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Benjamin M Segal

Publications and source records attributed to Benjamin M Segal.

12 recordsLinked to original sources
PubMed2006

CXC chemokine ligand 13 plays a role in experimental autoimmune encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is a Tcell-mediated autoimmune disease of the CNS that is widely used as an animal model of multiple sclerosis. In this study, we investigate the role of CXCL13, a chemokine involved in the development and organization of secondary lymphoid tissues, in the pathogenesis of EAE. We detected CXCL13 mRNA and protein in spinal cords of mice with EAE. CXCL13-deficient mice exhibited a mild, self-limited form of disease. CXCL13 appeared to be important for the establishment of chronic white matter lesions. Furthermore, adoptive transfer experiments with CXCL13-deficient hosts indicate that the chemokine plays a distinct role during the effector phase. Our findings raise the possibility that reagents that antagonize or inhibit CXCL13 might be useful for the treatment of neuroinflammatory diseases such as multiple sclerosis.

Acute Disease↗
PubMed2006

IL-12 driven upregulation of P-selectin ligand on myelin-specific T cells is a critical step in an animal model of autoimmune demyelination.

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory demyelinating disease of the central nervous system. IL-12p40 monokines play a critical role in the generation of EAE-inducing CD4+T cells. Here we show that IL-12 directly upregulates the expression of the adhesion molecule, P-selectin glycoprotein ligand (PSGL-1), on B10.PL MBP-TCR transgenic T cells during their initial encounter with antigen. Pre-incubation of IL-12-stimulated myelin-reactive CD4+T cells with a blocking antibody against PSGL-1 reduced the incidence and severity of EAE. We conclude that IL-12-driven PSGL-1 expression can facilitate the development of autoimmune demyelination.

Adoptive Transfer↗
PubMed2005

Increased rejection of primary tumors in mice lacking B cells: inhibition of anti-tumor CTL and TH1 cytokine responses by B cells.

We investigated the role of B cells in tumor immunity by studying immune responses of mice genetically lacking B cells to primary tumors. IgM(-/-) B cell-deficient mice (BCDM) exhibited enhanced resistance to 3 histologically diverse syngeneic tumors as compared to the wild-type (WT) mice. EL4 thymoma and MC38 colon carcinoma grew progressively in WT mice, but regressed spontaneously in BCDM whereas growth of B16 melanoma was slowed significantly in BCDM as compared to the WT mice. BCDM exhibited increased T cell infiltration of tumors, higher T(H)1 cytokine response and, in the case of MC38, a higher anti-tumor CTL response. The increased tumor resistance of BCDM did not seem to result from intrinsic changes in their non-B immunocytes because adoptive transfer of WT splenic B cells to BCDM abrogated tumor rejection and resulted in diminished anti-tumor T(H)1 cytokine and CTL responses. Studies involving BCR-transgenic mice indicated that B cells may inhibit anti-tumor T cell responses by antigen-nonspecific mechanisms since neither tumor-specific antibodies nor cognate T:B interactions were necessary for inhibition of tumor immunity by B cells. IFN-gamma secretion in splenocyte:tumor co-cultures of tumor-challenged BCDM was inhibited by WT but not CD40(-/-) B cells indicating that B cells may inhibit anti-tumor T(H)1 cytokine responses in a CD40-dependent manner. Adoptive transfer of CD40(-/-) B cells into BCDM resulted in restored growth of MC38 suggesting additional factors other than CD40 are involved in dampening anti-tumor responses. The effects of B cells on anti-tumor response warrant further study.

Animals↗
PubMed2005

Cutting edge: IL-12 induces CD4+CD25- T cell activation in the presence of T regulatory cells.

IL-12p40 cytokines have been implicated in the development of organ-specific autoimmune diseases as well as pathogen-specific adaptive immunity. In addition to inducing IFN-gamma, IL-12 stimulates effector CD4(+) T cells to express adhesion molecules and homing receptors that facilitate their migration to sites of inflammation. In this study, we expand upon those observations by demonstrating an alternative pathway by which IL-12 could promote Th1 inflammatory responses in mice, namely, by restoring proliferation and cytokine expression by effector T cells in the presence of CD4(+)CD25(+) regulatory T cells (Treg). This effect of IL-12 was not replicated by IL-23 or IFN-gamma and was dependent on signaling through the IL-12R expressed on CD25(-) responder cells, but not on Treg. Our studies suggest that IL-12 could act in concert with other proinflammatory factors to stimulate CD4(+)CD25(-) T cell activation in the presence of Treg.

Animals↗
PubMed2004

Experimental autoimmune encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory demyleinating disease of the central nervous system that is induced in laboratory animals by the generation of an immune response against myelin epitopes. It has been used as a prototype of Th1-driven, organ-specific autoimmunity and as a model for the human disease multiple sclerosis. This chapter describes two classic protocols for EAE induction (active immunization and adoptive transfer). Subheading 3.3. describes methods for rating clinical disease in symptomatic animals. Subheading 3.4. includes instructions for the isolation of mononuclear cells from the inflamed spinal cords from mice with EAE.

Adoptive Transfer↗
PubMed2003

Experimental autoimmune encephalomyelitis: cytokines, effector T cells, and antigen-presenting cells in a prototypical Th1-mediated autoimmune disease.

Experimental autoimmune encephalomyelitis (EAE) is widely depicted as the prototypical CD4+ Th1-mediated autoimmune disease. Microglia and perivascular macrophages are believed to act as antigen-presenting cells during the effector phase of EAE. In this article, recent data that challenge these conceptions are reviewed. Several recent studies have shown that myelin-reactive CD8+ T cells can mediate inflammatory demyelination. Furthermore, dendritic-like cells have been detected in EAE lesions and implicated in encephalitogenic T-cell activation. Although Th1 polarizing monokines, such as interleukin-12 (IL-12) and possibly IL-23, are critical for the manifestation of EAE, individual Th1 effector cytokines were found to be dispensible.

Animals↗
PubMed2003

IL-12 dependent/IFN gamma independent expression of CCR5 by myelin-reactive T cells correlates with encephalitogenicity.

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory demyelinating disease with similarities to multiple sclerosis (MS). It is induced in mice by the transfer of myelin-reactive T cells. Here we demonstrate that IL-12 stimulates myelin-reactive T cells to up-regulate the beta-chemokine receptor, CCR5, in correlation with the acquisition of central nervous system-infiltrating and encephalitogenic properties. These effects of IL-12 are IFN gamma-independent. The CCR5 ligands, RANTES and MIP-1 alpha, are expressed in the spinal cords of mice at EAE onset. Our results suggest that reagents that block CCR5/beta-chemokine interactions and/or antagonize IL-12 might be useful for treatment of autoimmune demyelination.

Animals↗
PubMed2002

Activation of APCs through CD40 or Toll-like receptor 9 overcomes tolerance and precipitates autoimmune disease.

Some autoreactive T cells normally escape thymic selection and persist in the periphery. This is true of myelin-reactive CD4(+) T cells, the effectors of experimental autoimmune encephalomyelitis (EAE) in laboratory animals and the presumed mediators of multiple sclerosis in humans. Nonetheless, most individuals do not succumb to autoimmune disease. There is growing evidence that while peripheral APCs stimulate immune responses against foreign Ags in the setting of tissue destruction and "danger," they actually maintain tolerance against self Ags under steady state conditions. We hypothesized that tolerance against candidate autoantigens could be reversed by activation of APCs via CD40 or Toll-like receptor 9 signaling. Adult SJL mice injected i.p. with a peptide fragment of proteolipid protein (a candidate autoantigen in multiple sclerosis) emulsified in IFA fail to mount lymphoproliferative or cytokine responses and are protected from EAE upon subsequent challenge with the Ag combined with adjuvants. Here we report that tolerized proteolipid protein-specific lymph node cells regain the ability to divide, differentiate along a Th1 lineage, and transfer EAE when reactivated in the presence of agonistic Abs against CD40 or CpG oligonucleotides. The effects of both anti-CD40 and CpG oligonucleotides are dependent upon induction of IL-12. Our findings suggest two mechanisms to explain the well-documented association between infectious illnesses and flare-ups of multiple sclerosis. Microbial pathogens could 1) release molecules that bind Toll-like receptors, and/or 2) stimulate microbe-specific T cells to express CD40 ligand, thereby licensing APCs that bear both microbial and autoantigens to break tolerance.

Abatacept↗
PubMed2002

Cutting Edge: IL-10-producing CD4+ T cells mediate tumor rejection.

IL-10 has potent immunosuppressive properties, and IL-10-producing CD4+ Tr1 cells have been characterized as regulators of Th1-mediated immunity. In this study, using a s.c. model of glioma cell growth in mice, we demonstrate that CD4+, but not CD8+, T cells play a critical role in tumor rejection following vaccination with irradiated glioma cells. Surprisingly, glioma-specific CD4+ T cells produce IL-10 but neither IL-4 nor IFN-gamma, and glioma rejection is compromised in IL-10(-/-) hosts. Hence, our findings demonstrate that IL-10-producing CD4+ T cells can manifest antitumor functions and suggest that IL-10 may have proinflammatory effects in disease states.

Animals↗
PubMedDate not supplied

Fatigue in multiple sclerosis: current understanding and future directions.

Fatigue is a very common symptom of multiple sclerosis (MS). Theoretically, fatigue may be related to neuromodulation by soluble products of the autoimmune process or by disruption of central nervous system pathways necessary for sustained activity, but little empirical evidence supports these possibilities. Amantadine, pemoline, and modafanil improved fatigue in placebo-controlled clinical trials, but these studies all had significant limitations. Difficulty measuring fatigue has impeded studies of its characteristics, mechanisms, and therapeutics. Most studies have relied on self-report questionnaires. These may be inappropriate, however, because they can be easily confounded by other symptoms of MS, they are entirely subjective, and they require patients to make difficult retrospective assessments. Studies of fatigue would be improved by including measures of more rigorously defined, quantifiable components of fatigue. For example, motor fatigue can be measured as the decline in strength during sustained muscle contractions. Cognitive fatigue can be measured as the analogous decline in cognitive performance during tasks requiring sustained attention. Lassitude is defined as a subjective sense of reduced energy, and it can be measured with the use of a visual analog diary. These measures provide reproducible results and demonstrate significant differences between MS patients and healthy controls. Dividing fatigue into these components can provide objective assessments that are less likely to be confounded by other symptoms of MS, such as weakness, spasticity, cognitive impairment, and depressed mood.

Evidence-Based Medicine↗