Accumulation Of Lymphoid Cells Research Articles

Posttransplant Tertiary Lymphoid Organs.

Tertiary lymphoid organs (TLOs), also known as tertiary or ectopic lymphoid structures or tissues, are accumulations of lymphoid cells in sites other than canonical lymphoid organs, that arise through lymphoid neogenesis during chronic inflammation in autoimmunity, microbial infection, cancer, aging, and transplantation, the focus of this review. Lymph nodes and TLOs are compared regarding their cellular composition, organization, vascular components, and migratory signal regulation. These characteristics of posttransplant TLOs (PT-TLOs) are described with individual examples in a wide range of organs including heart, kidney, trachea, lung, artery, skin, leg, hand, and face, in many species including human, mouse, rat, and monkey. The requirements for induction and maintenance of TLOs include sustained exposure to autoantigens, alloantigens, tumor antigens, ischemic reperfusion, nephrotoxic agents, and aging. Several staging schemes have been put forth regarding their function in organ rejection. PT-TLOs most often are associated with organ rejection, but in some cases contribute to tolerance. The role of PT-TLOs in cancer is considered in the case of immunosuppression. Furthermore, TLOs can be associated with development of lymphomas. Challenges for PT-TLO research are considered regarding staging, imaging, and opportunities for their therapeutic manipulation to inhibit rejection and encourage tolerance.

Effect of chicken infectious bronchitis vaccine on morphogenesis and differentiation of cells in caecal tonsils

The study of the chickens’ immune system morphofunctional state allows assessing critical periods of their development and the body as a whole, as well as the effectiveness of vaccine prevention methods. The purpose of this study was to identify morphological and immunohistochemical changes in the caecal tonsils of chickens aged 8, 20, 40, 90, 110 days for vaccine prevention of infectious bronchitis. During the study, the following research methods were used: cytological, histological, immunohistochemical, morphometric, light-optical, statistical. Histological preparations of caecal tonsils of poultry aged 8, 20, 40, 90, 110 days of vaccinated and unvaccinated groups were analysed and studied. Up to 20 days of age, no lymphoid nodules were detected in the caecal tonsils of chickens, both vaccinated and non-vaccinated groups. Histological and morphometric studies were conducted, which showed that vaccination of poultry accelerates the development of lymphoid formations in the early stages of the postnatal period of ontogenesis, especially in chickens aged 20 days, which is manifested by an increase in the number and size of lymphoid nodules of caecal tonsils relative to the control group. Immunohistochemical studies have established that the placement and accumulation of T-lymphocytes with markers CD4+ , CD8+ , as well as B-lymphocytes (CD20+ ) and CD45RA+ cells in caecal tonsils, namely in lymphoid nodules and diffuse accumulation of lymphoid cells, depend on the age of chickens and multiplicity of vaccinations. It was proved that in chickens aged 8 days, the number of T-lymphocyte subpopulations with surface markers CD4+ , CD8+ prevailed over CD45RA+ and CD20+ . With the increase in the number of immunizations (after three-fold vaccination against infectious bronchitis of chickens), immunocytometric studies indicated that in vaccinated chickens aged 40 and 90 days, there was a clear increase in the number of mature B-lymphocytes by 1.58 and 1.37 times, respectively. Considering the fact that the number of CD8+ lymphocytes in vaccinated chickens aged 40 days was 1.49 times greater than the number of CD4+ cells, this led to a sharp decrease in the immunoregulatory index of the caecal tonsils, which must be factored in when carrying out preventive vaccinations

IL-18 and VEGF-A trigger type 2 innate lymphoid cell accumulation and pro-tumoral function in chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is a hematologic malignancy associated to an unregulated growth of myeloid cells in bone marrow (BM) and peripheral blood (PB), characterized by the BCR-ABL1 translocation. Given the known cytokine impairment in the leukemic niche of CML, we investigated the impact of this microenvironmental dysregulation on innate lymphoid cells (ILC), whose role in cancer has recently emerged. Three ILC subsets are identified based on transcriptional profiles and cytokine secretion. We observed that interleukin 18 (IL-18) and vascular endothelial growth factor A (VEGF-A) are increased in CML patients' sera and that ILC2 are enriched in CML PB and BM. We found that IL-18 drives ILC2 proliferation and that CML ILC2 highly express CXCR4 and CXCR7 BM-homing receptors, potentially explaining their enrichment in PB and BM, respectively. Next, we showed that ILC2 are hyper-activated through a tumor-derived VEGF-Adependent mechanism, which leads to higher IL-13 secretion. In response to IL-13, leukemic cells increase their clonogenic capacity. Finally, we discovered that the pro-tumoral axis involving VEGF-A, IL-18 and ILC2 was disrupted upon tyrosine kinase inhibitor treatment, normalizing the levels of all these players in CML patients responding to therapy. Overall, our study uncovers the involvement of ILC2 in CML progression, mediated by VEGF-A and IL-18.

Blockade of CD73 Increases the Cytotoxic Effects of Fludarabine in Chronic Lymphocytic Leukemia

Background: Ecto-5’-nucleotidase (CD73) is a membrane-bound enzyme that converts adenosine 5’-monophosphate into adenosine. It is proven that the presence of elevated levels of adenosine in the tumor microenvironment induces tumor growth while suppressing immune responses against tumor cells. According to several studies, it is reported that the expression of CD73 is increased in several types of malignancies. In chronic lymphocytic leukemia (CLL), a hematological malignancy characterized by the increased proliferation and accumulation of lymphoid cells in peripheral blood (PB) and lymphoid tissues, CD73 expression is associated with higher-risk disease. Moreover, it is reported that CD73 may contribute to fludarabine (a chemotherapeutic widely used for the treatment of CLL) resistance as well. Methods: We separated mononuclear cells obtained from PB and bone marrow (BM) from eleven CLL patients. Cells were treated individually or in combination with fludarabine and anti-CD73 siRNA (transfection by lipofectamine), and the effect of treatment on cell survival was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. Results: We found that the highest level of apoptosis induction was observed in cells treated with fludarabine combined with CD73 inhibition, compared to the untreated (P<0.01). Our findings are in support of a study reporting the association between CD73 overactivation and fludarabine resistance. Conclusion: These findings suggest that CD73 inhibition can be a potential target for CLL treatment and can help overcome endurance towards fludarabine and can better the prognosis of CLL-affected individuals.

Influence of PSG peptides on the morphofunctional state of the spleen in allogenous bone marrow cell transplantation

It is known that proteins associated with pregnancy provide immune tolerance during pregnancy. One of them is pregnancy-specific β1-glycoprotein (PSG), which has a pronounced immunomodulatory effect. Tetrapeptide fragments (YECE, YQCE, YVCS, and YACS) have been identified in the primary structure of PSG that have immunopharmacological potential. The aim of the study was to evaluate the effect of short peptide fragments of PSG on the morphological and immunohistochemical state of the spleen and its compartments during allogeneic transplantation of a suspension of red bone marrow cells in an in vivo experiment in Wistar rats. It was found that intraperitoneal injection of bone marrow cells in the dynamics of the experiment (35 days) caused splenic hyperplasia with accumulation of lymphoid cells and macrophages in the functional areas of the organ. Administration of short peptide fragments of PSG against the background of allogeneic bone marrow transplantation promotes activation of cells of the immune system in the spleen toward their proliferation (Ki-67) and differentiation, while reducing the content of macrophages (CD68). Thus, short peptide fragments of PSG stabilize proliferative processes and promote the development of adaptive responses in response to an allogeneic graft.

PI3K\u03b4 inhibition prevents IL33, ILC2s and inflammatory eosinophils in persistent airway inflammation

BackgroundPhosphoinositide-3-kinase-delta (PI3Kδ) inhibition is a promising therapeutic approach for inflammatory conditions due to its role in leucocyte proliferation, migration and activation. However, the effect of PI3Kδ inhibition on group 2 innate lymphoid cells (ILC2s) and inflammatory eosinophils remains unknown. Using a murine model exhibiting persistent airway inflammation we sought to understand the effect of PI3Kδ inhibition, montelukast and anti-IL5 antibody treatment on IL33 expression, group-2-innate lymphoid cells, inflammatory eosinophils, and goblet cell metaplasia.ResultsMice were sensitised to house dust mite and after allowing inflammation to resolve, were re-challenged with house dust mite to re-initiate airway inflammation. ILC2s were found to persist in the airways following house dust mite sensitisation and after re-challenge their numbers increased further along with accumulation of inflammatory eosinophils. In contrast to montelukast or anti-IL5 antibody treatment, PI3Kδ inhibition ablated IL33 expression and prevented group-2-innate lymphoid cell accumulation. Only PI3Kδ inhibition and IL5 neutralization reduced the infiltration of inflammatory eosinophils. Moreover, PI3Kδ inhibition reduced goblet cell metaplasia.ConclusionsHence, we show that PI3Kδ inhibition dampens allergic inflammatory responses by ablating key cell types and cytokines involved in T-helper-2-driven inflammatory responses.

HMGA1-pseudogene7 transgenic mice develop B cell lymphomas

We have recently identified and characterized two pseudogenes (HMGA1P6 and HMGA1P7) of the HMGA1 gene, which has a critical role in malignant cell transformation and cancer progression. HMGA1P6 and HMGAP17 act as microRNA decoy for HMGA1 and other cancer-related genes upregulating their protein levels. We have previously shown that they are upregulated in several human carcinomas, and their expression positively correlates with a poor prognosis and an advanced cancer stage. To evaluate in vivo oncogenic activity of HMGA1 pseudogenes, we have generated a HMGA1P7 transgenic mouse line overexpressing this pseudogene. By a mean age of 12 months, about 50% of the transgenic mice developed splenomegaly and accumulation of lymphoid cells in several body compartments. For these mice FACS and immunohistochemical analyses suggested the diagnosis of B-cell lymphoma that was further supported by clonality analyses and RNA expression profile of the pathological tissues of the HMGA1P7 transgenic tissues. Therefore, these results clearly demonstrate the oncogenic activity of HMGA1 pseudogenes in vivo.

Role of chemical composition and redox modification of poorly soluble nanomaterials on their ability to enhance allergic airway sensitisation in mice

BackgroundEngineered nanoparticles (NPs) have been shown to enhance allergic airways disease in mice. However, the influence of the different physicochemical properties of these particles on their adjuvant properties is largely unknown. Here we investigate the effects of chemical composition and redox activity of poorly soluble NPs on their adjuvant potency in a mouse model of airway hypersensitivity.ResultsNPs of roughly similar sizes with different chemical composition and redox activity, including CeO2, Zr-doped CeO2, Co3O4, Fe-doped Co3O4(using Fe2O3 or Fe3O4) and TiO2 NPs, all showed adjuvant activity. OVA induced immune responses following intranasal exposure of BALB/c mice to 0.02% OVA in combination with 200 μg NPs during sensitization (on day 1, 3, 6 and 8) and 0.5% OVA only during challenge (day 22, 23 and 24) were more pronounced compared to the same OVA treatment regime without NPs. Changes in OVA-specific IgE and IgG1 plasma levels, differential cell count and cytokines in bronchoalveolar lavage fluid (BALF), and histopathological detection of mucosa cell metaplasia and eosinophil density in the conducting airways were observed. Adjuvant activity of the CeO2 NPs was primarily mediated via the Th2 response, while that of the Co3O4 NPs was characterised by no or less marked increases in IgE plasma levels, BALF IL-4 and IL-5 concentrations and percentages of eosinophils in BALF and more pronounced increases in BALF IL-6 concentrations and percentages of lymphocytes in BALF. Co-exposure to Co3O4 NPs with OVA and subsequent OVA challenge also induced perivascular and peribronchiolar lymphoid cell accumulation and formation of ectopic lymphoid tissue in lungs. Responses to OVA combined with various NPs were not affected by the amount of doping or redox activity of the NPs.ConclusionsThe findings indicate that chemical composition of NPs influences both the relative potency of NPs to exacerbate allergic airway sensitization and the type of immune response. However, no relation between the acellular redox activity and the observed adjuvant activity of the different NPs was found. Further research is needed to pinpoint the precise physiological properties of NPs and biological mechanisms determining adjuvant activity in order to facilitate a safe-by-design approach to NP development.

Effects of caponisation and age on the histology of the internal organs of Leghorn cockerels

ABSTRACT1. Poultry researchers seek the most efficient bird line to produce capons (castrated cockerels). The previous studies did not include results from histopathological analyses of internal organs after caponisation. No data have been published on whether adipose tissue accumulates in internal organs or if caponisation changes the structure of the lymphoid organs and the accumulation of lymphoid cells.2. The aim of this study was to analyse the occurrence of histopathological lesions in internal organs from Leghorn (layer-type) capons and cockerels at different times of fattening.3. Two hundred, one-day-old Leghorn cockerels were used in this experiment. At 8 weeks of age, the birds were randomly divided into a control group (100 uncastrated cockerels) and a second group consisting of 100 castrated birds. At 12, 16, 20, 24 and 28 weeks of age, six cockerels and six capons were slaughtered. Samples of all internal organs from six cockerels and six capons at each slaughter age were evaluated.4. The main histopathological differences between capons and cockerels were related to the accumulation of adipose tissue, with higher values noted in capons, especially in the gizzard and the caecum submucosa and fatty degeneration in liver hepatocytes.5. Additionally, differences were observed more often in cockerels than in capons with regard to depletion of lymphoid cells in lymphoid organs, including the thymus and bursa of Fabricius in 28-week-old birds and the spleen in 24-week-old birds.6. These studies prove that caponisation causes the accumulation of fat in internal organs and changes the structure of lymphoid organs.7. Age influences the occurrence of desirable lesions, such as the accumulation of adipose tissue within the examined organs, and older capons (24 and 28 weeks old) are better sources of high quality, potentially edible tissues.

Tim-3/galectin-9 pathway and mMDSC control primary and secondary resistances to PD-1 blockade in lung cancer patients

ABSTRACTNivolumab, a monoclonal antibody targeting PD-1, is currently approved for metastatic non-small cell lung cancer (mNSCLC) treatment after failure of first-line chemotherapy. However, only a quarter of patients benefit from this therapy with objective clinical response. In this context, there is an unmet need for improved understanding of resistance mechanisms. Thus, we studied a prospective cohort of mNSCLC (n = 61) treated in second or third-line with nivolumab. We analyzed various blood myeloid and lymphoid markers by flow cytometry (176 variables) at baseline, and after 15 and 30 days of therapy. By attempting to link the evolution of peripheral lymphoid, myeloid cells and anti-PD-1 response, we observed that accumulation of lymphoid cells and monocytic MDSC (mMDSC) expressing, respectively, Tim-3 and galectin-9 is implicated in resistance to PD-1 blockade both for patients with primary or acquired secondary resistance to anti-PD-1. In vitro, anti-Tim-3 blocking antibody reverses resistance to anti-PD-1 in PBMC from lung cancer patients and high levels of blood mMDSC negatively impact on anti-PD-1 efficacy. Together, these data underline that the galectin-9/Tim-3 pathway and mMDSC are key mechanisms of primary or secondary resistance to anti-PD-1 and could be a new target for immunotherapy drug combinations.

Probing GATA factor function in mouse Leydig cells via testicular injection of adenoviral vectors.

Testicular Leydig cells produce androgens essential for proper male reproductive development and fertility. Here, we describe a new Leydig cell ablation model based on Cre/Lox recombination of mouse Gata4 and Gata6, two genes implicated in the transcriptional regulation of steroidogenesis. The testicular interstitium of adult Gata4flox/flox ; Gata6flox/flox mice was injected with adenoviral vectors encoding Cre + GFP (Ad-Cre-IRES-GFP) or GFP alone (Ad-GFP). The vectors efficiently and selectively transduced Leydig cells, as evidenced by GFP reporter expression. Three days after Ad-Cre-IRES-GFP injection, expression of androgen biosynthetic genes (Hsd3b1, Cyp17a1 and Hsd17b3) was reduced, whereas expression of another Leydig cell marker, Insl3, was unchanged. Six days after Ad-Cre-IRES-GFP treatment, the testicular interstitium was devoid of Leydig cells, and there was a concomitant loss of all Leydig cell markers. Chromatin condensation, nuclear fragmentation, mitochondrial swelling, and other ultrastructural changes were evident in the degenerating Leydig cells. Liquid chromatography-tandem mass spectrometry demonstrated reduced levels of androstenedione and testosterone in testes from mice injected with Ad-Cre-IRES-GFP. Late effects of treatment included testicular atrophy, infertility and the accumulation of lymphoid cells in the testicular interstitium. We conclude that adenoviral-mediated gene delivery is an expeditious way to probe Leydig cell function in vivo Our findings reinforce the notion that GATA factors are key regulators of steroidogenesis and testicular somatic cell survival.Free Finnish abstract: A Finnish translation of this abstract is freely available at http://www.reproduction-online.org/content/154/4/455/suppl/DC2.

Vessel wall morphology is equivalent for different artery types and localizations of advanced human aneurysms.

Aneurysm formation occurs most frequently as abdominal aortic aneurysm (AAA), but is also seen in other localizations like thoracic or peripheral aneurysm. While initial mechanisms for aneurysm induction remain elusive, observations from AAA samples show transmural inflammation with proteolytic imbalance and repair mechanisms triggered by the innate immune system. However, limited knowledge exists about aneurysm pathology, especially for others than AAA. We compared 42 AAA, 15 popliteal, 3 ascending aortic, five iliac, two femoral, two brachial, one visceral and two secondary aneurysms to non-aneurysmatic controls by histologic analysis, immunohistochemistry and cytokine expression. Muscular and elastic type arteries show a uniform way of aneurysm formation. All samples show similar morphology. The changes compared to controls are distinct and include matrix remodeling with smooth muscle cell phenotype switch and angiogenesis, adventitial lymphoid cell accumulation and M1 macrophage homing together with neutrophil inflammation. Inflammatory cytokines are up-regulated accordingly. Comparative analysis of different disease entities can identify characteristic pathomechanisms. The phenotype of human advanced aneurysm disease is observed for elastic and muscular type arteries, does not differ between disease localizations and might, thus, be a unique response of the vasculature to the still unknown trigger of aneurysm formation.

Contrasting roles for the receptor for advanced glycation end-products on structural cells in allergic airway inflammation vs. airway hyperresponsiveness.

The receptor for advanced glycation end-products (RAGE) is a multiligand receptor that belongs to the immunoglobulin superfamily. RAGE is reported to be involved in various inflammatory disorders; however, studies that address the role of RAGE in allergic airway disease are inconclusive. RAGE-sufficient (RAGE+/+) and RAGE-deficient (RAGE-/-) mice were sensitized to ovalbumin, and airway responses were monitored after ovalbumin challenge. RAGE-/- mice showed reduced eosinophilic inflammation and goblet cell metaplasia, lower T helper type 2 (Th2) cytokine production from spleen and peribronchial lymph node mononuclear cells, and lower numbers of group 2 innate lymphoid cells in the lung compared with RAGE+/+ mice following sensitization and challenge. Experiments using irradiated, chimeric mice showed that the mice expressing RAGE on radio-resistant structural cells but not hematopoietic cells developed allergic airway inflammation; however, the mice expressing RAGE on hematopoietic cells but not structural cells showed reduced airway inflammation. In contrast, absence of RAGE expression on structural cells enhanced innate airway hyperresponsiveness (AHR). In the absence of RAGE, increased interleukin (IL)-33 levels in the lung were detected, and blockade of IL-33 receptor ST2 suppressed innate AHR in RAGE-/- mice. These data identify the importance of RAGE expressed on lung structural cells in the development of allergic airway inflammation, T helper type 2 cell activation, and group 2 innate lymphoid cell accumulation in the airways. RAGE on lung structural cells also regulated innate AHR, likely through the IL-33-ST2 pathway. Thus manipulating RAGE represents a novel therapeutic target in controlling allergic airway responses.

Cutting edge: c-Kit signaling differentially regulates type 2 innate lymphoid cell accumulation and susceptibility to central nervous system demyelination in male and female SJL mice.

Multiple sclerosis preferentially affects women, and this sexual dimorphism is recapitulated in the SJL mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). In this study, we demonstrate that signaling through c-Kit exerts distinct effects on EAE susceptibility in male and female SJL mice. Previous studies in females show that Kit mutant (W/W(v)) mice are less susceptible to EAE than are wild-type mice. However, male W/W(v) mice exhibit exacerbated disease, a phenotype independent of mast cells and corresponding to a shift from a Th2- to a Th17-dominated T cell response. We demonstrate a previously undescribed deficit in c-Kit(+) type 2 innate lymphoid cells (ILC2s) in W/W(v) mice. ILC2s are also significantly reduced in EAE-susceptible wild-type females, indicating that both c-Kit signals and undefined male-specific factors are required for ILC2 function. We propose that deficiencies in Th2-promoting ILC2s remove an attenuating influence on the encephalitogenic T cell response and therefore increases disease susceptibility.

Pathological aspects of bovine focal fibrogranulomatous proliferative panniculitis (Lechiguana).

Lechiguana is a disease of cattle caused by an interaction between Dermatobia hominis warble and the bacteria Manheimia granulomatis. It is characterized by subcutaneous swellings that grow rapidly and result in death after 3 to 8 months. The objective of this paper was to investigate some vascular and fibrogenic changes of the disease at different lesion stages by histochemical and immunohistochemical techniques. A peculiar histopathological aspect observed during a proliferative phase (before treatment) was the intense vasculitis, described as degenerative and fibro-proliferative, expressed by the oncogene p53, possibly caused by the presence of bacteria in close contact with enthotelial cells, along with dense accumulations of lymphoid cells around venules. The synthesis of collagen fibers during the development of Lechiguana lesions assume a structural aspect of star arrangement with fiber radiation centers that gradually interconnect to design the Extracellular Matrix (ECM) framework, seen by Confocal Laser Scanning Microscopy (CSLM). Angiogenesis was the most characteristic finding in both proliferative and regressive stages as seen by the immunohistochemical expression of cytoskeleton proteins and von Willebrand (Factor VIII-Related Antigen). Additionally, in all tissues samples, active ECM elements like Metalloproteinases (MMPs), Tissue Inhibitors Metalloproteinases (TIMP) and Fibronectin (FN) were mainly associated to vessels structures. The extraordinary regression of exuberant granulation tissue after treatment is undoubtedly associated to the maintenance of the vascular components observed during the regressive phase.

Lymphatic vessels and tertiary lymphoid organs

Tertiary lymphoid organs (TLOs) are accumulations of lymphoid cells in chronic inflammation that resemble LNs in their cellular content and organization, high endothelial venules, and lymphatic vessels (LVs). Although acute inflammation can result in defective LVs, TLO LVs appear to function normally in that they drain fluid and transport cells that respond to chemokines and sphingosine-1-phosphate (S1P) gradients. Molecular regulation of TLO LVs differs from lymphangiogenesis in ontogeny with a dependence on cytokines and hematopoietic cells. Ongoing work to elucidate the function and molecular regulation of LVs in TLOs is providing insight into therapies for conditions as diverse as lymphedema, autoimmunity, and cancer.

Mild proteinuria in a patient with glomerularlimited intravascular large B-cell lymphoma

Intravascular large B-cell lymphoma (IVLBCL) is a rare type of non- Hodgkin lymphoma characterized by a disseminated intravascular proliferation of tumor cells in the lumina of small vessels. Although the kidney is one of the target organs of IVLBCL, lymphoma cells that localize only in glomeruli are extremely rare. We report a 55-year-old Chinese patient diagnosed as glomerular-limited IVLBCL by percutaneous renal biopsy. The patient was referred to our institution for further examination of mild proteinuria and anemia without lymphoma symptoms. He had daily urinary excretion of 0.65 g proteins with normal renal function. Percutaneous renal biopsy showed that lymphoid cell accumulation was encircled within the glomerular capillary lumina only in certain glomeruli, resulting in marked obstruction of capillary structure. However, almost all of the peritubular capillary and tubulointerstitium were intact. Immunohistochemical analysis confirmed the diagnosis of intravascular large B-cell lymphoma. Extensive systemic examinations showed no other organ involvement. With these characteristic changes, glomerularlimited IVLBCL were considered as an exceptional renal manifestation of intravascular lymphoma diagnosised by percutaneous renal biopsy.

Neutrophil Gelatinase Associated Lipocalin (NGAL) regulates the onset of serum autoantibodies in pristane induced lupus (P4059)

Abstract NGAL (lipocalin-2), a member of the lipocalin superfamily, is expressed by neutrophils, hepatocytes, and renal resident cells following inflammatory conditions, and is involved in innate immunity during infection. Previously, we found that NGAL worsens renal disease in nephrotoxic nephritis. However, its relevance to adaptive immunity has not been fully explored. To investigate a possible role for NGAL in autoreactive antibody responses in experimental lupus, we injected pristane into B6 (n=10) and NGAL-deficient B6 (NGAL-/-) (n=10) mice. Analyzing the levels of serum autoantibodies at 3 months post injection, we found that B6 NGAL-/- mice had significant increases in IgG2a and IgG2b anti-double stranded DNA antibodies. Similarly, the titers of IgG2a and IgG2b antibodies to single stranded DNA and histone were significantly increased in pristane challenged NGAL-/- mice as compared to NGAL sufficient mice. Furthermore, elevated serum anti-ribonucleoprotein antibodies were found in pristane treated NGAL-/- mice by immunoprecipitation. Although autoantibody titers in NGAL-/- mice were not increased at baseline, our results are consistent with the apoptotic defects and accumulation of lymphoid cells reported previously in these mice. We also found significant upregulation of IRF5, IP-10, CXCL13, CXCR5, CxCR3, PD-1, PD-L1, and activation induced cytidine deaminase (AID) in spleens of NGAL-/- mice compared to WT mice. In vitro, we found that pristane and other inflammatory mediators promoted NGAL secretion by splenocytes. In conclusion, NGAL deficiency accelerates the onset of anti-nuclear antibodies in pristane induced lupus, suggesting that NGAL may regulate the spontaneous or induced humoral autoimmunity.

Progressive Reactive Lymphoid Connective Tissue Disease and Development of Autoantibodies in Scavenger Receptor A5–Deficient Mice

Scavenger receptor A5 (SCARA5) is a member of the class A scavenger receptors, with most similarity to SCARA1 (SR-A) and SCARA2 (MARCO), which are primarily expressed by macrophages and dendritic cells, in which they participate in clearance of various polyanionic macromolecules, pollution particles, and pathogens. The biological role of SCARA5 has been unknown. Herein, we show that SCARA5 is an endocytotic receptor whose ligand repertoire includes the typical scavenger receptor ligands, whole bacteria, and purified Gram-negative bacterial lipopolysaccharide. In contrast to expression of SCARA1 and SCARA2 in immune cells, SCARA5 is found in a subset of fibroblast-like cells in the interstitial stroma of most organs, with additional expression in the epithelial cells of testis and choroid plexus. SCARA5-null mice develop with age lymphoid cell accumulation in many organs, in particular the lungs, and show decreased endocytotic function in fibroblasts. Furthermore, about one-third of the mice develop antinuclear antibodies. These disturbances are reminiscent of those found in many human autoimmune connective tissue disorders, which suggests that defects in fibroblast SCARA5 can underlie some forms of autoimmune disease.

Pathological Features of Experimental Bovine Leukaemia Viral (BLV) Infection in Rats and Rabbits

Abstract Rabbits and rats were inoculated with material derived from FLK cells producing permanently bovine leukaemia virus (BLV). The viral presence in the inoculum was proved by transmission electron microscopy, immunofluorescence, immunogold labelling demonstrating viral Tax protein, and PCR analysis. About 30 % of the infected animals sustained BLV seropositivity during the experiment, and demonstrated symptoms of lympholeukaemia - clinical manifestation of an immunosuppressive condition, increased number of lymphocytes and lymphoblasts, and preneoplastic lymphoid cell accumulations in the liver, lungs, kidneys, and lymph nodes. BLV DNA, detected by PCR in diseased animals, indicates the role of BLV as an aetiological factor of lympholeukaemia, developed in these animals after BLV infection. The alterations in rats were more pronounced than those in rabbits. The results prove that these two species of laboratory animals, especially rats, are suitable models for the in vivo studies of leukaemogenesis caused by BLV/HTLV infections.