Altered collagen II 263-272 peptide immunization induces inhibition of collagen-induced arthritis through a shift toward Th2-type response

Therapeutic potential of tolerance-based peptide vaccines in autoimmune diseases

Autoimmune diseases are caused by the dysfunction of the body's immune regulatory system, which leads to the recognition of self-antigens and the destruction of self-tissues and is mediated by immune cells such as T and B cells, and affects 5-10% of the population worldwide. Current treatments such as non-steroidal anti-inflammatory drugs and glucocorticoids can only relieve symptoms of the disease and are accompanied by serious side effects that affect patient quality of life. The recent rise in antigen-specific therapies, especially vaccines carrying autoantigenic peptides, promises to change this disadvantage, where research has increased dramatically in the last decade. This therapy established specific immune tolerance by delivering peptide fragments containing disease-specific self-antigen epitopes to suppress excessive immune responses, thereby exerting a therapeutic effect, with high safety and specificity. This article presents the latest progress on the treatment of autoimmune diseases with autoantigen peptide vaccines. It includes the construction of peptide vaccine delivery system, the mechanism of inducing immune tolerance and its application.

Characteristics of the (Auto)Reactive T Cells in Rheumatoid Arthritis According to the Immune Epitope Database

T cells are known to be involved in the pathogenesis of rheumatoid arthritis (RA). Accordingly, and to better understand T cells' contribution to RA, a comprehensive review based on an analysis of the Immune Epitope Database (IEDB) was conducted. An immune CD8+ T cell senescence response is reported in RA and inflammatory diseases, which is driven by active viral antigens from latent viruses and cryptic self-apoptotic peptides. RA-associated pro-inflammatory CD4+ T cells are selected by MHC class II and immunodominant peptides, which are derived from molecular chaperones, host extra-cellular and cellular peptides that could be post-translationally modified (PTM), and bacterial cross-reactive peptides. A large panel of techniques have been used to characterize (auto)reactive T cells and RA-associated peptides with regards to their interaction with the MHC and TCR, capacity to enter the docking site of the shared epitope (DRB1-SE), capacity to induce T cell proliferation, capacity to select T cell subsets (Th1/Th17, Treg), and clinical contribution. Among docking DRB1-SE peptides, those with PTM expand autoreactive and high-affinity CD4+ memory T cells in RA patients with an active disease. Considering original therapeutic options in RA, mutated, or altered peptide ligands (APL) have been developed and are tested in clinical trials.

Predicting the effects of potentially therapeutic modified peptides on polyclonal T cell populations in a mouse model of multiple sclerosis

Altered peptide ligands (APLs) have routinely been studied in clonal populations of Th cells that express a single T cell receptor (TCR), but results generated in this manner poorly predict the effects of APLs on polyclonal Th cells in vivo, contributing to the failure of phase II clinical trials of APLs in autoimmune diseases such as multiple sclerosis (MS). We have used a panel of APLs derived from an encephalitogenic epitope of myelin proteolipid protein to investigate the relationship between antigen cross-reactivity in a polyclonal environment, encephalitogenicity, and the capacity of an APL to provide protection against experimental autoimmune encephalomyelitis (EAE) in SJL mice. In general, polyclonal Th cell lines specific for encephalitogenic APLs cross-reacted with other encephalitogenic APLs, but not with non-encephalitogenic APLs, and vice versa. This, alongside analysis of TCR Vβ usage, suggested that encephalitogenic and non-encephalitogenic subgroups of APLs expand largely non-cross-reactive Th cell populations. As an exception to the rule, one non-encephalitogenic APL, L188, induced proliferation in polyclonal CD4⁺ T cells specific for the native encephalitogen, with minimal induction of cytokine production. Co-immunization of L188 alongside the native encephalitogen slightly enhanced disease development. In contrast, another APL, A188, which induced IL-10 production without proliferation in CD4⁺ T cells specific for the native encephalitogen, was able to protect against development of EAE in a dose-dependent fashion when co-immunized alongside the native encephalitogen. These results suggest that testing against polyclonal Th cell lines in vitro may be an effective strategy for distinguishing between potentially therapeutic and non-therapeutic APLs.

Taming the TCR: antigen-specific immunotherapeutic agents for autoimmune diseases

Current treatments for autoimmune diseases are typically non-specific anti-inflammatory agents that affect not only the autoreactive cells but also the parts of the immune system that are required to maintain health. There is a need for the development of antigen-specific therapeutic agents that can effectively prevent the autoimmune attack while leaving the rest of the immune system functioning as normal. The simplest way to achieve this is using the autoantigen itself as a tolerizing agent; however, there is some risk involved with administering a potentially pathogenic antigen. In this review, we focus instead on the development and use of modified T cell receptor (TCR) ligands, in which the peptide ligand is modified to change the response by the T cell from a disease inducing to a protective response, and still retain the antigen-specificity necessary to target the autoreactive T cells. We review the use of modified TCR ligands as therapeutic agents in animal models of autoimmunity and in human autoimmune disease, and finally consider how they need to be improved in order to use them effectively in patients with autoimmune disease.

Superior molecularly altered influenza virus hemagglutinin peptide 308-317 inhibits collagen-induced arthritis by inducing CD4+ Treg cell expansion

OBJECTIVE

To investigate the inhibitory effect and possible mechanism of a novel influenza virus hemagglutinin 308-317 peptide (altered HA308-317 peptide) in collagen-induced arthritis (CIA).

METHODS

CIA was induced in DBA/1 mice by immunization with type II collagen (CII). Altered HA308-317 peptide, wild HA308-317 peptide, wild CII263-272 peptide, and irrelevant peptide were administered intranasally beginning at arthritis onset. Clinical and histologic scores were assessed, and cytokine levels were determined in the serum or in supernatants from splenocytes. Characteristics of T cell subsets in response to different peptides were analyzed both in vivo and in vitro.

RESULTS

Intranasal administration of wild CII263-272 peptide, wild HA308-317 peptide, or altered HA308-317 peptide could significantly ameliorate CIA, but altered HA308-317 peptide showed greater therapeutic effects than wild CII263-272 peptide and wild HA308-317 peptide. The effect of altered HA308-317 peptide was associated with a substantial decrease in production of interleukin-17 (IL-17) and interferon-γ (IFNγ) and with a marked increase in production of IL-10 and transforming growth factor β, both in serum and in supernatants from splenocytes treated with altered HA308-317 peptide. Both the number and function of CD4+ Treg cells were significantly up-regulated by altered HA308-317 peptide, with a decreased induction of Th1 cells (CD4+IFNγ+) and Th17 cells (CD4+IL-17+). Adoptive transfer of CD4+CD25+ T cells from altered HA308-317 peptide-treated mice resulted in greater suppressive capacity in ameliorating CIA severity than did adoptive transfer of CD4+CD25+ T cells from wild HA308-317 peptide-treated, wild CII263-272 peptide-treated, or irrelevant peptide-treated mice.

CONCLUSION

Intranasal administration of altered HA308-317 peptide potently suppressed the severity of CIA by increasing the number and function of CD4+ Treg cells, suggesting that altered HA308-317 peptide might be a promising candidate for treatment of rheumatoid arthritis.

Identification of small-molecule inhibitors against human leukocyte antigen-death receptor 4 (HLA-DR4) through a comprehensive strategy

Rheumatoid arthritis (RA) is an autoimmune disease mediated by T-lymphocytes and associated with the human leukocyte antigen-death receptor 4 (HLA-DR4). The HLA-DR4 protein selectively interacts with the antigenic peptides on the cell surface and presents them to the T cell receptor (TCR) on CD4+ T cells. The HLA-DR4-antigen-TCR complex initiates the autoimmune response and eventually causes the chronic inflammation within patients bodies. To inhibit HLA-DR4-restricted T cell activation, an ideal approach is to discover non-T cell stimulating substrates that specifically bind to HLA-DR4. In this paper, a comprehensive structure-based design strategy involved de novo design approach, pharmacophore search, and dock method was presented and applied to "simplify" the known binding peptide ligand of HLA-DR4 and identified specific small-molecule inhibitors for HLA-DR4. The designed three-step strategy successfully identified five nonpeptide ligands with novel scaffolds from a chemical library containing 4 × 10(6) commercially available compounds within a tolerable computing time. The identified five chemicals, BAS-0219606, T0506-2494, 6436645, 3S-71981, and KM 11073, are all non-T cell stimulators and are able to significantly inhibit HLA-DR4-restricted T cell activation induced by type II collagen (CII) 263-272 peptide. IC(50) for the best two potentials, BAS-0219606 and T0506-2494, was 31 and 17 μM, respectively, which is equivalent or better than the known peptide ligands. It is hopeful that they can be used as effective therapeutic means for further treatment of RA patients. In addition, the comprehensive strategy presented in this paper exhibited itself to be an effective flow line from peptide ligands to small-molecule inhibitors and will have applications to other targets.

Purified proteins from Leishmania amastigotes-induced delayed type hypersensitivity reactions and remission of collagen-induced arthritis in animal models

A treatment preparation composed of purified Leishmania (L) antigenic fractions (AS210) induced linear delayed type hypersensitivity (DTH) reactions over a 1-40 microg dose range, in guinea pigs. When a DBA-1 mouse collagen induced arthritis (CIA) model was used to compare AS210 treatment against: a polyvalent vaccine (AS110-1), a monovalent vaccine (AS110-2) and placebo, the AS210 treated mice had the least amount of forepaw inflammation and the lowest mean arthritis scores (MAS). When MAS for day(s) 1-40 were analyzed using one way ANOVA, statistically significant (P < 0.05) differences were seen for the following study groups: PBS versus Dexamethasone and PBS versus AS210. Subsequently, the ANOVA analysis results were corroborated by the Mann-Whitney test: analysis of the first group (P < 0.001) and analysis of the second group (P < 0.001). Comparison between dexamethasone and AS210 at different time intervals by Mann-Whitney test were as follows: day 0-day 5 both treatments had equal values (P = 1.00), from day-7 to 20 AS210 treatment had lower MAS values than dexamethasone (P = 0.037), and from day-21 to 30, AS210 MAS were similar to dexamethasone values (P = 0.319). No statistical difference was observed between AS110-1, AS110-2, and placebo groups.