and HSP70 (38%), and the 68-kD neurofilament (3%). The antibody response in patients with MS was heterogeneous; CSF antibodies in individual patients reacted with different autoantigens. These autoantibodies were locally synthesized in the CNS and were of the immunoglobulin G class. Finally, we found that treatment with steroids decreased autoantibody reactivity, epitope spreading, and intrathecal autoantibody synthesis.

CONCLUSIONS

These studies provide a new avenue to investigate the local antibody response in the CNS, which may serve as a biomarker to monitor both disease progression and response to therapy in MS.

Immunoglobulin Class of Natural Human Antibodies Reactive with Treponema pallidum

To aid the development of serological tests for incubating syphilis, a characterization was made of the background of natural anti-Treponema pallidum antibodies against which the initial immune response to syphilis takes place. Sera from presumed normal persons were studied with monospecific antisera in an indirect fluorescent-antibody procedure. Of 36 sera tested at a 1:5 dilution, all showed IgG reactivity with T. pallidum (Nichols strain), 58% showed IgM reactivity, and 20% showed IgA reactivity. The titer of IgG reactivity was considerably higher than that of the other two immunoglobulins. Heating the sera for 1 hr at 65 C abolished IgA and IgM anti-T. pallidum reactivity, but one-third of the sera retained IgG reactivity. Human Cohn fractions II and III(1) from three commercial sources contained mostly IgG antibodies reactive with T. pallidum, but IgM and IgA antibodies were also present. IgG reactivity was found in a pool of presumably normal maternal sera from 20 mothers and in a corresponding pool of umbilical cord serum from their infants. IgM and IgA reactivities were present only in the maternal serum pool.

Immunological efficacy of heat shock protein 60 peptide DiaPep277 therapy in clinical type I diabetes

An immunogenic peptide (p277) from the 60-kDa heat shock protein (hsp60) arrested beta-cell destruction in non-obese diabetic mice. A randomized, double-blind, phase Ib/II clinical trial of DiaPep277 peptide treatment was performed in recent-onset type 1 diabetes patients with remaining insulin production. We studied the immunological efficacy of this peptide therapy and correlated this with clinical outcome. Forty-eight C-peptide-positive patients were assigned subcutaneous injections of 0.2, 1.0 or 2.5 mg p277 (n = 12 per dosage) at entry, and 1, 6 and 12 months, or four placebo injections (n = 12). T cell autoimmunity to hsp60, DiaPep277, glutamic acid decarboxylase and tetanus toxoid (recall response control) were assayed by proliferation and cytokine secretion assays (enzyme-linked immunospot) at regular intervals until 18 months after the first injection. All treated patients at each dosage of peptide demonstrated an altered immune response to DiaPep277, while the majority of placebo-treated patients remained non-responsive to treatment (P = 0.00001), indicating a 100% efficacy of immunization. Cytokine production in response to therapy was dominated by interleukin (IL)-10. IL-10 production before therapy and decreasing autoantigen-specific T cell proliferation were associated with beta-cell preservation. Third-party control immune responses were unaffected by therapy. No potentially adverse immunological side effects were noted. DiaPep277 is immunogenic in type 1 diabetic subjects and has immune modulating properties. Immunological monitoring distinguished therapy from placebo treatment and could determine immunological efficacy. Declining or temporary proliferative responses to peptide DiaPep277 treatment may serve as an immunological biomarker for clinical efficacy.

Treatment of new-onset type 1 diabetes with peptide DiaPep277 is safe and associated with preserved beta-cell function: extension of a randomized, double-blind, phase II trial

BACKGROUND

Treatment with DiaPep277, a peptide derived from HSP60, has been shown to preserve beta-cell function in non-obese diabetic mouse (NOD) mice and in a trial with newly diagnosed human patients with type 1 diabetes treated over a 10-month period. This article extends the clinical trial observations to a total of 20 months of treatment to determine the safety and the effects of repeated doses of DiaPep277 on endogenous insulin secretion, metabolic control, and exogenous insulin requirements.

METHODS

Thirty-five male patients (aged 16-58) with a basal C-peptide greater than 0.1 nmol/L were assigned to periodic treatment with DiaPep277 (1 mg) or placebo for a 12-month treatment and 18-month observation protocol, later extended to an additional year of treatment. Stimulated C-peptide, HbA1c, and an exogenous insulin dose were the clinical endpoints.

RESULTS

At 18 months, stimulated C-peptide concentrations had fallen in the placebo group (p = 0.0005) but were maintained in the DiaPep277 group. The need for exogenous insulin was higher in the placebo group than in the DiaPep277 group. Mean HbA1c concentrations were similar in both groups. After extension of the study, patients continuing treatment with DiaPep277 and those switched from placebo to DiaPep277 manifested a trend towards a greater preservation of beta-cell function compared to patients maintained on or switched to placebo. The safety profile of DiaPep277 was similar between the treatment and placebo groups, and no drug-related adverse events occurred.

CONCLUSIONS

Periodic treatment of subjects with DiaPep277 over 2 years was safe and associated preservation of endogenous insulin secretion up to 18 months was observed.

Antigen-chip technology for accessing global information about the state of the body

Traditionally, immunologic diagnosis has been based on an attempt to correlate each disease with a specific immune reactivity, such as an antibody or a T-cell response to a single antigen specific for the disease entity. The state of the body, however, appears to be encoded by the immune system in collectives of reactivities and not by single reactivities. Here we describe our use of microarray technology and informatics to develop an antigen chip capable of detecting global patterns of antibodies binding to hundreds of antigens simultaneously. The patterns fashion diagnostic signatures.

Anti-ergotypic Immunoregulation

T-cell vaccination (TCV) controls pathogenic autoimmune T-cell responses via two different regulatory cell populations: anti-idiotypic and anti-ergotypic T cells. Anti-idiotypic T cells recognize clone-specific determinants, like the CDR3 region of the T-cell receptor. Anti-ergotypic T cells recognize antigenic determinants derived from activation markers, which are upregulated by activated T cells, like CD25. In this review, we analyse the different components of the anti-ergotypic response: (1) the target T cells, which can be CD8+ or CD4+ T cells that express TCRalphabeta or TCRgammadelta; (2) the ergotope, which can be a T cell-restricted ergotope not expressed by other cell types or a widely expressed, shared ergotope and (3) the anti-ergotypic T cells, which are detectable in the naive immune system, but whose numbers can be expanded during the induction of an immune response against, or as a result of TCV or specific, anti-ergotypic vaccination. Finally, we discuss possible interactions between anti-ergotypic regulators and other regulatory T cells. We propose that the expression of major histocompatibility complex class II molecules by regulatory CD4+CD25+ T cells may make possible the cross-regulation of anti-ergotypic and CD4+CD25+ regulatory T cells, fine-tuning immunoregulation in the mature immune system.

Alpha tropomyosin as a self-antigen in patients with Behçet's disease

We report for the first time a significant increased lymphoproliferative response to alpha tropomyosin as well as observing autoantibodies to tropomyosin observed in Behcet's disease (BD) patients with posterior uveitis. Peripheral blood mononuclear cells (PBMCs) from 18 BD patients with posterior uveitis, 18 patients with other forms of noninfectious uveitis, 9 patients with retinal damage due to photocoagulation as well as 18 healthy donors were evaluated for antigen-specific lymphoproliferative responses to alpha tropomyosin and its derivative peptides. The proliferative responses of PBMCs to these antigens were studied using (3)H thymidine incorporation assay. Serum samples were also screened by ELISA for autoantibodies against tropomyosin. Six of the 18 (33%) BD patients with posterior uveitis showed increased proliferative response to alpha tropomyosin or its derivative peptides, while none of the healthy, disease controls were positive. The mean lymphoproliferative responses to tropomyosin were significantly higher (P < 0.02) in the BD patients compared to healthy or disease controls. Higher titres of anti-tropomyosin antibodies were also seen in four of the 18 BD patients but none in the healthy or disease control groups (P < 0.002). The occurrence of these abnormalities supports a possible role for alpha tropomyosin as a self-antigen in a subset of patients with Behcet's disease.

T cell vaccination in multiple sclerosis relapsing-remitting nonresponders patients

Myelin autoreactive T cells are involved in the pathogenesis of multiple sclerosis (MS) and lead to propagation of the disease. We evaluated the efficacy of T cell vaccination (TCV) therapy for patients with aggressive relapsing-remitting MS who failed to respond to immunomodulatory treatments. Twenty nonresponders relapsing-remitting MS patients were immunized with autologous attenuated T cell lines after activation with synthetic myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) encephalitogenic peptides. Each patient received three vaccinations in 6- to 8-week intervals. Annual relapse rate decreased from 2.6 to 1.1, P = 0.026. Neurological disability stabilized as compared with the 2- and 1-year pretreatment progression rates. Significant reduction in the number and volume of active lesions, as well as reduction in T2 lesion burden, was demonstrated by quantitative MRI analysis. No serious adverse events were observed. Our findings suggest that TCV has beneficial clinical effects in MS patients who, in spite of immunomodulatory treatments, continue to deteriorate. TCV could serve as a potential alternative therapy for this subgroup of nonresponders patients.

Peptide therapy for Type I diabetes: the immunological homunculus and the rationale for vaccination

The autoimmune process that produces Type I (insulin-dependent) diabetes mellitus seems to respond favourably to therapeutic vaccination with a peptide of the 60 kDa heat shock protein. This article is a personal review of the observations and the thinking that gave rise to the idea of therapeutic peptide vaccination. The rationale for vaccination therapy is compared to other approaches aimed at specific immunological treatment for autoimmune disease.

Autoimmunization to epidermal growth factor, a component of the immunological homunculus

Epidermal growth factor (EGF) is being tried as a vaccine in cancer immunotherapy with the aim of inducing neutralizing antibodies that might affect EGF-dependent tumors. Here we summarize our experience using the EGF self-molecule as an autoimmunigen. We report here that IgG anti-EGF antibodies are prevalent in healthy people and that augmentation of the response to EGF requires conjugation to an effective carrier and an adjuvant. Paradoxically, the response to EGF immunization could be enhanced by an 'immunosuppressive' treatment with cyclophosphamide, most probably by suppressing active control mechanisms. EGF is expressed in the thymus. Thus, EGF may be added to the immunological homunculus, the class of self-antigens to which there is both natural autoimmunity and natural regulation of the autoimmunity. The results using EGF as a vaccine can teach us about the homunculus and how to activate it.

T-cell vaccination for autoimmune disease: a panorama

T-cell vaccination refers to a form of cell therapy, usually autologous, aimed at curing or ameliorating autoimmune diseases. This review considers five questions: What is TCV? How is it done? How does it work? Why does it work? And what is its future?

Self prion protein peptides are immunogenic in Lewis rats

Prion diseases are caused by abnormal folding of the prion protein. The paradigm is that the prion protein is not immunogenic because the immune system must be tolerant to such a self protein. In an attempt to identify immunogenic prion peptides, we immunized Lewis rats with peptides that fitted the MHC class II RT1.B(1)motif. Both humoral and cellular immunity to the prion peptides were obtained without any harmful effects to young animals. However, when 8-month-old rats were immunized, a sixth (6/36) of the rats developed severe skin inflammation with concomitant hair loss. These findings suggest that immunity to self-prion peptides can be readily induced in Lewis rats and that this immune response may have pathogenic consequences in older rats.

Modeling the influence of TH1- and TH2-type cells in autoimmune diseases

A sharp TH1/TH2 dichotomy has often been used to define the effects of cytokines on autoimmune diseases. However contradictory results in recent research indicate that the situation may be more complex. Here, we build a simple mathematical model aimed at settling the contradictions. The model is applied using Ordinary Differential Equations (ODE). We show here that a TH1/TH2 paradigm is only an external view of a complex multivariate system.

Beta-cell function in new-onset type 1 diabetes and immunomodulation with a heat-shock protein peptide (DiaPep277): a randomised, double-blind, phase II trial

BACKGROUND

Type 1 diabetes results from autoimmune destruction of insulin-producing pancreatic beta cells. The 60 kDa heat-shock protein (hsp60) is one of the known target self antigens. An immunomodulatory peptide from hsp60, p277, arrested beta-cell destruction and maintained insulin production in newly diabetic NOD mice. We did a randomised, double-blind, phase II study of peptide treatment in patients with newly diagnosed (<6 months) type 1 diabetes.

METHODS

35 patients with type 1 diabetes and basal C-peptide concentrations above 0.1 nmol/L were assigned subcutaneous injections of 1 mg p277 and 40 mg mannitol in vegetable oil (DiaPep277; n=18) at entry, 1 month, and 6 months, or three placebo injections (mannitol in vehicle; placebo; n=17). The primary endpoint was glucagon-stimulated C-peptide production. Secondary endpoints were metabolic control and T-cell autoimmunity to hsp60 and to p277 (assayed by cytokine secretion). 31 patients completed 10 months of follow-up and were included in the intention-to-treat analysis.

FINDINGS

At 10 months, mean C-peptide concentrations had fallen in the placebo group (n=16) but were maintained in the DiaPep277 group (n=15; 0.26 [SD 0.11] vs 0.93 [0.35] nmol/L; p=0.039). Need for exogenous insulin was higher in the placebo than in the DiaPep277 group (0.67 [0.33] vs 0.43 [0.17] U/kg; p=0.042). Haemoglobin A1c concentrations were low (around 7%) in both groups. T-cell reactivity to hsp60 and p277 in the DiaPep277 group showed an enhanced T-helper-2 cytokine phenotype. No adverse effects were noted.

INTERPRETATION

Although this study was small, treatment of newly diagnosed type 1 diabetes with DiaPep277 seems to preserve endogenous insulin production, perhaps through induction of a shift from T-helper-1 to T-helper-2 cytokines produced by the autoimmune T cells.

Proliferative lesions of ovarian granulosa cells and reversible hormonal changes induced in rats by a selective estrogen receptor modulator

This study assessed the effects of raloxifene. a selective estrogen receptor modulator (SERM), on ovarian morphology and circulating hormone levels in rats. Female Fischer-344 rats (65/group) were given dietary raloxifene for 6 months at average daily doses of 0, 15, 75, and 365 mg/kg. Morphologic evaluation of ovaries was conducted on 25 rats/group at the end of the treatment period and from 20 rats per group after 1 and 3 months withdrawal from treatment. Plasma hormone analyses were conducted on 10 rats per group at the end of the treatment period and after each withdrawal period. Treatment with raloxifene for 6 months resulted in disruption of the hypothalamic-pituitary-ovarian axis, manifested by increased plasma concentrations of luteinizing hormone (LH) and estradiol-17beta (E2), and failure of ovulation, manifested by ovarian follicular prominence (retained anovulatory follicles), lack of corpora lutea (CL), and depressed plasma progesterone (P4). Many (56% to 80%) rats in all raloxifene treated groups had focal, minimal to slight hyperplasia of granulosa cells within individual retained follicles. A few treated rats in the mid- and high-dose groups (2 of 25 and 3 of 25, respectively) had more extensive focal proliferation of granulosa cells. These foci were approximately 3 to 6 mm in overall size and were characterized by moderate papillary proliferation of large granulosa cells associated with cystic spaces, often with hemorrhage. In 4 of the 5 rats with this focal cystic granulosa cell hyperplasia, the remainder of the involved ovary and the contralateral ovary were atrophic. After 1 or 3 months of drug withdrawal, most previously treated rats examined had morphologic evidence of ovarian cyclic changes, including developing follicles, various stages of CL, and normal plasma levels of LH, E2, and P4. Continued lack of cyclic changes was limited to 4 of 20 rats from the low-dose group after 1 month of recovery and to 1 low dose rat after 3 months. Intrafollicular granulosa cell hyperplasia was not seen in rats in the reversibility phase. Areas of prior focal cystic granulosa cell hyperplasia were represented by focal sclerosis that included hemorrhage and/or hemosiderin. The foci of sclerosis were associated with cystic spaces after 1 month and were solid after 3 months. A granulosa cell tumor, approximately 12-13 mm diameter, was present in a high-dose rat in the 3-month reversibility group. This tumor effaced 1 ovary and was characterized by proliferative granulosa cells, usually in papillary formations and cords within cystic spaces. This rat had atrophy of the uninvolved ovary, excessive plasma levels of E2 and prolactin, and high P4 levels considering the absence of CL. The results of this study indicate that ovarian granulosa cells in rats are susceptible to proliferative changes when stimulated chronically with excessive trophic hormones. Most of these proliferative changes were reversible upon cessation of the hormonal stimulation. However, the proliferative lesion in one treated rat progressed to apparent autonomous (neoplastic) growth.

Autoantibody patterns in diabetes-prone NOD mice and in standard C57BL/6 mice

Autoantibodies are commonly found in healthy individuals and strains of mice that are not prone to autoimmunity. The present study was undertaken to identify self antigens recognized by serum autoantibodies from unimmunized mice of two strains: NOD mice prone to spontaneously develop autoimmune diabetes and C57BL/6 mice known to be relatively resistant to autoimmune disease. IgM and IgG autoantibodies detected in the sera of NOD and C57BL/6 mice manifested different patterns of reactivity. The IgM autoantibodies from C57BL/6 serum reacted with more self antigens and showed higher OD values than the IgM autoantibodies from NOD mice. In contrast, the IgG autoantibodies from NOD serum reacted with more antigens and displayed higher OD readings than did IgG autoantibodies from C57BL/6 mice. Among the antigens recognized by the autoantibodies, particularly of the IgG class, were self antigens known to induce experimental autoimmune diseases in NOD and C57BL/6 mice. In addition, IgG autoantibodies from NOD mice reacted with self antigens reported to mark the spontaneous autoimmune diabetes that characterizes this strain of mice. These results suggest that naturally occurring IgG autoantibodies reflect susceptibility to induction of specific autoimmune diseases. In addition, the results suggest that IgM autoantibodies may by associated with mechanisms that might prevent autoimmune disease.

Autoantibodies to pancreatic hsp60 precede the development of glucose intolerance in patients with cystic fibrosis

Persons expressing the genetic disease cystic fibrosis (CF) suffer from a high risk of developing impaired glucose tolerance and diabetes. The development of diabetes in CF has been attributed, in the past, to the destruction of pancreatic islets and their resident beta-cells secondary to the destruction of the surrounding tissue by mechanical clogging of the pancreatic exocrine ducts. However, the discovery that autoimmunity to the 60-kDa heat shock protein (hsp60) may cause type I diabetes in NOD mice raises the possibility that hsp60 autoimmunity may be involved in CF diabetes too; could the hyperimmunization to bacterial hsp60 characteristic of CF spread to self-hsp60 and hence to autoimmune diabetes? We now report that rising levels of IgG autoantibodies to hsp60 do indeed precede the appearance of glucose intolerance and diabetes in CF patients. We produced a recombinant human pancreatic hsp60 protein and investigated the IgG antibody response to hsp60 in prediabetic and non-diabetic patients with CF. To detect hsp60 autoantibodies in the presence of high levels of antibodies to bacterial hsp60, we absorbed test sera with the 60-kDa GroEL of Pseudomonas aeruginosa and used an immunostaining technique. Using this technique, 32 prediabetic CF patients were evaluated over a five-year period, three years, on the average, before the onset of glucose intolerance. We found that a significant increase in hsp60 autoantibody preceded impaired glucose tolerance (P=0.042, n=17), diabetes (P=0.011, n=15) and glucose intolerance (P=0.005, n=32). As has been observed in NOD mice and in type I diabetic patients, the hsp60 autoantibodies decline at the outbreak of glucose intolerance in the CF patients. The association of CF diabetes with the rise and fall of hsp60 autoimmunity suggests that the pathogenesis of the diabetes may not be merely mechanical, but arise in the wake of bacterial hyperimmunisation.

Autoimmunity to the p53 protein is a feature of systemic lupus erythematosus (SLE) related to anti-DNA antibodies

The induction of anti-DNA autoantibodies in systemic lupus erythematosus (SLE) patients is problematic because mammalian DNA is poorly immunogenic at best. Here we demonstrate a chain of connected antibodies in SLE patient sera that could account for the induction of anti-DNA antibody, and possibly for some of the pathogenic features of SLE. We now report that SLE patients, in addition to anti-DNA, produce antibodies to the carboxy-terminal domain of the tumour suppressor molecule p53; this p53 domain recognizes damaged DNA. Hence, these anti-p53 antibodies could mimic damaged DNA immunologically. Indeed, SLE sera do contain anti-idiotypic antibodies to a prototypic anti-p53 antibody. Moreover, SLE anti-DNA antibodies also recognize this type of anti-p53 antibody. Indeed, binding of affinity-purified anti-DNA both to DNA and to the anti-p53 antibody could be blocked by a p53 peptide derived from the DNA-binding domain. This mimicry of the p53 DNA-binding domain by the SLE anti-DNA antibodies is functional: activation of the p53 molecule could be inhibited by such anti-DNA antibodies. Thus, anti-DNA antibodies may arise in SLE patients by a chain of idiotypic autoimmunity centered around p53 autoimmunity. The SLE anti-DNA and anti-p53 antibodies can functionally block p53 activation, and so could affect apoptosis.

Modulation of proteinase-K resistant prion protein by prion peptide immunization

Prion diseases are caused by conformational alterations in the prion protein (PrP). The immune system has been assumed to be non-responsive to the self-prion protein, therefore, PrP autoimmunity has not been investigated. Here, we immunized various strains of mice with PrP peptides, some selected to fit the MHC class II-peptide binding motif. We found that specific PrP peptides elicited strong immune responses in NOD, C57BL/6 and A/J mice. To test the functional effect of this immunization, we examined the expression of proteinase-K-resistant PrP by a scrapie-infected tumor transplanted to immunized syngeneic A/J mice. PrP peptide vaccination did not affect the growth of the infected tumor transplant, but significantly reduced the level of protease-resistant PrP. Our results demonstrate that self-PrP peptides are immunogenic in mice and suggest that this immune response might affect PrP-scrapie levels in certain conditions.

Proliferative lesions of ovarian granulosa cells and reversible hormonal changes induced in rats by a selective estrogen receptor modulator

This study assessed the effects of raloxifene, a selective estrogen receptor modulator (SERM), on ovarian morphology and circulating hormone levels in rats. Female Fischer-344 rats (65/group) were given dietary raloxifene for 6 months at average daily doses of 0, 15, 75, and 365 mg/kg. Morphologic evaluation of ovaries was conducted on 25 rats/group at the end of the treatment period and from 20 rats per group after 1 and 3 months withdrawal from treatment. Plasma hormone analyses were conducted on 10 rats pergroup at the end of the treatment period and aftereach withdrawal period. Treatment with raloxifene for 6 months resulted in disruption of the hypothalamic-pituitary-ovarian axis, manifested by increased plasma concentrations of luteinizing hormone (LH) and estradiol-17beta (E2), and failure of ovulation, manifested by ovarian follicular prominence (retained anovulatory follicles), lack of corpora lutea (CL), and depressed plasma progesterone (P4). Many (56% to 80%) rats in all raloxifene treated groups had focal, minimal to slight hyperplasia of granulosa cells within individual retained follicles. A few treated rats in the mid- and high-dose groups (2 of 25 and 3 of 25, respectively) had more extensive focal proliferation of granulosa cells. These foci were approximately 3 to 6 mm in overall size and were characterized by moderate papillary proliferation of large granulosa cells associated with cystic spaces, often with hemorrhage. In 4 of the 5 rats with this focal cystic granulosa cell hyperplasia, the remainder of the involved ovary and the contralateral ovary were atrophic. After 1 or 3 months of drug withdrawal, most previously treated rats examined had morphologic evidence of ovarian cyclic changes. including developing follicles, various stages of CL, and normal plasma levels of LH, E2, and P4. Continued lack of cyclic changes was limited to 4 of 20 rats from the low-dose group after 1 month of recovery and to 1 low dose rat after 3 months. Intrafollicular granulosa cell hyperplasia was not seen in rats in the reversibility phase. Areas of prior focal cystic granulosa cell hyperplasia were represented by focal sclerosis that included hemorrhage and/or hemosiderin. The foci of sclerosis were associated with cystic spaces after 1 month and were solid after 3 months. A granulosa cell tumor, approximately 12-13 mm diameter, was present in a high-dose rat in the 3-month reversibility group. This tumor effaced 1 ovary and was characterized by proliferative granulosa cells, usually in papillary formations and cords within cystic spaces. This rat had atrophy of the uninvolved ovary, excessive plasma levels of E2 and prolactin, and high P4 levels considering the absence of CL. The results of this study indicate that ovarian granulosa cells in rats are susceptible to proliferative changes when stimulated chronically with excessive trophic hormones. Most of these proliferative changes were reversible upon cessation of the hormonal stimulation. However, the proliferative lesion in one treated rat progressed to apparent autonomous (neoplastic) growth.

Protective autoimmunity is a physiological response to CNS trauma

Primary damage caused by injury to the CNS is often followed by delayed degeneration of initially spared neurons. Studies in our laboratory have shown that active or passive immunization with CNS myelin-associated self-antigens can reduce this secondary loss. Here we show, using four experimental paradigms in rodents, that CNS trauma spontaneously evokes a beneficial T cell-dependent immune response, which reduces neuronal loss. (1) Survival of retinal ganglion cells in rats was significantly higher when optic nerve injury was preceded by an unrelated CNS (spinal cord) injury. (2) Locomotor activity of rat hindlimbs (measured in an open field using a locomotor rating scale) after contusive injury of the spinal cord (T8) was significantly better (by three to four score grades) after passive transfer of myelin basic protein (MBP)-activated splenocytes derived from spinally injured rats than in untreated injured control rats or rats similarly treated with splenocytes from naive animals or with splenocytes from spinally injured rats activated ex vivo with ovalbumin or without any ex vivo activation. (3) Neuronal survival after optic nerve injury was 40% lower in adult rats devoid of mature T cells (caused by thymectomy at birth) than in normal rats. (4) Retinal ganglion cell survival after optic nerve injury was higher (119 +/- 3.7%) in transgenic mice overexpressing a T cell receptor (TcR) for MBP and lower (85 +/- 1.3%) in mice overexpressing a T cell receptor for the non-self antigen ovalbumin than in matched wild types. Taken together, the results imply that CNS injury evokes a T cell-dependent neuroprotective response.

Antigenic mimicry, clonal selection and autoimmunity

The triggering of autoimmunity by infection or immunization is often blamed on antigenic mimicry. But the concept of antigen mimicry impinges on our understanding of adaptive immunity in general, and not only on autoimmunity. Here are some thoughts about the consequences of immune mimicry.

The paradigms of causality and treatment for autoimmune disease

A key concept in medicine is that rational therapy rests on accurate diagnosis; quite simply, therapy that is not tuned to the cause of the disease will not cure the patient. This does not mean that effective treatments cannot emerge from faulty diagnoses. In truth, much of our therapeutic ensemble is composed of drugs developed as a result of chance observation, random screening, intuition or prescientific tradition. Nevertheless, the way to effective therapy is best paved by understanding. Effects are inherent in their causes, so if we want to cure autoimmune diseases using the scientific method, we are obliged to inquire into their causes. By reducing the discordant complexity of the disease to the single cause that underlies it, we can hope to learn the most efficient way to manipulate the disease process. How do we identify a cause when we see one? Quite simply, a single cause is that which is both necessary and sufficient to produce the effect. Here, I explore the general paradigm of autoimmune causality, using multiple sclerosis as a specific example.

Disaccharides derived from heparin or heparan sulfate regulate IL-8 and IL-1 beta secretion by intestinal epithelial cells

BACKGROUND & AIMS

Intestinal epithelial cells can produce cytokines and chemokines that play an important role in the mucosal immune response. Regulation of this secretion is important to prevent inflammatory tissue damage. Disaccharides derived from heparan sulfate and heparin have been shown to down-regulate inflammation in vivo. We tested the effect of such disaccharides on cytokine secretion by intestinal epithelial cells.

METHODS

Spontaneous and tumor necrosis factor (TNF)-alpha-stimulated interleukin (IL)-8 and IL-1 beta secretion and mRNA expression were assessed in HT-29 and Caco-2 intestinal epithelial cell lines in the presence of a panel of heparin and heparan sulfate disaccharides.

RESULTS

Specific disaccharides suppressed spontaneous and TNF-alpha-induced mediator secretion in a dose-dependent manner. Disaccharide activity was structurally restricted. Preincubation of cells with nonsuppressing disaccharides blocked the activity of suppressing disaccharides. The number of sulfate moieties determined the ability of nonsuppressing disaccharides to block the effect of suppressive disaccharides. No suppression of mRNA expression was noted, and intracellular mediator levels were not reduced.

CONCLUSIONS

Disaccharides derived from heparin and heparan sulfate regulate proinflammatory mediator secretion from intestinal epithelial cells. Dose dependence and competition by structurally diverging disaccharides suggest a receptor-mediated mechanism. Unchanged mRNA and intracellular mediator levels suggest that the disaccharides act at posttranscriptional stages.

Vaccination with empty plasmid DNA or CpG oligonucleotide inhibits diabetes in nonobese diabetic mice: modulation of spontaneous 60-kDa heat shock protein autoimmunity

Nonobese diabetic (NOD) mice develop insulitis and diabetes through a process involving autoimmunity to the 60-kDa heat shock protein (HSP60). Treatment of NOD mice with HSP60 or with peptides derived from HSP60 inhibits this diabetogenic process. We now report that NOD diabetes can be inhibited by vaccination with a DNA construct encoding human HSP60, with the pcDNA3 empty vector, or with an oligonucleotide containing the CpG motif. Prevention of diabetes was associated with a decrease in the degree of insulitis and with down-regulation of spontaneous proliferative T cell responses to HSP60 and its peptide p277. Moreover, both the pcDNA3 vector and the CpG oligonucleotide induced specific Abs, primarily of the IgG2b isotype, to HSP60 and p277, and not to other islet Ags (glutamic acid decarboxylase or insulin) or to an unrelated recombinant Ag expressed in bacteria (GST). The IgG2b isotype of the specific Abs together with the decrease in T cell proliferative responses indicate a shift of the autoimmune process to a Th2 type in treated mice. These results suggest that immunostimulation by bacterial DNA motifs can modulate spontaneous HSP60 autoimmunity and inhibit NOD diabetes.

Production of neurotrophins by activated T cells: implications for neuroprotective autoimmunity

Neurotrophins (NTs) promote neuronal survival and maintenance during development and after injury. However, their role in the communication between the nervous system and the immune system is not yet clear. We observed recently that passively transferred activated T cells of various antigen specificities home to the injured central nervous system (CNS), yet only autoimmune T cells specific to a CNS antigen, myelin basic protein (MBP), protect neurons from secondary degeneration after crush injury of the rat optic nerve. Here we examined the involvement of NTs in T-cell-mediated neuroprotection, and the possible significance of the antigen specificity of the T cells in this activity. Analysis of cytokine and NT expression in various rat T cell lines showed that the T cells express mRNA for cytokines of Th1, Th2, and Th3 phenotypes. In addition, the T cells express mRNA and protein specific to nerve growth factor, brain-derived neurotrophic factor, NT-3, and NT-4/5. Antigen activation significantly increased NT secretion. Thus, reactivation of CNS autoimmune T cells by locally presented antigens to which they are specific can lead to enhanced secretion of NTs and possibly also of other factors in injured optic nerves. mRNA for TrkA, TrkB and p75 receptors was expressed in the injured nerve, suggesting that these specific receptors can mediate the effects of the T-cell-derived NTs. The neuroprotective effect of the passively transferred autoimmune anti-MBP T cells in injured optic nerves was significantly decreased after local applicaiton of a tyrosine kinase inhibitor known to be associated with NT-receptor activity. These results suggest that the neuroprotective effect of autoimmune T cells involves the secretion of factors such as NTs by the T cells reactivated by their specific antigen in the injured CNS. T cell intervention in the injured CNS might prove to be a useful means of promoting post-injury CNS maintenance and recovery, possibly via supply of NTs and other factors.

Suppression of experimental autoimmune encephalomyelitis by intravenously administered polyclonal immunoglobulins

Experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats either by active immunization with myelin basic protein (MBP) or by adoptive transfer using anti-MBP specific CD4(+)T cells. Treatment with human polyclonal immunoglobulins (IgG) effectively suppressed active EAE. Time-dependent experiments demonstrated that the effect of IgG was manifested only when treatment was given immediately after immunization; administration from day 7 after disease induction did not suppress the disease. In the adoptive transfer model of EAE, IgG had no effect in vivo. However, pretreatment in vitro of the antigen-specific T-cells with IgG inhibited their ability to mediate adoptive EAE, as it did in active EAE. Similarly, in vitro IgG pretreatment of the antigen-specific T-cells suppressed the proliferative response to MBP. Fluorescent Activated Cell Sorter (FACS) analysis demonstrated the binding of IgG to activated T-cell lines that was inhibited by soluble Fc molecules. The differential effects of IgG on active EAE and on the adoptive transfer of EAE suggest that IgG in vivo can suppress disease by acting during the early phase of the immune response which involves naive T cells. The inhibition of T-cell proliferation and adoptive transfer of EAE by incubation of T cells in vitro appears to require higher concentrations of IgG than those obtained in vivo.

Passive or active immunization with myelin basic protein promotes recovery from spinal cord contusion

Partial injury to the spinal cord can propagate itself, sometimes leading to paralysis attributable to degeneration of initially undamaged neurons. We demonstrated recently that autoimmune T cells directed against the CNS antigen myelin basic protein (MBP) reduce degeneration after optic nerve crush injury in rats. Here we show that not only transfer of T cells but also active immunization with MBP promotes recovery from spinal cord injury. Anesthetized adult Lewis rats subjected to spinal cord contusion at T7 or T9, using the New York University impactor, were injected systemically with anti-MBP T cells at the time of contusion or 1 week later. Another group of rats was immunized, 1 week before contusion, with MBP emulsified in incomplete Freund's adjuvant (IFA). Functional recovery was assessed in a randomized, double-blinded manner, using the open-field behavioral test of Basso, Beattie, and Bresnahan. The functional outcome of contusion at T7 differed from that at T9 (2.9+/-0.4, n = 25, compared with 8.3+/-0.4, n = 12; p<0.003). In both cases, a single T cell treatment resulted in significantly better recovery than that observed in control rats treated with T cells directed against the nonself antigen ovalbumin. Delayed treatment with T cells (1 week after contusion) resulted in significantly better recovery (7.0+/-1; n = 6) than that observed in control rats treated with PBS (2.0+/-0.8; n = 6; p<0.01; nonparametric ANOVA). Rats immunized with MBP obtained a recovery score of 6.1+/-0.8 (n = 6) compared with a score of 3.0+/-0.8 (n = 5; p<0.05) in control rats injected with PBS in IFA. Morphometric analysis, immunohistochemical staining, and diffusion anisotropy magnetic resonance imaging showed that the behavioral outcome was correlated with tissue preservation. The results suggest that T cell-mediated immune activity, achieved by either adoptive transfer or active immunization, enhances recovery from spinal cord injury by conferring effective neuroprotection. The autoimmune T cells, once reactivated at the lesion site through recognition of their specific antigen, are a potential source of various protective factors whose production is locally regulated.

Selection of anti-myelin basic protein T-cell lines in the lewis rat: V-beta 8.2 dominance and conserved complementarity-determining-region-3 motifs are dependent on serine at position 78 of myelin basic protein

In the Lewis rat, the dominant T cell repertoire to myelin basic protein (MBP) is directed to the peptide 71-87 and the T cell receptors of pathogenic T cells are of the Vbeta 8.2 genotype with short CDR3 sequences having a characteristic motif. However, this paradigm has been reached through analysis of long-term encephalitogenic lines and clones. We initiated the present study to examine the process of selection of the TCR Vbeta 8.2 and characteristic CDR3 motifs upon immunization with guinea-pig MBP, and rat or guinea-pig 71-87 peptides. We found that the dominance of Vbeta 8.2 developed progressively over 4-6 in vitro stimulations. Following immunization with rat 70-86, which differs from the guinea-pig peptide in one amino acid at position 78, the dominance of Vbeta 8.2 and the characteristic CDR sequences are not seen. Thus, Vbeta 8.2 dominance and specific CDR3 TCR motifs are seen with heterologous GpMBP but not with self rat MBP.

Autoimmune T cells retard the loss of function in injured rat optic nerves

We recently demonstrated that autoimmune T cells protect neurons from secondary degeneration after central nervous system (CNS) axotomy in rats. Here we show, using both morphological and electrophysiological analyses, that the neuroprotection is long-lasting and is manifested functionally. After partial crush injury of the rat optic nerve, systemic injection of autoimmune T cells specific to myelin basic protein significantly diminished the loss of retinal ganglion cells and conducting axons, and significantly retarded the loss of the visual response evoked by light stimulation. These results support our challenge to the traditional concept of autoimmunity as always harmful, and suggest that in certain situations T cell autoimmunity may actually be beneficial. It might be possible to employ T cell intervention to slow down functional loss in the injured CNS.

T cell immunity to copolymer 1 confers neuroprotection on the damaged optic nerve: possible therapy for optic neuropathies

We recently reported that the posttraumatic spread of degeneration in the damaged optic nerve can be attenuated by the adoptive transfer of autoimmune T cells specific to myelin basic protein. However, it would be desirable to obtain immune neuroprotection free of any possible autoimmune disease. In an attempt to obtain disease-free immune neuroprotection, we used the synthetic four-amino acid polymer copolymer 1 (Cop-1), which is known not to be encephalitogenic despite its cross-reactivity with myelin basic protein. We show here that active immunization with Cop-1 administered in adjuvant, as well as adoptive transfer of T cells reactive to Cop-1, can inhibit the progression of secondary degeneration after crush injury of the rat optic nerve. These results have implications for the treatment of optic neuropathies.

Autoimmunity can benefit self-maintenance

Autoimmunity is usually considered only as a cause of disease; nevertheless, human T-cell repertoires are filled naturally with autoimmune lymphocytes. Here, we review evidence that autoimmune T cells can help heal damaged tissues, indicating that natural autoimmunity could also be a cause of health.

Discrimination and dialogue in the immune system

This paper presents reasons for concluding that the immune system maintains the individual body throughout the vicissitudes of life without the need to make an absolute distinction between self and nonself. Self-maintenance and defence against parasites both require measured inflammation, and the immune system, in both its innate and adaptive arms, regulates inflammation. The intensity, dynamics and orchestration of inflammation emerge from an ongoing dialogue.

Systemic lupus erythematosus in mice, spontaneous and induced, is associated with autoimmunity to the C-terminal domain of p53 that recognizes damaged DNA

The tumor suppressor molecule p53 features a regulatory domain at the C terminus that recognizes damaged DNA. Since damaged DNA might be involved in activating anti-DNA autoantibodies, we tested whether autoimmunity to the C terminus of p53 might mark murine systemic lupus erythematosus (SLE). We now report that MRL / MpJ-Fas(lpr) mice, which spontaneously develop SLE, produce antibodies both to the C terminus of p53 and to a monoclonal antibody (PAb-421) that binds the p53 C terminus. Anti-idiotypic antibodies to PAb-421 (sampled as monoclonal antibodies) could also bind DNA. Thus, the PAb-421 antibody mimics DNA, and the anti-idiotypic antibody to PAb-421 mimics the p53 DNA-binding site. This mimicry was functional; immunization of BALB / c mice to PAb-421 induced anti-DNA antibodies and antibodies to the C terminus of p53, and most of the mice developed an SLE-like disease. Immunization of C57BL / 6 mice to PAb-421 induced antibodies to p53, but not to its C-terminal domain. The C57BL / 6 mice also did not develop anti-DNA antibodies or the SLE-like disease. Thus, network autoimmunity to the domain of p53 that recognizes damaged DNA can be a pathogenic feature in SLE in genetically susceptible strains of mice.

Autoimmune T cells as potential neuroprotective therapy for spinal cord injury

Autoimmune T cells against central nervous system myelin associated peptide reduce the spread of damage and promote recovery in injured rat spinal cord, findings that might lead to neuroprotective cell therapy without risk of autoimmune disease.

The reversible effects of raloxifene on luteinizing hormone levels and ovarian morphology in mice

Raloxifene is a selective estrogen receptor modulator that has estrogen agonist effects on bone and serum lipids and estrogen antagonist effects on breast and uterine tissues. This study assessed the effects of raloxifene hydrochloride (HCl) treatment on circulating luteinizing hormone (LH) levels and ovarian morphology in sexually mature, 15-week-old, female CD-1 mice. Mice were maintained on diets providing average daily doses of 0 or 233 mg/kg raloxifene for 2 weeks (Study 1) or 0, 7.9, or 236 mg/kg raloxifene for 4 weeks (Study 2). At the end of the treatment period, blood samples were collected every 2 hours for 24 h in Study 1 (5 mice per group) and at 10:00 a.m. and 10:00 p.m. in Study 2 (8 mice per group). Serum LH levels were measured by radioimmunoassay. Ovarian histomorphology was evaluated in the 10 mice per group (Study 1) and the 8 mice per group (Study 2). For the reversibility phase (Study 2), mice were fed untreated diets for 3 weeks; serum LH levels and ovarian histomorphology were then assessed. Raloxifene treatment at 233 mg/kg/day for 2 weeks (Study 1) significantly elevated circulating LH levels by 4- to 7-fold compared with control. Raloxifene-treated mice had elevated LH levels sustained over the 24-h sampling period and did not exhibit the preovulatory LH surge evident in some control mice at the 4:00 p.m., 6:00 p.m., and 8:00 p. m. time points. Mice treated with 236 mg/day raloxifene for 4 weeks (Study 2) had elevated LH levels (4.4-fold compared to control), whereas mice exposed to 7.9 mg/kg/day raloxifene had a slight, nonsignificant increase in LH (2-fold compared to control). In both dose groups, LH levels were indistinguishable from controls 3 weeks after raloxifene treatment was discontinued. The ovaries in six of the eight mice treated with 7.9 mg/kg/day raloxifene had dilated and/or anovulatory follicles. One mouse in this group had a single hemorrhagic follicle; however, corpora lutea distribution was normal, indicating that ovulation was occurring. Raloxifene-treated mice in Study 1 and mice treated with a comparable raloxifene dose (236 mg/day) in Study 2 had histomorphological changes in the ovary indicative of arrested follicular maturation, including anovulatory hemorrhagic follicles, some developing follicles, and very few corpora lutea. At the end of the reversibility phase, hemorrhagic follicles were no longer evident and follicular maturation and corpora lutea distribution were normal. Raloxifene treatment in mice produces a dose-dependent, sustained elevation in serum LH levels and is associated with changes in ovarian follicular morphology. These changes are reversible upon discontinuation of raloxifene treatment.

Disaccharides generated from heparan sulphate or heparin modulate chemokine-induced T-cell adhesion to extracellular matrix

We have found previously that disaccharides (DS) enzymatically generated from heparin or heparan sulphate can modulate tumour necrosis factor-alpha (TNF-alpha) secretion from immune cells in vitro and cell-mediated immune reactions in vivo. Here, we show that such DS can modulate the adhesion and migration of human T cells. We found that certain heparin- and heparan sulphate-derived DS induced, in a dose-dependent manner, the adhesion of human T cells to both extracellular matrix (ECM) and immobilized fibronectin (FN); maximal T-cell adhesion occurred with 1 ng/ml of DS. The levels of T-cell adhesion to ECM that were induced by the tested DS molecules resembled those induced by the prototypic chemokine, macrophage inflammatory protein 1beta (MIP-1beta). However, the kinetics of DS-induced T-cell adhesion to FN resembled that induced by phorbol myristate acetate (PMA), but not that induced by MIP-1beta. This adhesion appeared to involve beta1 integrin recognition and activation, and was associated with specific intracellular activation pathways. Although a first exposure of T cells to certain DS molecules appeared to result in cell adhesion, a subsequent exposure of T cells to pro-adhesive chemokines, such as MIP-1beta or RANTES, but not to other pro-adhesive stimuli, for example interleukin-2 or CD3 cross-linking, resulted in inhibition of T-cell adhesion to and chemotactic migration through FN. Hence, we propose that the breakdown products of tissues generated by inflammatory enzymes are part of an intrinsic functional programme, and not necessarily molecular waste. Moreover, because the DS molecules exert their modulatory functions within a limited time, it appears that the historical encounters of the tissue-invading cells with the constituents of inflamed loci may dictate the cells' behaviour upon subsequent exposure to proinflammatory mediators.

Acceleration of autoimmune diabetes by cyclophosphamide is associated with an enhanced IFN-gamma secretion pathway

Cyclophosphamide (CY), an alkylating cytostatic drug, is known for its ability to accelerate a number of experimental autoimmune diseases including spontaneous diabetes in NOD mice. The mechanism(s) by which CY renders autoreactive lymphocytes more pathogenic is largely unknown, but it has been postulated that the drug preferentially depletes regulatory (suppressor) T cells. It has been suggested that in cell-mediated autoimmune diseases, Th2-like lymphocytes secreting IL-4 and/or IL-10 provide protection, while Th1-like cells secreting IFN-gamma are pathogenic. In this study, we analysed the effects of CY on autoimmune diabetes and cytokines in two mouse models: the spontaneous diabetes of NOD mice and the diabetes induced in C57BL/KsJ mice by multiple injections of low dose streptozotocin (LD-STZ). In both models, CY induced severe lymphopenia and accelerated the progression to hyperglycemia. This was associated with changes in splenic cytokine patterns indicating a shift towards the IFN-gamma-secreting phenotype. We provide here evidence that IFN-gamma producers are relatively resistant to depletion by CY and that Th0 clones can be shifted towards Th1. However, direct exposure of T lymphocytes to CY may not be a necessary condition for exacerbation of diabetes; NOD.scid mice treated with CY before adoptive transfer of NOD splenocytes developed diabetes at a higher rate than did controls. Thus, the acceleration of diabetes by CY seems to be a complex event, which includes the relatively high resistance of IFN-gamma producers to the drug, their rapid reconstitution, and a Th1 shift of surviving T cell clones.

Autoimmune maintenance and neuroprotection of the central nervous system

The genesis of immune privilege high in the evolutionary tree suggests that immune privilege is necessary, if not advantageous for the progressive development of the CNS. Upon reaching a certain degree of complexity, it seems as if the CNS was obliged to restrain the immune system from penetrating the blood-brain barrier. CNS autoimmunity against myelin proteins is known to be a contributory factor in the pathophysiology of multiple sclerosis and in the animal model of experimental autoimmune encephalomyelitis (EAE) (Wekerle, 1993). Such autoimmunity has therefore been regarded as detrimental and hence obviously undesirable. However, recent findings in our laboratory suggest that T-cell autoimmunity to CNS self-antigens (Moalem et al., 1999), if expressed at the right time and the right place, can do much good in the CNS. We shall review the experiments briefly, and then discuss their implications for our understanding of immune privilege and CNS maintenance after injury.

Experimental autoimmune keratitis induced in rats by anti-cornea T-cell lines

PURPOSE

Idiopathic inflammation of the cornea, keratitis, has been proposed to result from an autoimmune process, but thus far no convenient animal model of keratitis exists. An attempt was made to establish an animal model for keratitis, to investigate possible autoimmune mechanisms.

METHODS

T-cell lines were established from lymph node cells removed from rats immunized with bovine corneal epithelium (BCE) extract. After restimulation in vitro with BCE or a specific corneal antigen, the cells were transferred by intraperitoneal injection into naive rats, rats subjected to total body irradiation, or rats in which only one eye was irradiated.

RESULTS

Neither direct immunization with corneal antigens nor transfer of activated anti-corneal T-cells into naive rats gave any signs of keratitis. Irradiation alone did not induce corneal inflammation. Transfer of corneal-specific activated T cells into irradiated rats produced keratitis starting around day 4 and culminating around day 8. The disease was self-limiting and the severity dependent on the dose and site of radiation. Keratitis was characterized by corneal haze, conjunctival and episcleral hyperemia, episcleral hemorrhages, chemosis, corneal infiltrates, and vascularization. Immunohistochemistry showed T-cell and macrophage infiltration of epithelium and stroma in the affected corneas.

CONCLUSIONS

Thus, keratitis may be produced by T cells reactive to corneal antigens, provided that the target tissue has been made susceptible by irradiation. The effectiveness of T-cell vaccination in preventing adoptive keratitis suggests that systemic as well as local tissue factors may regulate the disease process.

Inhibition of diabetes in NOD mice by idiotypic induction of SLE

The present study was undertaken to investigate whether active induction of systemic lupus erythematosus (SLE) in non-obese diabetic (NOD) mice could affect their development of insulin-dependent diabetes mellitus (IDDM). NOD mice were immunized with a human IgM mAb carrying the 16/6 idiotype (MIV-7) or with control human IgM. The mice were bled monthly and tested for SLE-associated autoantibodies in the serum and for the presence of leukopenia, thrombocytopenia, proteinuria and immunoglobulin deposits in the kidneys. The development of diabetes was determined by a blood glucose level exceeding 15 mM on two consecutive weekly determinations and by the presence of insulitis in the pancreas. The NOD mice immunized with MIV-7 developed high and persistent levels of autoantibodies, including anti-DNA, anti-histones and anti-cardiolipin, untreated mice and those immunized with normal human IgM did not produce these autoantibodies. The MIV-7-immunized mice also manifested an elevated erythrocyte sedimentation rate, leukopenia, thrombocytopenia and significant proteinuria, as well as deposits of Ig in their kidney glomeruli. Thus, NOD mice immunized with MIV-7 developed both autoantibodies and clinical features of SLE. The MIV-7-treated mice, however, showed a significantly lower incidence of IDDM (25%vs. 90%, P<0.003), accompanied by amelioration of the insulitis. The present study indicates that the induction of SLE by idiotypic immunization can protect NOD mice from developing IDDM, pointing to the importance of immune dysregulation in shift from one autoimmune disease to another.

Prolongation of rat skin and cardiac allograft survival by low molecular weight heparin

BACKGROUND

We have previously reported that very low doses of low molecular weight heparin compounds (LMWH) inhibit a variety of T-cell-mediated reactions by down-regulation of TNF-alpha production. This study tested the efficacy of LMWH in organ transplantation.

METHODS

Skin and heterotopic heart transplantations were performed between recipient Wistar rats and donor BN rats. Two doses of LMWH were given sc, 1 and 20 micrograms, each in three protocols, with day of grafting as Day 0: (A) Daily: -1, 0, 1 ellipsis, (B) Late Weekly: -1, 6, 13 ellipsis, and (C) Early Weekly: -7, 0, 7 ellipsis. Doses and schedules were selected based on efficacy in autoimmune models. Skin graft rejection was defined by complete separation of the graft, and heart transplant rejection was defined as cessation of heartbeat.

RESULTS

Treatment with 1 microgram (26.8 +/- 2.0 days) and 20 micrograms (24.5 +/- 2.3 days) of LMWH using the Early Weekly protocol significantly prolonged skin allograft survival compared to controls (17.8 +/- 4.4 days), P < 0.001 for both, whereas other protocols did not. Compared to controls (8.3 +/- 1.4 days), treatment with both 1 and 20 micrograms of LMWH using all three protocols significantly prolonged cardiac allograft survival. The efficacy, however, varied considerably. Increase in graft survival ranged from 18% (1 microgram, Daily, 9.8 +/- 0.7 days, P = 0.02) to more than twofold (20 micrograms, Early Weekly, 20.8 +/- 5.5 days, P < 0.001) according to the dose and schedule of LMWH.

CONCLUSIONS

Treatment with very low doses of nonanticoagulant LMWH preparations having anti-TNF-alpha activity significantly prolongs rat skin and cardiac allograft survival in a dose- and schedule-dependent manner.

Differential T cell response in central and peripheral nerve injury: connection with immune privilege

The central nervous system (CNS), unlike the peripheral nervous system (PNS), is an immune-privileged site in which local immune responses are restricted. Whereas immune privilege in the intact CNS has been studied intensively, little is known about its effects after trauma. In this study, we examined the influence of CNS immune privilege on T cell response to central nerve injury. Immunocytochemistry revealed a significantly greater accumulation of endogenous T cells in the injured rat sciatic nerve than in the injured rat optic nerve (representing PNS and CNS white matter trauma, respectively). Use of the in situ terminal deoxytransferase-catalyzed DNA nick end labeling (TUNEL) procedure revealed extensive death of accumulating T cells in injured CNS nerves as well as in CNS nerves of rats with acute experimental autoimmune encephalomyelitis, but not in injured PNS nerves. Although Fas ligand (FasL) protein was expressed in white matter tissue of both systems, it was more pronounced in the CNS. Expression of major histocompatibility complex (MHC) class II antigens was found to be constitutive in the PNS, but in the CNS was induced only after injury. Our findings suggest that the T cell response to central nerve injury is restricted by the reduced expression of MHC class II antigens, the pronounced FasL expression, and the elimination of infiltrating lymphocytes through cell death.

Innate and adaptive immune responses can be beneficial for CNS repair

The limitation of immune responsiveness in the mammalian CNS has been attributed to the intricate nature of neuronal networks, which would appear to be more susceptible than other tissues to the threat of permanent disorganization when exposed to massive inflammation. This line of logic led to the conclusion that all forms of CNS inflammation would do more harm than good and, hence, the less immune intervention the better. However, mounting evidence indicates that some forms of immune-system intervention can help to protect or restore CNS integrity. We have shown that the innate immune system, represented by activated macrophages, can facilitate the processes of regeneration in the severed spinal cord. More recently, we found that autoimmune T cells that are specific for a component of myelin can protect CNS neurons from the catastrophic secondary degeneration, which extends traumatic lesions to adjacent CNS areas that did not suffer direct damage. The challenge, therefore, is to learn how to modify immune interactions in the traumatized CNS in order to promote its post-injury maintenance and repair.

A shared TCR CDR3 sequence in NOD mouse autoimmune diabetes

T cells involved in autoimmune diseases have been characterized by the genetic elements used to construct their autoimmune TCR. In the present study, we sequenced the alpha and beta chains of the TCR expressed by a CD4(+) T cell clone, C9, functional in NOD mouse diabetes. Clone C9 can adoptively transfer diabetes or, when attenuated, C9 can be used to vaccinate NOD mice against diabetes. Clone C9 recognizes a peptide epitope (p277) of the 60 kDa heat shock protein (hsp60) molecule. We now report that the C9 TCR beta chain features a CDR3 peptide sequence that is prevalent among NOD mice. This CDR3 element is detectable by 2 weeks of age in the thymus, and later in the spleen and in the autoimmune insulitis. Thus, a TCR CDR3beta sequence appears to be a common idiotope associated with mouse diabetes.

Regulation of NOD mouse autoimmune diabetes by T cells that recognize a TCR CDR3 peptide

NOD mice spontaneously develop type I diabetes resulting from autoimmune destruction of their insulin-producing beta cells. Among the self-antigens targeted by NOD autoimmune T cells is a peptide, p277, from the sequence of the 60 kDa heat shock protein (hsp60). Common to the anti-p277 T cell populations of NOD mice is an idiotope, C9, that spans the CDR3 region of the C9 TCR. We now report: (i) that the C9 idiotope peptide can be presented directly to anti-C9 anti-idiotypic T cells by C9 T cells, (ii) that spontaneous anti-C9 anti-idiotypic T cell activity falls as disease progresses, but immunization can activate the anti-idiotypic T cells to regulate the autoimmune process, (iii) that the anti-idiotypic T cells secrete IFN-gamma, but appear to control the disease by down-regulating the IFN-gamma produced by the pathogenic population of anti-p277 T cells, (iv) that intrathymic administration of the C9 idiotope peptide at 1 week of age can accelerate the disease, and (v) that administering the p277 target peptide can up-regulate the anti-idiotypic T cells and arrest the disease process. Thus, the development of NOD diabetes can be regulated by a balance between anti-idiotypic and anti-target peptide autoimmunity, and anti-idiotypic regulation can lead to changes in the cytokine secretion of the autoimmune T cells involved in the disease process.

The 60-kDa heat shock protein modulates allograft rejection

Allograft rejection is a process of immune reactivity triggered by foreign transplantation antigens. We now demonstrate that the 60-kDa heat shock protein (hsp60), a molecule that is identical in the donor and the recipient, can regulate allograft immunity. In wild-type mice, hsp60 expression was greatly enhanced in allografts being rejected. By using MHC class II (Ealpha) promoter hsp60 transgenic mice either as donors of skin with enhanced expression of hsp60, or as allograft recipients with decreased hsp60 autoimmunity, we found that augmented expression of mouse hsp60 in the allograft accelerated its rejection, whereas reduced autoimmunity to mouse hsp60 in graft recipients delayed the process. Moreover, in nontransgenic mice, therapeutic administration of hsp60 or hsp60 peptides, known to modulate naturally occurring hsp60 autoimmunity, led to delayed allograft rejection. Thus, we demonstrate that hsp60 expression and hsp60 autoimmunity can influence and modify the immune response to foreign antigens. Hence, autoimmunity to self-hsp60 epitopes is not necessarily an aberration, but may serve physiologically and therapeutically to modulate foreign immunity.