Experimental autoimmune encephalomyelitis in the rat.

There are several diverse rat models of experimental autoimmune encephalomyelitis (EAE) that can be used to investigate the pathogenesis and regulation of autoimmunity against CNS myelin. The disease course of these models ranges from an acute monophasic disease with limited demyelination to a chronic relapsing or chronic progressive course marked by severe demyelination. These models enable the study of encephalitogenic T cells and demyelinating antibody specific for major neuroantigens such as myelin basic protein (MBP), myelin oligodendrocyte glycoprotein (MOG), or proteolipid protein (PLP), among other important CNS autoantigens.

Myelin basic protein-reactive T cells persist in an inactive state in the bone marrow of Lewis rats that have recovered from autoimmune encephalomyelitis.

Lewis rats immunized with guinea pig myelin basic protein residues 68-86 develop acute experimental autoimmune encephalomyelitis and recover. The predominant T cell receptor expressed by the encephalitogenic T cells is TCRBV8S2. They persist in bone marrow many weeks after recovery.

Experimental autoimmune encephalomyelitis in the rat.

This unit details the materials and methods required for both active induction and adoptive transfer of experimental autoimmune encephalomyelitis (EAE) in the SJL mouse strain using intact proteins or peptides from the two major myelin proteins: proteolipid protein (PLP) and myelin basic protein (MBP). Detailed materials and methods required for the purification of both PLP and MBP are also described. Modifications of the specified protocols may be necessary for efficient induction of active or adoptive EAE in other mouse strains.

Characterization of a subset of bone marrow-derived natural killer cells that regulates T cell activation in rats.

We report that bone marrow-derived natural killer (BMNK) cells from DA or F344 rats inhibit PMA/ionomycin-induced T cell proliferation. These NK-regulatory cells are NKR-P1A(dim), whereas a minor subpopulation is NKR-P1A(bright). Only the NKR-P1A(dim) BMNK cells inhibit T cell proliferation.

Synergistic interaction between Toll-like receptor agonists is required for induction of experimental autoimmune encephalomyelitis in Lewis rats.

To investigate whether TLR agonists can replace mycobacteria in adjuvant to induce EAE in Lewis rats, we immunized rats with MBP peptide (MBP(68-86)) in IFA, supplemented with TLR agonists. Rats immunized with MBP(68-86) plus CpG-ODN or LPS in IFA did not develop EAE. In contrast, rats immunized with MBP(68-86) plus CpG-ODN and LPS in IFA developed clinical EAE.

Molecular mimicry and horror autotoxicus: do chlamydial infections elicit autoimmunity?

All species of the order Chlamydiales are obligate intracellular eubacterial pathogens of their various hosts. Two chlamydial species, Chlamydia trachomatis and Chlamydia pneumoniae, are primarily human pathogens, and each is known to cause important diseases. Some strains of C.

Substance P regulates natural killer cell interferon-gamma production and resistance to Pseudomonas aeruginosa infection.

Studies have shown that after Pseudomonas aeruginosa (P. aeruginosa) corneal infection, BALB/c mice that are capable of resolving the disease, locally produce IFN-gamma. As T cells are not detected in the infected cornea of these mice, antibody depletion was used to test whether NK cells produce the cytokine.

NK cells inhibit T cell proliferation via p21-mediated cell cycle arrest.

NK cells have been shown to influence immune responses via direct interaction with cells of the adaptive immune system, such as dendritic cells, B cells, and T cells. A role for NK cells in down-regulation of T cell responses has been implicated in several studies; however, the underlying mechanism of this suppression has remained elusive. In this study we show that dark Agouti rat NK cells inhibit syngeneic T cell proliferation via up-regulation of the cell cycle inhibitor, p21, resulting in a G0/G1 stage cell cycle arrest.

Autoreactive T cells persist in rats protected against experimental autoimmune encephalomyelitis and can be activated through stimulation of innate immunity.

Lewis rats can be rendered unresponsive to experimental autoimmune encephalomyelitis by immunization with myelin basic protein (MBP), or MBP68-86, the dominant encephalitogenic MBP epitope for this strain, administered in IFA. However, protected rats harbor potentially encephalitogenic T cells, which are maintained in an inactive state. We investigated whether these quiescent effector cells could be activated in vitro.

MHC class II peptide flanking residues of exogenous antigens influence recognition by autoreactive T cells.

Molecular mimicry between exogenous microbial antigens and self-epitopes has been proposed as a triggering mechanism for autoimmune diseases for many years. We reported that a peptide from a protein specific to Chlamydia pneumoniae (Cpn0483) which shares a motif with the dominant encephalitogenic epitope of the self-antigen, rat myelin basic protein (rat68-86), elicits experimental autoimmune encephalomyelitis (EAE) in Lewis rats. We recently observed that rat68-86 utilizes aspartic acid (D) and arginine (R) in the common motif as primary and secondary TCR contacts, respectively.

Infectious agents and multiple sclerosis--are Chlamydia pneumoniae and human herpes virus 6 involved?

A good deal of evidence suggests an infectious component in the development of multiple sclerosis (MS) and, to date, some 20 bacteria and viruses have been associated with the disease. Recent independent sets of studies have implicated the respiratory bacterium Chlamydia pneumoniae and human herpes virus 6 (HHV-6) in the pathogenesis of MS. However, as is the case for essentially all earlier microbial associations, experimental evidence linking either this bacterium or this virus to MS is equivocal.

Human herpesvirus 6 and Chlamydia pneumoniae as etiologic agents in multiple sclerosis - a critical review.

Multiple sclerosis (MS) is thought by many investigators to have an infectious component, and several microorganisms have been associated with the disease during the last three decades. Recent studies have implicated both human herpesvirus 6 (HHV-6) and the obligate intracellular bacterium Chlamydia pneumoniae in the etiology of MS. As with earlier studies of other potential agents, however, evidence linking either of these organisms to the disease is equivocal.

Experimental autoimmune encephalomyelitis in the rat: lessons in T-cell immunology and autoreactivity.

Experimental autoimmune encephalomyelitis (EAE) in the rat is an acute paralytic disease from which most animals spontaneously recover. The disease can be induced in susceptible inbred Lewis and DA rats with myelin basic protein (MBP), or encephalitogenic MBP peptides administered in complete Freund's adjuvant (CFA). The disease can be adoptively transferred to syngeneic recipients with primed T cells that have been reactivated in vitro with antigen.

DA rat NK(+)CD3(-) cells inhibit autoreactive T-cell responses.

We isolated natural killer (NK) cells from DA rat bone marrow (BM) by staining with PE anti-NKR-P1A and FACS sorting (>98% NK(+)). The purified NK cells inhibit T-cell proliferation in a dosage-dependent fashion and suppressed production of the proinflammatory Th1 cytokine, IFN-gamma. When activated in vitro with Con A supernatant (CAS), the purified NK cells secrete the beta-chemokine monocyte chemoattractant protein-1 (MCP-1) and upregulate MCP-1 mRNA.

A Chlamydia pneumoniae-specific peptide induces experimental autoimmune encephalomyelitis in rats.

It has been reported recently that the bacterial respiratory pathogen Chlamydia pneumoniae is present in the cerebrospinal fluid of a subset of multiple sclerosis (MS) patients. However, it is not known whether this organism is a causative agent of MS, or merely an opportunistic pathogen that takes advantage of a disease process initiated by some other means. We report identification of a 20-mer peptide from a protein specific to C.

Parental genes do not codominantly confer susceptibility to experimental autoimmune encephalomyelitis in F1 rats.

Lewis (LEW) and DA rats are highly susceptible to experimental autoimmune encephalomyelitis (EAE) induced with guinea pig myelin basic protein (MBP), but respond to different epitopes. The dominant epitope for LEW rats is MBP73-86, and disease is mediated primarily by Vbeta8.2 Th1 cells.

Suppressor cells in demyelinating disease: a new paradigm for the new millennium.

This brief review highlights investigations conducted over the past three decades concerning the role of suppressor T cells in the regulation of experimental autoimmune encephalomyelitis (EAE). In addition, more recent studies are summarized which suggest that apoptosis of autoreactive T cells is also involved in the regulation of EAE. The possibility that natural killer (NK) cells mediate apoptosis is also considered.

Strain variation in autoimmunity: attempted tolerization of DA rats results in the induction of experimental autoimmune encephalomyelitis.

This paper reports that DA rats develop experimental autoimmune encephalomyelitis (EAE) when immunized with encephalitogenic myelin basic protein (MBP) peptide (MBP63-81) in IFA. In contrast, most rodent strains are tolerized by this procedure. Doses as low as 5 micrograms peptide + IFA induced EAE in DA rats.

Inhibition of autoimmune T cell responses in the DA rat by bone marrow-derived NK cells in vitro: implications for autoimmunity.

Regulation of the immune response is critical to homeostasis. While innate immunity can influence the development of adaptive immune responses, its role in regulation is less well understood. Recently, NK cells have been implicated in the control of experimental autoimmune encephalomyelitis, an animal model for multiple sclerosis.

Critical requirement for aspartic acid at position 82 of myelin basic protein 73-86 for recruitment of V beta 8.2+ T cells and encephalitogenicity in the Lewis rat.

We synthesized single amino acid-substituted peptide analogues of guinea pig myelin basic protein (MBP) 73-86 to study the importance of aspartic acid at residue 82 (QKSQRSQDENPV), which previous reports have suggested is a critical TCR contact residue. Whereas the wild-type 73-86 peptide elicited severe experimental autoimmune encephalomyelitis (EAE) in the Lewis rat, none of the peptide analogues with substitutions at position 82 were capable of inducing EAE. The inability to cause EAE was not due to a failure to bind MHC or to elicit T cell proliferation and cytokine secretion.

Delineation of two encephalitogenic myelin basic protein epitopes for DA rats.

We studied synthetic peptides that correspond to two regions of the guinea pig myelin basic protein (MBP) molecule which elicit experimental autoimmune encephalomyelitis (EAE) in DA rats. Using truncated peptides, we determined that two encephalitogenic epitopes reside within MBP63-81, a major determinant defined by MBP residues, 63-76, and a minor encephalitogenic epitope defined by residues, 66-81. Experiments with alanine-substituted analogs of MBP63-76 revealed that the HYGSLP sequence is critical for encephalitogenicity.

Concordance and contradiction concerning cytokines and chemokines in experimental demyelinating disease.

Experimental autoimmune encephalomyelitis (EAE) has served as a model for human demyelinating diseases, including multiple sclerosis. EAE is mediated by CD4+ T lymphocytes of the TH1 subset. These T cells produce inflammatory cytokines and chemokines that are associated with pathogenicity.

Interstrain variability of autoimmune encephalomyelitis in rats: multiple encephalitogenic myelin basic protein epitopes for DA rats.

We investigated T cell epitopes of guinea pig myelin basic protein (MBP) that induce experimental autoimmune encephalomyelitis (EAE) in DA rats, using synthetic peptides that correspond to regions of the guinea pig MBP molecule that are homologous to rat MBP. Four peptides were encephalitogenic when tested in DA rats. MBP63-81, which partially overlaps the dominant encephalitogenic MBP epitope for Lewis (LEW) rats, caused severe EAE in the DA strain but did not elicit EAE in LEW rats.

Regulation of cytokine gene expression in experimental autoimmune encephalomyelitis.

We previously reported that recovery of Lewis rats from experimental autoimmune encephalomyelitis (EAE) is associated with the appearance of suppressor T cells (Ts). These Ts secrete TGF-beta which down-regulates the production of inflammatory cytokines by the effector T cells that mediate this disease. In the present study, we immunized Lewis rats with myelin basic protein (MBP)+CFA, and evaluated purified T cells and MBP-activated spleen cells (SpC) during the paralytic phase (day 12) and after recovery (days 30-33) for TGF-beta and interferon (IFN)-gamma mRNA.