Visuospatial and Verbal Memory Differences in Amish Individuals With Alzheimer Disease and Related Dementias

BACKGROUND

Verbal and visuospatial memory impairments are common to Alzheimer disease and Related Dementias (ADRD), but the patterns of decline in these domains may reflect genetic and lifestyle influences. The latter may be pertinent to populations such as the Amish who have unique lifestyle experiences.

METHODS

Our data set included 420 Amish and 401 CERAD individuals. Sex-adjusted, age-adjusted, and education-adjusted Z-scores were calculated for the recall portions of the Constructional Praxis Delay (CPD) and Word List Delay (WLD). ANOVAs were then used to examine the main and interaction effects of cohort (Amish, CERAD), cognitive status (case, control), and sex on CPD and WLD Z-scores.

RESULTS

The Amish performed better on the CPD than the CERAD cohort. In addition, the difference between cases and controls on the CPD and WLD were smaller in the Amish and Amish female cases performed better on the WLD than the CERAD female cases.

DISCUSSION

The Amish performed better on the CPD task, and ADRD-related declines in CPD and WLD were less severe in the Amish. In addition, Amish females with ADRD may have preferential preservation of WLD. This study provides evidence that the Amish exhibit distinct patterns of verbal and visuospatial memory loss associated with aging and ADRD.

Iron and CF-related anemia: expanding clinical and biochemical relationships

INTRODUCTION

This cross-sectional study was conducted to assess the relationship between iron levels in the plasma and sputum of cystic fibrosis (CF) patients.

METHODS

Demographic, clinical, and iron-related laboratory data were prospectively obtained from 25 patients with stable clinical features and 14 patients with worsened clinical features since their most recent evaluations.

RESULTS

Compared to patients with stable clinical features, those who experienced clinical deterioration demonstrated significantly worse lung function and were more frequently malnourished and diabetic. Members of the latter group were also significantly more hypoferremic and had higher sputum iron content than patients with stable clinical features. No significant correlation was found between plasma and sputum iron levels when the groups were analyzed together and separately.

CONCLUSIONS

Sputum iron content does not correlate with iron-related hematologic tests. Hypoferremia is common in CF and correlates with poor lung function and overall health.

99th Dahlem conference on infection, inflammation and chronic inflammatory disorders: triggering of autoimmune diseases by infections

Human autoimmune diseases, such as multiple sclerosis, type 1 diabetes, rheumatoid arthritis and systemic lupus erythematosus (SLE), are linked genetically to distinct major histocompatibility complex (MHC) class II molecules and other immune modulators. However, genetic predisposition is only one risk factor for the development of these diseases, and low concordance rates in monozygotic twins as well as geographical distribution of disease risk suggest a critical role for environmental factors in the triggering of these autoimmune diseases. Among potential environmental factors, infections have been implicated in the onset and/or promotion of autoimmunity. This review will discuss human autoimmune diseases with a potential viral cause, and outline potential mechanisms by which pathogens can trigger autoimmune disease as discerned from various animal models of infection-induced autoimmune disease.

The role of infections in autoimmune disease

Autoimmunity occurs when the immune system recognizes and attacks host tissue. In addition to genetic factors, environmental triggers (in particular viruses, bacteria and other infectious pathogens) are thought to play a major role in the development of autoimmune diseases. In this review, we (i) describe the ways in which an infectious agent can initiate or exacerbate autoimmunity; (ii) discuss the evidence linking certain infectious agents to autoimmune diseases in humans; and (iii) describe the animal models used to study the link between infection and autoimmunity.

Effect of hematopoietic growth factors on severity of experimental autoimmune encephalomyelitis

We have investigated the influence of different hematopoietic growth factors, including granulocyte colony-stimulating factor (G-CSF), stem cell factor (SCF), Flt-3 ligand (Flt-3L) and thrombopoietin (TPO), on the course of relapsing experimental autoimmune encephalomyelitis, a mouse model of multiple sclerosis. Disease course and central nervous system histology were evaluated in all groups. When given after immunization but before either disease onset or during remission, Flt-3L, SCF and G-CSF exacerbated disease severity whereas TPO had no effect compared to non-cytokine-treated controls. When compared to controls, TPO did not exacerbate disease. We conclude that autoimmune disease severity may be affected by hematopoietic growth factors currently being employed in hematopoietic stem cell transplantation of patients with autoimmune disease. The mechanism of their effects remains unknown: it may be related to both T helper (Th) 1/Th2 skewing and/or homing of inflammatory cells to the disease-affected organ.

A virus-induced molecular mimicry model of multiple sclerosis

Multiple sclerosis1 (MS) is an immune-mediated autoimmune demyelinating disease in humans. The initiating event in MS is unknown, but epidemiological evidence suggests that virus infections may be important and one possible mechanism for induction of infection-induced autoimmune disease is molecular mimicry. To test the ability of a virus encoding a self myelin mimic epitope to induce an autoimmune response, we have developed a mouse model wherein the immunodominant myelin epitope PLP139-151, or mimics of this epitope, were inserted into a nonpathogenic variant of Theiler's murine encephalomyelitis virus (TMEV). SJL mice infected with TMEV containing PLP139-151 or a mimic of PLP139-151 expressed by the protease IV protein of Haemophilus influenzae, sharing only 6/13 amino acids with the native epitope, developed an early-onset demyelinating disease associated with activation of CD4+ T cells reactive with PLP139-151. We have used this molecular mimicry model to further address the requirements for mimic epitope processing and presentation during infection and the requirements for TCR recognition and MHC binding of mimic epitopes. We have also investigated whether molecular mimicry may require multiple infections, with either the mimic-encoding virus or an unrelated virus, to initiate autoimmune disease. Finally, we have asked whether a virus encoding a molecular mimic has to directly infect the target organ to induce autoimmune disease. Overall, this virus-induced molecular mimicry model has provided critical information regarding the mechanisms by which infection-induced molecular mimicry can induce autoimmune diseases.

Dynamical coupling of wind and ocean waves through wave-induced air flow

Understanding the physical mechanisms behind the generation of ocean waves by wind has been a longstanding challenge. Previous studies have assumed that ocean waves induce fluctuations in velocity and pressure of the overlying air that are synchronized with the waves, and numerical models have supported this assumption. In a complex feedback, these fluctuations provide the energy for wave generation. The spatial and temporal structure of the wave-induced airflow therefore holds the key to the physics of wind-wave coupling, but detailed observations have proved difficult. Here we present an analysis of wind velocities and ocean surface elevations observed over the open ocean. We use a linear filter to identify the wave-induced air flow from the measurements and find that its structure is in agreement with 'critical-layer' theory. Considering that the wave-induced momentum flux is then controlled by the wave spectrum and that it varies considerably in vertical direction, a simple parameterization of the total air-sea momentum flux is unlikely to exist.

Sutureless Cataract Surgery without Phacoemulsification

Abstract

Virus-induced autoimmunity: potential role of viruses in initiation, perpetuation, and progression of T-cell-mediated autoimmune disease

Virus infections have been implicated in the initiation of multiple human autoimmune diseases. This article focuses on reviewing the role of viruses in initiation, progression, and perpetuation of autoimmune diseases. Various mechanisms by which virus infections can induce autoimmune responses including molecular mimicry, epitope spreading, direct bystander activation, and release of cryptic epitopes are discussed. Evidence implicating virus infections in the pathogenesis of various human autoimmune diseases is reviewed. Last, the characteristics of animal models that have been developed for the study of the potential role of viruses in the initiation and progression of autoimmune disease are reviewed.

Virus-induced autoimmunity: epitope spreading to myelin autoepitopes in Theiler's virus infection of the central nervous system

Epidemiological studies indicate that host immunogenetics and history of infection, particularly by viruses, may be a necessary cofactor for the induction of a variety of autoimmune diseases. To date, however, there is no clear-cut evidence, either in experimental animal models or in human autoimmune disease, that supports either molecular mimicry (Wucherpfennig and Strominger, 1995; Fujinami and Oldstone, 1985) or a role for superantigens (Scherer et al., 1993) in the initiation of T cell-mediated autoimmunity. In contrast, the current data provide compelling evidence in support of a major role for epitope spreading in the induction of myelin-specific autoimmunity in mice persistently infected with TMEV. It is significant that two picornaviruses closely related to TMEV, coxsackievirus (Rose and Hill, 1996) and encephalomyocarditis virus (EMCV) (Kyu et al., 1992), have been similarly shown to persist (either the viral RNA or the infectious virus) in their target organs and have been associated with the development of chronic autoimmune diseases, including myocarditis and diabetes. Thus, inflammatory responses induced by viruses that trigger proinflammatory Th1 responses, and have the ability to persist in genetically susceptible hosts, may lead to chronic organ-specific autoimmune disease via epitope spreading. Epitope spreading has important implications for the design of antigen-specific therapies for the potential treatment of MS and other autoimmune diseases. This process indicates that autoimmune diseases are evolving entities and that the specificity of the effector autoantigen-specific T cells varies during the chronic disease process. Our experiments employing tolerance in R-EAE clearly indicate that antigen-specific treatment of ongoing disease is possible for preventing disease relapses, provided the proper relapse-associated epitope is targeted (Vanderlugt et al., 1999). However, the ability to identify relapse-associated epitopes in humans will be a difficult task because immunodominance will vary in every individual. The use of costimulatory antagonists that can induce anergy without requiring prior knowledge of the exact epitopes (Miller et al., 1995b), or the use of therapies that induce bystander suppression (Nicholson et al., 1997; Brocke et al., 1996), may thus be more practical current alternative therapies for the treatment of human autoimmune disease.

Functional role of epitope spreading in the chronic pathogenesis of autoimmune and virus-induced demyelinating diseases

These results support a model of epitope spreading (Figure 4) wherein localized virus-specific T cell-mediated inflammatory processes lead to the recruitment/activation of CNS-resident APCs which can serve both as effector cells for myelin destruction and as APCs which efficiently process/present endogenous self epitopes to autoreactive T cells. Thus, inflammatory responses induced by viruses which trigger pro-inflammatory Th1 responses and have the ability to persist in genetically susceptible hosts, may lead to chronic organ-specific autoimmune disease via epitope spreading. Regardless of the specificity of the T cells (myelin peptides in R-EAE or TMEV epitopes in TMEV-IDD) responsible for initiating myelin destruction, epitope spreading plays an important contributory role in the chronic disease process in genetically susceptible SJL mice. Epitope spreading has obvious important implications to the design of antigen-specific therapies for the potential treatment of MS and other autoimmune diseases. This process indicates that autoimmune diseases are evolving pathologies and that the specificity of the effector autoantigen-specific T cells varies during the chronic disease process.

Characteristics and performance of the Sunna high dose dosemeter using green photoluminescence and UV absorption readout methods

Growth in the use of ionising radiation for medical sterilisation and the potential for wide-scale international food irradiation have created the need for robust, mass-producible, inexpensive, and highly accurate radiation dosemeters. The Sunna dosemeter, lithium fluoride injection-moulded in a polyethylene matrix, can be read out using either green photoluminescence or ultraviolet (UV) absorption. The Sunna dosemeter can be mass-produced inexpensively with high precision. Both the photoluminescent and the UV absorption reader are simple and inexpensive. Both methods of analysis display negligible humidity effects, minimal dose rate dependence, acceptable post-irradiation effects, and permit measurements with a precision of nearly 1% 1sigma. The UV method shows negligible irradiation temperature effects from -30 degrees C to +60 degrees C. The photoluminescence method shows negligible irradiation temperature effects above room temperature for sterilisation dose levels and above. The dosimetry characteristics of these two readout methods are presented along with performance data in commercial sterilisation facilities.

Direct activation of innate and antigen-presenting functions of microglia following infection with Theiler's virus

Microglia are resident central nervous system (CNS) macrophages. Theiler's murine encephalomyelitis virus (TMEV) infection of SJL/J mice causes persistent infection of CNS microglia, leading to the development of a chronic-progressive CD4(+) T-cell-mediated autoimmune demyelinating disease. We asked if TMEV infection of microglia activates their innate immune functions and/or activates their ability to serve as antigen-presenting cells for activation of T-cell responses to virus and endogenous myelin epitopes. The results indicate that microglia lines can be persistently infected with TMEV and that infection significantly upregulates the expression of cytokines involved in innate immunity (tumor necrosis factor alpha, interleukin-6 [IL-6], IL-18, and, most importantly, type I interferons) along with upregulation of major histocompatibility complex class II, IL-12, and various costimulatory molecules (B7-1, B7-2, CD40, and ICAM-1). Most significantly, TMEV-infected microglia were able to efficiently process and present both endogenous virus epitopes and exogenous myelin epitopes to inflammatory CD4(+) Th1 cells. Thus, TMEV infection of microglia activates these cells to initiate an innate immune response which may lead to the activation of naive and memory virus- and myelin-specific adaptive immune responses within the CNS.

Prolonged Hya-disparate skin graft survival in ethanol-consuming mice: correlation with impaired delayed hypersensitivity

BACKGROUND

Ethanol consumption impairs cell-mediated immunity and enhances humoral immunity. Among cell-mediated immune reactions, little is known of the effect of ethanol on chronic graft rejection. Allograft responses against the male-specific minor histocompatibility antigen, Hya, are widely used to study chronic graft rejection.

METHODS

Female C57BL/6 (B6) mice were fed ethanol-containing liquid diets, were pair-fed an isocaloric liquid control diet, or were fed solid diet and water ad libitum. One week after diet initiation, the mice were grafted with split thickness, orthotopic male tail skin grafts, and the integrity of the grafts was monitored as the diet continued. Delayed hypersensitivity (DTH) was also determined in these same mice. In addition, Hya-cytolytic T-cell-deficient syngeneic major histocompatibility complex mutant B6.C-H2bm13 (bm13) and B6.C-H2bm14 (bm14) mice were assessed for skin graft rejection, DTH, and cytotoxic T-lymphocyte (CTL) activity.

RESULTS

Ethanol-consuming female B6 mice are impaired in their ability to reject syngeneic male skin grafts and to develop Hya-specific DTH responses. To address the underlying mechanism, we show that Hya graft rejection correlates with DTH and not with CTL activity. Female B6 mice clearly differ from female bm13 and bm14 mice in their ability to generate CTLs against Hya antigen. Despite their inability to make Hya-specific CTL responses, bm13 and bm14 female mice, nevertheless, make Hya-specific DTH responses and ultimately reject Hya-disparate skin grafts, indicating that Hya-specific graft rejection results from DTH. Ethanol, by impairing Hya-specific DTH, inhibits Hya-specific skin graft rejection.

CONCLUSIONS

We demonstrate that ethanol consumption impairs Hya-specific graft rejection. In addition, experiments with mice unable to generate anti-Hya CTLs support previous observations suggesting that DTH responses are sufficient to cause rejection of Hya-incompatible grafts.

Developmental outcomes in very low birth weight infants: a six-year study

Advances in neonatal care have led to survival of more Very Low Birth Weight (VLBW) infants weighing < 1,500 grams with growing concerns about neuro-developmental outcomes. To identify relationships between outcomes and birth weight, we evaluated 213 VLBW infants over a six-year period using a standardized test to identify relationships between outcomes and birth weight, and participation in early intervention programs at a one-year follow-up. Average Mental Development Indices were obtained for the majority of infants across all birth weight categories with the smallest group (500-750 grams) scoring significantly lower than infants in all other categories. Infants who did not participate in early intervention scored better which suggests this group was healthier and less likely to need intervention services. Further clarification of the salient components of early intervention is recommended in future studies.

Tibiotalocalcaneal arthrodesis: a biomechanical analysis of the rotational stability of the Biomet Ankle Arthrodesis Nail

We hypothesized that the posterior-to-anterior (PA) calcaneal interlocking screw of the Biomet Ankle Arthrodesis Nail would increase rotational stability secondary to increased bone purchase compared with the standard lateral-to-medial (transverse) screw. Each of 10 fresh human cadaver lower limbs (five matched pairs) were stabilized with a nail inserted retrograde through the calcaneus, talus, and tibia according to standard technique. One limb of each pair was fixed with a transverse calcaneal screw; the contralateral limb, with a PA calcaneal screw. Each limb was then subjected to torsional testing on an MTS Mini Bionix load frame. The PA screw construct was significantly stiffer than the transverse screw construct: 1.96 and 1.41 Nm/E, respectively (P < 0.036).

A virus-induced molecular mimicry model of multiple sclerosis

Molecular mimicry is the process by which virus infection activates T cells that are cross-reactive with self antigens. Infection of SJL/J mice with the neurotropic picornavirus Theiler's murine encephalomyelitis virus (TMEV) leads to a progressive CD4(+) T cell-mediated demyelinating disease similar to multiple sclerosis. To study the potential of virus-induced molecular mimicry to initiate autoimmune demyelination, a nonpathogenic TMEV variant was engineered to encode a 30-mer peptide encompassing the immunodominant encephalitogenic myelin proteolipid protein (PLP139-151) epitope. Infection with the PLP139-151-encoding TMEV led within 10-14 days to a rapid-onset paralytic demyelinating disease characterized by PLP139-151-specific CD4(+) Th1 responses; insertion of a non-self ovalbumin sequence led to restoration of the normal late-onset disease. Early-onset disease was also observed in mice infected with a TMEV encoding PLP139-151 with an amino acid substitution at the secondary T cell receptor (TCR) contact residue (H147A), but not in mice infected with TMEV encoding a PLP139-151 substitution at the primary TCR contact (W144A). Most significantly, mice infected with TMEV encoding a Haemophilus influenzae mimic peptide, sharing only 6 of 13 amino acids with PLP139-151, displayed rapid-onset disease and developed cross-reactive PLP139-151-specific CD4(+) Th1 responses. To our knowledge, this is the first study showing that a naturally infectious virus encoding a myelin epitope mimic can directly initiate organ-specific T cell-mediated autoimmunity.

Characterization of BALB/c mice B lymphocyte autoimmune responses to skin basement membrane component type XVII collagen, the target antigen of autoimmune skin disease bullous pemphigoid

Bullous pemphigoid is an autoimmune blistering skin disease characterized by IgG autoantibodies targeting the skin basement membrane component type XVII collagen (BPAg2). To gain understanding of the disease's induction phase, we subcutaneously immunized adult BALB/c mice with peptides of human and/or the murine-equivalent BPAg2 pathogenic NC16A domain. Female mice were injected with peptides (human, murine, or combined human and murine), or PBS control emulsified in CFA, on a four-week interval. At the fourth and subsequent immunizations, all peptide-immunized mice were given murine peptides. Two weeks after the sixth immunization, ELISA detected IgG circulating autoantibodies against self peptides in 92% (47/51) of mice immunized with murine peptides; whereas none of the preimmune sera or the sera from PBS control-immunized mice reacted to the self peptides. In four mice their autoantibodies labeled mouse skin basement membrane. Breaking B-cell tolerance to BPAg2 sets the first step in dissecting the disease's induction phase.

Madura foot: treatment of Nocardia nova infection with antibiotics alone

This case report documents the presentation of a 29-year-old woman with a deep Nocardia nova infection of the foot involving the bones. The patient responded well to prolonged antibiotic therapy, with essentially complete resolution of her symptoms. The results suggest that surgical intervention in these unusual cases may be unnecessary and that good clinical results can be obtained pharmacologically.

Enhanced susceptibility to Theiler's virus-induced demyelinating disease in perforin-deficient mice

Theiler's virus induces immune-mediated demyelinating disease similar to human MS in susceptible mice. Though the MHC class II-restricted T cell response is critical, susceptibility/resistance is also associated with a MHC class I haplotype. Here we report that perforin-deficient C57BL/6 mice (pKO) are susceptible to demyelination and develop clinical disease. The levels of primary demyelination, proliferation, Th1 responses, and viral load were also markedly enhanced. In addition, immunization of pKO mice with UV-inactivated virus further enhanced clinical incidence and accelerated the disease course. Thus, perforin is most likely involved in viral clearance, hence protection from the disease.

Multiple pathways to induction of virus-induced autoimmune demyelination: lessons from Theiler's virus infection

Infection of SJL mice with wild-type BeAn strain of Theiler's murine encephalomyelitis virus (TMEV) leads to CD4(+)T cell-mediated CNS demyelination characterized by the development of anti-myelin epitope autoimmune responses via epitope spreading during the chronic stage of disease. To exmine the feasibility of virus-encoded mimic epitopes to initiate CNS autoimmunity, we recently developed a molecular mimicry model of virus-induced demyelinating disease wherein a non-pathogenic variant strain of TMEV was engineered to encode a 30-mer peptide encompassing the immunodominant myelin proteolipid protein, PLP139-151, epitope. SJL mice infected intracerebrally with TMEV encoding either the native PLP139-151 determinant or various peptide mimics of the epitope develop an early onset demyelinating disease mediated by activated PLP139-151-specific Th1 cells. The autoimmune nature of this early-onset demyelinating disease is shown by the fact that induction of tolerance to the PLP139-151 peptide prevents clinical disease and associated PLP139-151-specific T cell responses without affecting T cell reactivity to virus epitopes. Most significantly, TMEV encoding a molecular mimic peptide derived from the Haemophilus influenzae bacteria, homologous at only six out of thirteen of the core amino acids, led to CNS disease. These studies provide conclusive evidence that virus-induced myelin-specific autoreactive T cells can be induced by molecular mimicry and provide a useful model to study the disease inducing ability of viruses encoding human-disease-related mimicry peptides.

Discordant effects of anti-VLA-4 treatment before and after onset of relapsing experimental autoimmune encephalomyelitis

Initial migration of encephalitogenic T cells to the central nervous system (CNS) in relapsing experimental autoimmune encephalomyelitis (R-EAE), an animal model of multiple sclerosis (MS), depends on the interaction of the alpha4 integrin (VLA-4) expressed on activated T cells with VCAM-1 expressed on activated cerebrovascular endothelial cells. Alternate homing mechanisms may be employed by infiltrating inflammatory cells after disease onset. We thus compared the ability of anti-VLA-4 to regulate proteolipid protein (PLP) 139-151-induced R-EAE when administered either before or after disease onset. Preclinical administration of anti-VLA-4 either to naive recipients of primed encephalitogenic T cells or to mice 1 week after peptide priming, i.e., before clinical disease onset, inhibited the onset and severity of clinical disease. In contrast, Ab treatment either at the peak of acute disease or during remission exacerbated disease relapses and increased the accumulation of CD4(+) T cells in the CNS. Most significantly, anti-VLA-4 treatment either before or during ongoing R-EAE enhanced Th1 responses to both the priming peptide and endogenous myelin epitopes released secondary to acute tissue damage. Collectively, these results suggest that treatment with anti-VLA-4 Ab has multiple effects on the immune system and may be problematic in treating established autoimmune diseases such as MS.

Prevention of autoimmune myocarditis through the induction of antigen-specific peripheral immune tolerance

BACKGROUND

Autoimmunity to cardiac antigens, in particular cardiac myosin, has been observed in humans with myocarditis and in animals with experimental inflammatory heart disease. Current treatments for myocarditis are in many cases immunosuppressive and might lead to increased cardiac damage by reducing host defenses against infectious agents. Therefore, we sought to develop an antigen-specific approach to inhibit autoimmunity in mice with myosin-induced experimental autoimmune myocarditis.

METHODS AND RESULTS

Syngeneic splenocytes, coupled with cardiac myosin by use of ethylene carbodiimide, were administered intravenously before disease induction, and the effects of this peripheral tolerization on myosin-induced myocarditis were assessed. This antigen-specific immunotherapy significantly reduced both the incidence and severity of myocarditis, with the prevention of myocyte necrosis, mononuclear cell infiltration, and fibrosis. Myosin-specific delayed-type hypersensitivity and antibody production were significantly reduced, demonstrating that peripheral tolerance affected both T- and B-cell responsiveness to the autoantigen.

CONCLUSIONS

These results suggest that the induction of antigen-specific peripheral immune tolerance may be an effective approach for the treatment of myocarditides with autoimmune involvement.

Dorsomedial cutaneous nerve syndrome: treatment with nerve transection and burial into bone

Damage to the dorsomedial cutaneous nerve of the foot, which innervates the medial hallux, may occur with crush injury or iatrogenically with bunion surgery. Severe neuritic pain after bunion surgery may alert the surgeon that this small nerve has been damaged. The term "dorsomedial cutaneous nerve syndrome" is suggested for this condition, and nine patients with such forefoot presentations, all of which were unresponsive to nonoperative interventions, are described. The nerve had been either transected or bound in scar tissue; in these nine cases, the nerve was then resected and buried in the proximal aspect of the first metatarsal or the medial cuneiform. Most patients underwent an additional procedure (other than the nerve procedure), such as revision bunionectomy or arthrodesis, but all felt they could clearly delineate nerve pain from bone or joint pain. All patients experienced marked relief of their symptoms, usually within days after the surgery, and were satisfied with the results. The verbal analog pain score, on a scale of 0 (no pain) to 10 (pain requiring amputation), improved from a preoperative level of 8.6 to a postoperative level of 2.0. Resection and burial of this nerve appears to be a useful treatment for neuritis unresponsive to nonoperative measures.

Autoimmune intervention by CD154 blockade prevents T cell retention and effector function in the target organ

The CD40-CD154 interaction is an attractive target for therapeutic intervention in many autoimmune disorders, including multiple sclerosis. Previously, we showed that CD154 blockade both inhibited the onset of experimental autoimmune encephalomyelitis and blocked clinical disease progression (relapses) in mice with established disease. The mechanism of this protection is poorly understood. Because CD154 plays a role in Th1 development, its blockade has been thought to promote anti-inflammatory Th2 responses. However, these conclusions have primarily been based on extrapolated data from in vitro experiments, which may not accurately reflect the more complex events occurring in vivo. In this paper we determine how the immune response develops under the influence of therapeutic CD154 blockade in vivo. We demonstrate that anti-CD154 treatment does not alter the early expansion of Ag-specific T cells in secondary lymphoid organs or result in deviation to a Th2-dominant response. Interestingly, the late expansion and retention of Th1 cells in the lymph nodes were markedly reduced following immunization of Ab-treated mice, and this coincided with a recompartmentalization of these cells to the spleen. Most importantly, anti-CD154 treatment eliminated the retention/expansion of encephalitogenic Th1 cells, but not their entry into the CNS. These data indicate that a major mechanism by which CD154 blockade protects against autoimmune disease is by controlling the amplitude of acute phase Th1 responses in the draining lymph nodes and by preventing the sustained expansion of effector cells within the target organ.

Controversies in ankle fracture treatment. Indications for fixation of stable Weber type B fractures and indications for syndesmosis stabilization

Although the treatment of ankle fractures is often straightforward, several controversies remain. This article reviews the need for open reduction and internal fixation of the displaced supination-external rotation fracture, and contrasts the studies that mandate anatomic reduction with clinical results. The many issues surrounding syndesmosis fixation are also reviewed, including the need for fixation of distal fractures and the timing of screw fixation.

Temporal development of autoreactive Th1 responses and endogenous presentation of self myelin epitopes by central nervous system-resident APCs in Theiler's virus-infected mice

Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease is a chronic-progressive, immune-mediated CNS demyelinating disease and a relevant model of multiple sclerosis. Myelin destruction is initiated by TMEV-specific CD4(+) T cells targeting persistently infected CNS-resident APCs leading to activation of myelin epitope-specific CD4(+) T cells via epitope spreading. We examined the temporal development of virus- and myelin-specific T cell responses and acquisition of virus and myelin epitopes by CNS-resident APCs during the chronic disease course. CD4(+) T cell responses to virus epitopes arise within 1 wk after infection and persist over a >300-day period. In contrast, myelin-specific T cell responses are first apparent approximately 50-60 days postinfection, appear in an ordered progression associated with their relative encephalitogenic dominance, and also persist. Consistent with disease initiation by virus-specific CD4(+) T cells, CNS mononuclear cells from TMEV-infected SJL mice endogenously process and present virus epitopes throughout the disease course, while myelin epitopes are presented only after initiation of myelin damage (>50-60 days postinfection). Activated F4/80(+) APCs expressing high levels of MHC class II and B7 costimulatory molecules and ingested myelin debris chronically accumulate in the CNS. These results suggest a process of autoimmune induction in which virus-specific T cell-mediated bystander myelin destruction leads to the recruitment and activation of infiltrating and CNS-resident APCs that process and present endogenous myelin epitopes to autoreactive T cells in a hierarchical order.

Divergent roles for p55 and p75 tumor necrosis factor receptors in the pathogenesis of MOG(35-55)-induced experimental autoimmune encephalomyelitis

To clarify the role of tumor necrosis factor (TNF) in the inflammatory aspects of autoimmunity vs its potential role in the apoptotic elimination of autoreactive effector cells, we assessed the roles of the p55 (TNFR1/Tnfrsf1a/CD120a) and p75 (TNFR2/Tnfrsf1b/CD120b) TNF receptors in the pathogenesis of MOG(35-55)-induced experimental autoimmune encephalomyelitis (EAE). TNFR p55/p75(-/-) double knockout mice were completely resistant to clinical disease. TNFR p55(-/-) single knockout mice were also totally resistant to EAE, exhibiting reduced MOG(35-55)- specific proliferative responses and Th1 cytokine production, despite displaying equivalent DTH responses. Importantly, IL-5 was significantly increased in p55(-/-) mice. In contrast, p75(-/-) knockout mice exhibited exacerbated EAE, enhanced Th1 cytokine production, and enhanced CD4(+) and F4/80(+) CNS infiltration. Thus, p55/TNFR1 is required for the initiation of pathologic disease, whereas p75/TNFR2 may be important in regulating the immune response. These results have important implications for therapies targeting p55 and p75 receptors for treating autoimmune diseases.

Genetic control of pathogenic mechanisms in autoimmune demyelinating disease

Multiple sclerosis is a disease of discrete phenotypes in different individuals. Animal models have been useful in identifying self-antigens that become the focus of autoimmune attack and genetic loci that control susceptibility to disease. We have previously demonstrated a role for Fas-dependent pathogenesis in the induction of EAE in B10.PL mice immunized with MBP. Others have indicated a Fas-independent mechanism predominates in SJL mice immunized with PLP. Here we compare the response of (B10.PLxSJL)F1 and parental mice under similar conditions for induction of EAE. The results indicate that immunodominance and dominant pathogenic mechanisms are both under genetic control, but can be inherited independently. The data also indicate that the dominant pathogenic mechanism can change during the course of disease in an individual. Elucidation of the genetic elements controlling pathogenesis during the course of disease would provide important information in designing therapeutic strategies for individuals in a heterogeneous patient population.

CTLA-4 downregulates epitope spreading and mediates remission in relapsing experimental autoimmune encephalomyelitis

During the progression of relapsing experimental autoimmune encephalomyelitis (R-EAE), in SJL mice, disease relapses are mediated by T cells specific for non-cross-reactive myelin epitopes, a process termed 'epitope spreading'. CTLA-4, a negative regulator of T cell function modulates R-EAE, in that CTLA-4 blockade exacerbates clinical R-EAE. Herein, we show that CTLA-4-mediated signaling negatively regulates the dynamic spread of autoreactive T cell responses during the course of autoimmune disease. Anti-CTLA-4 mAb, administration at various points during the progression of R-EAE exacerbated subsequent clinical disease and enhanced T cell reactivity to both inducing and relapse-associated epitopes. In addition, CTLA-4 blockade during acute disease inhibited clinical remission. Thus, CTLA-4-mediated events are critical for intrinsic regulation of epitope spreading during autoimmune disease.

Mometasone furoate administered once daily is as effective as twice-daily administration for treatment of mild-to-moderate persistent asthma

BACKGROUND

Despite current recommendations, many patients with persistent asthma are still treated with bronchodilators alone.

OBJECTIVE

The safety and efficacy of two once daily dosing regimens (200 microg and 400 microg) of mometasone furoate (MF) administered in the morning by using a dry-powder inhaler (DPI) were compared with those of a twice daily dosing regimen (200 microg administered twice daily) in patients with mild-to-moderate persistent asthma previously taking only inhaled beta(2)-adrenergic agonists.

METHODS

All patients (306 patients; age range, 12-70 years) were given a diagnosis of asthma for at least 6 months before enrollment in this 12-week, placebo-controlled, double-blind, randomized study. The primary efficacy variable was change in FEV(1) from baseline to endpoint (last evaluable visit).

RESULTS

At endpoint, FEV(1) was significantly improved (P < or =.02) after MF-DPI 400 microg once daily morning treatment and MF-DPI 200 microg twice daily treatment (16.0% and 16.1%, respectively) compared with placebo (5.5%). The improvement seen with MF-DPI 200 microg once daily morning treatment (10.4%) was not significantly different from that with placebo. Secondary efficacy variables also showed significant improvement for the MF-DPI 400 microg once daily morning treatment group and the MF-DPI 200 microg twice daily treatment group compared with the placebo group. All doses of MF administered by means of a DPI were well tolerated.

CONCLUSION

This is the first study to demonstrate that a total daily dose of 400 microg of MF administered by means of a DPI is an effective treatment for patients with mild-to-moderate persistent asthma previously taking only inhaled beta(2)-adrenergic agonists. This treatment was equally effective when administered either as a once daily or twice daily regimen.

CD28 costimulatory blockade exacerbates disease severity and accelerates epitope spreading in a virus-induced autoimmune disease

Theiler's murine encephalomyelitis virus (TMEV) is a natural mouse pathogen which causes a lifelong persistent infection of the central nervous system (CNS) accompanied by T-cell-mediated myelin destruction leading to chronic, progressive hind limb paralysis. TMEV-induced demyelinating disease (TMEV-IDD) is considered to be a highly relevant animal model for the human autoimmune disease multiple sclerosis (MS), which is thought to be initiated as a secondary consequence of a virus infection. Although TMEV-IDD is initiated by virus-specific CD4(+) T cells targeting CNS-persistent virus, CD4(+) T-cell responses against self myelin protein epitopes activated via epitope spreading contribute to chronic disease pathogenesis. We thus examined the ability of antibodies directed against B7 costimulatory molecules to regulate this chronic virus-induced immunopathologic process. Contrary to previous studies showing that blockade of B7-CD28 costimulatory interactions inhibit the initiation of experimental autoimmune encephalomyelitis, treatment of SJL mice at the time of TMEV infection with murine CTLA-4 immunoglobulin or a combination of anti-B7-1 and anti-B7-2 antibodies significantly enhanced clinical disease severity. Costimulatory blockade inhibited early TMEV-specific T-cell and antibody responses critical in clearing peripheral virus infection. The inhibition of virus-specific immune responses led to significantly increased CNS viral titers resulting in increased damage to myelin-producing oligodendrocytes. Following clearance of the costimulatory antagonists, epitope spreading to myelin epitopes was accelerated as a result of the increased availability of myelin epitopes leading to a more severe chronic disease course. Our results raise concern about the potential use of B7-CD28 costimulatory blockade to treat human autoimmune diseases potentially associated with acute or persistent virus infections.

Aging and DNA polymerase alpha: modulation by dietary restriction

Aging is an inevitable characteristic of biological processes in living organisms. For the last several years, investigators have proposed numerous mechanisms to explain the basic understanding of aging and its intervention and have provided many insights into the molecular bases and the biological events that contribute to the progressive decline in function observed during cellular aging. It is probable that a number of interacting factors, such as increased somatic mutations, changes in genetic expression, and decreased efficiency of protein synthesis, may contribute to the age-dependent deterioration of physiological processes. One cellular function involved in all of the above factors is that of normal DNA synthesis required for maintaining genomic integrity. This suggests that changes in function of DNA replicative enzymes are almost certain to be a factor in one or more of the negative cellular phenomena associated with aging. This is a particularly attractive hypothesis, since the accumulation of inactive or error-prone DNA polymerases during aging would be expected to initiate a sequence of events leading to synthesis of altered proteins and the general dysfunction of a wide range of cellular processes. Dietary restriction is the only anti-aging regimen uniquely suited to identifying these cellular processes and could play a significant role in maintaining cellular mechanisms necessary to reduce the rate at which mutations accumulate during aging. The observation that dietary restriction may impede the age-related decline in the activity and fidelity of DNA polymerases and in the decline of repair DNA synthesis, suggests potential mechanisms by which dietary restriction could extend the lifespan of animals, including humans.

CD8(+) T cells from Theiler's virus-resistant BALB/cByJ mice downregulate pathogenic virus-specific CD4(+) T cells

Theiler's murine encephalomyelitis virus (TMEV) is a picornavirus which induces an immune-mediated demyelinating disease in susceptible strains of mice and serves as a relevant animal model for multiple sclerosis. Treatment with low dose irradiation prior to infection with the BeAn strain of TMEV renders the genetically resistant BALB/cByJ (C/cByJ) mice susceptible to disease. Previous studies have shown that disease resistance in the C/cByJ is mediated by a 'regulatory' CD8(+) T cell population, which does not appear to function via a cytolytic mechanism. We show here that TMEV-specific CD4(+) T cell blasts transferred into susceptible, irradiated C/cByJ accelerate clinical disease and enhance TMEV-specific DTH and proliferation in these animals. Significantly, CD8(+) cells from infected, resistant C/cByJ mice specifically downregulate the in vivo disease potentiation and diminish virus specific DTH, and proliferative and pro-inflammatory cytokine responses (IFNgamma and IL-2) in recipients of TMEV-specific CD4(+) T cell blasts. These results indicate that TMEV infection of resistant C/cByJ mice induces a radiosensitive population of regulatory CD8(+) T cells which actively downregulate inherent Th1 responses which have disease initiating potential.

Interferon gamma induction during oral tolerance reduces T-cell migration to sites of inflammation

BACKGROUND & AIMS

Previous data suggest that oral antigen induces interferon (IFN)-gamma production in intestinal T cells. However, oral tolerance is associated with decreased production of IFN-gamma by T cells after antigen sensitization. The aim of this study was to examine the role of IFN-gamma in oral tolerance.

METHODS

Oral tolerance was examined in BALB/c mice after the adoptive transfer of T cells from chicken ovalbumin (OVA(323-339))-specific, DO11.10 x RAG-1(-/-) T-cell receptor transgenic mice.

RESULTS

OVA feeding induced systemic tolerance of delayed-type hypersensitivity (DTH) and antibody responses. OVA feeding up-regulated IFN-gamma production by transgenic T cells in Peyer's patch and mesenteric lymph node but not splenic tissues. Treatment of OVA-fed mice with neutralizing monoclonal antibody to IFN-gamma prevented tolerance of DTH responses. Analysis of transgenic T-cell numbers in DTH sites by immunohistochemical staining suggested that induction of IFN-gamma by oral antigen decreased accumulation of transgenic T cells in cutaneous sites of antigen injection. IFN-gamma-deficient or wild-type DO11.10 and BALB/c mice were used to show that IFN-gamma production by donor transgenic T cells was critical for oral tolerance.

CONCLUSIONS

These data suggest that the induction of IFN-gamma by oral antigen contributes to systemic tolerance by decreasing migration of T cells to peripheral sites of inflammation.

Treatment of established relapsing experimental autoimmune encephalomyelitis with the proteasome inhibitor PS-519

PLP139-151-induced relapsing experimental autoimmune encephalomyelitis (R-EAE) in SJL mice is a Th1-mediated autoimmune demyelinating disease model for multiple sclerosis (MS) in which the primary disease relapse is mediated by T cells specific for the endogenous PLP178-191 epitope. This complex inflammatory process requires the co-ordinated expression of a wide variety of immune-related genes active at a variety of stages of the autoimmune process which are regulated, in part, by the transcription factor nuclear factor (NF)-kappaB which is activated via the ubiquitin-proteasome pathway. We asked if in vivo administration of a selective inhibitor of the ubiquitin-proteasome pathway, PS-519, which downregulates activation of NF-kappaB, could downregulate ongoing R-EAE. Administration of PS-519 during the remission phase, following acute clinical disease was effective in significantly reducing the incidence of clinical relapses, CNS histopathology, and T cell responses to both the initiating and relapse-associated PLP epitopes. The inhibition of clinical disease was dependent upon continuous administration of PS-519 in that recovery of T cell function and onset of disease relapses developed within 10-14 days of drug withdrawal. The data suggest that targeting the ubiquitin proteasome pathway, in particular NF-kappaB, may offer a novel and efficacious approach for the treatment of progressive autoimmune diseases, including MS.

Lymphocytes from mice chronically infected with Theiler's murine encephalomyelitis virus produce demyelination of organotypic cultures after stimulation with the major encephalitogenic epitope of myelin proteolipid protein. Epitope spreading in TMEV infection has functional activity

Theiler's murine encephalomyelitis virus (TMEV) infection produces a chronic inflammatory disease of the spinal cord white matter, with striking similarities to both experimental allergic encephalomyelitis (EAE) and human multiple sclerosis (MS). The first phase of demyelination in this model appears to be dependent on a delayed-type hypersensitivity (DTH) response to viral antigens, driven by CD4+, Th1 lymphocytes. Macrophages, recruited in the infected CNS, would be responsible for most of the myelin damage. Recently, new populations of CD4+ lymphocytes were demonstrated in infected mice, this time with specificity for myelin antigens, particularly PLP. This suggests that, in the chronic phase of the disease, an autoimmune mechanism of demyelination, similar to EAE, may participate in the process of myelin destruction. The present study represents a first step in exploring the functional activity of these anti-myelin lymphocytes that emerge during the chronic phase of the disease. Lymphocytes were removed from chronically infected animals, they were stimulated with the major PLP encephalitogenic epitope for SJL/J mice, and they were added to organotypic myelinated spinal cord cultures for different lengths of time. Results show that lymphocytes stimulated with the major PLP epitope have a powerful capacity for demyelinating these cultures, while MBP stimulated lymphocytes and lymphocytes from control animals do not. This study, suggests that the anti-myelin response that emerges during the chronic phase of the infection is functionally active. A similar phenomenon of epitope spreading from virus to organ specific antigens may take place in humans and be involved in a number of immune-mediated diseases, including MS.

Absence of growth retardation in children with perennial allergic rhinitis after one year of treatment with mometasone furoate aqueous nasal spray

OBJECTIVE

Intranasal corticosteroids are used widely for the treatment of allergic rhinitis because they are effective and well tolerated. However, their potential to suppress growth of pediatric subjects with allergic rhinitis continues to be a concern, particularly in light of reports of growth suppression after treatment with intranasal beclomethasone dipropionate or intranasal budesonide (see the article by Skoner et al in this month's issue). A 1-year study of prepubertal patients between 3 and 9 years of age with perennial allergic rhinitis was conducted to assess the effects on growth of mometasone furoate aqueous nasal spray (MFNS), a new once-daily (QD) intranasal corticosteroid with negligible bioavailability.

METHODS

This was a randomized, placebo-controlled, double-blind, multicenter study. Ninety-eight subjects were randomized to treatment with either MFNS 100 microg QD or placebo for 1 year. Each subject's height was required to be between the 5th and 95th percentile at baseline, and skeletal age at screening was required to be within 2 years of chronological age, as determined by left wrist x-rays. Washout periods for medications that affect either childhood growth or allergic rhinitis symptoms were established based on estimated period of effect, and these medications were prohibited during the study. However, short courses of either oral prednisone lasting no longer than 7 days or low-potency topical dermatologic corticosteroids lasting no longer than 10 days were permitted if necessary. Height was measured with a calibrated stadiometer at baseline and at 4, 8, 12, 26, 39, and 52 weeks, and the primary safety variable was the change in standing height. The rate of growth was also calculated for each subject as the slope (linear regression) of the change in height from baseline using data from all visits of subjects who had at least 2 visits. Hypothalamic-pituitary-adrenocortical- (HPA)-axis function was assessed via cosyntropin stimulation testing at baseline and at 26 and 52 weeks. All analyses were based on all randomized subjects (intent-to-treat principle). The change from baseline in standing height was analyzed by a 2-way analysis of variance that extracted sources of variation attributable to treatment, center, and treatment-by-center interaction.

RESULTS

Demographic characteristics were similar at baseline. Eighty-two subjects completed the study (42 in the MFNS group and 40 in the placebo group), and 93% of subjects achieved at least 80% compliance with therapy. After 1 year of treatment, no suppression of growth was seen in subjects treated with MFNS, and mean standing heights were similar for both treatment groups at all time points. For the primary safety variable (change in height from baseline), both treatment groups were similar at all time points except for weeks 8 and 52. Subjects treated with MFNS had a slightly greater mean increase in height than subjects treated with placebo at these time points: the change in height was 6.95 cm versus 6.35 cm at the 1-year time point. However, the rate of growth (.018 cm/day) averaged for all time points over the course of the study was similar for both treatment groups. Additional analyses found that MFNS did not retard growth in any sex or age subgroup of subjects. The use of exogenous corticosteroids other than the study drug was also similar among the 2 treatment groups. Results from cosyntropin stimulation testing confirmed the absence of systemic effects of MFNS. The change from baseline in the difference between prestimulation and poststimulation levels was similar for both treatment groups after 1 year of treatment, with no evidence of HPA-axis suppression in MFNS-treated subjects at any time point. Incidences of treatment-related adverse events were similar for both treatment groups, with 16% of MFNS-treated subjects reporting adverse events, compared with 22% of placebo-treated subjects.

CONCLUSIONS

(ABSTRACT TRUNCATED)

Fas-mediated apoptosis in clinical remissions of relapsing experimental autoimmune encephalomyelitis

PLP139-51-induced experimental autoimmune encephalomyelitis (R-EAE) displays a relapsing-remitting paralytic course in female SJL mice. We investigated the role of apoptosis/activation-induced cell death (AICD) in the spontaneous recovery from acute disease. Clinical EAE was significantly enhanced in Fas (CD95/APO-1)-deficient SJL lpr/lpr mice, which displayed significantly increased mean peak clinical scores, reduced remission rates, and increased mortality when compared with their SJL +/lpr littermates. PLP139-151-specific proliferative responses were fairly equivalent in the 2 groups, but draining lymph node T cells from SJL lpr/lpr mice produced dramatically increased levels of IFN-gamma. Central nervous system (CNS) Fas and FasL mRNA levels in wild-type SJL (H-2(s)) mice peaked just before spontaneous disease remission and gradually declined as disease remitted. We applied the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay to detect apoptosis in situ in spinal cords of mice at various clinical stages of EAE. Most TUNEL(+) cells were found during active periods of inflammation: the acute, peak, and relapse time points. Significantly fewer apoptotic cells were observed at preclinical and remission time points. Collectively, these findings indicate that Fas-mediated apoptosis/AICD plays a major role in the spontaneous remission after the initial acute inflammatory episode and represents an important intrinsic mechanism in regulation of autoimmune responses.

Pathologic role and temporal appearance of newly emerging autoepitopes in relapsing experimental autoimmune encephalomyelitis

Relapsing experimental autoimmune encephalomyelitis (R-EAE) is a CD4+ T cell-mediated demyelinating disease model for multiple sclerosis. Myelin destruction during the initial relapsing phase of R-EAE in SJL mice initiated by immunization with the proteolipid protein (PLP) epitope PLP139-151 is associated with activation of T cells specific for the endogenous, non-cross-reactive PLP178-191 epitope (intramolecular epitope spreading), while relapses in R-EAE induced with the myelin basic protein (MBP) epitope MBP84-104 are associated with PLP139-151-specific responses (intermolecular epitope spreading). Here, we demonstrate that T cells specific for endogenous myelin epitopes play the major pathologic role in mediating clinical relapses. T cells specific for relapse-associated epitopes can serially transfer disease to naive recipients and are demonstrable in the CNS of mice with chronic R-EAE. More importantly, induction of myelin-specific tolerance to relapse-associated epitopes, by i.v. injection of ethylene carbodiimide-fixed peptide-pulsed APCs, either before disease initiation or during remission from acute disease effectively blocks the expression of the initial disease relapse. Further, blockade of B7-1-mediated costimulation with anti-B7-1 F(ab) during disease remission from acute PLP139-151-induced disease prevents clinical relapses by inhibiting activation of PLP178-191-specific T cells. The protective effects of anti-B7-1 F(ab) treatment are long-lasting and highly effective even when administered following the initial relapsing episode wherein spreading to a MBP epitope (MBP84-104) is inhibited. Collectively, these data indicate that epitope spreading is B7-1 dependent, plays a major pathologic role in disease progression, and follows a hierarchical order associated with the relative encephalitogenic dominance of the myelin epitopes (PLP139-151 > PLP178-191 > MBP84-104).

The (temporary?) queering of Japanese TV

One of the primary texts of the "out" queer cinema of Japan is the television serial D s kai, first aired in 1993. Unlike Western television shows positing queer characters, D s kai presents its gay characters without apology or excuses, and as leads rather than as colorful appendages. At the same time, however, the show filters gay eroticism through the (hetero)normative mode of serial melodrama, at once pushing the boundaries of national permissiveness while normalizing and homogenizing homosexuality by rendering it within a conventional form.

A critical role for B7/CD28 costimulation in experimental autoimmune encephalomyelitis: a comparative study using costimulatory molecule-deficient mice and monoclonal antibody blockade

The B7/CD28 pathway provides critical costimulatory signals required for complete T cell activation and has served as a potential target for immunotherapeutic strategies designed to regulate autoimmune diseases. This study was designed to examine the roles of CD28 and its individual ligands, B7-1 and B7-2, in experimental autoimmune encephalomyelitis (EAE), a Th1-mediated inflammatory disease of the CNS. EAE induction in CD28- or B7-deficient nonobese diabetic (NOD) mice was compared with the effects of B7/CD28 blockade using Abs in wild-type NOD mice. Disease severity was significantly reduced in CD28-deficient as well as anti-B7-1/B7-2-treated NOD mice. B7-2 appeared to play the more dominant role as there was a moderate decrease in disease incidence and severity in B7-2-deficient animals. EAE resistance was not due to the lack of effective priming of the myelin peptide-specific T cells in vivo. T cells isolated from CD28-deficient animals produced equivalent amounts of IFN-gamma and TNF-alpha in response to the immunogen, proteolipid protein 56-70. In fact, IFN-gamma and TNF-alpha production by Ag-specific T cells was enhanced in both the B7-1 and B7-2-deficient NOD mice. In contrast, peptide-specific delayed-type hypersensitivity responses in these animals were significantly decreased, suggesting a critical role for CD28 costimulation in in vivo trafficking and systemic immunity. Collectively, these results support a critical role for CD28 costimulation in EAE induction.