Abstract 1847: Anti-GARP antibody DS-1055a augments antitumor immunity by depleting highly suppressive GARP+ regulatory T cells

Immune checkpoint blockers (ICBs) have drastically changed the clinical care of cancer; however, the population of patients who can benefit is relatively small because of intrinsic or acquired resistance to immune therapy. To evade immune destruction, tumors exploit several distinct strategies including immunosuppressive cells such as regulatory T (Treg) cells. Treg cells, an essential component for maintaining self-tolerance, inhibit antitumor immunity, consequently hindering protective cancer immunosurveillance and hampering effective antitumor immune responses in tumor-bearing hosts. It is often reported that a high ratio of Treg cells to effector CD8+ T cells is associated with poor prognosis in patients with cancer, and Treg cells represent one of the most important factors associated with resistance to ICBs, suggesting that Treg cells represent a new promising target for anti-cancer therapy. In this study, we performed a comprehensive screening to identify a tumor-infiltrating Treg cell-specific molecule among immune cell subsets in humans. Glycoprotein A repetitions predominant (GARP) was identified as a suitable target for selective Treg cell depletion in the tumor microenvironment (TME) of multiple caner types. In the periphery, GARP was selectively induced in Treg cells, but not in effector T cells, by polyclonal stimulation in humans. DS-1055a, a novel afucosylated anti-human GARP antibody, effectively depleted GARP+ Treg cells, leading to the activation of effector T cells. Moreover, DS-1055a decreased FOXP3+CD4+ T cell counts in the TME and exhibited remarkable antitumor activity in a human peripheral blood mononuclear cell-transplanted humanized mouse model bearing HT-29 tumors. From these results, we propose that DS-1055a can be a new Treg cell-targeted regent that augments antitumor T cell immunity by depleting GARP+ Treg cells. Currently, a Phase I study of DS-1055a is on-going (NCT04419532).

Citation Format: Kazuki Satoh, Yoichi Kobayashi, Kaori Fujimaki, Masato Hata, Shinko Hayashi, Saori Ishida, Daisuke Sugiyama, Takahiko Sato, Lim Kyungtaek, Megumi Miyamoto, Shiho Kozuma, Michinori Kadokura, Kenichi Wakita, Kazuki Hirahara, Masato Amano, Ichiro Watanabe, Atsushi Okamoto, Andrea Tuettenberg, Helmut Jonuleit, Atsushi Tanemura, Shoichi Maruyama, Toshinori Agatsuma, Teiji Wada, Hiroyoshi Nishikawa. Anti-GARP antibody DS-1055a augments antitumor immunity by depleting highly suppressive GARP+ regulatory T cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1847.

Novel anti-GARP antibody DS-1055a augments anti-tumor immunity by depleting highly suppressive GARP+ regulatory T cells

Regulatory T (Treg) cells, which are essential for maintaining self-tolerance, inhibit anti-tumor immunity, consequently hindering protective cancer immunosurveillance, and hampering effective anti-tumor immune responses in tumor-bearing hosts. Here, we show that depletion of Treg cells via targeting glycoprotein A repetitions predominant (GARP) induces effective anti-tumor immune responses. GARP was specifically expressed by highly suppressive Treg cells in the tumor microenvironment (TME) of multiple cancer types in humans. In the periphery, GARP was selectively induced in Treg cells, but not in effector T cells, by polyclonal stimulation. DS-1055a, a novel afucosylated anti-human GARP monoclonal antibody, efficiently depleted GARP+ Treg cells, leading to the activation of effector T cells. Moreover, DS-1055a decreased FoxP3+CD4+ T cells in the TME and exhibited remarkable anti-tumor activity in humanized mice bearing HT-29 tumors. We propose that DS-1055a is a new Treg-cell-targeted cancer immunotherapy agent with augmentation of anti-tumor immunity.

Pathogenicity of memory Th2 cells is linked to stage of allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) consists of three developmental stages that are based on the presence/absence of antigen-specific IgE and symptoms. The pathogenic Th2 (Tpath2) cells constitute a population of Th2 cells with additional potentially pathogenic characteristics. We examined the relationship between Tpath2 cells and the stages of allergic rhinitis by focusing on ST2, which is an IL-33 receptor.

METHODS

Patients with Japanese cedar pollen-induced AR (JCP-AR) and healthy volunteers were divided into "nonsensitized," "asymptomatic sensitized (AS)," and "JCP-AR" groups. We analyzed the ST2 expression and the Th2 function of cultured CD4⁺ T cells. Next, we observed the progress of patients in the AS stage around the time of seasonal pollen dispersal, with the characteristics of Th2 cells.

RESULTS

The ST2 expression of T cells was only upregulated in the AR group. The production of IL-4 and IL-13 was found in CD4⁺ T cells obtained from AS by stimulation with JCP, but reactivity to IL-33 was not observed. Although IL-33 did not induce the elevation of IL-4 production in the JCP-AR group, IL-33 substantially increased the production of IL-5 and IL-13 in comparison with antigen stimulation alone. In newly afflicted patients, the increased expression of ST2 and elevated reactivity to IL-33 was observed, even before the pollen dispersal season.

CONCLUSIONS

Our study demonstrated that the pathogenicity of memory Th2 cells is linked to sensitization and the stage of allergic rhinitis. Therefore, Tpath2 cells may provide useful insights into the mechanism of the onset and progression of allergic rhinitis.

Elucidation of Distinct Roles of Guinea Pig CXCR1 and CXCR2 in Neutrophil Migration toward IL-8 and GROα by Specific Antibodies

Chemokine receptors CXCR1 and CXCR2 are conserved between guinea pigs and humans, but the distinct role of each receptor in chemotactic responses of neutrophils against chemokine ligands has not been elucidated due in part to the lack of specific inhibitors against these receptors in guinea pigs. In this study, we investigated the roles of guinea pig CXCR1 and CXCR2 on neutrophils in chemotactic responses to guinea pig interleukin (IL)-8 and growth-regulated oncogene (GRO)α by using specific inhibitory antibodies against these receptors. Neutrophil migration induced by IL-8 was partially inhibited by either anti-CXCR1 antibody or anti-CXCR2 antibody. In addition, the migration was inhibited completely when both anti-CXCR1 and anti-CXCR2 antibodies were combined. On the other hand, neutrophil migration induced by GROα was not inhibited by anti-CXCR1 antibody while inhibited profoundly by anti-CXCR2 antibody. These results indicated that CXCR1 and CXCR2 mediated migration induced by the IL-8 synergistically and only CXCR2 mediated migration induced by GROα in guinea pig neutrophils. Our findings on ligand selectivity of CXCR1 and CXCR2 in guinea pigs are consistent with those in humans.

Generation and Characterization of Inhibitory Antibodies Specific to Guinea Pig CXCR1 and CXCR2

CXCR1 and CXCR2 are chemokine receptors that have different selectivity of chemokine ligands, but the distinct role of each receptor is not clearly understood. This is due to the absence of specific inhibitors in guinea pigs, which are the appropriate species for investigation of CXCR1 and CXCR2 because of their functional similarity to humans. In this study, we generated and evaluated monoclonal antibodies that specifically bound to guinea pig CXCR1 (gpCXCR1) and guinea pig CXCR2 (gpCXCR2) for acquisition of specific inhibitors. To assess the activity of antibodies, we established CHO-K1 cells stably expressing either gpCXCR1 or gpCXCR2 (CHO/gpCXCR1 or CHO/gpCXCR2). CHO/gpCXCR1 showed migration in response to guinea pig interleukin (IL)-8, and CHO/gpCXCR2 showed migration in response to both guinea pig IL-8 and guinea pig growth-regulated oncogene α. The receptor selectivities of the chemokines of guinea pigs were the same as the human orthologs. The inhibitory activities of the anti-gpCXCR1 and anti-gpCXCR2 monoclonal antibodies on cell migration were observed in a concentration-dependent manner. In conclusion, we successfully obtained inhibitory antibodies specific to gpCXCR1 and gpCXCR2. These inhibitory antibodies will be useful to clarify the physiological roles of CXCR1 and CXCR2 in guinea pigs.

JTK-853, a novel non-nucleoside hepatitis C virus polymerase inhibitor, demonstrates a high genetic barrier to resistance in vitro

JTK-853 is a novel, non-nucleoside, palm site-binding hepatitis C virus (HCV) polymerase inhibitor that has demonstrated antiviral activity in HCV-infected patients during 3 days of treatment. To estimate the genetic barrier of JTK-853 to resistance in vitro, colony formation assays were conducted using HCV replicon cells (genotypes 1a and 1b). The colony formation assays revealed that the numbers of resistant colonies for JTK-853 were much lower than those for other direct-acting antivirals, including palm site- or thumb pocket-binding non-nucleoside HCV polymerase inhibitors (NNIs), an NS5A inhibitor (NS5Ai), and a protease inhibitor (PI). Furthermore, the numbers of resistant colonies for JTK-853 in combination with the NS5Ai or PI were lower than those for other combinations of NS5Ai + NNI, and NS5Ai + PI. Our findings demonstrate that JTK-853 has a high genetic barrier to resistance, and suggest that its combination therapies will be potent in suppressing the emergence of drug resistance in HCV-infected patients.

Entry point to the Sylvian fissure for the pterional transsylvian approach

BACKGROUND

Although the anatomy of the Sylvian fissure is understood, there is little information on where to start its dissection in the pterional transsylvian (PT-TS) approach. At small craniotomy using the PT-TS approach, we set the entry point to the Sylvian fissure at 15 mm behind the anterior edge of the craniotomy along the Sylvian fissure and designated this site "point 15." Here we compared the utility of "point 15" with the Sylvian point (point on the Sylvian fissure giving rise to the horizontal and anterior ascending rami) that had been recommended earlier as the entry site for opening the Sylvian fissure.

MATERIALS AND METHODS

This study includes 16 patients with 7 ruptured and 9 unruptured anterior circulation aneurysms. We evaluated the usefulness of "point 15" in the PT-TS approach for aneurysmal neck clipping with respect to the adequacy of anatomical exposure and low invasiveness.

RESULTS

In 12 patients "point 15" provided for excellent anatomical exposure of the Sylvian fissure; complete neck clipping was possible with minimal brain retraction and damage. In two patients with ruptured aneurysms and thick subarachnoid hemorrhage and in two patients with unruptured aneurysms, the dissection had to be enlarged 3 to 4 mm distally without reaching the Sylvian point. In the latter two patients the Sylvian veins were tethered to frontal and temporal lobes.

CONCLUSIONS

The "point 15" was an easily set entry point to the Sylvian fissure. It provided for sufficient anatomical exposure at surgery for anterior circulation aneurysms; additional posterior dissection was required in rare cases. We found that "point 15" was useful in small craniotomies using the PT-TS approach.

Extradural total petrous apex resection with trigeminal translocation for improved exposure of the posterior cavernous sinus and petroclival region

We have analyzed a strategy for improved exposure of the posterior cavernous sinus and petroclival region through an extradural subtemporal approach to be utilized in the removal of neoplastic processes with involvement of the apical petrous bone and posterior cavernous sinus. This surgical approach includes the following elements for improved exposure of the posterior cavernous sinus through the middle fossa corridor: (1) maximal extradural exposure and mobilization of the trigeminal nerve complex, allowing its elevation and anterior displacement, (2) complete extradural removal of the anterior petrous pyramid from the porus acousticus to the petrous apex under direct vision, (3) total exposure of the abducens nerve from the posterior fossa to its point of cross over the intracavernous carotid artery, and (4) wide extradural exposure of the cavernous carotid artery in the foramen lacerum region. This strategy can be combined with other related approaches; specifically, frontotemporal or posterior transpetrosal exposures for extensive lesions.Microsurgical dissection and morphometric analysis were performed in 20 fixed cadaver specimens for the purposes of validating the method for clinical application and determining the key elements to maximization of exposure. The trigeminal complex could be anteromedially retracted 4.8 mm +/- 1.3 (range = 3 to 6 mm) without skeletonization of V(2) and V(3). Liberating these two divisions from their bony canals to their first peripheral branch (10.4 mm +/- 2.5 and 5.4 mm +/- 1.1, respectively) resulted in increased mobilization an average of 9.1 mm +/- 1.7 (7 to 14 mm). Further mobilization is achieved by dividing the attachment between the trigeminal connective tissue sheath and the fibrous carotid ring at the foramen lacerum. An average of 13.0 mm +/- 3.1 (7 to 20 mm) of the posterior intracavernous carotid artery was exposed. Detailed microanatomic observations and a comprehensive morphometric analysis of the relevant anatomic relationships were made.

Differences in immunological alterations and underlying viral infections in two well-defined severe drug eruptions

BACKGROUND

Similar drugs (e.g. anticonvulsants) have been implicated in the development of two distinct forms of severe cutaneous drug reactions, Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) and drug-induced hypersensitivity syndrome (DIHS)/drug rash with eosinophilia and systemic symptoms (DRESS).

AIM

To investigate immunological alterations and underlying viral infections that could contribute to the variability in the clinical presentations of these diseases.

METHODS

We retrospectively analysed clinical variables, serum immunoglobulin levels, numbers of circulating white blood cells, lymphocytes and their subsets, serum levels of several cytokines, and underlying viral infections in both drug reactions, using samples obtained at onset from 9 patients with SJS/TEN and 19 patients with DIHS/DRESS.

RESULTS

There were significant differences between the two drug eruptions in the duration of drug intake before onset, the levels of IgG, IgA and IgM, the numbers of circulating white blood cell, lymphocyte, CD3+ T cell and CD8+ T cells, the serum levels of interferon-γ, and the titres of anti-herpes simplex virus IgG at onset.

CONCLUSIONS

The difference in the pattern of immune responses shaped in part by previous and underlying viral infections at the time of drug exposure could cause a marked deviation in the pathological phenotype of severe drug eruptions. Elucidating these host factors may provide a basis for therapeutic approaches in patients with severe drug reactions.

Paraumbilical peritoneal incision using the little finger in shunt operations for hydrocephalus: technical note

INTRODUCTION

The shunt operation remains the standard procedure for the treatment of hydrocephalus. We describe a simple minilaparotomy method that involves perforation of the peritoneum with the surgeon's little finger.

TECHNIQUE

After placing a small paraumbilical incision at the skin and fascia, the little finger is introduced through the incision to perforate the pre-peritoneal fat and peritoneum. The finger should be inserted at a 30-45° angle to the horizontal plane to avoid injuring the underlying viscera and major blood vessels and to put sufficient shear force on the peritoneum. A catheter is inserted into the abdominal cavity after visual confirmation of proper perforation.

CONCLUSION

As the paraumbilical wound is not noticeable postoperatively due to the presence of the natural umbilical skin fold, this method yields a cosmetically appealing result.

Approaches to immunotherapies for Japanese cedar pollinosis

Japanese cedar (Cryptomeria japonica; CJ) pollinosis is a typical type I allergy induced by CJ pollen and one of the most common allergic diseases in Japan. New immunotherapies have been developed for treatment of CJ pollinosis. We focus here on new immunotherapies for CJ pollinosis including sublingual immunotherapy with crude extract of CJ antigen, oral immunotherapy with transgenic rice expressing CJ allergens, a peptide vaccine using T cell epitopes of CJ allergens, DNA vaccines encoding either the CJ allergen gene or T cell epitope gene, and adjuvant-conjugated vaccines using CJ allergen conjugated with adjuvants such as CpG oligodeoxynucleotide or pullulan.

Inhibition of neutrophil migration in mice by mouse formyl peptide receptors 1 and 2 dual agonist: indication of cross-desensitization in vivo

It has been reported that the stimulation of neutrophils with N-formyl-Met-Leu-Phe (fMLF), an agonist for formyl peptide receptor (Fpr) 1, renders cells unresponsive to other chemoattractants in vitro. This is known as cross-desensitization, but its functional relevance in neutrophil migration in vivo has not been investigated. Here, we show that precedent stimulation of mouse neutrophils with compound 43, a non-peptidyl agonist for mouse Fpr1 and Fpr2, rendered the cells unresponsive to a second stimulation with C5a, leukotriene B₄, or keratinocyte-derived cytokine (KC) in calcium mobilization and chemotaxis assays in vitro. The expression of chemokine (C-X-C motif) receptor 2 (CXCR2) on the surface of neutrophils was concomitantly diminished by stimulating the cells with the compound. Moreover, oral administration of the compound to mice before they were exposed to lipopolysaccharide (LPS) aerosol resulted in a dose-dependent reduction in the neutrophil count in bronchoalveolar lavage fluid. The expression of CXCR2 on blood neutrophils was also reduced in the compound-administered mice. The recipient mice that underwent adoptive transfer of fluorescence-labelled neutrophils that had been incubated with the compound showed a substantial decrease in neutrophil counts in bronchoalveolar lavage fluid after they were exposed to LPS, when compared with the control mice to which vehicle-treated neutrophils had been transferred. These results are consistent with the idea that the agonist for Fpr1 and Fpr2 induced cross-desensitization in neutrophils and attenuated neutrophil migration into the airways. Our results also revealed the unpredicted effect of an Fpr1 and Fpr2 dual agonist, which may act as a functional antagonist for multiple chemoattractant receptors in vivo.

Novel CC chemokine receptor 4 antagonist RS-1154 inhibits ovalbumin-induced ear swelling in mice

CC chemokine ligand 17 (CCL17/thymus and activation-regulated chemokine: TARC) and CCL22 (macrophage-derived chemokine: MDC) selectively bind to CC chemokine receptor 4 (CCR4). The CCR4 system is considered to be responsible for the pathology of allergic diseases such as atopic dermatitis. To find and develop potential medicines against allergic diseases, we screened an in-house library to search for compounds having a profile as a CCR4 antagonist. From among the screening hits, we focused on 3-{2-[(2R)-2-phenyl-4-(4-pyridin-4-ylbenzyl)morpholin-2-yl]ethyl}quinazoline-2,4(1H,3H)-dione (named RS-1154), which had been newly synthesized in our laboratory. This compound inhibited the binding of [(125)I]CCL17 to human CCR4-expressing CHO cells with an IC(50) value of 27.7 nM and moreover inhibited CCL17-induced migration of DO11.10 mice-derived T helper 2 cells with an IC(50) value of 1.5 nM in vitro. We then examined the effect of RS-1154 in an ovalbumin-induced ear swelling assay. The ear thickness was decreased by intravenous administration of anti-CCL17 or anti-CCL22 antibodies, suggesting that the CCR4 system is involved in the ear swelling. Though partially, the oral administration of RS-1154 also significantly ameliorated the ear swelling at the doses of 30 and 100 mg/kg. Furthermore, the serum level of interleukin-4 decreased after the administration of RS-1154. In this study, we succeeded in obtaining a newly-synthesized compound, RS-1154, which has a potential to inhibit the chemotaxis of T helper 2 cells in vitro and to ameliorate ovalbumin-induced ear swelling in vivo. These results raise the possibility that RS-1154 or one of derivatives might become a therapeutic agent for atopic dermatitis patients.

Risk factors for severe impetiginized atopic dermatitis in Japan and assessment of its microbiological features

Patients with atopic dermatitis (AD) are susceptible to cutaneous bacterial infection. When such patients develop infection, some have extensive impetiginized dermatitis with high fever. To clarify the risk factors for severe impetiginized AD and its microbiological features, we reviewed clinical and microbiological data of 14 patients with impetiginized AD who were admitted to our hospital between the years 1999 and 2006. All patients had poorly controlled AD with eczematous lesions on the extensive body surface. The mean age was 28.2 years (range 18-35). Cultures of the lesional skin yielded both Streptococcus pyogenes and Staphylococcus aureus in 12 patients. S. pyogenes alone was isolated in two cases. These observations suggest that poorly controlled AD in adults is a risk factor for severe impetiginized AD and that S. pyogenes might play an important role in the development of severe clinical symptoms.

Utility of the lymphocyte transformation test in the diagnosis of drug sensitivity: dependence on its timing and the type of drug eruption

BACKGROUND

Lymphocyte transformation test (LTT) is a safety and reproducible test to assess activation of drug-specific T cells in vitro; however, there are several practical concerns such as the time of testing and the influence of treatment. Our aim was to define the right timing to perform LTT for determining the causative agent in various types of drug reactions.

METHODS

Lymphocyte transformation test was performed at different time points during the evolution of three types of drug reactions, maculo-papular type of drug eruptions (MP), Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), and drug-induced hypersensitivity syndrome/drug rash and eosinophilia with systemic symptoms (DIHS/DRESS).

RESULTS

Positive LTT reactions were obtained when the test was performed at the acute stage but not the recovery stage in MP and SJS/TEN, while positive LTT reactions were obtained at the recovery stage but not the acute stage in DIHS/DRESS, regardless of treatment with systemic prednisolone.

CONCLUSIONS

Lymphocyte transformation test is a reliable method to define the causative agent, when LTT is performed at the right timing depending on the type of drug reactions. Lymphocyte transformation test should be performed within 1 week after the onset of skin rashes in patients with MP and SJS/TEN; and 5-8 weeks after in patients with DIHS/DRESS, respectively.

Intraoral administration of a T-cell epitope peptide induces immunological tolerance in Cry j 2-sensitized mice

Sublingual immunotherapy using allergen-derived peptides is feasible as a novel specific immunotherapy, but its efficacy has not yet been demonstrated in either humans or animals. In addition, it remains obscure whether the oral immune system is involved in the mechanism of sublingual immunotherapy. Here, we show that the intraoral administration of the T-cell epitope peptide P2-246-259 derived from Cry j 2, a major Japanese cedar (Cryptomeria japonica) pollen allergen, to Cry j 2-sensitized mice induces immunological tolerance, and that ex vivo lymph node cell proliferation to P2-246-259 and Cry j 2 was inhibited. In addition, intraoral administration was shown to be superior to intragastric administration in terms of tolerance induction, suggesting that the oral immune system contributes to the induction of immunological tolerance. Therefore, the significant efficacy of sublingual immunotherapy using a peptide on allergen-specific T-cells was demonstrated in animals, and this may be potentiated by the oral mucosal immune system.

The Majority of Human Peripheral Blood CD4+CD25highFoxp3+ Regulatory T Cells Bear Functional Skin-Homing Receptors

CD4+CD25+ T regulatory cells (Treg) are thought to be important in the peripheral tolerance. Recent evidence suggests that human peripheral blood CD4+CD25+ T cells are heterogeneous and contain both CD4+CD25(high) T cells with potent regulatory activity and many more CD4+CD25(low/med) nonregulatory T cells. In this study, we found that virtually all peripheral blood CD4+CD25(high)Foxp3+ Treg expressed high levels of the chemokine receptor CCR4. In addition, 80% of Treg expressed cutaneous lymphocyte Ag (CLA) and 73% expressed CCR6. These molecules were functional, as CLA+ Treg showed CD62E ligand activity and demonstrable chemotactic responses to the CCR4 ligands CCL22 and CCL17 and to the CCR6 ligand CCL20. The phenotype and chemotactic response of these Treg were significantly different from those of CD4+CD25(med) nonregulatory T cells. We further demonstrated that blood CLA+ Treg inhibited CD4+CD25- T cell proliferation induced by anti-CD3. Based on homing receptor profile, CLA+ Treg should enter normal skin. We next isolated CD4+CD25(high) T cells directly from normal human skin; these cells suppressed proliferation of skin CD4+CD25- T cells. Therefore, the majority of true circulating Treg express functional skin-homing receptors, and human Treg may regulate local immune responses in normal human skin.

Expression of Interleukin-18 and Caspase-1 in Cutaneous T-Cell Lymphoma

PURPOSE

Cutaneous T-cell lymphoma (CTCL) is a malignancy of skin-homing Th2 T cells. Clonal T cells and CTCL skin lesions typically express Th2 cytokines, including interleukin (IL)-4, IL-5, and IL-10, but fail to produce Th1 cytokines. However, the reason for Th2 bias is unknown. IL-18 is a pleiotropic proinflammatory cytokine produced by monocytes/macrophages lineage as well as epithelial cells, such as human keratinocytes. In the absence of IL-12, IL-18 leads to increased immunoglobulin E production from B cells and enhanced production of IL-4 and IL-13 by basophils, mast cells, and CD4(+) T cells. We have analyzed cytokines in CTCL patients, which may bias the immune response around the Th1/Th2 axis.

EXPERIMENTAL DESIGN

We examined plasma of 95 CTCL patients and skin of 20 CTCL patients for IL-18, caspase-1, IL-12, and other cytokines. To identify the presence or absence of these cytokine proteins in CTCL and normal skin, we cultured explants from skin biopsies on three-dimensional matrices.

RESULTS

Plasma levels of IL-18 and its converting enzyme, caspase-1, were significantly elevated in CTCL. mRNA levels for these factors were also elevated in CTCL skin lesions. Matrices populated with CTCL lesional skin produced significant amounts of IL-18 and caspase-1; however, production of IL-12 protein was barely detectable.

CONCLUSIONS

We propose that the high levels of IL-18 expression in lesional CTCL skin contribute to increased plasma levels of IL-18 and that this, in the face of significantly lower levels of IL-12, may contribute to the Th2 bias seen in this disease.

Skin-derived interleukin-7 contributes to the proliferation of lymphocytes in cutaneous T-cell lymphoma

Cutaneous T-cell lymphomas (CTCLs) are malignancies of T cells that have a special affinity for the skin. We have previously reported that much of the T-cell receptor repertoire is altered in CTCL, and both malignant and nonmalignant clones are numerically expanded, presumably in response to T-cell trophic cytokines. We therefore examined levels of the T-cell trophic cytokines IL-2, IL-4, IL-7, IL-12, IL-13, and IL-15 in plasma in 93 CTCL patients and healthy controls. Only IL-7 levels were elevated in CTCL. We next looked at lesional skin from patients with CTCL and found elevated levels of IL-7 mRNA. Explant cultures of normal and lesional CTCL skin biopsies revealed significantly more IL-7 protein production in CTCL skin. Additionally, cultures of CTCL skin released greater numbers of T cells than normal skin; this was blocked by the addition of an IL-7 neutralizing antibody. Finally, these cultures induced proliferation of normal peripheral skin-homing T cells that were added to the cultures. These observations led us to postulate that IL-7 produced by skin cells contributes to the survival and proliferation of T cells within skin lesions and is likely the source of elevated circulating IL-7 in CTCL.

Oral administration of a T cell epitope inhibits symptoms and reactions of allergic rhinitis in Japanese cedar pollen allergen-sensitized mice

Although the concept of a T cell epitope in specific immunoprophylaxis was proposed more than a decade ago, it had not been well demonstrated since then that a T cell epitope inhibits symptoms and reactions of allergic disease in animal models. In this study, we have established a system to evaluate symptoms and reactions of allergic rhinitis in mice, and investigated whether oral administration of a T cell epitope relieves sensitized mice of allergic rhinitis. P2-246-259 (RAEVSYVHVNGAKF) is a BALB/c mouse T-cell epitope of Cry j 2, which is a major Japanese cedar (Cryptomeria japonica) pollen allergen. Mice were administered orally with 200 microg/animal of P2-246-259 four times within 2 weeks before sensitization, and sensitized intranasally with Cry j 2 twice. Of the cardinal symptoms of allergic rhinitis, we assessed sneezing and airway obstruction, but could not estimate rhinorrhea or pruritus. Sneezing frequency was significantly increased by challenge with Cry j 2. Concerning allergic reactions, vascular permeability of the nasal mucosa in the early phase and hyperreactivity to histamine in the late phase were also exacerbated by the challenge. These symptoms and reactions of allergic rhinitis were significantly inhibited by oral administration of P2-246-259. These results indicate utility of mice as models for allergic rhinitis; furthermore, the effects of P2-246-259 on allergic rhinitis imply that oral administration of a T cell epitope is a promising approach for specific immunoprophylaxis.

Analysis of sequential immunoglobulin E-binding epitope of Japanese cedar pollen allergen (Cry j 2) in humans, monkeys and mice

BACKGROUND

Japanese cedar (Cryptomeria japonica; CJ) pollinosis has been reported to occur naturally in Japanese monkeys (Macaca fuscata) as well as in humans. Most human patients and monkeys with pollinosis have specific IgE for Cry j 2, a major allergen of CJ pollen.

OBJECTIVE

The main purpose of this study was to identify IgE B cell epitopes of Cry j 2 using a synthetic peptide in humans, monkeys and mice.

METHODS

We synthesized 38 overlapping peptides that span the entire length of Cry j 2. We examined the B cell epitopes of Cry j 2 that are recognized by IgE in the sera of human patients and monkeys with pollinosis and immunized mice using synthetic peptides of Cry j 2. We also examined the reaction of Cry j 2-specific mouse monoclonal IgG antibodies to the peptides. Furthermore, we conducted a histamine release assay with leucocytes from a pollinosis patient using human serum albumin (HSA) conjugated with the peptides as a B cell epitope.

RESULTS

We found that 16 of the 20 pollinosis patients who had specific IgE to Cry j 2 also exhibited IgE reaction with some Cry j 2 peptides. Of these 16 patients, 10 exhibited IgE reaction with Cry j 2 peptide no. 13 (121GQCKWVNGREICNDRDRPTA140). Five of the seven monkeys with CJ pollinosis exhibited a reaction with peptide no. 13. Furthermore, IgE in mice immunized with Cry j 2 and two mouse monoclonal IgG antibodies reacted with peptide no. 13. Peptide no. 13-conjugated HSA showed the release of histamine from basophils. Furthermore, to determine the minimum epitope in peptide no. 13, we conducted an enzyme-linked immunosorbent assay inhibition test. The core of the epitope in humans, monkeys and mice was 124KWVNGREI131.

CONCLUSION

We found that 124KWVNGREI131 is an important B cell epitope recognized by IgE in humans, monkeys and mice.

Chronic inflammation of the skin can be induced in IgE transgenic mice by means of a single challenge of multivalent antigen

BACKGROUND

It is now widely accepted that IgE mediates immediate-type allergic response. However, the pathologic role of IgE is controversial in the chronic allergic inflammation observed in atopic diseases, such as asthma and atopic dermatitis.

OBJECTIVE

We investigated the role of IgE in cutaneous allergic reactions by using 2 newly developed lines of antigen-specific IgE transgenic mice.

METHODS

IgE transgenic mice were administered subcutaneously with corresponding antigens, and the subsequent ear swelling was measured.

RESULTS

A single subcutaneous administration of TNP-conjugated ovalbumin (OVA) into the ears of nonimmunized mice carrying the TNP-specific IgE transgene elicited immediate-phase and late-phase ear swelling as expected, which peaked at 20 minutes and 8 hours later, respectively. Interestingly, however, 2 to 3 days after the antigen challenge, more intense ear swelling appeared. Its magnitude and duration were dependent on the valency of TNP in OVA, as well as the dose of TNP-OVA, and it lasted over 1 month when 100 microg of OVA conjugated with 11 molecules of TNP was given. Interestingly, administration of OVA to OVA-specific IgE transgenic mice elicited immediate-phase and late-phase ear swelling but not third-phase ear swelling. Massive infiltration of inflammatory cells was observed in the third-phase ear swelling of TNP-specific IgE transgenic mice. Cyclosporine A almost completely inhibited the third-phase ear swelling and cellular infiltration, whereas an antihistamine, cyproheptadine, did not show any significant effect on the third-phase reaction.

CONCLUSION

These results indicate that IgE can trigger not only immediate-type hypersensitivity but also chronic allergic inflammation. Our findings highlight a novel immunopathologic role of IgE in chronic atopic disorders.

Three T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen antigens, retain their immunogenicity and tolerogenicity in a linked peptide

It has been demonstrated in detail that administration of a dominant T-cell determinant to animals induces activation or immunological tolerance of T cells. However, it has not been determined whether multiple T-cell determinants, when integrated into a single peptide, retain their potential to induce T-cell activation and tolerance. We prepared a synthetic peptide comprising three T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen antigens, and investigated the immunogenicity and tolerogenicity of each T-cell determinant in the linked peptide by means of lymph node cell proliferation assays using mice. Lymph node cells from mice immunized with each of the three T-cell determinants proliferated against the linked peptide in a dose-dependent manner, similar to that of the immunized peptide. Lymph node cells from mice immunized with the linked peptide proliferated against all of the three T-cell determinants. In addition, the degree of proliferation against the three T-cell determinants occurred according to their original immunogenicity, as observed in the native protein antigens. Oral administration of the linked peptide to mice before they were immunized with Cry j 1 and Cry j 2 inhibited lymph node cell proliferation against the three T-cell determinants, depending on the dose of the linked peptide administered. In conclusion, it was demonstrated that three T-cell determinants retain their original immunogenicity and tolerogenicity in a linked peptide comprising them.

Linking chiral indices and transport properties of double-walled carbon nanotubes

We performed in situ transport measurements in a transmission-electron microscope (TEM) on individual double-walled carbon nanotubes (DWNT). Using selected-area electron diffraction, the chiral indices of the two tubes constituting the DWNTs were determined through careful comparison with theory. We discuss the case of a DWNT whose two tubes have a gap at half filling and show a finite density of delocalized state at the Fermi level. The exact determination of chiral indices should be reachable in any transport-measurement experiment with samples that allow TEM characterization.

Preferential acetazolamide-induced vasodilation based on vessel size and organ: confirmation of peripheral vasodilation with use of colored microspheres

When carbonic anhydrase activity decreases, the regional blood flow (rBF) in organs increases as hypercapnia develops. However, the effects of acetazolamide (AZ)-induced vasodilation have not been estimated with respect to vessel size and organs. The aim of this study was to determine the diameter of the capillaries in various organs that respond to inhibition of carbonic anhydrase activity by AZ. White rabbits were anesthetized with urethane and ketamine and infused with AZ. While the systolic blood pressure (SBP), pH, hemoglobin concentration, and base excess did not change, the partial pressure of arterial oxygen (PaO2) increased significantly and the partial pressure of arterial carbon dioxide (PaCO2) decreased significantly with AZ. The rBF was calculated by using 3 different sizes (15, 25, and 50 microm) of colored microspheres (CM). The rBF measured with 15 microm CM in the brain, kidneys, and liver increased in response to AZ, and the rBF in these organs was different with the different sizes of CM. However, the rBF calculated by using the different sizes of CM in the stomach and abdominal muscle did not change after the administration of AZ. The AZ-induced vasodilation occurred in all sizes of vessels in the liver, in the small and medium-sized vessels in kidneys, and in the larger capillaries in the brain.

Preclinical evaluation of an immunotherapeutic peptide comprising 7 T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen allergens

BACKGROUND

Peptide immunotherapy is a new approach to treating allergic diseases, but a therapeutic peptide for Japanese cedar pollinosis has not yet been developed.

OBJECTIVE

The aim of this study is to prepare and preclinically evaluate a hybrid peptide comprising 7 T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen allergens.

METHODS

The recombinant hybrid peptide was prepared after immunodominance of 7 T-cell determinants was confirmed by means of PBMC proliferation assay in 113 volunteers with pollinosis. The hybrid peptide was compared with a mixture of the 7 T-cell determinants in a dose-dependent PBMC proliferation assay in 6 volunteers with pollinosis. PBMC proliferation and binding activity of serum IgE antibody against the hybrid peptide, Cry j 1, and Cry j 2 were investigated in 48 volunteers with pollinosis.

RESULTS

The hybrid peptide induced T-cell proliferation with an average 100-fold lower concentration than a mixture of the 7 peptides. PBMCs from 44 (92%) of 48 volunteers proliferated against the hybrid peptide, with significant correlation (r = 0.87) in T-cell proliferation against Cry j 1 and Cry j 2. No serum IgE antibodies specific to Cry j 1 or Cry j 2 bound to the hybrid peptide.

CONCLUSION

A hybrid peptide comprising 7 T-cell determinants has the potential for inducing T-cell proliferative responses that is superior to the potential of a mixture of the T-cell determinants and comparable with that of Cry j 1 and Cry j 2. The hybrid peptide will be of use in specific immunotherapy against Japanese cedar pollinosis.

Seasonal changes of humoral and cellular immune responses to Japanese cedar (Cryptomeria japonica) pollen allergens in Japanese monkeys (Macaca fuscata) with pollinosis

The natural occurrence of Japanese cedar [Cryptomeria japonica (CJ)] pollinosis has been reported in Japanese monkeys (Macaca fuscata). The present study was designed to investigate seasonal changes in immunological reactions to CJ pollen allergens in monkeys with CJ pollinosis. Blood samples were collected from six monkeys with CJ pollinosis before and after CJ pollen season. Seasonal changes in specific IgE and IgG to major allergens (Cry j 1 and Cry j 2) were observed before and after CJ pollen season. The humoral responses decreased significantly before CJ pollen and increased after CJ pollen season. Similar seasonal changes in peripheral blood mononuclear cells proliferative responses to CJ allergens were observed before and after CJ pollen season. These humoral and cellular immune responses might serve as a biomarker for assessing new immunotherapies for monkeys with pollinosis.

Element-selective single atom imaging

Electron energy-loss spectroscopy (EELS) is widely used to identify elemental compositions of materials studied by microscopy. We demonstrate that the sensitivity and spatial resolution of EELS can be extended to the single-atom limit. A chemical map for gadolinium (Gd) clearly reveals the distribution of Gd atoms inside a single chain of metallofullerene molecules (Gd@C82) generated within a single-wall carbon nanotube. This characterization technique thus provides the "eyes" to see and identify individual atoms in nanostructures. It is likely to find broad application in nanoscale science and technology research.

One-dimensional metallofullerene crystal generated inside single-walled carbon nanotubes

Electron microscope imaging for gadolinium metallofullerenes encapsulating in single-wall carbon nanotubes [(Gd@C82)n@SWNTs] identifies the single Gd atom encaged in each. The intermolecular distance between Gd@C82 is extremely regular, regarding the chains of Gd@C82 as novel one-dimensional crystals. Chemical state analysis of Gd atoms suggests evidence for charge transfer from Gd to either a fullerene cage or a nanotube. The slopes of the temperature dependence of electric resistance for the mat-like films of (Gd@C82)n@SWNTs and (C60)n@SWNTs are much steeper than that for empty SWNTs, suggesting the electron scattering due to the electrostatic potential from inside fullerenes playing an important role.

The incidence of Japanese cedar pollinosis and sensitization to the pollen allergens among Japanese monkeys in a troop

The natural occurrence of Japanese cedar (Cryptomeria japonica; CJ) pollinosis has been reported in Japanese monkeys (Macaca fuscata), an appropriate animal model for developing antipollinosis therapies. However, there has been no study on the incidence of Japanese cedar pollinosis in monkeys. To evaluate the incidence of CJ pollinosis in Japanese monkeys, we investigated the presence of pollinosis symptoms among monkeys in a troop, and the response to CJ allergens in pollinosis monkeys. We examined the presence of pollinosis symptoms in 272 monkeys in a troop throughout the CJ pollination season (February to April). Of the 272 monkeys, 21 (7.7%) showed pollinosis symptoms during the CJ pollen season. Blood samples were taken from the 21 monkeys that showed pollinosis symptoms and were tested for the presence of immunoglobulin E (IgE) antibody for CJ allergens. All 21 monkeys with CJ pollinosis had anti-CJ IgE. Of the 21 monkeys, peripheral blood mononuclear cells (PBMC) could be taken from 12, all of which showed CJ allergen-specific PBMC proliferation. The incidence of CJ pollinosis in a troop was 7.7%. The monkeys with CJ pollinosis demonstrated specific IgE and PBMC proliferation for CJ allergens.

The incidence of japanese cedar pollinosis and sensitization to the pollen allergens among Japanese monkeys in a troop

The natural occurrence of Japanese cedar (Cryptomeria japonica; CJ) pollinosis has been reported in Japanese monkeys (Macaca fuscata), an appropriate animal model for developing antipollinosis therapies. However, there has been no study on the incidence of Japanese cedar pollinosis in monkeys. To evaluate the incidence of CJ pollinosis in Japanese monkeys, we investigated the presence of pollinosis symptoms among monkeys in a troop, and the response to CJ allergens in pollinosis monkeys. We examined the presence of pollinosis symptoms in 272 monkeys in a troop throughout the CJ pollination season (February to April). Of the 272 monkeys, 21 (7.7%) showed pollinosis symptoms during the CJ pollen season. Blood samples were taken from the 21 monkeys that showed pollinosis symptoms and were tested for the presence of immunoglobulin E (IgE) antibody for CJ allergens. All 21 monkeys with CJ pollinosis had anti-CJ IgE. Of the 21 monkeys, peripheral blood mononuclear cells (PBMC) could be taken from 12, all of which showed CJ allergen-specific PBMC proliferation. The incidence of CJ pollinosis in a troop was 7.7%. The monkeys with CJ pollinosis demonstrated specific IgE and PBMC proliferation for CJ allergens.

Acetazolamide-induced increase in blood flow to rabbit organs is confirmed using colored microspheres

Inhibitors of carbonic anhydrase activity have been found to increase blood and organ PCO2 and to increase blood flow (BF) in individual organs. To determine whether carbonic anhydrase inhibition coordinately induces an increase in BF in several organs, we assayed the effect of the carbonic anhydrase inhibitor, acetazolamide (AZ), on BF in rabbit organs using the colored microsphere (CM) assay. Eight female white rabbits were anesthetized with ketamine and urethane, and administered three sequential doses of 4 mg/kg AZ. After each dose, the rabbits were injected with 9 x 10(5) CMs of different colors, and arterial blood was collected. We found that AZ had no effect on blood pressure, body temperature, hemoglobin concentration, or PaCO2. In contrast, 12 mg/kg AZ significantly increased PaO2 and significantly decreased base excess. When we measured organ BF, we observed, in response to 12 mg/kg AZ, an 82% increase in brain BF and a 55% increase in kidney BF, but no change in BF of the liver, stomach wall, or abdominal muscle. These findings suggest that the inhibition of carbonic anhydrase activity by AZ, which decreases the rate of CO2 conversion to HCO3-, causes the retention of CO2 in tissues and organs, and thus increases BF in specific organs. Administration of carbonic anhydrase inhibitors, such as AZ, may increase BF to the brain and kidney without reducing PaO2, thereby increasing the supply of oxygen in conditions involving hypoxia such as ischemia and shock.

Oral administration of a dominant T-cell determinant peptide inhibits allergen-specific TH1 and TH2 cell responses in Cry j 2-primed mice

BACKGROUND

Oral immunotherapy with a peptide for allergic immune responses is theoretically a promising therapy but has not been established yet.

OBJECTIVE

To evaluate immune suppressive efficacy of oral administration of an immunodominant peptide, we investigated changes in T-cell proliferation, TH1 - and TH2 -cytokine production, and TH1 - and TH2 -mediated antibody production in mice after oral administration of a peptide.

METHODS

Peptide p246-259, containing a dominant T-cell determinant of Cry j 2, which is the major allergen in Japanese cedar pollen, was used in this study. Groups of mice received p246-259 or PBS alone before or after they were primed intranasally with Cry j 2 and cholera toxin. In another experiment mice were primed intraperitoneally with Cry j 2 and alum. Proliferative response and cytokine production by nasal-associated lymph node cells against Cry j 2 were investigated. Amounts of systemic anti-Cry j 2 IgE and IgG antibodies were also measured.

RESULTS

Oral administration of the peptide to mice before, or even after, the sensitization induced oral tolerance in T-cell responses against the allergen; the tolerance was associated with decreased production of TH1 (IFN-gamma and IL-2) and TH2 (IL-4) cytokines. Allergen-specific TH1 -mediated (IgG2a and IgG2b) and TH2 -mediated (IgG1 and IgE) antibody responses were also inhibited.

CONCLUSIONS

Oral administration of a dominant T-cell determinant peptide induces immunologic tolerance in both TH1 and TH2 cell responses against the whole protein allergen. Our study is the first, to our knowledge, to demonstrate the potential for peptide-based oral immunotherapy in order to treat allergic immune responses.

[Difficulty to diagnose the cause of death in emergency room]

We evaluated the diagnoses noted on the medical records of 275 patients admitted to Saga Medical College Hospital during the six-year period 1990-1995: 245 patients with cardiopulmonary arrest on arrival (CPAOA) and 30 patients with cardiopulmonary arrest occurring in the emergency room (CPAER). The most frequent cause of CPAOA was heart disease, and the next frequent cause was respiratory disease. In the CPAER patients, the most frequent cause was heart disease, while the next frequent was acute aortic dissection. There were discrepancies in the respective causes of cardiac arrest between the CPAOA and CPAER patients, which was probably due to difficulty in diagnosis in the emergency room. In the emergency room, the cardiopulmonary resuscitation is the first treatment to be performed for CPAOA, the examination for the cause of cardiac arrest is the next followed after the heart beating. However, the cause of cardiac arrest can not be diagnosed in the emergency room for the CPAOA patients without the successful resuscitation, because the examinations for the cause of cardiac arrest can not be performed for the patients without beating heart in the emergency room. Therefore, it is concluded that there exists a need to improve the training for finding out the abnormal death with the inspection and the medico-legal autopsy. It may be suggested that the training system of forensic medicine is ideal for clinical physician who can study the decision of the diseases ranging from toxicosis to acute cardiopulmonary arrest in both the emergency and the forensic medicine.

Induction of oral tolerance in splenocyte-reconstituted SCID mice

The participation of each lymphocyte compartment in the induction of oral tolerance for antibody response was investigated by means of a new cell-transfer experimental system, using severe combined immunodeficiency (SCID) mice. Various lymphocyte compartments from BALB/c mice were transferred into SCID mice and these mice were evaluated for oral tolerance induction. First, whole splenocytes from BALB/c mice were transferred into SCID mice and these mice were orally administered bovine alpha s1-casein. The specific antibody response in these mice after subsequent immunization with antigen was greatly reduced compared to controls which were not fed the antigen, and it was demonstrated that oral tolerance was induced in SCID mice bearing donor splenocytes. Oral tolerance was induced in SCID mice that were reconstituted with only T cells, revealing that B cells were not required for the induction of oral tolerance. Further, oral tolerance was induced in SCID mice reconstituted with CD8-depleted splenocytes but not in mice reconstituted with only CD8+ T cells. These results demonstrate that oral tolerance could be induced in SCID mice bearing normal splenocytes and that interaction of CD4+ T cells with antigen-presenting cells other than B cells are responsible for the induction of oral tolerance. Our experimental system may be useful for investigations with human lymphocytes.

Intracellular Mg2+ depletion depresses the delayed rectifier K+ current in guinea pig ventricular myocytes

The effects of various [Mg2+]i, particularly low [Mg2+]i, on the delayed rectifier K+ current (IK) were studied in guinea pig ventricular myocytes with the patch clamp technique. The magnitude of IK was evaluated from the amplitude of its tail current elicited on repolarization following the depolarizing steps. The pipette-perfusion technique was also used. The initial variations of IK magnitude were dependent on [Mg2+]i in the internal solutions with which the whole-cell recording was begun. With 0.03 to 1 mM [Mg2+]i, IK was relatively stable after patch rupture, showing a minimal decay with time; with 3 mM [Mg2+]i, IK rapidly declined; with [Mg2+]i, less than 0.01 mM IK transiently increased after patch break, but declined progressively thereafter as the magnitude of IK decreased to about 30% of the initial magnitude in 10 min. The decline of IK at low [Mg2+]i showed the following features. The decline was accompanied little by changes in the voltage-activation relation or by changes in the kinetics of current deactivation. The decline was not related to changes in [Ca2+]i and was also observed in ATP gamma S-loaded, isoprenaline-stimulated cells, in which IK channels were presumed to be persistently phosphorylated. An application of okadaic acid did not prevent the decline of IK during Mg2+ depletion. It is suggested that a presence of [Mg2+]i higher than 0.01 mM is required to maintain IK in guinea pig ventricular cells. The depression of IK at low [Mg2+]i appears to involve a phosphorylation-dephosphorylation-independent mechanism.