Number Of Lymphoid Cells Research Articles

Long-Term Reconstitution of Transduced Rhesus CD34+ Cells Mobilized by G-CSF and Plerixafor.

AbstractAbstract 1449Granulocyte colony-stimulating factor (G-CSF) in combination with plerixafor (AMD3100) produces significant mobilization of peripheral blood stem cells in the rhesus macaque model. The CD34+ cell population mobilized possesses a unique gene expression profile, suggesting a different proportion of progenitor/stem cells. To evaluate whether these CD34+ cells can stably reconstitute blood cells, we performed hematopoietic stem cell transplantation using G-CSF and plerixafor-mobilized rhesus CD34+ cells that were transduced with chimeric HIV1-based lentiviral vector including the SIV-capsid (χHIV vector). In our experiments, G-CSF and plerixafor mobilization (N=3) yielded a 2-fold higher CD34+ cell number, compared to that observed for G-CSF and stem cell factor (SCF) combination (N=5) (8.6 ± 1.8 × 107 vs. 3.6 ± 0.5 × 107, p<0.01). Transduction rates with χHIV vector, however, were 4-fold lower in G-CSF and plerixafor-mobilized CD34+ cells, compared to G-CSF and SCF (13 ± 4% vs. 57 ± 5%, p<0.01). CD123+ (IL3 receptor) rates were higher in CD34+ cells mobilized by G-CSF and plerixafor (16.4%) or plerixafor alone (21.3%), when compared to G-CSF alone (2.6%). To determine their repopulating ability, G-CSF and plerixafor-mobilized CD34+ cells were transduced with EGFP-expressing χHIV vector at MOI 50 and transplanted into lethally-irradiated rhesus macaques (N=3). Blood counts and transgene expression levels were followed for more than one year. Animals transplanted with G-CSF and plerixafor-mobilized cells showed engraftment of all lineages and earlier recovery of lymphocytes, compared to animals who received G-CSF and SCF-mobilized grafts (1200 ± 300/μl vs. 3300 ± 900/μl on day 30, p<0.05). One month after transplantation, there was a transient development of a skin rash, cold agglutinin reaction, and IgG and IgM type plasma paraproteins in one of the three animals transplanted with G-CSF and plerixafor cells. This animal had the most rapid lymphocyte recovery. These data suggested that G-CSF and plerixafor-mobilized CD34+ cells contained an increased amount of early lymphoid progenitor cells, compared to those arising from the G-CSF and SCF mobilization. One year after transplantation, transgene expression levels were 2–5% in the first animal, 2–5% in the second animal, and 5–10% in the third animal in all lineage cells. These data indicated G-CSF and plerixafor-mobilized CD34+ cells could stably reconstitute peripheral blood in the rhesus macaque. Next, we evaluated the correlation of transgene expression levels between in vitro bulk CD34+ cells and lymphocytes at one month, three months, and six months post-transplantation. At one and three months after transplantation, data from G-CSF and plerixafor mobilization showed higher ratio of %EGFP in lymphocytes to that of in vitro CD34+ cells when compared to that of G-CSF and SCF mobilization. At six months after transplantation the ratios were similar. These results again suggest that G-CSF and plerixafor-mobilized CD34+ cells might include a larger proportion of early lymphoid progenitor cells when compared to G-CSF and SCF mobilization. In summary, G-CSF and plerixafor mobilization increased CD34+ cell numbers. G-CSF and plerixafor-mobilized CD34+ cells contained an increased number of lymphoid progenitor cells and a hematopoietic stem cell population that was capable of reconstituting blood cells as demonstrated by earlier lymphoid recovery and stable multilineage transgene expression in vivo, respectively. Our findings should impact the development of new clinical mobilization protocols. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Monoclonal gammopathy without hyperglobulinemia in 2 dogs with IgA secretory neoplasms

Two dogs, an 8.5-year-old intact male Golden Retriever and a 10-year-old spayed female English Springer Spaniel, each with varied clinical histories, were referred to the Colorado State University Veterinary Teaching Hospital for evaluation of hypercalcemia and severe anemia, respectively. In each dog, serum total protein and globulin concentrations were within reference intervals. Cytologic examination of bone marrow aspirates from both dogs revealed moderate to marked numbers of atypical lymphoid cells with plasma cell features. Using serum immunofixation and serum immunoglobulin (Ig) quantification, a monoclonal Ig protein was identified. In conjunction with other clinicopathologic and molecular findings, IgA secretory neoplasms, B-cell lymphoma with plasmacytoid features and multiple myeloma (MM), were diagnosed. To our knowledge, these cases represent the first descriptions of IgA-secreting neoplasms in dogs that lacked hyperglobulinemia. In cases of suspected B-cell lymphoma or MM in dogs, serum proteins should be fully evaluated for the presence of a monoclonal Ig even in dogs that lack characteristic hyperproteinemia or hyperglobulinemia. This evaluation will aid in the diagnosis of secretory B-cell lymphoma or MM leading to appropriate clinical and therapeutic case management.

Thymus atrophy and regeneration following dexamethasone administration to beef cattle

Thymus atrophy and regeneration were studied in 13- to 22-month-old beef calves treated with dexamethasone (DMT), using anabolic dosages and implementing different withdrawal times. Two trials were conducted. In trial...

Long Term Survival of Primary Skeletal Muscle Lymphoma in a Miniature Dachshund

An 8-year-old miniature dachshund presented with a right femoral muscle mass and anorexia. Cytology of the mass revealed a number of small-sized lymphoid cells containing a pleomorphic-shaped dense nucleus and narrow pale cytoplasm. Histopathology indicated that neoplastic lymphoid cells proliferated in skeletal muscles and replaced the muscular architecture. Immunohistochemical and genetic examinations confirmed the diagnosis of primary skeletal muscle lymphoma classified as the pleomorphic small cell type and T-cell low-grade. Although the dog suffered at least three relapses by combination chemotherapy, the dog survived 713 days after the initial presentation.

Role of mTOR in Hematopoiesis and Hematopoietic Stem Cell Regulation.

Abstract 1490Poster Board I-513The mammalian target of rapamycin (mTOR) integrates nutrients, growth factors, and cellular energy status to control protein synthesis that determines cell growth and metabolism. It is also known that mTOR plays an essential role in cell survival by regulating Akt/PKB signaling. By using the inhibitor rapamycin, mTOR has previously been suggested to regulate proliferation of megakaryocyte progenitors and late stage of megakaryocyte differentiation without a general impact on normal hematopoiesis or hematopoietic stem cell (HSC) function. Due to limitations of rapamycin and the early lethality of conventional mTOR gene targeted mice, the physiological role of mTOR in blood development remains undefined. In this study, we have utilized an inducible conditional mTOR knockout mouse model by crossbreeding mTORflox/flox mice with Mx-Cre mice that allow interferon-induced mTOR deletion in the bone marrow following a transplantation and polyI:C induction protocol, in an effort to determine the genetic role of mTOR in hematopoiesis. Depletion of mTOR drastically affected hematopoiesis in a blood cell autonomous manner in Mx-Cre;mTORflox/flox bone marrow transplant recipients: the mice showed marked reduction in BM cellularity and in the numbers of myeloid and lymphoid lineage cells, erythrocytes, and platelets in peripheral blood, bone marrow, and thymus, leading to bone marrow failure, blood cell exhaustion and lethality. In vitro colony-forming activities by bone marrow or spleen progenitors were completely abolished in the absence of mTOR. Interestingly, the number and frequency of HSCs in bone marrow (Lin−Sca-1+c-Kit+) increased transiently while the number of early progenitors (CMP, GMP, MEP, CLP) detected by cell surface markers remained unchanged or only mildly affected in the mutant mice within 14 days after polyI:C treatment. Concomitantly, mTOR deletion led to a massive egress of HSCs from bone marrow to distal organs including spleen (∼60-fold increase). Transplantation of mTOR−/− bone marrow cells into NOD-SCID mice or competitive transplantation of mTOR−/− bone marrow cells into BoyJ mice further demonstrated that mTOR deficiency caused a complete failure in HSC engraftment and repopulation. Surprisingly, at the cellular level these phenotypes are associated with increased proliferation of HSCs in vivo and in vitro by 60% and 2.5-fold, respectively, as assessed by 5-bromodeoxyuridine incorporation assays whereas the cell survival index appears to be unaffected. Moreover, mTOR−/− HSCs and progenitor cells displayed impaired adhesion to fibronectin CH296 fragment (∼30% decrease) and migration toward SDF-1α gradients (∼30% decrease). At the molecular level, gene chip microarray analysis of mTOR−/− HSCs revealed that the cell cycle regulators myb, wee1, FANCD2, and FANCE were significantly downregulated while Rb and E2F5 were upregulated, the survival/apoptosis regulators MCL1 and BCL2L1 were upregulated, and the actin cytoskeleton and cell extracellular matrix adhesion regulators Arp2/3 complex subunit 5, paxillin, laminin α5, integrin β3, and myosin light chain 6B were upregulated. Further, immunoblotting analysis of isolated Lin− cells showed that SCF-stimulated activation of translational regulators S6K and 4E-BP and survival regulator Akt were abolished upon mTOR deletion. Taken together, these data suggest that mTOR is a critical regulator of HSC quiescence, self-renewal, and engraftment through the regulation of cell cycle, survival and actin cytoskeleton signals, and is essential in multiple stages of hematopoiesis. DisclosuresCancelas: CERUS CO: Research Funding; CARIDIAN BCT: Research Funding; HEMERUS INC: Research Funding.

Lymphoma‐Associated Polymyositis in Dogs

Lymphoma‐Associated Polymyositis in Dogs

Autoaspiration Versus Manual Aspiration in Transbronchial Needle Aspiration in Diagnosis of Intrathoracic Lymphadenopathy

Traditionally, aspiration with high negative pressure is recommended to obtain a specimen in transbronchial needle aspiration (TBNA). Undeniably, however, the assistant experiences difficulty in the generation of the negative pressure and precise control of the syringe while performing the procedure. To evaluate the effectiveness of the autoaspiration method created by our plunger lock in comparison with the conventional manual aspiration in the diagnosis of intrathoracic lymphadenopathy by TBNA. A prospective study was conducted on all patients referred for diagnostic TBNA of enlarged intrathoracic lymph nodes. Both automatic and manual aspiration techniques were performed after the needle had been completely inserted into the nodes. The diagnostic yield and the numbers of diagnostic cells or benign lymphoid cells obtained by each technique were compared in the same node. A total of 31 intrathoracic lymph nodes in 24 patients were prospectively studied. Twenty-four nodes (77.4%) were malignancies whereas 7 nodes (22.6%) were benign disease. Adequate lymph node samples were obtained in 30 targets (96.8%), and TBNA revealed definite diagnosis for 25 nodes (80.6%). Both aspiration techniques showed exactly the same diagnostic yield. However, the autoaspiration technique provided significantly more adequate samples than manual aspiration techniques did (P=0.003). The autoaspiration method using our plunger lock was superior to the manual method in obtaining the numbers of adequate samples in TBNA procedures.

Comparative studies on the secondary lymphoid tissue areas in the chicken bursa of Fabricius and calf ileal Peyer's patch

The chicken bursa of Fabricius and calf ileal Peyer's patch are thought to be the primary lymphoid organs of B cell development. In the bursa, the existence of secondary lymphoid tissue, called the diffusely infiltrated area, has been recognized. Recently, we have found the presence of a region of secondary lymphoid tissue in the ileal Peyer's patch at the period of the most rapid growth of this organ. In this study, we compared the development of these secondary lymphoid tissue regions in the bursa and ileal Peyer's patch histologically. Before hatching, lymphatic follicle formation occurred in the bursa, but not in the diffusely infiltrated area, where only a small number of lymphoid cells were found. However, during fetal calf development, lymphatic follicle formation occurred not only in the primary lymphoid organ but also in the secondary lymphoid tissue regions. Therefore, the prenatal development of the secondary lymphoid tissue regions of the bursa and ileal Peyer's patch were distinct. After hatching, formation of the germinal center, which contained many CD4 + cells, was observed in the diffusely infiltrated area of the bursa. After birth, many CD4 + cells and IgG mRNA expression were observed in the lymphatic follicle of the secondary lymphoid tissue regions in the ileal Peyer's patch, but rarely in the ileal Peyer's patch lymphatic follicles. The change of character of these secondary lymphoid tissue regions at the postnatal stage might be dependent on external antigens.

Differential Regional Immune Response in Chagas Disease

Following infection, lymphocytes expand exponentially and differentiate into effector cells to control infection and coordinate the multiple effector arms of the immune response. Soon after this expansion, the majority of antigen-specific lymphocytes die, thus keeping homeostasis, and a small pool of memory cells develops, providing long-term immunity to subsequent reinfection. The extent of infection and rate of pathogen clearance are thought to determine both the magnitude of cell expansion and the homeostatic contraction to a stable number of memory cells. This straight correlation between the kinetics of T cell response and the dynamics of lymphoid tissue cell numbers is a constant feature in acute infections yielded by pathogens that are cleared during the course of response. However, the regional dynamics of the immune response mounted against pathogens that are able to establish a persistent infection remain poorly understood. Herein we discuss the differential lymphocyte dynamics in distinct central and peripheral lymphoid organs following acute infection by Trypanosoma cruzi, the causative agent of Chagas disease. While the thymus and mesenteric lymph nodes undergo a severe atrophy with massive lymphocyte depletion, the spleen and subcutaneous lymph nodes expand due to T and B cell activation/proliferation. These events are regulated by cytokines, as well as parasite-derived moieties. In this regard, identifying the molecular mechanisms underlying regional lymphocyte dynamics secondary to T. cruzi infection may hopefully contribute to the design of novel immune intervention strategies to control pathology in this infection.

The significance of OX40 and OX40L to T‐cell biology and immune disease

OX40 (CD134) and its binding partner, OX40L (CD252), are members of the tumor necrosis factor receptor/tumor necrosis factor superfamily and are expressed on activated CD4(+) and CD8(+) T cells as well as on a number of other lymphoid and non-lymphoid cells. Costimulatory signals from OX40 to a conventional T cell promote division and survival, augmenting the clonal expansion of effector and memory populations as they are being generated to antigen. OX40 additionally suppresses the differentiation and activity of T-regulatory cells, further amplifying this process. OX40 and OX40L also regulate cytokine production from T cells, antigen-presenting cells, natural killer cells, and natural killer T cells, and modulate cytokine receptor signaling. In line with these important modulatory functions, OX40-OX40L interactions have been found to play a central role in the development of multiple inflammatory and autoimmune diseases, making them attractive candidates for intervention in the clinic. Conversely, stimulating OX40 has shown it to be a candidate for therapeutic immunization strategies for cancer and infectious disease. This review provides a broad overview of the biology of OX40 including the intracellular signals from OX40 that impact many aspects of immune function and have promoted OX40 as one of the most prominent costimulatory molecules known to control T cells.

Luteinizing Hormone-Releasing Hormone Enhances T Cell Recovery following Allogeneic Bone Marrow Transplantation

Posttransplant immunodeficiency, specifically a lack of T cell reconstitution, is a major complication of allogeneic bone marrow transplantation. This immunosuppression results in an increase in morbidity and mortality from infections and very likely contributes to relapse. In this study, we demonstrate that sex steroid ablation using leuprolide acetate, a luteinizing hormone-releasing hormone agonist (LHRHa), increases the number of lymphoid and myeloid progenitor cells in the bone marrow and developing thymocytes in the thymus. Although few differences are observed in the peripheral myeloid compartments, the enhanced thymic reconstitution following LHRHa treatment and allogeneic bone marrow transplantation leads to enhanced peripheral T cell recovery, predominantly in the naive T cell compartment. This results in an increase in T cell function in vivo and in vitro. Graft-versus-host-disease is not exacerbated by LHRHa treatment and graft-versus-tumor activity is maintained. Because LHRHa allows for reversible (and temporary) sex steroid ablation, has a strong safety profile, and has been clinically approved for diseases such as prostate and breast cancer, this drug treatment represents a novel therapeutic approach to reversal of thymic atrophy and enhancement of immunity following immunosuppression.

Proliferation of multiple sclerosis cerebrospinal fluid lymphocytes after stimulation with measles virus antigens.

A method for measuring the proliferative response of cerebrospinal fluid (CSF) lymphocytes upon stimulation and mitogens and viral antigens has been developed. The number of lymphoid cells in DNA synthesis after in vitro stimulation is counted and the results expressed as a percentage of the total number of surviving lymphocytes. Preliminary results on four MS patients indicated that their CSF lymphocytes responded considerably more strongly to purified measles virus antigen than did corresponding peripheral blood lymphocytes (PBL). The responses to crude herpes virus antigen were at least as strong in PBL as in CSF lymphocyte cultures from the same patients. The CSF lymphocytes responded slightly stronger to phytohemagglutinin than PBL did.

Comparative analysis of mononuclear cells isolated from mucosal lymphoid follicles of the human ileum and colon

Studies of human mucosal lymphoid follicles are rare and have been limited to children's Peyer's patches, which are visible at endoscopy. We investigated lymphoid follicles in ileum biopsies of 87 patients and surgical colon specimens from 66 cancer patients, and examined phenotype and function of isolated follicular immune cells. Two (0-10) and 12 (0-117) follicles per patient were found in ileum and colon samples respectively (P < 0.001). The number of lymphoid follicles mononuclear cells (LFMC) that could be isolated per patient was higher from colon compared with ileum specimens [725 000 (0-23 Mio) versus 100 000 (0-1.3 Mio), P < 0.001]. T cells were predominant in both LFMC and lamina propria mononuclear cells (LPMC), but B cells were more and plasma cells less frequent in LFMC. T cells from mucosal follicles were more frequently CD4-positive and CD62L-positive, but less frequently CD8-positive, CD103-positive and CD69-positive than lamina propria T cells. LFMC from ileum compared with colon showed no differences in mononuclear cell composition. Anti-CD3/CD28 stimulation induced similar proliferation of LFMC and LPMC from ileum and colon, as well as secretion of high levels of interferon-gamma, tumour necrosis factor-alpha and interleukin (IL)-2, but lower levels of IL-4, IL-6 and IL-10. LFMC from colon secreted more IL-2 than those from ileum. Our study shows that mucosal lymphoid follicles can be identified clearly in adult human colon and yield viable immune cells sufficient for phenotypical and functional analysis. The cellular composition of LFMC from ileum and colon is similar, and both secrete predominantly T helper type 1 cytokines.

Regulatory T cells contribute to the immunoregulatory effect on graft versus host reaction after liver transplantation in donor-dominant one-way MHC matching rats

Acute graft-versus-host disease following liver transplantation (LTx-aGVHD) poses a major diagnostic and therapeutic challenge, and the mortality rate is as high as 85%. Even the liver contains large numbers of lymphoid cells in the parenchyma and surgical damage of liver transplantation would induce an immunosuppressive, the incidence of LTx-aGVHD is just approximately 1–2%. CD4 +CD25 +regulatory T (Treg) cells have recently been shown to suppress proliferative responses of CD4 +CD25 −T cells to alloantigenic stimulation in vitro and are required for ex vivo tolerization of donor T cells, which results in their reduced potential to induce aGVHD after bone marrow transplantation. To investigate the role of Treg in LTx-aGVHD, we compared the proportional frequency of Treg in syngeneic liver transplantation recipients (sLT group), semiallogeneic liver transplantation recipients (Semi-LT group), LTx-aGVHD induced recipients (LTx-aGVHD group) and healthy controls. Here we show that replacement of (LewisXBN)F1 liver by Lewis liver alone in Semi-LT group was not sufficient to induce aGVHD, and all recipients grew in a normal pattern as the syngeneic LT from Lewis to Lewis rat. However, when 4 × 10 8 of donor splenocytes were transferred simultaneously with LT, the morbidity of lethal aGVHD were 100%. A relative stable percentage of Treg, defined as CD4, CD25 and Foxp3, was detected in peripheral blood mononuclear cells (PBMCs) of sLT group compared with healthy controls. In early time after transplantation, no significantly change of Treg population was observed in these recipients after semiallogeneic liver transplantation in comparison with healthy controls ( P > 0.05). However, Treg levels showed a relative increase 4 days after transplantation. Especially on 12th and 16th day after transplantation, there was significantly increased proportion of Treg cells compared with healthy controls ( P < 0.05). The present of Treg decreased progressively in LTx-aGVHD group, which was significantly lower than group 1 and group 2 on the 12th and 16th day after liver transplantation ( p < 0.05). In conclusion, recipients in semi-LT group harbor an increased percentage of Treg in peripheral blood compared with controls. Treg have an immunoregulatory effect on graft versus host reaction after liver transplantation. Additional donor splenocyte transplanted with the liver provoke the development of aGVHD after liver transplantation, and reversed the change of Treg in PBMCs as in Semi-LT group, which destroy the balance between Treg and conventional effector T cells which determine the outcome of aGVHD after liver transplantation.

Prevention of Autoimmunity and Control of Recall Response to Exogenous Antigen by Fas Death Receptor Ligand Expression on T Cells

Mice with mutations in the gene encoding Fas ligand (FasL) develop lymphoproliferation and systemic autoimmune diseases. However, the cellular subset responsible for the prevention of autoimmunity in FasL-deficient mice remains undetermined. Here, we show that mice with FasL loss on either B or T cells had identical life span as littermates, and both genotypes developed signs of autoimmunity. In addition, we show that T cell-dependent death was vital for the elimination of aberrant T cells and for controlling the numbers of B cells and dendritic cells that dampen autoimmune responses. Furthermore, we show that the loss of FasL on T cells affected the follicular dentritic cell network in the germinal centers, leading to an impaired recall response to exogenous antigen. These results disclose the distinct roles of cellular subsets in FasL-dependent control of autoimmunity and provide further insight into the role of FasL in humoral immunity.

Cytological assessment of conventional transbronchial fine needle aspiration of lymph nodes

Transbronchial fine needle aspiration (TBNA) is a minimally invasive bronchoscopic technique that allows pathological examination of mediastinal and hilar lymph nodes. The aim of this study was to assess the cytopathological outcome of TBNA. One hundred and eighty-seven patients who underwent TBNA of mediastinal and hilar lesions from May 2000 to June 2007 were reviewed. TBNA results were considered to be adequate if the cytological material revealed a malignant lesion or sufficient number of benign lymphoid cells. In the current study, 40 cases (21.9%) were reported as inadequate. When inadequate tests were excluded, the overall sensitivity and accuracy of TBNA in the diagnosis of malignant lesions were 83.5% and 88.0% respectively. The lowest sensitivity was noted in lymph node involvement by lymphoma. Regarding the workload associated with TBNA cytology, we found that the average number of conventionally prepared cytological slides per case was high (17 slides per case). Our results confirm that conventional TBNA is a sensitive and useful technique but it is relatively expensive and the protocols should be adapted to allow appropriate material to be collected for ancillary diagnostic tests.

In vivoboosting of lung natural killer and lymphokine-activated killer cell activity by interleukin-2: comparison of systemic, intrapleural and inhalation routes

Natural killer (NK) cells are thought to play a role in host defence against malignancy and infection, in immunoregulation and as precursor cells in a generation of lymphokine-activated killer (LAK) cells which can lyse NK-resistant tumour cells. As the lung is a major site for malignancy and infection and as there are large numbers of lymphoid cells including NK cells in the interstitial compartment of the lung, we evaluated the capacity of interleukin-2 (IL-2), a lymphokine capable of augmenting NK activity in vitro, to augment lung NK cell activity in vivo, using different routes of IL-2 administration. We compared both systemic (i.v. and i.p.) and local (intrapleural and inhalation) routes of IL-2 administration (50,000 U/daily for 5 days) using CBA mice, assessing NK and LAK cell activity in the spleen (systemic) and in the lung. The target cells used for these studies were the YAC-1 (NK-sensitive) and P815, NO36 and HA56 (NK-resistant, LAK-sensitive) cell lines. Splenic NK activity was increased by 1.4-1.9-fold for i.v./i.p., respectively, compared with controls with both systemic routes of administration, and lung NK activity was increased 3.2-fold and 3.8-fold (i.v./i.p, respectively, P less than 0.05), to levels which were comparable to systemic (splenic) NK activity following the same therapy. Intrapleural IL-2 administration similarly enhanced lung NK activity (3.3-fold) and splenic NK activity (1.3-fold; P less than 0.05 versus controls for both). Surprisingly, inhaled IL-2 suppressed both splenic and lung NK cell activity (84 +/- 8% and 78 +/- 10% suppression, respectively, P less than 0.05). LAK cell activity was also enhanced in the lung by 1.8-8-fold in response to i.v., i.p. and intrapleural IL-2, whereas inhaled IL-2 was ineffective in generating LAK cell activity. These results suggest that the systemic and intrapleural administration of IL-2 effectively boost pulmonary NK and LAK activity whereas inhalation of IL-2 does not. Thus, in clinical situations where boosting of local lung NK or LAK cell activity is desired, these routes of IL-2 administration may be effective.

Visceral Fat Accumulation Induced by a High‐fat Diet Causes the Atrophy of Mesenteric Lymph Nodes in Obese Mice

A high intake of fat in the diet plays a crucial role in promoting obesity and obesity-related pathologies, and especially visceral obesity is closely associated with obesity-related complications. Because adipose tissue is anatomically associated with lymph nodes, the secondary lymphoid organ, we hypothesized that fat tissue-derived factors may influence the cellularity of lymphoid tissue embedded in fat. Mesenteric and inguinal lymph nodes were isolated from obese mice fed a high-fat diet and control mice fed a regular diet. T-cell population, activation state, and the extent of apoptosis were determined by flow cytometric analysis or terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) assay. The weight of mesenteric lymph nodes and the total number of lymphoid cells in the obese mice significantly decreased compared with those in the control mice; however, no change was observed in the weight of inguinal lymph nodes. The numbers of CD4(+) and CD8(+) T cells in the mesenteric lymph nodes of obese mice significantly decreased compared with those of the control. Enhanced T-cell activation and apoptosis were observed in the mesenteric lymph node cells of the obese mice. The treatment of lymph node cells with free fatty acids, oxidative stress, and chylomicrons, which are obesity-related factors, resulted in lymph node T-cell activation and apoptosis. These results suggest that visceral fat accumulation with a high-fat diet can cause the atrophy of mesenteric lymph nodes by enhancing activation-induced lymphoid cell apoptosis. Dietary fat-induced visceral obesity may be crucial for obesity-related immune dysfunction.

Loss of tolerance in C57BL/6 mice to the autoantigen E2 subunit of pyruvate dehydrogenase by a xenobiotic with ensuing biliary ductular disease†

There have been important advances in defining effector mechanisms for several human autoimmune diseases. However, for most human autoimmune diseases, the induction stage is less well defined and there are very few clues on etiology. Our laboratory has focused on defining the molecular basis of autoantibody recognition and epitope modification in primary biliary cirrhosis (PBC). Our work has demonstrated that antibodies to mitochondria, the hallmark of disease, are directed against a very conserved site of pyruvate dehydrogenase, the E2 subunit of pyruvate dehydrogenase (PDC-E2). We have also demonstrated that several chemical xenobiotics, chosen based on quantitative structural activity relationship analysis and rigorous epitope analysis, when coupled to the lysine residue that normally binds the lipoic acid cofactor of PDC-E2, reacts as well or better to PBC sera than native autoantigen. In the present studies, we immunized C57BL/6 mice with one such xenobiotic, 2-octynoic acid, coupled to bovine serum albumin and we followed the mice for 24 weeks. Animals were studied for appearance of histologic lesions as well as appearance of antibodies to PDC-E2, serum levels of tumor necrosis factor-alpha and interferon-gamma, and splenic and liver lymphoid phenotyping by flow cytometry. Mice immunized with 2-octynoic acid manifest autoimmune cholangitis, typical mitochondrial autoantibodies, increased liver lymphoid cell numbers, an increase in CD8(+) liver infiltrating cells, particularly CD8(+) T cells that coexpress CD44, and finally an elevation of serum tumor necrosis factor-alpha and interferon-gamma. these data provide a persuasive argument in favor of an environmental origin for human PBC.

Non‐invasive imaging of adaptive immunity using positron emission tomography

Non-invasive monitoring of adaptive immunity in infection, cancer, and autoimmunity remains a major challenge. Current techniques to monitor lymphocytes involve numeric and functional determinations of immune cells isolated from the peripheral blood (most often) and tissue (rarely). Invasive measurements are prone to sampling errors and are poorly reflective of the dynamic changes in the location, number, and movement of lymphoid cells. These limitations indicate the need for non-invasive whole-body imaging methodologies that allow longitudinal, quantitative, and functional analyses of the immune system in vivo. Positron emission tomography (PET), a clinically based whole-body imaging modality, has the potential to revolutionize diagnostics and therapeutic monitoring in both clinical and pre-clinical settings. This review discusses studies using PET to image adaptive immune responses in small animal models. We address the challenges inherent in assessing whole-body immunity with PET and recent developments that can improve its performance. Finally, we discuss work to translate PET immune imaging into clinical practice.