Harnessing autoimmunity with dominant self-peptide: Modulating the sustainability of tissue-preferential antigen-specific Tregs by governing the binding stability via peptide flanking residues.

Sensitization to self-peptides induces various immunological responses, from autoimmunity to tumor immunity, depending on the peptide sequence; however, the underlying mechanisms remain unclear, and thus, curative therapeutic options considering immunity balance are limited. Herein, two overlapping dominant peptides of myelin proteolipid protein, PLP136-150 and PLP139-151, which induce different forms of experimental autoimmune encephalomyelitis (EAE), monophasic and relapsing EAE, respectively, were investigated. Mice with monophasic EAE exhibited highly resistant to EAE re-induction with any encephalitogenic peptides, whereas mice with relapsing EAE were susceptible, and progressed, to EAE re-induction. This resistance to relapse and re-induction in monophasic EAE mice was associated with the maintenance of potent CD69+CD103+CD4+CD25high regulatory T-cells (Tregs) enriched with antigen specificity, which expanded preferentially in the central nervous system with sustained suppressive activity. This tissue-preferential sustainability of potent antigen-specific Tregs was correlated with the antigenicity of PLP136-150, depending on its flanking residues. That is, the flanking residues of PLP136-150 enable to form pivotally arranged strong hydrogen bonds that secured its binding stability to MHC-class II. These potent Tregs acting tissue-preferentially were induced only by sensitization of PLP136-150, not by its tolerance induction, independent of EAE development. These findings suggest that, for optimal therapy, "benign autoimmunity" can be critically achieved through inverse vaccination with self-peptides by manipulating their flanking residues.

Retinoic acid-induced autoantigen-specific type 1 regulatory T cells suppress autoimmunity.

Regulatory T (Treg) cells help to maintain tolerance and prevent the development of autoimmune diseases. Retinoic acid (RA) can promote peripheral conversion of naïve T cells into Foxp3+ Treg cells. Here, we show that RA can act as an adjuvant to induce antigen-specific type 1 Treg (Tr1) cells, which is augmented by co-administration of IL-2. Immunization of mice with the model antigen KLH in the presence of RA and IL-2 induces T cells that secrete IL-10, but not IL-17 or IFN-γ, and express LAG-3, CD49b and PD-1 but not Foxp3, a phenotype typical of Tr1 cells. Furthermore, immunization of mice with the autoantigen MOG in the presence of RA and IL-2 induces Tr1 cells, which suppress pathogenic Th1 and Th17 cells that mediate the development of experimental autoimmune encephalomyelitis (EAE), an autoimmune disease of the CNS. Furthermore, immunization with a surrogate autoantigen, RA and IL-2 prevents development of spontaneous autoimmune uveitis. Our findings demonstrate that the induction of autoantigen-specific Tr1 cells can prevent the development of autoimmunity.

Epitope Mapping of SERCA2a Identifies an Antigenic Determinant That Induces Mainly Atrial Myocarditis in A/J Mice.

Sarcoplasmic/endoplasmic reticulum Ca2+ adenosine triphosphatase (SERCA)2a, a critical regulator of calcium homeostasis, is known to be decreased in heart failure. Patients with myocarditis or dilated cardiomyopathy develop autoantibodies to SERCA2a suggesting that they may have pathogenetic significance. In this report, we describe epitope mapping analysis of SERCA2a in A/J mice that leads us to make five observations: 1) SERCA2a contains multiple T cell epitopes that induce varying degrees of myocarditis. One epitope, SERCA2a 971-990, induces widespread atrial inflammation without affecting noncardiac tissues; the cardiac abnormalities could be noninvasively captured by echocardiography, electrocardiography, and magnetic resonance microscopy imaging. 2) SERCA2a 971-990-induced disease was associated with the induction of CD4 T cell responses and the epitope preferentially binds MHC class II/IAk rather than IEk By creating IAk/and IEk/SERCA2a 971-990 dextramers, the T cell responses were determined by flow cytometry to be Ag specific. 3) SERCA2a 971-990-sensitized T cells produce both Th1 and Th17 cytokines. 4) Animals immunized with SERCA2a 971-990 showed Ag-specific Abs with enhanced production of IgG2a and IgG2b isotypes, suggesting that SERCA2a 971-990 can potentially act as a common epitope for both T cells and B cells. 5) Finally, SERCA2a 971-990-sensitized T cells were able to transfer disease to naive recipients. Together, these data indicate that SERCA2a is a critical autoantigen in the mediation of atrial inflammation in mice and that our model may be helpful to study the inflammatory events that underlie the development of conditions such as atrial fibrillation in humans.

Identification of an Epitope from Adenine Nucleotide Translocator 1 That Induces Inflammation in Heart in A/J Mice.

Heart failure, a leading cause of death in humans, can emanate from myocarditis. Although most individuals with myocarditis recover spontaneously, some develop chronic dilated cardiomyopathy. Myocarditis may result from both infectious and noninfectious causes, including autoimmune responses to cardiac antigens. In support of this notion, intracellular cardiac antigens, like cardiac myosin heavy chain-α, cardiac troponin-I, and adenine nucleotide translocator 1 (ANT1), have been identified as autoantigens in cardiac autoimmunity. Herein, we demonstrate that ANT1 can induce autoimmune myocarditis in A/J mice by generating autoreactive T cells. We show that ANT1 encompasses multiple immunodominant epitopes (namely, ANT1 21-40, ANT1 31-50, ANT1 171-190, and ANT1 181-200). Although all four peptides induce comparable T-cell responses, only ANT1 21-40 was found to be a major myocarditogenic epitope in immunized animals. The myocarditis-inducing ability of ANT1 21-40 was associated with the generation of T cells producing predominantly IL-17A, and the antigen-sensitized T cells could transfer the disease to naïve recipients. These data indicate that cardiac mitochondrial proteins can be target autoantigens in myocarditis, supporting the notion that the antigens released as a result of primary damage may contribute to the persistence of chronic inflammation through autoimmunity.

A Urinary Metabolic Signature for Multiple Sclerosis and Neuromyelitis Optica.

Urine is a metabolite-rich biofluid that reflects the body's effort to maintain chemical and osmotic homeostasis. Clinical diagnosis routinely relies on urine samples because the collection process is easy and noninvasive. Despite these advantages, urine is an under-investigated source of biomarkers for multiple sclerosis (MS). Nuclear magnetic resonance spectroscopy (NMR) has become a common approach for analyzing urinary metabolites for disease diagnosis and biomarker discovery. For illustration of the potential of urinary metabolites for diagnosing and treating MS patients, and for differentiating between MS and other illnesses, 38 urine samples were collected from healthy controls, MS patients, and neuromyelitis optica-spectrum disorder (NMO-SD) patients and analyzed with NMR, multivariate statistics, one-way ANOVA, and univariate statistics. Urine from MS patients exhibited a statistically distinct metabolic signature from healthy and NMO-SD controls. A total of 27 metabolites were differentially altered in the urine from MS and NMO-SD patients and were associated with synthesis and degradation of ketone bodies, amino acids, propionate and pyruvate metabolism, tricarboxylic acid cycle, and glycolysis. Metabolites altered in urine from MS patients were shown to be related to known pathogenic processes relevant to MS, including alterations in energy and fatty acid metabolism, mitochondrial activity, and the gut microbiota.

Whole genomic sequence analysis of Bacillus infantis: defining the genetic blueprint of strain NRRL B-14911, an emerging cardiopathogenic microbe.

BACKGROUND: We recently reported the identification of Bacillus sp. NRRL B-14911 that induces heart autoimmunity by generating cardiac-reactive T cells through molecular mimicry. This marine bacterium was originally isolated from the Gulf of Mexico, but no associations with human diseases were reported. Therefore, to characterize its biological and medical significance, we sought to determine and analyze the complete genome sequence of Bacillus sp. NRRL B-14911. RESULTS: Based on the phylogenetic analysis of 16S ribosomal RNA (rRNA) genes, sequence analysis of the 16S-23S rDNA intergenic transcribed spacers, phenotypic microarray, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry, we propose that this organism belongs to the species Bacillus infantis, previously shown to be associated with sepsis in a newborn child. Analysis of the complete genome of Bacillus sp. NRRL B-14911 revealed several virulence factors including adhesins, invasins, colonization factors, siderophores and transporters. Likewise, the bacterial genome encodes a wide range of methyl transferases, transporters, enzymatic and biochemical pathways, and insertion sequence elements that are distinct from other closely related bacilli. CONCLUSIONS: The complete genome sequence of Bacillus sp. NRRL B-14911 provided in this study may facilitate genetic manipulations to assess gene functions associated with bacterial survival and virulence. Additionally, this bacterium may serve as a useful tool to establish a disease model that permits systematic analysis of autoimmune events in various susceptible rodent strains.

Investigation into Cardiac Myhc-α 334-352-Specific TCR Transgenic Mice Reveals a Role for Cytotoxic CD4 T Cells in the Development of Cardiac Autoimmunity.

Myocarditis is one of the major causes of heart failure in children and young adults and can lead to dilated cardiomyopathy. Lymphocytic myocarditis could result from autoreactive CD4+ and CD8+ T cells, but defining antigen specificity in disease pathogenesis is challenging. To address this issue, we generated T cell receptor (TCR) transgenic (Tg) C57BL/6J mice specific to cardiac myosin heavy chain (Myhc)-α 334-352 and found that Myhc-α-specific TCRs were expressed in both CD4+ and CD8+ T cells. To investigate if the phenotype is more pronounced in a myocarditis-susceptible genetic background, we backcrossed with A/J mice. At the fourth generation of backcrossing, we observed that Tg T cells from naïve mice responded to Myhc-α 334-352, as evaluated by proliferation assay and carboxyfluorescein succinimidyl ester staining. The T cell responses included significant production of mainly pro-inflammatory cytokines, namely interferon (IFN)-γ, interleukin-17, and granulocyte macrophage-colony stimulating factor. While the naïve Tg mice had isolated myocardial lesions, immunization with Myhc-α 334-352 led to mild myocarditis, suggesting that further backcrossing to increase the percentage of A/J genome close to 99.99% might show a more severe disease phenotype. Further investigations led us to note that CD4+ T cells displayed the phenotype of cytotoxic T cells (CTLs) akin to those of conventional CD8+ CTLs, as determined by the expression of CD107a, IFN-γ, granzyme B natural killer cell receptor (NKG)2A, NKG2D, cytotoxic and regulatory T cell molecules, and eomesodermin. Taken together, the transgenic system described in this report may be a helpful tool to distinguish the roles of cytotoxic cardiac antigen-specific CD4+ T cells vs. those of CD8+ T cells in the pathogenesis of myocarditis.

Mt10 Vaccine Protects Diversity Outbred Mice from CVB3 Infection by Producing Virus-Specific Neutralizing Antibodies and Diverse Antibody Isotypes.

Group B coxsackieviruses (CVBs) cause a wide range of diseases in humans, but no vaccines are currently available to prevent these infections. Previously, we had demonstrated that a live attenuated CVB3 vaccine virus, Mutant 10 (Mt10), offers protection against multiple CVB serotypes as evaluated in various inbred mouse strains; however, the applicability of these findings to the outbred human population remains uncertain. To address this issue, we used Diversity Outbred (DO) mice, whose genome is derived from eight inbred mouse strains that may capture the level of genetic diversity of the outbred human population. To determine the efficacy of the Mt10 vaccine, we established the CVB3 infection model in the DO mice. We noted that CVB3 infection resulted mainly in pancreatitis, although viral RNA was detected in both the pancreas and heart. Histologically, the pancreatic lesions comprised of necrosis, post-necrotic atrophy, and lymphocyte infiltration. In evaluating the efficacy of the Mt10 vaccine, both male and female DO mice were completely protected in challenge studies with CVB3, and viral RNA was not detected in the heart or pancreas. Likewise, vaccine recipients of both sexes showed significant levels of virus-neutralizing antibodies. Furthermore, by using the CVB3 viral protein 1, virus-reactive antibodies were found to be diverse in the order of IgG2c, followed by IgG2a, IgG2b/IgG3, and IgG1. Together, the data suggest that the Mt10 vaccine virus can offer protection against CVB infections that may have translational significance.

Autoimmunity in viral myocarditis.

PURPOSE OF REVIEW: To review how autoimmunity is induced in viral myocarditis. RECENT FINDINGS: Clinical and experimental myocarditis follows microbial infections, but autoimmunity to cardiac antigens leads to heart failure since infected myocytes are sparse and virus clearance is rapid. In mice, CD4+ T cells specific for cardiac alpha myosin heavy chain (αMYHC) cause myocarditis and mice tolerized to αMYHC are protected from virus challenge proving pathogenesis depends upon autoimmunity. Most importantly, multiple microbes share the same mimicking epitope with αMYHC. Serial infections with very different microbes could result in memory responses to the shared epitope leading to aggressive and severe heart failure. A similar phenomenon may explain autoimmune diseases with suspected infectious causes, where specific pathogens have not been identified. Production of the relevant cardiac epitope for antigen presentation requires more than myosin release from dead myocytes. Otherwise, myocarditis would commonly follow myocardial infarcts. The inherent nature of the innate immune response associated with viral infections in the heart is crucial to cardiac epitope expression. SUMMARY: Antigenic mimicry between microbes and cardiac proteins causes autoimmunity in myocarditis. Characteristics of innate immunity associated with cardiac infection determine relevant epitope expression (cryptic epitopes).

Transgenic Mice Expressing Functional TCRs Specific to Cardiac Myhc-α 334-352 on Both CD4 and CD8 T Cells Are Resistant to the Development of Myocarditis on C57BL/6 Genetic Background.

Myocarditis is a predominant cause of congestive heart failure and sudden death in children and young adolescents that can lead to dilated cardiomyopathy. Lymphocytic myocarditis mediated by T cells can result from the recognition of cardiac antigens that may involve CD4 or CD8 T cells or both. In this report, we describe the generation of T cell receptor (TCR) transgenic mice on a C57BL/6 genetic background specific to cardiac myosin heavy chain (Myhc)-α 334-352 and make the following observations: First, we verified that Myhc-α 334-352 was immunogenic in wild-type C57BL/6 mice and induced antigen-specific CD4 T cell responses despite being a poor binder of IAb; however, the immunized animals developed only mild myocarditis. Second, TCRs specific to Myhc-α 334-352 in transgenic mice were expressed in both CD4 and CD8 T cells, suggesting that the expression of epitope-specific TCR is common to both cell types. Third, although T cells from naïve transgenic mice did not respond to Myhc-α 334-352, both CD4 and CD8 T cells from animals immunized with Myhc-α 334-352 responded to the peptide, indicating that antigen priming is necessary to break tolerance. Fourth, although the transgenic T cells could produce significant amounts of interferon-γ and interleukin-17, the immunized animals developed only mild disease, indicating that other soluble factors might be necessary for developing severe myocarditis. Alternatively, the C57BL/6 genetic background might be a major contributing factor for resistance to the development of myocarditis. Taken together, our model permits the determination of the roles of both CD4 and CD8 T cells to understand the disease-resistance mechanisms of myocarditis in a single transgenic system antigen-specifically.

Coxsackievirus B3 infection leads to the generation of cardiac myosin heavy chain-α-reactive CD4 T cells in A/J mice.

Enteroviruses like coxsackievirus B3 (CVB3) are common suspects in myocarditis/dilated cardiomyopathy patients. Autoimmunity has been proposed as an underlying mechanism, but direct evidence of its role is lacking. To delineate autoimmune response in CVB3 myocarditis, we used IA(k) dextramers for cardiac myosin heavy chain (Myhc)-α 334-352. We have demonstrated that myocarditis-susceptible A/J mice infected with CVB3 generate Myhc-α-reactive CD4 T cells and such a repertoire was absent in naïve mice as measured by proliferative response to Myhc-α 334-352 and IA(k) dextramer staining. We also detected Myhc-α 334-352 dextramer(+) cells in the hearts of CVB3-infected mice. The autoreactive T cell repertoire derived from infected mice contained a high frequency of interleukin-17-producing cells capable of inducing myocarditis in naïve recipients. The data suggest that CVB3, a bona fide pathogen of cardiovascular system that primarily infects the heart can lead to the secondary generation of autoreactive T cells and contribute to cardiac pathology.

Identification of a second mimicry epitope from Acanthamoeba castellanii that induces CNS autoimmunity by generating cross-reactive T cells for MBP 89-101 in SJL mice.

We had previously reported that Acanthamoeba castellanii (ACA) contains a mimicry epitope for proteolipid protein 139-151 capable of inducing central nervous system (CNS) autoimmunity in SJL/J mice. We now present evidence that ACA also contains a mimicry epitope for myelin basic protein (MBP) 89-101, a derivative from amoebic nicotinamide adenine dinucleotide dehydrogenase subunit 2 (NAD). The epitope, NAD 108-120, contains a discontinuous stretch of six amino acids in the core region (VVFFKNIILIGFL) sharing 46% identity with MBP 89-101 (VHFFKNIVTPRTP; identical residues are underlined). SJL mice immunized with NAD 108-120 develop encephalomyelitis similar to the disease induced by the cognate peptide. We demonstrate that NAD 108-120 induces T cells that cross-react with MBP 89-101; the antigen-sensitized T cells, which produce predominantly T helper (T(h)) 1 and T(h)17 cytokines, transfer disease in naive SJL recipients reminiscent of the disease induced with MBP 89-101. This is the first report to demonstrate that a solitary microbe can induce CNS autoimmunity by generating cross-reactive T cells for multiple myelin antigens.

Detection of autoreactive CD4 T cells using major histocompatibility complex class II dextramers.

BACKGROUND: Tetramers are useful tools to enumerate the frequencies of antigen-specific T cells. However, unlike CD8 T cells, CD4 T cells - especially self-reactive cells - are challenging to detect with major histocompatibility complex (MHC) class II tetramers because of low frequencies and low affinities of their T cell receptors to MHC-peptide complexes. Here, we report the use of fluorescent multimers, designated MHC dextramers that contain a large number of peptide-MHC complexes per reagent. RESULTS: The utility of MHC dextramers was evaluated in three autoimmune disease models: 1) proteolipid protein (PLP) 139-151-induced experimental autoimmune encephalomyelitis in SJL/J (H-2s) mice; 2) myelin oligodendrocyte glycoprotein (MOG) 35-55-induced experimental autoimmune encephalomyelitis in C57Bl/6 (H-2b) mice; and 3) cardiac myosin heavy chain (Myhc)-α 334-352-induced experimental autoimmune myocarditis in A/J (H-2a) mice. Flow cytometrically, we demonstrate that IAs/PLP 139-151, IAb/MOG 35-55 and IAk/Myhc-α 334-352 dextramers detect the antigen-sensitized cells with specificity, and with a detection sensitivity significantly higher than that achieved with conventional tetramers. Furthermore, we show that binding of dextramers, but not tetramers, is less dependent on the activation status of cells, permitting enumeration of antigen-specific cells ex vivo. CONCLUSIONS: The data suggest that MHC dextramers are useful tools to track the generation and functionalities of self-reactive CD4 cells in various experimental systems.

Identification of novel mimicry epitopes for cardiac myosin heavy chain-α that induce autoimmune myocarditis in A/J mice.

Myocarditis is one cause of sudden cardiac death in young adolescents, and individuals affected with myocarditis can develop dilated cardiomyopathy, a frequent reason for heart transplantation. Exposure to environmental microbes has been suspected in the initiation of heart autoimmunity, but the direct causal link is lacking. We report here identification of novel mimicry epitopes that bear sequences similar to those in cardiac myosin heavy chain (MYHC)-α 334-352. These epitopes represent Bacillus spp., Magnetospirillum gryphiswaldense, Cryptococcus neoformans and Zea mays. The mimicry peptides induced varying degrees of myocarditis in A/J mice reminiscent of the disease induced with MYHC-α 334-352. We demonstrate that the mimics induce cross-reactive T cell responses for MYHC-α 334-352 as verified by MHC class II IA(k)/tetramer staining and Th-1 and Th-17 cytokines similar to those of MYHC-α 334-352. The data suggest that exposure to environmental microbes which are otherwise innocuous can predispose to heart autoimmunity by molecular mimicry.

miR-27b*, an oxidative stress-responsive microRNA modulates nuclear factor-kB pathway in RAW 264.7 cells.

Reactive oxygen species (ROS) produced in macrophages is critical for microbial killing, but they also take part in inflammation and antigen presentation functions. MicroRNAs (miRNAs) are endogenous regulators of gene expression, and they can control immune responses. To dissect the complex nature of ROS-mediated effects in macrophages, we sought to characterize miRNAs that are responsive to oxidative stress-induced with hydrogen peroxide (H(2)O(2)) in the mouse macrophage cell line, RAW 264.7. We have identified a set of unique miRNAs that are differentially expressed in response to H(2)O(2). These include miR-27a*, miR-27b*, miR-29b*, miR-24-2*, and miR-21*, all of which were downregulated except for miR-21*. By using luciferase reporter vector containing nuclear factor-kB (NF-kB) response elements, we demonstrate that overexpression of miR-27b* suppresses lipopolysaccharide-induced activation of NF-kB in RAW 264.7 cells. Our data suggest that macrophage functions can be regulated by oxidative stress-responsive miRNAs by modulating the NF-kB pathway.

TCA cycle inactivation in Staphylococcus aureus alters nitric oxide production in RAW 264.7 cells.

Inactivation of the Staphylococcus aureus tricarboxylic acid (TCA) cycle delays the resolution of cutaneous ulcers in a mouse soft tissue infection model. In this study, it was observed that cutaneous lesions in mice infected with wild-type or isogenic aconitase mutant S. aureus strains contained comparable inflammatory infiltrates, suggesting the delayed resolution was independent of the recruitment of immune cells. These observations led us to hypothesize that staphylococcal metabolism can modulate the host immune response. Using an in vitro model system involving RAW 264.7 cells, the authors observed that cells cultured with S. aureus aconitase mutant strains produced significantly lower amounts of nitric oxide (NO(•)) and an inducible nitric oxide synthase as compared to those cells exposed to wild-type bacteria. Despite the decrease in NO(•) synthesis, the expression of antigen-presentation and costimulatory molecules was similar in cells cultured with wild-type and those cultured with aconitase mutant bacteria. The data suggest that staphylococci can evade innate immune responses and potentially enhance their ability to survive in infected hosts by altering their metabolism. This may also explain the occurrence of TCA cycle mutants in clinical S. aureus isolates.

Attenuated strain of CVB3 with a mutation in the CAR-interacting region protects against both myocarditis and pancreatitis.

Coxsackievirus B3 (CVB3), is commonly implicated in myocarditis, which can lead to dilated cardiomyopathy, in addition to causing acute pancreatitis and meningitis. Yet, no vaccines are currently available to prevent this infection. Here, we describe the derivation of a live attenuated vaccine virus, termed mutant (Mt) 10, encoding a single amino acid substitution H790A within the viral protein 1, that prevents CVB3 infection in mice and protects from both myocarditis and pancreatitis in challenge studies. We noted that animals vaccinated with Mt 10 developed virus-neutralizing antibodies, predominantly containing IgG2a and IgG2b, and to a lesser extent IgG3 and IgG1. Furthermore, by using major histocompatibility complex class II dextramers and tetramers, we demonstrated that Mt 10 induces antigen-specific T cell responses that preferentially produce interferon-γ. Finally, neither vaccine recipients nor those challenged with the wild-type virus revealed evidence of autoimmunity or cardiac injury as determined by T cell response to cardiac myosin and measurement of circulating cardiac troponin I levels, respectively. Together, our data suggest that Mt 10 is a vaccine candidate that prevents CVB3 infection through the induction of neutralizing antibodies and antigen-specific T cell responses, the two critical components needed for complete protection against virus infections in vaccine studies.

Evidence for Anti-Viral Effects of Complete Freund's Adjuvant in the Mouse Model of Enterovirus Infection.

Group B coxsackieviruses (CVBs) belonging to the genus, Enterovirus and contain six serotypes that induce various diseases, whose occurrence may involve the mediation of more than one serotype. We recently identified immunogenic epitopes within coxsackieviruses B3 (CVB3) viral protein 1 that induce anti-viral T cell responses in mouse models of CVB infections. In our investigations to determine the protective responses of the viral epitopes, we unexpectedly noted that animals immunized with complete Freund's adjuvant (CFA) alone and later challenged with CVB3 were completely protected against myocarditis. Similarly, the pancreatitis-inducing ability of CVB3 was remarkably reduced to only 10% in the CFA group as opposed to 73.3% in the control group that received no CFA. Additionally, no mortalities were noted in the CFA group, whereas 40% of control animals died during the course of 21 days post-infection with CVB3. Taken together, our data suggest that the adjuvant effects of CFA may be sufficient for protection against CVB infections. These observations may provide new insights into our understanding of the occurrence of viral infections.

Mechanisms of sex hormones in autoimmunity: focus on EAE.

Sex-related differences in the occurrence of autoimmune diseases is well documented, with females showing a greater propensity to develop these diseases than their male counterparts. Sex hormones, namely dihydrotestosterone and estrogens, have been shown to ameliorate the severity of inflammatory diseases. Immunologically, the beneficial effects of sex hormones have been ascribed to the suppression of effector lymphocyte responses accompanied by immune deviation from pro-inflammatory to anti-inflammatory cytokine production. In this review, we present our view of the mechanisms of sex hormones that contribute to their ability to suppress autoimmune responses with an emphasis on the pathogenesis of experimental autoimmune encephalomyelitis.

Identification of Immunogenic Epitopes That Permit the Detection of Antigen-Specific T Cell Responses in Multiple Serotypes of Group B Coxsackievirus Infections.

Coxsackievirus group B (CVB) contains six serotypes that can affect various organs. Some of these organ-specific diseases such as myocarditis and pancreatitis can be caused by more than one serotype. Thus, development of immunological tools common to multiple serotypes is desired. This is especially critical for analyzing antigen-specific T cell responses at a single cell level. To this end, we made efforts to identify the immunogenic epitopes of CVB3 leading us to localize three T cell epitopes within the viral protein 1 (VP1) namely, VP1 681-700, VP1 721-740 and VP1 771-790. First, we confirmed their immunogenicity in the immunization settings. Second, we sought to verify the ability of VP1 epitopes to bind major histocompatibility complex (MHC) class II (IAk) molecules. Third, we created MHC class II (IAk) dextramers and tetramers and ascertained the T cell responses to be antigen-specific. Fourth, we analyzed the T cell responses in animals infected with CVB3 and noted the magnitude of antigen-specific T cell responses occurring in the order of VP1 721-740 and VP1 681-700 followed by VP1 771-790 as verified by proliferation assay and IAk tetramer staining. All epitopes induced interferon (IFN)-γ as a major cytokine. Finally, we investigated whether the VP1 tools generated for CVB3 can also be used to verify T cell responses in infections caused by other serotypes. To this end, we established the CVB4 infection model in A/J mice and found that the CVB4 infection led to the induction of IFN-γ-producing T cell responses primarily for VP1 721-740 and VP1 681-700. Thus, the VP1-specific tools, particularly IAk tetramers can be used to monitor anti-viral T cell responses in multiple CVB serotypes.