Material radiopurity control in the XENONnT experiment

The selection of low-radioactive construction materials is of the utmost importance for rare-event searches and thus critical to the XENONnT experiment. Results of an extensive radioassay program are reported, in which material samples have been screened with gamma-ray spectroscopy, mass spectrometry, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{222}$$\end{document}222Rn emanation measurements. Furthermore, the cleanliness procedures applied to remove or mitigate surface contamination of detector materials are described. Screening results, used as inputs for a XENONnT Monte Carlo simulation, predict a reduction of materials background (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim $$\end{document}∼17%) with respect to its predecessor XENON1T. Through radon emanation measurements, the expected \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{222}$$\end{document}222Rn activity concentration in XENONnT is determined to be 4.2 (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{+0.5}_{-0.7}$$\end{document}-0.7+0.5) \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu $$\end{document}μBq/kg, a factor three lower with respect to XENON1T. This radon concentration will be further suppressed by means of the novel radon distillation system.

222 Rn emanation measurements for the XENON1T experiment

The selection of low-radioactive construction materials is of utmost importance for the success of low-energy rare event search experiments. Besides radioactive contaminants in the bulk, the emanation of radioactive radon atoms from material surfaces attains increasing relevance in the effort to further reduce the background of such experiments. In this work, we present the 222 Rn emanation measurements performed for the XENON1T dark matter experiment. Together with the bulk impurity screening campaign, the results enabled us to select the radio-purest construction materials, targeting a 222 Rn activity concentration of 10 μ Bq / kg in 3.2 t of xenon. The knowledge of the distribution of the 222 Rn sources allowed us to selectively eliminate problematic components in the course of the experiment. The predictions from the emanation measurements were compared to data of the 222 Rn activity concentration in XENON1T. The final 222 Rn activity concentration of ( 4.5 ± 0.1 ) μ Bq / kg in the target of XENON1T is the lowest ever achieved in a xenon dark matter experiment.

Randomized phase-II trial evaluating induction therapy with idarubicin and etoposide plus sequential or concurrent azacitidine and maintenance therapy with azacitidine

The aim of this randomized phase-II study was to evaluate the effect of substituting cytarabine by azacitidine in intensive induction therapy of patients with acute myeloid leukemia (AML). Patients were randomized to four induction schedules for two cycles: STANDARD (idarubicin, cytarabine, etoposide); and azacitidine given prior (PRIOR), concurrently (CONCURRENT), or after (AFTER) therapy with idarubicin and etoposide. Consolidation therapy consisted of allogeneic hematopoietic-cell transplantation or three courses of high-dose cytarabine followed by 2-year maintenance therapy with azacitidine in the azacitidine-arms. AML with CBFB-MYH11, RUNX1-RUNX1T1, mutated NPM1, and FLT3-ITD were excluded and accrued to genotype-specific trials. The primary end point was response to induction therapy. The statistical design was based on an optimal two-stage design applied for each arm separately. During the first stage, 104 patients (median age 62.6, range 18-82 years) were randomized; the study arms PRIOR and CONCURRENT were terminated early due to inefficacy. After randomization of 268 patients, all azacitidine-containing arms showed inferior response rates compared to STANDARD. Event-free and overall survival were significantly inferior in the azacitidine-containing arms compared to the standard arm (p < 0.001 and p = 0.03, respectively). The data from this trial do not support the substitution of cytarabine by azacitidine in intensive induction therapy.

Epidemiological, genetic, and clinical characterization by age of newly diagnosed acute myeloid leukemia based on an academic population-based registry study (AMLSG BiO)

We describe genetic and clinical characteristics of acute myeloid leukemia (AML) patients according to age from an academic population-based registry. Adult patients with newly diagnosed AML at 63 centers in Germany and Austria were followed within the AMLSG BiO registry (NCT01252485). Between January 1, 2012, and December 31, 2014, data of 3525 patients with AML (45% women) were collected. The median age was 65 years (range 18-94). The comparison of age-specific AML incidence rates with epidemiological cancer registries revealed excellent coverage in patients < 70 years old and good coverage up to the age of 80. The distribution according to the European LeukemiaNet (ELN) risk categorization from 2010 was 20% favorable, 31% intermediate-1, 28% intermediate-2, and 21% adverse. With increasing age, the relative but not the absolute prevalence of patients with ELN favorable and intermediate-1 risk (p < 0.001), with activating FLT3 mutations (p < 0.001), with ECOG performance status < 2 (p < 0.001), and with HCT-CI comorbidity index < 3 (p < 0.001) decreased. Regarding treatment, obesity and favorable risk were associated with an intensive treatment, whereas adverse risk, higher age, and comorbidity index > 0 were associated with non-intensive treatment or best supportive care. The AMLSG BiO registry provides reliable population-based distributions of genetic, clinical, and treatment characteristics according to age.

Characteristics and outcome of patients with therapy-related acute promyelocytic leukemia front-line treated with or without arsenic trioxide

Therapy-related acute promyelocytic leukemia (t-APL) is relatively rare, with limited data on outcome after treatment with arsenic trioxide (ATO) compared to standard intensive chemotherapy (CTX). We evaluated 103 adult t-APL patients undergoing treatment with all-trans retinoic acid (ATRA) alone (n=7) or in combination with ATO (n=24), CTX (n=53), or both (n=19). Complete remissions were achieved after induction therapy in 57% with ATRA, 100% with ATO/ATRA, 78% with CTX/ATRA, and 95% with CTX/ATO/ATRA. Early death rates were 43% for ATRA, 0% for ATO/ATRA, 12% for CTX/ATRA and 5% for CTX/ATO/ATRA. Three patients relapsed, two developed therapy-related acute myeloid leukemia and 13 died in remission including seven patients with recurrence of the prior malignancy. Median follow-up for survival was 3.7 years. None of the patients treated with ATRA alone survived beyond one year. Event-free survival was significantly higher after ATO-based therapy (95%, 95% CI, 82-99%) as compared to CTX/ATRA (78%, 95% CI, 64-87%; P=0.042), if deaths due to recurrence of the prior malignancy were censored. The estimated 2-year overall survival in intensively treated patients was 88% (95% CI, 80-93%) without difference according to treatment (P=0.47). ATO when added to ATRA or CTX/ATRA is feasible and leads to better outcomes as compared to CTX/ATRA in t-APL.

CCL21 (SLC) improves tumor protection by a DNA vaccine in a Her2/neu mouse tumor model

Secondary lymphoid-tissue chemokine (SLC/CCL21) is a CC chemokine that is constitutively expressed in various lymphoid tissues and binds to chemokine receptor CCR7 on mature dendritic cells (DCs) and distinct T-and B-cell sub-populations. In vivo, CCL21 regulates the encounters between DC and T cells and thus is a key regulator of adaptive immune responses. We asked whether CCL21 is able to augment immunogenicity of a DNA-based vaccine against Her2/neu in a Balb/c mouse model with syngeneic Her2/neu+ tumor cells (D2F2/E2). Mice were vaccinated intramuscularly with plasmid DNA (pDNA) on day 1 and boosted on day 15; tumor challenge was performed subcutaneously on day 25. Coexpression of CCL21 and Her-2/neu resulted in induction of a TH1-polarized immune response and substantial improvement of the protective effect of the DNA vaccine. Coexpression of tumor antigen pDNA(Her2/neu) with both pDNA(GM-CSF) and pDNA(CCL21) as adjuvants led to further improvement of protection by the vaccine (70% tumor-free mice on day 35 vs 40% with either adjuvant alone vs 5-10% with tumor antigen alone). Our results show that CCL21 is a potent adjuvant for DNA vaccination, particularly in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF). Clinical use of a pDNA(Her2/neu/CCL21/GM-CSF) vaccine might be particularly promising in minimal residual Her2/neu+ breast cancer.

Modulation of regulatory T cells and myeloid-derived suppressor cells by sorafenib and sunitinib in renal cell carcinoma patients

e16002

Background: Induction of regulatory T (Treg) and myeloid-derived suppressor cells (MDSC) is a major mechanism for the escape of tumors from immunological control. Increased levels of Treg cells have been described in renal cell cancer (RCC) patients and seem to correlate with an adverse outcome. Furthermore, reduction of Treg has been reported for RCC patients under sunitinib therapy. The aim of our study was to analyse the influence of sorafenib and sunitinib on the frequency of Treg and MDSC in patients with metastatic RCC (mRCC). Methods: The number of T reg, MDSC and lymphocyte subpopulations was analysed by flowcytometry in peripheral blood (pb) of patients (n=19) with histologically confirmed mRCC under treatment with either sunitinib (50 mg/d, n=11) or sorafenib (800 mg/d, n=8). After informed consent blood samples were taken before and during the 1st, 2nd, and 3rd month of therapy. Flowcytometric analysis was performed using fluorochrome labeled antibodies against CD3, CD4, CD8, CD25, CD127, FOXp3, CD33, C14, CD11b and HLA-DR. Results: The baseline level of Treg did not differ from healthy controls. However, there was a significant increase of CD3+CD4+CD25+FOXp3+Treg (13,5% vs. 36,3% of gated cells, p= 0.02) and the ratio FOXp3+/FOXp3- CD3+CD4+ T cells (0,16% vs. 0,56% of gated cells, p= 0.02) in the group of sorafenib-treated patients compared to sunitinib-treated patients during the 1st month of therapy and thereafter. This effect was confirmed in an intragroup analysis. There was no influence of Sunitinib on the frequency of Treg. Analysis of CD33+/HLA-DR-/11b+ MDSC did not reveal any change under treatment with sorafenib or sunitinib. Conclusions: Sorafenib, but not sunitinib, leads to an early and sustained increase of Treg in pb of mRCC patients. A negative influence of sorafenib on primary immune responses has been described and has mainly been attributed to functional impairment of dendritic cells (DC). Whether altered DC function under sorafenib is responsible for the induction of Treg in RCC patients will have to be addressed in future studies. In immunoresponsive tumors such as RCC, immunological effects of kinase inhibitors are particularly relevant for the design of combination trials with immunotherapeutic agents.

No significant financial relationships to disclose.

Activation of cortical and inhibited differentiation of medullary epithelial cells in the thymus of lymphotoxin-beta receptor-deficient mice: an ultrastructural study

The reciprocal influences of thymic lymphocyte and nonlymphocyte populations, i.e. thymic cross-talk, are necessary for the proper maturation of thymocytes and the development/maintenance of thymic stromal microenvironments. Although the molecular influences exerted by thymic stromal cells on maturing thymocytes have been extensively studied, the identity of signalling molecules used by thymocytes to influence the thymic stromal cells is still largely unknown. Our study provides the first ultrastructural evidence that the functional lymphotoxin-beta receptor (LTbetaR) signalling pathway is engaged in the cross-talk between thymocytes and the thymic stromal cell population. We show that LTbetaR signalling is of the utmost significance for the preservation of the subcellular integrity of all thymic epithelial cells. In the absence of LTbetaR there is (1) hypertrophy and activation of cortical thymic epithelial cells, (2) the complete loss of fully differentiated medullary thymic epithelial cells, and (3) the inhibited differentiation of remaining medullary thymic epithelial cells with the appearance of prominent intercellular cysts in the thymic medulla.

[Study of medicine: "full" load as a parameter for the organization of a successful curriculum]

QUESTION

The licensing regulations for doctors (AAppO) allow medical faculties a wide range of possibilities in their implementation. Are there parameters which are easy to survey and which at the same time contribute to the speedy detection of possible undesirable developments?

METHOD

The results of a retrospective student evaluation of the preclinical period clearly revealed that there are extreme fluctuations in the "perceived" stress of students in Semester one to four. In succession, classes were restructured so that stress was as equally balanced as possible throughout the four semesters.

RESULTS

Over a period of half a decade, the "perceived" stress of students in the four semesters of the preclinical period was stabilised at an optimum level. At the same time, the students' satisfaction with organisation of curriculum increased and their exam results improved significantly.

CONCLUSIONS

The parameter "perceived" stress has been conducive to developing the curriculum to such an extent that teaching in Lübeck has improved considerably. Simultaneously, new space for development has been created for both students and lecturers, which makes it possible to shape the academic aspect of medical studies in a more challenging manner.

HLA-A0201-positive, IL-7/B7.1-cotransfected allogeneic tumor cells as a vaccine in metastatic renal cell cancer—A clinical phase-I trial

3072

Background: Tumor vaccination remains a promising experimental approach in RCC. HLA-A0201-restricted T cell immunity against RCC is well established. RCC26 is an allogeneic HLA-A0201+ human RCC cell line, a T cell clone specifically recognising RCC26 and other RCC in the context of HLA-A0201 has previously been generated, the TCR of this T cell clone was characterised. Furthermore, IL-7/B7.1 cotransfected tumor cells are a potent vaccine in animal models. Methods: RCC26 was transfected with pKEx-IL-7-IR-B7 coding for human IL-7 and B7.1 (CD80). 10 HLA-A0201+ patients with metastatic RCC and disease progression under cytokine therapy were included. 10 vaccinations with 2.5–40x106 gene-modified irradiated tumor cells which had been produced under GMP conditions were performed s.c. over 22 weeks. Primary endpoints of the study were feasibility, safety and immunological response, secondary endpoint was clinical response. The protocol was approved by the ethics committee, all patients gave informed consent. Results: Gene-modified RCC26 cells produced IL-7 (3.4 ng/106 cells/24h), more than 90% of the cells were CD80+. Vaccination was feasible and safe with no severe toxicity. Local DTH-reactions were observed in 4 patients. Skin biopsies of the vaccination site showed lymphocytic infiltrates dominated by CD4+T cells. In 8 patients vaccination induced HLA- and /or antinuclear antibodies without clinical signs of autoimmunity. Analysis of the T cell response against RCC-associated antigens is under way. No partial or complete responses could be documented. However, 50% of the patients had stable disease with the longest TTP being 69 weeks. Mean TTP in our cohort was 25 weeks (range 4 to 69 weeks). Conclusion: Our results show that vaccination with an allogeneic gene-modified tumor cell line is feasible and safe. Stable disease lasting up to 69 weeks in a substantial proportion of patients suggests immunological activity of the vaccine. Vaccination of patients with a low tumor burden is a promising strategy for the future, i.e. after surgery or treatment with novel multi-kinase inhibitors.

No significant financial relationships to disclose.

CCL19 (ELC) as an adjuvant for DNA vaccination: induction of a TH1-type T-cell response and enhancement of antitumor immunity

Coexpression of tumor antigens together with immunomodulatory molecules is a strategy in DNA vaccination aiming at an amplification of the antitumor immune response. Epstein-Barr virus-induced-molecule-1-ligand-chemokine (ELC/CCL19) is a CC chemokine that binds to the chemokine receptor CCR7. CCR7 is expressed on mature dendritic cells (DC) and distinct T- and B-cell subpopulations. CCL19 (ELC) is mainly expressed in secondary lymphoid organs and plays a central role in regulating the encounters between DC and T cells. We asked whether CCL19 is able to augment immunogenicity of a DNA vaccine in a C57BL/6 mouse model with syngeneic MCA205 (beta-gal) tumor cells. Mice were vaccinated twice intramuscularly on days 1 and 15 and tumor challenge was performed subcutaneously on day 25. Coadministration of plasmid DNA (pDNA) (beta-gal) plus pDNA (CCL19) was compared with pDNA (beta-gal), pDNA (CCL19), mock vector and phosphate-buffered saline (PBS) alone. Coexpression of CCL19 resulted in enhancement of a Th1-polarized immune response with substantial improvement of the protective effect of the DNA vaccine. Immunohistochemical staining revealed an increased CD8+ T-cell infiltration in the tumor tissue of mice that had been immunized with pDNA (beta-gal) plus pDNA (CCL19). We conclude that CCL19 is an attractive adjuvant for DNA vaccination able to augment antitumor immunity and that this effect is partially caused by enhanced CD8+ T-cell recruitment.

Flt-3 ligand as adjuvant for DNA vaccination augments immune responses but does not skew TH1/TH2 polarization

Since transfection of dendritic cells (DC) plays a key role in DNA vaccination, in vivo expansion of DC might be a tool to increase vaccine efficacy. We asked whether Fms-like tyrosine kinase-3 ligand (Flt-3L), a growth factor for DC, can be used as an adjuvant for DNA vaccination. Beta-galactosidase (beta-gal) was used as a model antigen in C57BL/6 mice. Mice were immunized i.m. with DNA coding for beta-gal with or without additional injection of Flt-3L. In both cases, antigen-specific CD4+ and CD8+ T cells were detectable after vaccination. Compared with DNA alone, additional administration of Flt-3L led to a significant increase in the antigen-specific proliferative response. However, increased cytotoxicity by T cells was not observed. The cytokines secreted by splenocytes of immunized mice upon in vitro stimulation with antigen had a TH2 profile. Humoral responses against beta-gal preferentially consisted of IgG1 antibodies. Analysis of DC from Flt-3L-treated mice revealed an immature phenotype with low or absent expression levels of CD80, CD86 and CD40. We conclude that Flt-3L does not generally skew immune responses towards a TH1 type. More likely, factors determined by the antigen and/or the vaccination procedure itself are crucial for the resulting type of immune response. Flt-3L - under circumstances such as the one we have investigated - can also lead to suppression of TH1 T cell immunity, possibly by expansion of immature/unactivated DC.

Tumor necrosis factor-alpha regulates the expression of inducible costimulator receptor ligand on CD34(+) progenitor cells during differentiation into antigen presenting cells

The inducible costimulator receptor (ICOS) is a third member of the CD28 receptor family that regulates T cell activation and function. ICOS binds to a newly identified ligand on antigen presenting cells different from the CD152 ligands CD80 and CD86. We used soluble ICOSIg and a newly developed murine anti-human ICOS ligand (ICOSL) monoclonal antibody to further characterize the ICOSL during ontogeny of antigen presenting cells. In a previous study, we found that ICOSL is expressed on monocytes, dendritic cells, and B cells. To define when ICOSL is first expressed on myeloid antigen presenting cells, we examined ICOSL expression on CD34(+) cells in bone marrow. We found that CD34(bright) cells regardless of their myeloid commitment were ICOSL(-), whereas ICOSL was first expressed when CD34 expression diminished and the myeloid marker CD33 appeared. However, acute myeloid leukemia cells were ICOSL-negative, whereas among B-cell malignancies only some cases of the most mature tumors such as prolymphocytic leukemia and hairy cell leukemia were positive. Next, we investigated purified CD34(+) hematopoietic progenitor cells that did not constitutively express ICOSL but were induced to express ICOSL within 12 h after granulocyte/macrophage colony-stimulating factor/tumor necrosis factor alpha (TNF-alpha) stimulation. Interestingly, ICOSL was induced prior to CD80/CD86 induction on CD34(+) cells so that ICOSL was expressed in the absence of CD80/CD86. This suggests that ICOSL is an early differentiation marker along the monocytic/dendritic maturation pathway. Induction of ICOSL was dependent on TNF-alpha and was regulated via NF-kappa B as revealed by use of inhibitors specific for I kappa B alpha phosphorylation such as BAY 11-7082 and BAY 11-7085. The antigen presenting capacity of TNF-alpha stimulated CD34(+) cells was strongly inhibited by ICOSIg fusion proteins or by NF-kappa B inhibition. Thus, TNF-alpha-induced ICOSL expression seemed to be functionally important for the costimulatory capacity of CD34(+) hematopoietic progenitor cells.

Conditioning in the rat: an in vivo model to investigate the molecular mechanisms and clinical implications of brain-immune communication

A wealth of in vitro and ex vivo evidence has described both close anatomical interaction and functional bi-directional communication between the immune and central nervous systems (CNS). These data have provided a framework for understanding the physiological mechanisms whereby behavioural factors may impact immune-related disease. An understanding of this interaction, however, as well as verification of the biological relevance of communication among these systems, requires in vivo animal modelling. The development of psychoneuroimmunological models in the laboratory rat has played a key role in advancing the understanding of the influence of behaviour on immune status. One such paradigm is the behavioural conditioning of immune function in the rat. This elegant model is characterised by the ability to examine simultaneously both afferent and efferent brain-immune communication. Specifically, the role of peripheral cytokines in signalling the brain, as well as their anatomical and cellular targets in the CNS, can be identified. On the other hand, the neural and humoral pathways whereby the CNS influences the function and distribution of peripheral immunocytes can be demonstrated, together with the target hormone receptors on immunocompetent cells. Finally, the in vivo biological relevance of brain-immune communication is revealed by behavioural conditioning, demonstrating that clinically relevant conditions such as heart allograft survival can be modified by behavioural processes. Behavioural conditioning thereby provides an excellent example of the utility of in vivo laboratory rat models in psychoneuroimmunology research. Such paradigms not only provide a more complete knowledge of CNS-immune system interaction, but are the platform for determining potential clinical application of this information.

Migration of naive, effector and memory T cells: implications for the regulation of immune responses

T cells play an important role in protective immune responses and in the pathogenesis of many diseases. Understanding the mechanisms regulating their distribution in vivo may therefore be of therapeutic value. Reviewing studies that have followed the migration of labelled naive, effector and memory T cells in healthy animals reveals that all T-cell subsets enter all organs investigated. Within the tissue, two principally different migration patterns can be identified. First, naive and memory T cells accumulate in lymphoid organs for about 48 h after injection, as the time needed for migration through lymphoid organs is longer than through non-lymphoid organs. During this time, surface molecule expression is temporarily modified. These changes are reversed before leaving the lymphoid organs and entering the blood to start a new cycle of migration. Second, effector T cells are evenly distributed throughout the body, and most die in the tissues within 24 h. However, depending on the presence of cytokines, some are able to survive and to proliferate, and thereby accumulate in defined microenvironments of the body. Analysing the principles regulating T-cell migration and survival within the tissue may lead to the development of new options for the treatment of disease.

Proliferating macrophages, dendritic cells, natural killer cells, T and B lymphocytes in the middle ear and Eustachian tube mucosa during experimental acute otitis media in the rat

Although many studies focus on the increase of immunocompetent cells within the middle ear mucosa during acute otitis media it is poorly understood how this increase is mediated. The differentiation between two possible causes, i.e. immigration and local proliferation, would help to better understand the pathophysiology of this disease. Therefore, the number of proliferating macrophages, dendritic cells, natural killer cells and T and B lymphocytes was studied during acute otitis media in the rat middle ear mucosa (ME mucosa) and Eustachian tube mucosa (ET mucosa) by labelling proliferating leucocytes with the DNA precursor bromodeoxyuridine (BrdU). By removing the middle ear and Eustachian tube 24 h after BrdU injection, the contribution of immigrated newly formed cells was estimated. At this timepoint, many leucocytes in the ME and ET mucosa had incorporated BrdU (between 15 and 25% within the subsets). By analysing these tissues one hour after BrdU injection, the local proliferation rate was determined (between 2 and 9% within the subsets). Thus, the inflamed ME and ET mucosa are the destination of immunocompetent cells and, as our data show, the inflamed microenvironment supports local proliferation of immunocompetent cells.

Splenectomy of rats selectively reduces lymphocyte function-associated antigen 1 and intercellular adhesion molecule 1 expression on B-cell subsets in blood and lymph nodes

Splenectomy increases the number of B cells in the blood of humans and animals. It is unknown whether this is due to changes in migration, proliferation, or both. The numbers of naïve (IgD(+)IgM(+)), memory (IgD(-)IgM(high)), newly formed (IgM(high)CD90(high)), early recirculating follicular (IgM(low)CD90(high)), recirculating follicular (IgM(low)CD90(-)), and marginal zone (IgM(high)CD90(-)) phenotype B cells were determined in control and splenectomized rats by flow cytometry. All subsets increased significantly in the blood after splenectomy. Because surface molecules are involved in the regulation of migration and proliferation, their expression (lymphocyte function-associated antigen 1 [LFA-1], intercellular adhesion molecule 1 (ICAM-1), L-selectin, alpha4-integrins, CD44, major histocompatability complex class II, interleukin 2 receptor-alpha chain) was determined on B- and T-cell subsets of both groups. B cells, but not T cells, showed a significantly reduced LFA-1 and ICAM-1 expression in blood and lymph nodes, whereas the expression of the other surface molecules analyzed remained unchanged. The down-regulation of these molecules did not influence the adherence of B cells to high endothelial venules in vitro. In vivo, however, ICAM-1(low)-expressing B cells migrated significantly faster through lymph nodes (ICAM-1(low) 41 +/- 5 hours versus ICAM-1(high) 58 +/- 3 hours), whereas proliferation of B cells in bone marrow, lymph node, and blood remained unchanged. Thus, the presence of one organ is necessary for appropriate expression of LFA-1 and ICAM-1 on B cells in other, distant organs. The more rapid transit of ICAM-1(low) B cells through lymph nodes may be responsible for the increased B-cell number in the blood after splenectomy.

Prolonged alpha-adrenergic stimulation causes changes in leukocyte distribution and lymphocyte apoptosis in the rat

We have previously shown in the rat model that acutely or chronically increased peripheral catecholamines lead to suppression of lymphocyte responsiveness via alpha(2)-adrenoceptor activation. Here we investigated the effects of alpha-adrenergic treatment on total leukocyte numbers and proportions of leukocyte subsets in peripheral blood and lymphoid tissues. It was found that a 12-h treatment with subcutaneously implanted tablets, one containing norepinephrine (NE) and one propranolol, leads to an increase in total blood leukocyte counts, due to a pronounced increase in granulocytes. In contrast, the numbers of all classes of lymphocytes other than NK cells were decreased. This decrease in blood lymphocytes is apparently not due to redistribution, since in the thymus, spleen, mesenteric and peripheral lymph nodes, the total numbers of lymphocytes were decreased as well, without any changes in subpopulations. Analogous results were obtained with rats adrenalectomized before the catecholamine treatment. Animals that received the alpha-adrenergic treatment displayed significantly more apoptotic cells in the lymphoid organs, as determined by the TUNEL technique. In the spleen, the enhanced rate of apoptosis was confined to the white pulp; red pulp areas exhibited significantly fewer apoptotic cells. Thus, an increased alpha-adrenergic tone in rats led to a general loss of lymphocytes due to lymphocyte directed apoptosis that was independent of glucocorticoids.

Acute laryngotracheitis in the rat induced by Sendai virus: the influx of six different types of immunocompetent cells into the laryngeal mucosa differs strongly between the subglottic and the glottic compartment

OBJECTIVES

Acute laryngotracheitis is a disease in which mainly the subglottic area is infected, whereas adjacent parts of the larynx, especially the narrow glottic fold, remain unaffected. The reason for the difference between these two directly adjacent regions is unknown. Therefore, in the present study the influx of dendritic cells, neutrophils, T and B lymphocytes, natural killer cells, and macrophages into the mucosa of different laryngeal compartments was investigated after Sendai virus infection in the rat. The aims were to study both the influx of immunocompetent cells and the adhesion of the pathogen and to correlate them to the different reactions of the laryngeal areas during pseudocroup.

METHODS

Acute laryngotracheitis was induced by intranasal application of Sendai virus in brown Norway rats. This virus is exclusively pneumotropic in rodents and belongs to the parainfluenza virus type 1, the main pathogen of acute laryngotracheitis in children. The numbers of dendritic cells, neutrophils, T and B lymphocytes, natural killer cells, and macrophages were determined in the supraglottic, glottic, subglottic, and tracheal mucosa on days 2, 5, 7, and 14 after virus application. Furthermore, the nucleoprotein of the virus and major histocompatibility complex (MHC) Class II expression were detected immunohistologically on the laryngeal epithelium.

RESULTS

All cell subsets entered the laryngeal mucosa during inflammation. The highest influx was detected among dendritic cells subglottically. This was accompanied by a strong virus adhesion and MHC Class II expression on the subglottic epithelium. In contrast, only a few immunocompetent cells entered the adjacent glottic mucosa, and on the glottic epithelium staining for virus nucleoprotein and MHC Class II expression was weak.

CONCLUSIONS

The inflammatory response of the laryngeal mucosa shows great regional differences in this animal model during experimental viral infection. The response was characterized by a strong subglottic and a weak glottic reaction. A possible reason for this difference might be region-specific viral adhesion on the epithelium of the laryngeal areas, as well as differences in MHC Class II expression. Thus, these data agree with the clinical observation during acute laryngotracheitis and may explain why the subglottic part of the larynx is affected preferentially during pseudocroup. The molecular mechanisms mediating the different reactions await clarification.

Migration of T cells in vivo: molecular mechanisms and clinical implications

T cells play an important role in the pathogenesis of chronic and autoimmune inflammatory diseases. They are found in high numbers in involved tissues, such as the lamina propria of the gut in patients with Crohn disease. Modifying T-cell number and function may therefore be of therapeutic value. In principle, two mechanisms may be responsible for the development of such T-cell infiltrates: 1) an increased rate of T-cell immigration into involved tissues or 2) an increased proliferation rate, decreased T-cell death (apoptosis) rate, and prolonged retention of T cells already in the tissue. Based on the theory that T cells selectively target affected tissues through organ-specific adhesion-molecule pathways, current anti-adhesion-molecule therapy aims to interfere selectively with T-cell entry to stop tissue damage. However, the traffic of labeled T cells in unmanipulated animals shows that the entry of T-cell subsets into tissues is not organ-specific, even under conditions of differing adhesion molecule and chemokine receptor expression. In contrast, within various tissues, both movement and survival of T-cell subsets differ considerably. These observations suggest that the differential expression of adhesion molecules and chemokine receptors on T cells serves at least two functions in vivo. First, during migration of T cells out of the bloodstream, the different adhesion-molecule pathways provide redundancy, which guarantees that T-cell subsets are able to enter the different tissues in sufficient numbers (security). Second, adhesion molecules and chemokine receptors mediate T-cell interactions within the tissue that are characteristic for each subset and each microenvironment and determine the nature of the ensuing immune response (selectivity). Shifting the focus of anti-adhesion-molecule therapy toward the T cells in diseased tissue may lead to new treatment options.

Rapid exchange of large numbers of donor- and host leukocytes after human liver transplantation

After liver transplantation, the release of donor leukocytes into the host and the uptake of host leukocytes by the graft is one of the earliest immunologic interactions between donor and host. Using three-color flow cytometry, these interactions were investigated in eight patients from 5 min-24 h after receiving HLA unmatched liver grafts. Five minutes after reperfusion, 5.0 % +/- 1.4 % of all blood leukocytes in the host were of donor origin, decreasing to 1.1 % +/- 0.8 % after 24 h. Donor granulocytes preferentially disappeared from the host circulation, whereas no differences were found between NK-cells and various B- and T cell subpopulations. Furthermore, host granulocytes were preferentially retained in the donor liver. Thus, despite extensive pre-operative perfusion, more than 10(9) donor leukocytes quickly leave the liver graft while host granulocytes preferentially accumulate there. A better understanding of the molecular mechanisms mediating these early interactions might help to develop new strategies for diagnosis and therapy of liver graft rejection.

Gut-derived effector T cells circulating in the blood of the rat: preferential re-distribution by TGFbeta-1 and IL-4 maintained proliferation

Effector T cells generated in mesenteric lymph nodes (mLN) preferentially accumulate in mLN and sites drained by them, such as Peyer's patches and the lamina propria of the gut, after circulation in the blood. The molecular mechanisms mediating this re-distribution are poorly understood. To study this, rat T cells from mLN were activated via the T cell receptor and CD28, and injected either intravenously into congenic recipients, or maintained in culture in the presence of various cytokines. Three days later effector T cells were identified in vivo and in vitro, and surface molecule expression and proliferation rate was determined. The data show that in vivo effector mLN T cells express significantly higher levels of activation markers and maintain a higher proliferation rate after entering the mLN environment (tissue of origin) than after entering the peripheral LN environment (unrelated site). The proliferation is mediated by TGFbeta-1 and IL-4 present in mLN. The requirement for these cytokines is imprinted on effector mLN T cells during the initial activation. Thus, the preferential proliferation of effector mLN T cells in milieus providing the cytokine mixture experienced during activation ensures a privileged accumulation at sites where they are most needed. This can be used to manipulate the effector phase of an immune response.

Naive and memory T cells migrate in comparable numbers through the normal rat lung: only effector T cells accumulate and proliferate in the lamina propria of the bronchi

T cells reach the lung via the pulmonary and bronchial arteries that supply the alveolar and bronchial regions. Although these regions are differentially affected by T cell-mediated diseases, the migration of T-cell subsets in these two regions has not been studied. Naive, memory, and effector T cells were injected into congenic rats and traced in sections of normal lung. All three T-cell subsets were found in large numbers in the alveolar region and exited again quickly. Only effector T cells accumulated in the lamina propria of the bronchi. Further, 72 h after injection 6% of the effector T cells still proliferated in the lung, whereas apoptotic effector T cells were only observed 1 h after injection (0.2%). Thus, not only effector and memory but also naive T cells continuously migrated through the lung. The preferential accumulation of effector T cells in the bronchial lamina propria may explain why some diseases preferentially affect the bronchial region.

Recent thymic emigrants (CD4+) continuously migrate through lymphoid organs: within the tissue they alter surface molecule expression

T-cell progenitors migrate from bone marrow (BM) into the thymus. After maturation they are released as recent thymic emigrants (RTE) into the periphery ensuring the diversification of the T-cell repertoire. Both the kinetics with which RTE migrate through the periphery and the surface molecules they express are still unclear. In 1- and 18-month-old Lewis rats CD4+ RTE were identified in blood, spleen, lymph node, and thoracic duct lymph by flow cytometry (CD45RC- and CD90+), were differentiated from CD4+ naive (CD45RC+) and memory T cells (CD45RC-CD90-), and were characterized regarding the expression of surface molecules. Both in 1- and 18-month-old animals the percentage of RTE among the CD4+ population in blood was comparable to that in all other compartments. Surprisingly, RTE expressed alpha4-integrin, LFA-1, and interleukin (IL)-2 receptor at a significantly higher level than naive T cells and more comparable to memory T cells. Within lymphoid tissues RTE, naive, and memory T cells significantly upregulated the expression of CD44 and ICAM-1, and downregulated the expression of L-selectin. These changes were reversed before the cells re-entered the blood. Thus, our data indicate that CD4+ RTE travel through the periphery of young and old rats like mature T cells, continuously modulating their surface molecule expression.

The dialogue between the brain and immune system involves not only the HPA-axis

Starting out from our previous observations that defects in the immune system-brain feedback predispose to pathogenic immune responses, our interest focuses at the roles of adrenergic/cholinergic neurotransmitters in brain-immune interactions. We have shown in rodent models that 1) both catecholamines and acetylcholine are potent modulators of peripheral immune functions, 2) cholinergic signals are involved in the afferent signalling of the immune system, and 3) lymphocytes not only express functional adrenergic and cholinergic receptors, but synthesize and release neurotransmitters, such as acetylcholine, in quantitative dependence of differentiation and activation. Studies are presently being initiated to investigate the role(s) of these non-neuronal neurotransmitters within immune tissues, and to explore the relevance of excitatory amino acids as important central neurotransmitters in the brain-immune system dialogue.

In vivo immunomodulation by peripheral adrenergic and cholinergic agonists/antagonists in rat and mouse models

Our work is devoted to defining relationships between the immune system and the adrenergic and cholinergic systems in vivo. In the rat model, we have shown that the cells of different immune compartments express the genes of a defined set of adrenergic/cholinergic receptors, and it was shown that lymphocytes are a site of non-neuronal production of norepinephrine and acetylcholine. Furthermore, using implantable slow-release tablets containing adrenergic or cholinergic agonists/antagonists, distinct and partly opposite effects were observed on peripheral immune functions. Concerning sympathetic immunoregulation, our data--in contrast to those of other studies--suggest that an enhanced adrenergic tonus leads to immunosuppression primarily via alpha 2-receptor-mediated mechanisms. Beta-blockade strongly enhances this effect, most likely by inhibition of pineal melatonin synthesis. In recent experiments on the kinetics it was found that the continuous alpha-adrenergic treatment entails a strong suppression of cellular responsiveness during the first few hours, which is increasingly followed by a general loss of lymphocytes in blood and lymphoid organs most likely due to enhanced apoptosis. More recently, we have extended our studies to the mouse model. First data obtained with RNAse protection assays suggest a biphasic effect on the gene expression of several cytokines in spleen cells due to adrenergic in vivo treatment.

Role of T lymphocytes in rat 2,4,6-trinitrobenzene sulphonic acid (TNBS) induced colitis: increased mortality after gammadelta T cell depletion and no effect of alphabeta T cell depletion

BACKGROUND AND AIM

Indirect evidence suggests that CD4+ T cells have a pathogenic while gammadelta T cells have a protective role in the initiation and perpetuation of inflammatory bowel disease. To define the role of T cell subsets in a rat colitis model (2,4,6-trinitrobenzene sulphonic acid (TNBS)) we analysed colitis severity after effective depletion of T helper cells, alphabeta T cells, or gammadelta T cells.

METHODS

T helper cells, alphabeta T cells, or gammadelta T cells were depleted using previously described monoclonal antibodies directed at the CD4 molecule (OX38), the CD2 molecule (OX34, both depleting CD4+ T cells), the alphabeta T cell receptor (R73), and the gammadelta T cell receptor (V65). Depletion was verified by flow cytometry and/or immunohistology. Colitis was induced using intracolonic application of TNBS.

RESULTS

Surprisingly, depletion of T helper cells or alphabeta T cells had no influence on survival, macroscopic or microscopic scores, or myeloperoxidase activity following colitis induction. In contrast, depletion of gammadelta T cells resulted in significantly increased mortality (V65: 73%, n=15) compared with controls (30%, n=13; p<0.03). In addition, colitis was histologically more severe in the gammadelta T cell depleted group compared with controls (p<0.05).

CONCLUSIONS

T helper cells or alphabeta T cells did not influence the initiation or perpetuation of rat TNBS colitis. In contrast, gammadelta T cells had a protective role in rat TNBS colitis as depletion caused increased mortality.

Granulocyte/macrophage-colony-stimulating-factor plus interleukin-2 plus interferon alpha in the treatment of metastatic renal cell carcinoma: a pilot study

Granulocyte/macrophage-colony-stimulating factor (GM-CSF) plays a central role in the differentiation and function of dendritic cells, which are crucial for the elicitation of MHC-restricted T cell responses. Preclinical and the first clinical data provide a rationale for the application of GM-CSF in immunotherapy of cancer. Ten patients with renal cell carcinoma stage IV (Holland/ Robson) were treated in this pilot study. Therapy was started with GM-CSF alone (2 weeks). Interleukin (IL-2) and interferon alpha (IFNalpha) were added sequentially (3 weeks GM-CSF plus IL-2 or IFNalpha, 3 weeks GM-CSF plus IL-2 plus IFNalpha). Therapy was performed on an outpatient basis. The cytokine regimen was evaluated for toxicity, clinical response and immunomodulatory effects [fluorescence-activated cell sorting analysis of peripheral blood mononuclear cells (PBMC), mixed-lymphocyte reaction and cytotoxicity of PBMC]. GM-CSF treatment caused a significant increase in the number of PBMC expressing costimulatory molecules. Addition of IL-2 and IFNalpha led to an increase in CD3 , CD4+, CD8+ and CD56+ PBMC in week 9. In an autologous mixed-lymphocyte reaction a 2.1-fold increase in T cell proliferation was observed after 2 weeks of GM-CSF treatment, and cytotoxicity assays showed changes in natural-killer-(NK)- and non-NK-mediated cytotoxicity in some patients. Two patients achieved partial remission, one patient had a mixed response. The toxicity of the regimen was mild to moderate with fever, flu-like symptoms and nausea being observed in most patients. Severe organ toxicity was not observed. We conclude that GM-CSF might be useful for immunotherapy of renal cell carcinoma, especially in combination with T-cell-active cytokines. Further studies are warranted.

Infection of human monocyte-derived macrophages with Chlamydia trachomatis induces apoptosis of T cells: a potential mechanism for persistent infection

Viruses can escape T-cell surveillance by infecting macrophages and thereby induce apoptosis of noninfected T cells. This ability had not been demonstrated for bacteria. We investigated whether infection of macrophages with the important human pathogen Chlamydia trachomatis can induce T-cell apoptosis. Because Chlamydia-Mycoplasma coinfection is a frequent event, the ability of Mycoplasma fermentans-infected macrophages to induce T-cell apoptosis was also studied. Infected macrophages were cocultivated with autologous T cells in different activation states. Propidium iodide-based fluorescence-activated cell sorter analysis demonstrated that macrophages infected with viable chlamydiae induced T-cell death. Apoptosis was identified as the mode of death induction by using a terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling assay. Induction of T-cell death was macrophage dependent. Incubation of T cells with infectious chlamydiae in the absence of macrophages did not lead to T-cell apoptosis. UV irradiation of chlamydiae diminished the ability to induce death. T-cell death was induced by a cell-free supernatant of infected macrophages. Not only phytohemagglutinin-preactivated T cells but also non-mitogen-preactivated T cells were susceptible to C. trachomatis-induced apoptosis. In contrast, M. fermentans infection of macrophages did not induce T-cell death. Coinfection had no additional effect. In summary, intracellular chlamydial infection of macrophages can induce T-cell apoptosis. Apoptosis induction by chlamydiae possibly explains how persistently infected macrophages escape T-cell surveillance and why the Chlamydia-specific T-cell response is diminished during persistent chlamydial infection.

Conditioned suppression of contact sensitivity is independent of sympathetic splenic innervation

The present study investigated the role of sympathetic innervation of the spleen in conditioned suppression of a contact hypersensitivity (CHS) reaction. Behavioral conditioning was achieved by pairing saccharin drinking solution (conditioned stimulus, CS) with injection of cyclosporin A (CsA, 20 mg/kg; unconditioned stimulus, UCS). Four days after sensitization of the animals by application of a 5% 2,4-dinitrochlorobenzene (DNCB) to abdominal skin, the animals were challenged by applying a 1% DNCB solution to the ear. The CHS response was monitored by measuring the degree of ear swelling. Saccharin re-presentation reduced ear swelling to a magnitude that approached that achieved by CsA treatment. Histological examination demonstrated that the conditioned reduction of ear swelling was produced by a reduced leukocyte infiltration of the ear. Prior sympathetic denervation of the spleen did not alter the conditioned suppression of the CHS response. These data indicate that behavioral conditioning using CsA produces alterations of CHS that, unlike conditioned prolongation of heart allograft survival, are independent of sympathetically regulated conditioned alterations in the spleen.

A targeted DNA vaccine encoding fas ligand defines its dual role in the regulation of experimental autoimmune encephalomyelitis

This study used naked DNA vaccination to induce breakdown of tolerance to self and thus elicit immunological memory to native, membrane-bound Fas ligand (FasL). Upon induction of experimental autoimmune encephalomyelitis (EAE), this memory was turned on to provide protective immunity. FasL-specific autoantibodies isolated from protected animals differentially downregulated the in vitro production of TNF-alpha, but not IFN-gamma, by cultured T cells. These autoantibodies were highly protective when they were administered to rats at the onset of EAE. In contrast, administration of these FasL-specific Ab's to EAE rats after the peak of the acute phase of disease prevented spontaneous recovery from disease. This extended illness is partially explained by inhibition of mononuclear cell apoptosis at the target organ, which resulted in increased accumulation of T cells and macrophages at the site of inflammation. Hence, FasL exerts two distinct, stage-specific regulatory functions in the control of this T-cell mediated autoimmune disease of the central nervous system.

Health status and health professional visits in a rural area

Visits to physicians (MDs), physician assistants (PAs) or nurse practitioners (NPs) by residents of a rural county in the upper-middle west of the United States were analysed in this study. A telephone survey yielded 250 responses. The dependent variable was the natural logarithm of the number of times the respondent had seen a health professional (MD, PA or NP) in the past two years. Predisposing, enabling and medical need variables were tested as potential predictors of visits. Self-rated health status, being unable to perform usual activities, and feeling upset or 'down in the dumps' proved to be important predictors, as was having a usual source of care. Health insurance coverage and family income was not, however. Unexpectedly, smokers also reported more visits. The implications for policy and future research are discussed.

Bcr/abl+ autologous dendritic cells for vaccination in chronic myeloid leukemia

In chronic myeloid leukemia (CML) ex vivo generated DC are characterized by constitutive expression of bcr/abl and possibly other yet undefined leukemia-associated antigens, since these DC share a common progeny with leukemic cells. Induction of anti-leukemic T cell responses has been described in vitro. For a phase I vaccination study, autologous bcr/abl+ DC are generated under GMP conditions mainly from monocyte precursors in chronic phase CML patients. Lin-, CD80+, CD86+, CD83+, DR+ DC could be generated in sufficient numbers for s.c. vaccination with 1 x 10(6)-5 x 10(7) DC. Using monocyte precursors, the yield of DC per seeded PBMC was in the range of 1-6%. Furthermore, we could demonstrate in vitro that the T cell stimulatory ability of CD34+-derived DC can be augmented by a factor 2-3 by retroviral transduction with a gene coding for interleukin-7. DC-based vaccination strategies are a promising clinical approach, particularly as postremission immunotherapy in the setting of autologous stem cell transplantation.

Evaluation of a new simple and rapid enzyme-linked immunosorbent assay kit for neopterin determination

A new commercially available enzyme-linked immunosorbent assay (ELISA) kit has been evaluated for the measurement of neopterin concentrations in serum, plasma and urine. This competitive ELISA is technically simple, requires only small sample volume and is rapid to perform. The assay procedure consists of sequential 1.5 h and 10 min room temperature incubation steps. The ELISA is accurate, sensitive, specific, and precise. Linear regression analysis of neopterin concentrations measured with the new ELISA and with an established method yielded a highly significant correlation (r = 0.99). The new assay is applicable to ELISA workstations, thus enabling determination of neopterin in large series of samples. The neopterin ELISA kit has been used in routine laboratory testing of blood donations in a blood bank.

The cardiac Fas (APO-1/CD95) Receptor/Fas ligand system : relation to diastolic wall stress in volume-overload hypertrophy in vivo and activation of the transcription factor AP-1 in cardiac myocytes

BACKGROUND

Fas (APO-1/CD95) is a transmembrane receptor belonging to the tumor necrosis factor receptor superfamily. Cross-linking of Fas by Fas ligand (FasL), a tumor necrosis factor-alpha-related cytokine, promotes apoptosis and/or transcription factor activation in a highly cell-type-specific manner. The biological consequences of Fas activation in cardiomyocytes and the regulation of Fas and FasL abundance in the myocardium in vivo remain largely unknown.

METHODS AND RESULTS

As shown by immunohistochemistry, Fas was expressed on the sarcolemma of cardiomyocytes in left ventricular tissue sections. Moreover, FasL was constitutively expressed in the myocardium and in isolated cardiomyocytes, as revealed by reverse transcription polymerase chain reaction and Western blotting. Left ventricular abundance of Fas but not FasL was upregulated in a rat model of compensated volume-overload hypertrophy and was closely related to diastolic but not systolic wall stress as determined by MRI. Cardiomyocyte apoptosis was not enhanced in volume-overload hypertrophy despite the increased expression of Fas and the presence of FasL in the myocardium. Moreover, injection of mice with an agonistic anti-Fas antibody promoted hepatocyte but not cardiomyocyte apoptosis in vivo. Stimulation of isolated cardiomyocytes with recombinant FasL promoted an activation of the transcription factor AP-1 as shown by electrophoretic mobility shift assays but did not induce cell death.

CONCLUSIONS

Fas and FasL are constitutively expressed in the myocardium and in cardiomyocytes. Myocardial expression of Fas is closely related to diastolic loading conditions in vivo. Signaling pathways emanating from Fas are coupled to an activation of the transcription factor AP-1 in cardiomyocytes.

Conditioned alterations of specific blood leukocyte subsets are reconditionable

Behavioral conditioning has the ability to produce changes in immune function. However, it is unknown whether conditioned changes of immune function can be recalled on multiple occasions. To address this issue we paired a novel saccharin drinking solution with intraperitoneal cyclosporin A (CsA) injection in rats. Saccharin re-presentation produced a reduction in splenocyte proliferation that mirrored the effect of CsA. Such functional changes were paralleled by a significant conditioned leukopenia in peripheral blood, which opposed the leukocytosis induced by CsA. Using the conditioned leukopenia in blood as a 'diagnostic window' of conditioned immunosuppression, the maintenance of CsA-induced changes was investigated by examining blood samples collected repeatedly. Experiments on the same group of animals over a period of 1 year showed that the conditioned leukopenia was reproducible on multiple occasions by reimplementing either the whole conditioning paradigm or reexposure to the saccharin solution only. These results demonstrate that behaviorally conditioned alterations of immune parameters are maintained in subsequent trials, indicating the potential clinical feasibility of behavioral conditioning procedures.

Acute laryngitis in the rat induced by Moraxella catarrhalis and Bordetella pertussis: number of neutrophils, dendritic cells, and T and B lymphocytes accumulating during infection in the laryngeal mucosa strongly differs in adjacent locations

Infectious laryngotracheitis results in fulminant respiratory distress. During the disease, the subglottic mucosa is selectively infected and swollen, the reason for this preference being unknown. Therefore, in the present study the immunoreaction of the laryngeal mucosa was studied in the rat after inhalation of either heat-killed Moraxella catarrhalis (PVG rats) or application of viable Bordetella pertussis (BN rats). The number of neutrophils, macrophages, dendritic cells, and T and B lymphocytes was determined in the mucosa of the supraglottic, glottic, and subglottic area of the larynx as well as in the trachea. After application of the pathogens, the mucosa of the subglottic area was significantly more affected than the glottic mucosa. Already 1 h after application of M. catarrhalis, not only neutrophils but also dendritic cells and T and B lymphocytes were found both subepithelially and within the epithelium. They showed a similar kinetic progression, although at a different level. Two hours after application of M. catarrhalis, at the peak of inflammation, dendritic cells (173 +/- 10 cells/0.1 mm2) outnumbered neutrophils (54 +/- 9 cells/0.1 mm2), T lymphocytes (25 +/- 2 cells/0.1 mm2), and B lymphocytes (4.3 cells/0.1 mm2). The subglottic area (and the trachea) contained about three to five times more cells than the glottic area. In contrast, the number of local macrophages was lower in the subglottic area (24 +/- 5 cells/0.1 mm2) compared with that of the glottic area (38 +/- 6 cells/0.1 mm2), and did not change after application of both M. catarrhalis and B. pertussis. Thus, infectious laryngotracheitis in the rat closely resembles the clinical picture in children. In addition, the present results show a major difference in cellular influx in the mucosa of the glottic and subglottic area. This demonstrates that even in two closely adjacent locations, inflammatory responses of different magnitudes can occur, and it underlines the importance of regulatory mechanisms specific for the respective microenvironment.