IgG reactive to CTL-directed epitopes of self-antigens is either lacking or unbalanced in atopic dermatitis patients

Autoreactive T cells and their role in atopic dermatitis

Atopic dermatitis (AD) is an itchy, non-contagious relapsing and chronic inflammatory skin disease that usually develops in early childhood. This pathology is associated with food allergy, allergic asthma, allergic rhinitis and anaphylaxis which may persist in adulthood. The underlying mechanisms of AD (endotypes) are just beginning to be discovered and show a complex interaction of various pathways including skin barrier function and immune deviation. Immune reactions to self-proteins (autoantigens) of the skin have been identified in patients with inflammatory skin diseases, such as chronic spontaneous urticaria, connective tissue disease, pemphigus vulgaris and bullous pemphigoid. IgE antibodies and T cells directed against epitopes of the skin were observed in adult patients with severe and chronic AD as well. This was associated with disease severity and suggests a progression from allergic inflammation to severe autoimmune processes against the skin. IgE-mediated autoimmunity and self-reactive T cells might accelerate the ongoing skin inflammation or might contribute to the relapsing course of the disease. However, to date, the exact mechanisms of IgE-mediated autoimmunity and self-reactive T cells in the pathophysiology of AD are still unclear. The aim of this review is to evaluate the development of (autoreactive) T cells and their response to (auto)antigens, as well as the role of the peripheral tolerance in autoimmunity in the pathophysiology of AD, including the unmet needs and gaps.

IgE autoantibodies and autoreactive T cells and their role in children and adults with atopic dermatitis

The pathophysiology of atopic dermatitis (AD) is highly complex and understanding of disease endotypes may improve disease management. Immunoglobulins E (IgE) against human skin epitopes (IgE autoantibodies) are thought to play a role in disease progression and prolongation. These antibodies have been described in patients with severe and chronic AD, suggesting a progression from allergic inflammation to severe autoimmune processes against the skin. This review provides a summary of the current knowledge and gaps on IgE autoreactivity and self-reactive T cells in children and adults with AD based on a systematic search. Currently, the clinical relevance and the pathomechanism of IgE autoantibodies in AD needs to be further investigated. Additionally, it is unknown whether the presence of IgE autoantibodies in patients with AD is an epiphenomenon or a disease endotype. However, increased knowledge on the clinical relevance and the pathophysiologic role of IgE autoantibodies and self-reactive T cells in AD can have consequences for diagnosis and treatment. Responses to the current available treatments can be used for better understanding of the pathways and may shed new lights on the treatment options for patients with AD and autoreactivity against skin epitopes. To conclude, IgE autoantibodies and self-reactive T cells can contribute to the pathophysiology of AD based on the body of evidence in literature. However, many questions remain open. Future studies on autoreactivity in AD should especially focus on the clinical relevance, the contribution to the disease progression and chronicity on cellular level, the onset and therapeutic strategies.

Atopic dermatitis and autoimmunity: the occurrence of autoantibodies and their association with disease severity

Atopic dermatitis (AD) is a widespread condition that appears to be increasing in prevalence and severity worldwide, yet the underlying mechanisms are not well understood. Recent research has identified various similarities between AD and autoimmune conditions, as well as indicating that there may be an association between AD and autoimmunity. This systematic review evaluates the association between AD and autoimmunity, as well as between severity of disease in AD and autoimmunity, with an emphasis on the associations with autoantibodies. MEDLINE (1946 to December 2017) and Embase (1974 to December 2017) databases were searched. Further relevant articles were retrieved from reference lists. Only studies measuring direct indicators of autoimmunity, in humans, were included. Qualitative analysis was carried out for all studies. In addition, quantitative analysis was used to evaluate prevalence of IgE autoantibodies and anti-nuclear antibodies (ANAs) in AD patients and control subjects. The Mantel-Haenszel method was used with a random-effects model. 28 studies assessed the occurrence of autoantibodies in AD patients and 16 studies were used to evaluate association between disease severity and autoantibodies. Pooled analysis from 14 studies, involving 986 AD patients and 441 control subjects, showed that IgE autoantibodies were significantly more prevalent in patients with AD (P < 0.00001) than control subjects. Similar analysis was carried out for ANAs, with eight studies that involved 1045 AD patients and 1273 control subjects. ANAs were significantly more prevalent in patients with AD (P = 0.003). This quantitative analysis supported an association between AD and IgE autoantibodies, as well as between AD and ANAs. There was insufficient data to make similar conclusions for other indicators of autoimmunity. The weight of evidence also suggests an association between IgE autoantibodies and disease severity. There was insufficient evidence to make this link for other indicators of autoimmunity.

Tip110 Deletion Impaired Embryonic and Stem Cell Development Involving Downregulation of Stem Cell Factors Nanog, Oct4, and Sox2

HIV-1 Tat-interacting protein of 110 kDa, Tip110, plays important roles in multiple biological processes. In this study, we aimed to characterize the function of Tip110 in embryonic development. Transgenic mice lacking expression of a functional Tip110 gene (Tip110^-/- ) died post-implantation, and Tip110^-/- embryos exhibited developmental arrest between 8.5 and 9.5 days post coitum. However, in vitro cultures of Tip110^-/- embryos showed that Tip110 loss did not impair embryo growth from the zygote to the blastocyst. Extended in vitro cultures of Tip110^-/- blastocysts showed that Tip110 loss impaired both blastocyst outgrowth and self-renewal and survival of blastocyst-derived embryonic stem cells. Microarray analysis of Tip110^-/- embryonic stem cells revealed that Tip110 loss altered differentiation, pluripotency, and cycling of embryonic stem cells and was associated with downregulation of several major stem cell factors including Nanog, Oct4, and Sox2 through a complex network of signaling pathways. Taken together, these findings document for the first time the lethal effects of complete loss of Tip110 on mammalian embryonic development and suggest that Tip110 is an important regulator of not only embryonic development but also stem cell factors. Stem Cells 2017;35:1674-1686.

Tip110: Physical properties, primary structure, and biological functions

HIV-1 Tat-interacting protein of 110kDa (Tip110), also referred to as squamous cell carcinoma antigen recognized by T cells 3 (Sart3), p110 or p110(nrb), was initially identified as a cDNA clone (KIAA0156) without annotated functions. Over the past twenty years, several functions have been attributed to this protein. The proposed biological functions include roles for Tip110 in pre-mRNA splicing, gene transcription, stem cell biology, and development. Dysregulation of Tip110 is also a contributing factor in the development of cancer and other human diseases. It is clear that our understanding of this protein is rapidly evolving. In this review, we aimed to provide a summary of all the existing literature on this gene/protein and its proposed biological functions.

Antibody Reactive to a Hepatitis C Virus (HCV)-Derived Peptide Capable of Inducing HLA-A2 Restricted Cytotoxic T Lymphocytes Is Detectable in a Majority of HCV-Infected Individuals without HLA-A2 Restriction

Hepatitis C virus (HCV) is a single-strand RNA virus. Approximately 170 million people around the world are persistently infected and are at risk of liver cirrhosis or cancer. There is an urgent need to develop both therapeutic and diagnostic modalities of HCV. One approach to achieve these goals would be to determine highly immunodominant HCV peptides which are recognized by both cellular and humoral immunities. This study reports one such peptide, HCV-core protein at positions 35-44, having HLA-A2 binding motifs. IgG specific to this CTL-epitope peptide is consistently detectable in a majority of the patients with HCV infection regardless of the different HLA types, different disease conditions, and different HCV-genotypes tested. The sequence LPRR at positions 37-40 is considered to be the fine epitope recognized by the IgG. These results may provide new insights for the development of both therapeutic and diagnostic modalities of HCV at lower costs.

Does "autoreactivity" play a role in atopic dermatitis?

The role of autoimmunity in atopic dermatitis (AD) is unclear. We sought to critically examine the occurrence, correlation with severity, and possible causative role of autoreactivity in patients with AD. Our systematic review of studies identified from MEDLINE included 31 experiments that described autoreactivity in patients with AD. We defined autoreactivity as in vitro or in vivo evidence of immune response to autologous human, generic human, or recombinant human proteins or other tissue/cellular components. Autoreactivity prevalence in patients with AD ranged from 23% to 91% in 14 studies involving 2644 participants, although it did not appear to vary with age, sex, or disease duration. In contrast to studies of AD, IgE autoreactivity was not found in healthy subjects or in those with allergic rhinoconjunctivitis, psoriasis, systemic lupus erythematosus, or other inflammatory diseases (8 studies of 816 participants). Two reports found a positive correlation between autoreactivity and AD severity. We suggest that autoreactivity might be playing a causative role in AD based on the magnitude and specificity of the associations found; plausible mechanisms through IgE autoantibodies, IgG autoantibodies, and T(H)1 autoreactivity; and experimental elicitation of eczematous lesions after provocation. Whether autoantibodies contribute to AD chronicity now needs to be examined in longitudinal studies.

New multiplexed flow cytometric assay to measure anti‐peptide antibody: a novel tool for monitoring immune responses to peptides used for immunization

Peptide-based vaccination has a great potential for the prevention and treatment of various diseases. There is, however, no appropriate monitoring system to measure immune responses to vaccinated peptides, which hampers the development of therapeutically effective vaccine regimens to various diseases. In this study a new multiplexed flow cytometric assay using the Luminex system to monitor humoral immune responses to vaccinated peptides is described. Although the sensitivity is mostly equal to that of the traditional enzyme-linked immunosorbent assay (ELISA), the new assay has several advantages over ELISA in that it minimizes the amount of sera needed, running costs and working periods, and thus will be a novel tool for monitoring immune responses to vaccinated peptides.

Identification of hepatitis C virus (HCV) 2a-derived epitope peptides having the capacity to induce cytotoxic T lymphocytes in human leukocyte antigen-A24+ and HCV2a-infected patients

Since virus-specific cytotoxic T lymphocytes (CTLs) play a critical role in preventing the spread of hepatitis C virus (HCV), vaccine-based HCV-specific CTL induction could be a promising strategy to treat HCV-infected patients. In this study, we tried to identify HCV2a-derived epitopes, which can induce human leukocyte antigen (HLA)-A24-restricted and peptide-specific CTLs. Peripheral blood mononuclear cells of HCV2a-infected patients or healthy donors were stimulated in vitro with HCV2a-derived peptides, which were prepared based on the HLA-A24 binding motif. As a result, three peptides (HCV2a 576-584, HCV2a 627-635, and HCV2a 1085-1094) efficiently induced peptide-specific CTLs from HLA-A24(+) HCV2a-infected patients as well as healthy donors. The cytotoxicity was exhibited by peptide-specific CD8(+) T cells in an HLA-A24-restricted manner. In addition, the HCV2a 627-635 peptide was frequently recognized by immunoglobulin G of HCV2a-infected patients. These results indicate that the identified three HCV2a peptides might be applicable to peptide-based immunotherapy for HLA-A24(+) HCV2a-infected patients.

Identification of Peptide Vaccine Candidates for Prostate Cancer Patients with HLA-A3 Supertype Alleles

PURPOSE

The peptide vaccine candidates identified to date have been focused on the HLA-A2 and HLA-A24 alleles. The HLA-A11, HLA-A31, and HLA-A33 alleles share binding motifs and belong to an HLA-A3 supertype family. In this study, we attempted to identify CTL-directed peptide candidates, derived from prostate-related antigens and shared by HLA-A11+, HLA-A31+, and HLA-A33+ prostate cancer patients.

EXPERIMENTAL DESIGN

Based on the binding motif to the HLA-A3 supertype alleles, 42 peptides were prepared from prostate-specific antigen (PSA), prostate-specific membrane antigen (PSMA), and prostatic acid phosphatase (PAP). These peptides were first screened for their ability to be recognized by immunoglobulin G (IgG) of prostate cancer patients and subsequently for the potential to induce peptide-specific and prostate cancer-reactive CTLs from peripheral blood mononuclear cells (PBMC) of cancer patients with the HLA-A11, HLA-A31, and HLA-A33 alleles.

RESULTS

Five peptide candidates, including the PSA(16-24), PAP(155-163), PAP(248-257), PSMA(207-215), and PSMA(431-440) peptides, were frequently recognized by IgGs of prostate cancer patients. These peptides efficiently induced peptide-specific and prostate cancer-reactive CTLs from PBMCs of cancer patients with the HLA-A11, HLA-A31, and HLA-A33 alleles. Antibody blocking and cold inhibition experiments revealed that the HLA-A3 supertype-restricted cytotoxicity against prostate cancer cells could be ascribed to peptide-specific and CD8+ T cells.

CONCLUSIONS

We identified prostate-related antigen-derived new peptide candidates for HLA-A11-, HLA-A31-, and HLA-A33-positive prostate cancer patients. This information could facilitate the development of a peptide-based anticancer vaccine for patients with alleles other than HLA-A2 and HLA-A24.

Determination of Thrombopoietin-Derived Peptides Recognized by Both Cellular and Humoral Immunities in Healthy Donors and Patients with Thrombocytopenia

Thrombopoietin (TPO) is a cytokine that promotes megakaryocytopoiesis and thrombopoiesis and is considered a drug suitable for patients with thrombocytopenia. However, unexpected severe thrombocytopenia has developed in some healthy individuals participating in phase I clinical trials with a pegylated recombinant human megakaryocyte growth factor (PEG-rHuMGDF) that contained the first 163 amino acids of endogenous TPO, which resulted in hampering the further development of clinical trials. Autoimmune responses to PEG-rHuMGDF, which cross-reacted with endogenous TPO, were suggested to be involved in this rare but severe adverse event, although the immunogenic epitopes have not yet been determined. To better understand the molecular basis of such autoimmune reactions, we investigated the reactivity of 18 TPO-derived peptides with HLA-A2-binding motifs to plasma and T cells, both from patients with thrombocytopenia (n=24) and from healthy donors (HDs) (n=24). Four peptides, including those possessing amino acids in receptor-binding sites, were preferentially reactive to plasma from at least 20% of the patients, whereas one peptide at position 101-109 was equally reactive to those of the patients and the HDs. Each of the five peptides had the ability to induce peptide-specific cytotoxic T lymphocytes (CTLs) in both groups, albeit with less frequency among the patients. More important, each of these five peptides had the ability to induce HLA-A2-restricted and peptide-specific CTL activity reactive to cells that produce TPO. These results may provide new insights to gain a better understanding of autoimmune reactions to TPO.

Assessment of synthetic peptides of severe acute respiratory syndrome coronavirus recognized by long-lasting immunity

Abstract:  In order to determine highly immunogenic severe acute respiratory syndrome coronavirus (SARS‐CoV) epitope peptides capable of inducing long‐lasting immunity, we first screened immunoglobulin‐G (IgG) antibodies reactive to 197 different overlapping 15‐mers from the SARS‐CoV proteins in the sera of three infected patients. Forty‐two peptides among them were reactive to the sera from all three patients. Consequently, we tested for the reactivity of these 42 peptides to patients' sera (n = 45) at 6‐month post‐infection. The significantly higher levels of IgG antibodies specific to three (S791, M207 and N161) of 42 peptides were detectable in the post‐infection sera from 23 (51%), 27 (60%) and 19 (42%) of 45 patients, respectively. These three peptides, recognized by their long‐lasting immunity, may provide a better understanding of the immunogenicity of SARS‐CoV.

New type of natural antibodies reactive to cytotoxic T lymphocyte-directed cancer vaccine peptides

We recently reported the existence of antibodies (Abs) reactive to cytotoxic T lymphocyte-directed cancer vaccine peptides derived from non-mutated and proliferation-related self-proteins in the sera of healthy donors. The IgG class of these Abs was either lacking or unbalanced in atopic dermatitis patients, although the induction of a specific IgG by peptide vaccination was correlated with long survival in cancer patients, suggesting its positive role in the host defense. To understand the biological features of these Abs, we employed murine models due to the sequence homology of these peptides in human and mouse. Both IgM and IgG classes of these peptide-specific Abs were detected in all of the euthymic mice tested; however, only IgM was found in athymic nu/nu mice, and not in SCID mice. Maintenance of euthymic mice under germ-free conditions resulted in a lack of the IgG class of the Abs in these mice. Ab levels were found to increase with age-maturation, but they decreased under tumor bearing conditions or in cases of graft-versus-host disease. The Abs showed catalytic activity upon hydrogen peroxide (H2O2) production. These results suggest the existence of a novel type of natural Ab that is reactive to cancer vaccine peptides.

Identification of polycomb group protein enhancer of zeste homolog 2 (EZH2)-derived peptides immunogenic in HLA-A24+ prostate cancer patients

BACKGROUND

Antigens overexpressed in metastatic prostate cancer are appropriate targets in anti-cancer immunotherapy, and one candidate is the polycomb group protein enhancer of zeste homolog 2 (EZH2).

METHODS

Eleven EZH2-derived peptides were prepared based on the HLA-A24 binding motif. These peptide candidates were screened first by their ability to be recognized by immunoglobulin G (IgG), and then by their ability to induce peptide-specific cytotoxic T lymphocytes (CTLs).

RESULTS

IgGs reactive to three EZH2 peptides (EZH2-243 to -252, EZH2-291 to -299, and EZH2-735 to -;742) were detected in the plasma of almost half of prostate cancer patients. Among them, the EZH2-291 to -299 and EZH2-735 to -742 peptides effectively induced HLA-A24-restricted and prostate cancer-reactive CTLs from prostate cancer patients. The cytotoxicity was mainly dependent on EZH2 peptide-specific and CD8+ T cells.

CONCLUSIONS

These EZH2-291 to -299 and EZH2-735 to -742 peptides could be promising candidates for peptide-based immunotherapy for HLA-A24+ prostate cancer patients with metastases.

Identification of HER2/neu-Derived Peptides Capable of Inducing both Cellular and Humoral Immune Responses in HLA-A24 Positive Breast Cancer Patients

HRE2/neu-specific cellular and humoral immune responses are often detected in breast cancer patients, but identification of more immunogenic CTL epitope peptides is necessary prior to development of a cancer vaccine. There is accumulating evidence of strong immunogenicity of peptides capable of inducing both cellular and humoral immune responses. To identify such peptides, this study intended to determine HER2/neu-derived peptides capable of inducing both cellular and humoral immunity in HLA-A24(+) breast cancer patients. IgGs reactive to the HER2(342-350), HER2(485-493), and HER2(553-561) peptides were detected in the sera of these patients with the frequency of 47, 24, and 24%, respectively. These peptides also induced peptide-specific and tumor-reactive CTL activity in the peripheral blood mononuclear cells of HLA-A24(+) breast cancer patients with the frequency of 50, 63, and 25%, respectively, but such activity was not induced from any HLA-A24(-) patients. Cellular and humoral responses to each of these three peptides were also observed in PBMCs and sera from the other epithelial cancer patients. These results may provide a scientific basis for new clinical trials of HER2/neu-peptide-based immunotherapy for breast cancer and also other epithelial cancer patients.

Identification of epidermal growth factor receptor-derived peptides recognised by both cellular and humoral immune responses in HLA-A24+ non-small cell lung cancer patients

The epidermal growth factor receptor (EGFR) is one of the most appropriate target molecules for cancer therapy because of its high expression in epithelial cancers. A novel EGFR-tyrosine-kinase inhibitor, ZD1839, has been approved as a drug for non-small cell lung cancer (NSCLC), and many other agents are now being tested in clinical trials. Cytotoxic T lymphocyte (CTL)-directed epitope peptides could be another class of useful compounds in EGFR-targeted therapies. However, at present, there are no data on CTL-directed peptides of EGFR. Therefore, this study aimed to identify immunogenic EGFR-derived peptides in HLA-A24(+) NSCLC patients. We report in this study three such EGFR-derived peptides at positions 54-62, 124-132 and 800-809. These peptides were recognised by both cellular and humoral immune responses in most of the peripheral blood mononuclear cells (PBMCs) and sera from NSCLC patients that we tested. These results may provide a scientific basis for the development of EGFR-based immunotherapy.

Identification of epidermal growth factor receptor-derived peptides immunogenic for HLA-A2(+) cancer patients

Epidermal growth factor receptor (EGFR) is one of the most appropriate target molecules for cancer therapy because of its relatively high expression in about one-third of all epithelial cancers in correlation with neoplasmic progression. With respect to EGFR-targeted therapies, antibodies and tyrosine-kinase inhibitors have been intensively studied, a novel EGFR-tyrosine-kinase inhibitor ZD1839 has been approved as an anticancer drug, and many other agents are now under clinical trial. In addition, cytotoxic T lymphocyte (CTL)-directed epitope peptides could be another class of compounds useful in EGFR-targeted therapies. However, there is presently no information on CTL-directed peptides of EGFR. Therefore, from the viewpoint of development of peptide-based cancer therapy, this study was intended to determine the EGFR-derived peptides recognised by both cellular and humoral immunities in HLA-A2(+) epithelial cancer patients. We herein report finding of two such types of EGFR-derived peptides at position 479-488 and 1138-1147, both of which were recognised by the majority of patients' sera (IgG), and also possessed the ability to induce HLA-A2-restricted peptide-specific CTLs against EGFR-positive tumour cells in peripheral blood mononuclear cells (PBMCs) of epithelial cancer patients. These results may provide a scientific basis for the development of EGFR-based immunotherapy for HLA-A2(+) cancer patients.

Humoral Responses to Peptides Correlate with Overall Survival in Advanced Cancer Patients Vaccinated with Peptides Based on Pre-existing, Peptide-Specific Cellular Responses

Purpose: The aim of this study is to find a laboratory marker for overall survival in advanced cancer patients who were vaccinated with peptides based on pre-existing, peptide-specific CTL precursors in the circulation.

Experimental Design: A group of 113 patients with advanced cancer (28 colorectal, 22 prostate, 15 lung, 14 gastric, and 34 other cancers) was enrolled in a Phase I clinical study of peptide vaccination in which peptide-specific CTL precursors of prevaccination peripheral blood mononuclear cells were measured, followed by vaccination with these peptides (maximum of four). For cellular responses, pre and postvaccination (sixth) peripheral blood mononuclear cells were provided for measurement of both peptide-specific CTL precursors by IFN-γ release assay and tumor reactivity by 51Cr release assay. Delayed type hypersensitivity was also measured. For humoral response, pre and postvaccination (sixth) sera were provided for measurement of peptide-reactive IgG by an ELISA.

Results: The median survival time and 1-year survival rate of the total cases were 346 ± 64.9 days and 44.6%, respectively, and those of patients vaccinated more than six times (n = 91) were 409 ± 15 days and 54.4%, respectively. In these 91 patients, the overall survival of patients whose sera showed increased levels of peptide-reactive IgG (n = 60) was significantly more prolonged (P = 0.0003) than that of patients whose sera did not (n = 31), whereas none of cellular responses correlated with overall survival.

Conclusions: Peptide-specific IgG in postvaccination sera could be a suitable laboratory maker for the prediction of prolonged survival in advanced cancer patients vaccinated with peptides based on pre-existing CTL precursors.

Immunological evaluation of peptide vaccination for patients with gastric cancer based on pre-existing cellular response to peptide

There is no standard treatment modality for advanced gastric cancer (GC) at the present time. To develop a new treatment modality, we investigated the immunological responses of advanced GC patients (n = 13, 9 non-scirrhous and 4 scirrhous types) vaccinated with peptides to a regimen under which pre-vaccination peripheral blood mononuclear cells (PBMCs) were screened for their reactivity in vitro to each of 14 peptides on HLA-A24 or 16 peptides on -A2 allele, then only the reactive peptides (maximum: 4) were administered in vivo. This regimen was generally well tolerated, although grade I levels of fever and local skin reactions were observed in several patients. Delayed-type hypersensitivity (DTH) to the vaccinated peptides was observed in 4 patients. Increased cellular and humoral immune responses to the vaccinated peptides were observed in post-vaccination PBMCs from 4 of 8 patients and in post-vaccination sera of 8 of 10 patients tested, respectively. Prolonged survival was observed in patients showing cellular and humoral immune responses to the vaccinated peptides in the post-vaccination samples, including all 4 patients with the scirrhous type. These results encourage further development of peptide-based immunotherapy for GC patients.