Mycobacterium tuberculosis impedes CD40-dependent notch signaling to restrict Th17 polarization during infection

Early Th₁₇ responses are necessary to provide protection against Mycobacterium tuberculosis (Mtb). Mtb impedes Th₁₇ polarization by restricting CD40 co-stimulatory pathway on dendritic cells (DCs). We previously demonstrated that engaging CD40 on DCs increased Th₁₇ responses. However, the molecular mechanisms that contributed to Th₁₇ polarization were unknown. Here, we identify the Notch ligand DLL4 as necessary for Th₁₇ polarization and demonstrate that Mtb limits DLL4 on DCs to prevent optimal Th₁₇ responses. Although Mtb infection induced only low levels of DLL4, engaging CD40 on DCs increased DLL4 expression. Antibody blockade of DLL4 on DCs reduced Th₁₇ polarization in vitro and in vivo. In addition, we show that the Mtb Hip1 protease attenuates DLL4 expression on lung DCs by impeding CD40 signaling. Overall, our results demonstrate that Mtb impedes CD40-dependent DLL4 expression to restrict Th₁₇ responses and identify the CD40-DLL4 pathways as targets for developing new Th₁₇-inducing vaccines and adjuvants for tuberculosis.

•

Mtb restricts Th₁₇ responses by impairing CD40 signaling on dendritic cells

•

Engaging CD40 on DCs increases Notch ligand Dll4 transcript and surface expression

•

DLL4 is necessary for polarizing Th₁₇ and multifunctional T cells in the lungs of mice

•

Mtb impairs CD40/DLL4 pathway through the Hip1 serine protease immune evasion protein

Descripción morfométrica y faneroptica de la cabra “Chusca lojana” del bosque seco del Sur del Ecuador

En la Región Sur del Ecuador se encuentra la zona del bosque seco que abarca desde los 100 metros sobre el nivel del mar (m.s.n.m) hasta los 1200 m.s.n.m, lugar donde se ha adaptado la cabra criolla llamada “Chusca lojana”. El presente trabajo tuvo como objetivo la caracterización fenotípica de este recurso zoogenético, permitiendo disponer de un patrón o estándar racial con fines de identificación, estudio, selección y mejoramiento de esta población. La investigación comprendió una muestra de 163 cabras adultas manejadas en ambiente extensivo, considerando 21 medidas morfométricas y 10 características fanerópticas; para el análisis morfométrico se aplicó una estadística no paramétrica con el Test de Kruskal-Wallis considerando como variables el sexo y los biotipos. Los resultados permitieron identificar 4 biotipos, que de acuerdo a ciertas características peculiares que presentan a nivel de cabeza y orejas se las ha identificado como: Chusca “oreja corta y doblada”, Chusca “oreja de león”, Chusca oreja “torneada” y Chusca “muca”; en el aspecto faneróptico presentan cuernos opistoceros (58%) y ortoceros (37%), siendo un 22% acornes (biotipo Chusca muca), poseen barba y mamelas el 26 y 29%, respectivamente, presentando estas dos características un dimorfismo en favor de los machos; la mayoría de esta población presenta un perfil de rostro recto (67%) y subcóncavo (28%); la forma de la ubre es globosa (64%), el color de pezones (93%) y cascos (87%) es pigmentado; los machos presentan testículos pendulosos (70%) y una característica peculiar es que poseen un escroto dividido en dos sacos (40%). En conclusión, la cabra Chusca es un animal con una tendencia productiva más a leche que a carne, destacando su capacidad torácica que le permite recorrer con facilidad por la topografía irregular de la zona en busca de alimento.

Antiretroviral therapy does not reduce tuberculosis reactivation in a tuberculosis-HIV coinfection model

While the advent of combination antiretroviral therapy (ART) has significantly improved survival, tuberculosis (TB) remains the leading cause of death in the HIV-infected population. We used Mycobacterium tuberculosis/simian immunodeficiency virus-coinfected (M. tuberculosis/SIV-coinfected) macaques to model M. tuberculosis/HIV coinfection and study the impact of ART on TB reactivation due to HIV infection. Although ART significantly reduced viral loads and increased CD4+ T cell counts in blood and bronchoalveolar lavage (BAL) samples, it did not reduce the relative risk of SIV-induced TB reactivation in ART-treated macaques in the early phase of treatment. CD4+ T cells were poorly restored specifically in the lung interstitium, despite their significant restoration in the alveolar compartment of the lung as well as in the periphery. IDO1 induction in myeloid cells in the inducible bronchus-associated lymphoid tissue (iBALT) likely contributed to dysregulated T cell homing and impaired lung immunity. Thus, although ART was indispensable for controlling viral replication, restoring CD4+ T cells, and preventing opportunistic infection, it appeared inadequate in reversing the clinical signs of TB reactivation during the relatively short duration of ART administered in this study. This finding warrants the modeling of concurrent treatment of TB and HIV to potentially reduce the risk of reactivation of TB due to HIV to inform treatment strategies in patients with M. tuberculosis/HIV coinfection.

Pulmonary Mycobacterium tuberculosis control associates with CXCR3- and CCR6-expressing antigen-specific Th1 and Th17 cell recruitment

Mycobacterium tuberculosis-specific (M. tuberculosis-specific) T cell responses associated with immune control during asymptomatic latent tuberculosis infection (LTBI) remain poorly understood. Using a nonhuman primate aerosol model, we studied the kinetics, phenotypes, and functions of M. tuberculosis antigen-specific T cells in peripheral and lung compartments of M. tuberculosis-infected asymptomatic rhesus macaques by longitudinally sampling blood and bronchoalveolar lavage, for up to 24 weeks postinfection. We found substantially higher frequencies of M. tuberculosis-specific effector and memory CD4+ and CD8+ T cells producing IFN-γ in the airways compared with peripheral blood, and these frequencies were maintained throughout the study period. Moreover, M. tuberculosis-specific IL-17+ and IL-17+IFN-γ+ double-positive T cells were present in the airways but were largely absent in the periphery, suggesting that balanced mucosal Th1/Th17 responses are associated with LTBI. The majority of M. tuberculosis-specific CD4+ T cells that homed to the airways expressed the chemokine receptor CXCR3 and coexpressed CCR6. Notably, CXCR3+CD4+ cells were found in granulomatous and nongranulomatous regions of the lung and inversely correlated with M. tuberculosis burden. Our findings provide insights into antigen-specific T cell responses associated with asymptomatic M. tuberculosis infection that are relevant for developing better strategies to control TB.

P905 Value of global longitudinal strain (GLS) in the short term prognosis of geriatric patients with asymptomatic severe aortic stenosis

Funding Acknowledgements

VII Convocatoria del Banco de Santander and Alfonso X el Sabio University.

Background

Detection of symptoms in geriatric population with aortic stenosis (AS) is challenging, especially when they associate other comorbidities or frailty. Left ventricular global longitudinal strain (GLS) occurs before left ventricular ejection fraction impairment and could be useful for risk stratification and management of these patients.

Purpose

We sought to analyze the usefulness of GLS for predicting major cardiovascular adverse events (MACEs) in geriatric patients with asymptomatic severe AS.

Material and Methods:

Prospective study on 54 patients older than 70 years old with severe asymptomatic AS. Patient evaluation included biochemistry tests, electrocardiogram and echocardiography. We use a GLS cut-off point of 18% to dichotomize patients. Outcomes were defined as the composite of MACEs – occurrence of death from any cause, hospitalization for heart failure, appearance of symptoms or change in treatment.

Results

The mean age was 83.2 ± 7.1, with 60.4% of women. 24.5% showed atrial fibrillation. At 6 months of follow-up, 33% of patients reached the endpoint: 5.6% CHF, 11.1% death, 3.7% symptoms without changes in management and 13% were referred to an invasive treatment. The event-free survival rate at 6 months for the global population was 83%. 41.5 % of the subjects had GLS < 18%. Kaplan Meier analysis showed that the probability of freedom from MACEs was not significant in patients with lower GLS (Log Rank p = 0.39). In the multivariate analysis only AVA was an inverse predictor of events (AVA) HR 0.05 (95% CI 0.007- 0.471, p < 0.05).

Conclusions

The value of GLS was not a predictor of short term events in geriatric patients. Only assessment of AVA was an independent marker of MACES and in this kind of subjects.

Charasteristics of the global population Global N = 53 (%) GLS ≥ 18 N = 31 (58.5%) GLS < 18 N = 22 (41.5%) (p) HBP 42 (79.2) 27 (87.1) 19 (82.6) 0.09 Atrial fibrillation 13 (24.5) 6 (19.4) 7 (31.8) 0.29 CVD 6 (11.3) 1 (3.2) 5 (22.7) 0.02 LVEF: Normal >50% 48 (92) 31 (100) 17 (77.2) 0.05 Peak velocity 3.72 ± 0.72 3.81 ± 0.71 3.60 ± 0.74 0.315 Mean gradient 34.01 ± 14.06 35.61 ± 13.54 32.09 ± 15.07 0.29 Integral ratio 0.25 ± 0.08 0.26 ± 0.09 0.25 ± 0.08 0.83 AVA 0.8 ± 0.26 0.78 ± 0.27 0.83 ± 0.26 0.651 Indexed AVA 0.48 ± 0.16 0.48 ± 0.17 0.48 ± 0.16 0.9 AVA Aortic valve area; CVD: cerebro vascular disease; HBP: High blood presure; LVEF: left ventricule ejection fraction.

Abstract P905 Figure. Kapplan-Meier event-free survival curves

P225 Carcinoid heart disease: report of a case in a patients with trombocytopenia absent radius

Background

The carcinoid syndrome is characterized by extensive and several clinical manifestations. The diarrhea, the cutaneous flushing are the most frequents symptoms while cardiac manifestations (carcinoid heart disease) (CHD) occurs in a mean of 40%. Nowadays, the number of cases of CHD is lower than 20%, as a consequence of the widespread use of somatostatin analogues. At present, there is a mean delay in diagnosis of CHD of 1.5 years from the time of carcinoid syndrome detection. Hence, CHD is associated with a poor prognosis for clinical management.

Case report

We present a case of 45-years-old active woman, with Thrombocytopenia absent radius (TAR). This is characterized by a bilateral absence of the radio with the presence of both thumbs and thrombocytopenia. Our patient was attended for dyspnea of medium efforts, history of diarrhea, cutaneous flushing with tachycardia and elevated urinary 5-hydroxyindoleacetic acid (5-HIAA) (89,6 mg/24 (2,0-9,0)). The Transthoracic echocardiography showed morphologic changes that affected the tricuspid valve: diminished curvature of the leaflets, altered dynamic motion of the leaflets during diastole, fused and shortened chordae retraction and reduced excursion of the valve. A moderate to severe tricuspid regurgitation and tricuspid stenosis with gradient media de 5 mmHg was observed. In addition, the right ventricle was dilated, a severe pulmonary hypertension, a right pleural effusion and a minor pericardial effusion circumference were detected. All these findings were consistent with CHD.

Conclusions

This report describes an unusual case of CHD in TAR patient. In fact, the interest of this case is the role played by the echocardiogram in the differential diagnosis for tricuspid valve diseases. Tricuspid stenosis is an infrequent condition and it is usually related with rheumatic disease associated with mitral valve disease. Although the carcinoid syndrome is infrequent, any changes in the anatomical structure of the tricuspid valve (thickening, fibrosis and rigidity associated with stenosis and tricuspid regurgitation) should alert us to the suspicion of CHD

Abstract P225 Figure.

P1439 Familial dilated cardiomyopathy: assessment of left ventricular systolic and diastolic function by echocardiogram in asymptomatic patients

Funding Acknowledgements

Alfonso X El Sabio University

Introduction

Familial dilated cardiomyopathy (fDCM) represents 20% to 30% of idiopathic DCM (iDCM) ethiology. The assessment of cardiac function of these patients is awfully complex. Usually, myocardial fiber damages can not be detected in the early DCM stages. In this sense echocardiogram could be useful to detect incipient changes.

Purpose

The aim of this study was to characterize the systolic function of asymptomatic fDCM, compared within iDCM and control patients.

Material and methods

This study was carried out in 33 fDCM patients. A total of 4 fDCM families with LMNA gene mutation and 3 fDCM families with BLC2-associated athanogene 3 (BAG3) mutation were recruited. Moreover, a total of 30 iDCM and 66 healthy matched controls were enrolled in the study.

Results

58.14% were male. The average age was 45.3 ± 17 years. 72% showed sinus rhythm. Left bundle branch block (LBBB) was observed in 7.8% of patients. The LV ejection fraction (LVEF), sphericity index and mitral annular plane systolic excursion (MAPSE), were significantly improved in the fDCM patients compared to iDCM subjects. However, these parameters were aggravated compared with healthy controls. LVEF was enhanced in fDCM in contrast to iDCM (56% versus 35%; P < 0.001). Nevertheless, LVEF value was deteriorated in fDCM compared to healthy controls (56% versus 65%; P < 0.001). The values of septal and lateral annulus early diastolic velocity measured by DTI, were also diminished. All results are presented in Table 1.

Conclusions

Asymptomatic fDCM shown an intermediate value of LVEF between the iDCM and the control group. This ventricular remodeling process could be the consequence of a slight increase in the end-systolic diameter.

Patients Characteristics Patients Characteristics iDCM 30 patients fDCM 33 patients Control Group 66 Healthy P LVEF 32 (29.78-40) 56.0 (39.7-64.2) 65 (62-69.5) 0.001 EDD 62.5 (59.2-65.7) 53.7 (45.7-57.6) 45.50 (43-48.8) 0.001 ESD 53 (47-58.75) 36 (30.9-54.2) 27.9 (24-31) 0.001 MAPSE 11 (10-12.50) 14 (14-18) 19 (17-20) 0.001 Sphericity index 0.70 (0.66–0.79) 0.69 (0.66-0.79) 0.53 (0.48-58) 0.001 LA volume 61.5 (57-75.1) 32 (23-46.5) 17 (14.2-20) NS Septal annulus Early diastolic Velocity (cm/s) DTI 3.5 (3-4.2) 7.5 (1.6-8.8) 9 (7.9-11) 0.001 Lateral annulus Early diastolic Velocity (cm/s) DT 7.2 (5-8.9) 9.5 (1.8-11.8) 13 (10.37-15) 0.001 Table1. Echocardiografic findings in patients. LVEF: left ventricular ejection fraction; EDD: end-diastolic diameter; ESD: end systolic diameter; MAPSE:mitral annular plane systoluc excursion; LA: left atrium; TDI: Tissue Doppler imagin.

Abstract P1439 Figure. Familial dilated cardiomyopathy

P1516Novel cardiotropic AAV variant C102 vectors show superior gene delivery & reduced immunogenicity in non-human primates, transduction of human cardiomyocytes, & correction of Fabry disease phenotype

Background

Cardiac-targeted gene therapy vectors are needed. Fabry disease is a rare, X-linked disorder caused by mutations in the GLA gene, which encodes α-galactosidase A (GLA). Storage and accumulation of glycolipid substrates of GLA leads to organ damage. Cardiovascular disease is the most common cause of mortality in Fabry disease (75% of deaths). Enzyme replacement therapy (ERT; first line treatment for most patients) demonstrates clearance of Gb3 from capillary endothelial cells. However, Gb3 accumulation in podocytes, cardiomyocytes, and vascular smooth muscle cells persists. Gene replacement strategies leveraging adeno-associated virus (AAV) vectors with high tropism for affected organs (namely the heart) may directly address the underlying pathophysiology of Fabry disease.

Purpose

To unlock the full potential of cardiac gene therapy, novel targeted vectors are needed with enhanced tropism for specific target tissues when delivered in vivo.

Methods

An industrialized “directed evolution” approach (Therapeutic Vector Evolution) was applied in the most relevant animal species (non-human primate; NHP) which led to the discovery of C102, a novel AAV variant capable of efficient gene delivery throughout the primate heart following a single intravenous (IV) administration. C102 biodistribution using a ubiquitous promoter was evaluated in mice and NHP at doses at least 10-fold lower than current AAV-based clinical trials for neuromuscular gene therapy. Animal studies conformed to the NIH Principles of Laboratory Animal Care. To evaluate the ability of the C102 capsid to transduce human target cells relevant to Fabry disease, human pluripotent stem cell-derived cardiomyocytes were transduced. To evaluate the ability of C102 to correct Fabry disease, cultured patient fibroblasts were transduced with the C102.GLA product.

Results

Following a single IV administration in mice, the onset of C102.luciferase expression was rapid (14 days) and durable. Dose-dependent luciferase activity was observed in Fabry disease target tissues, including heart and liver. Following a single IV administration in NHP, superior delivery to heart was demonstrated and immunogenicity was markedly reduced compared to first generation wild-type vectors (AAV8,9), and genomes were present throughout the heart and skeletal muscle groups. In human cardiomyocytes in vitro, C102.EGFP demonstrated significantly higher transduction compared to wild-type AAV1 and 9 vectors (immunofluorescence imaging and quantification by flow cytometry) at all doses. Following transduction with increasing doses of the C102.GLA product in Fabry patient fibroblasts, dose-dependent GLA expression and function was observed.

C102 Genome Delivery in NHP

Conclusion

The data generated using the novel C102 capsid and the C102.GLA Fabry product validate the Therapeutic Vector Evolution approach for cardiac tissue targeting in vivo and provide a strong preclinical data package to enable clinical translation.

Deletion of BCG Hip1 protease enhances dendritic cell and CD4 T cell responses

Dendritic cells (DCs) play a key role in the generation of CD4 T cell responses to pathogens. Mycobacterium tuberculosis (Mtb) harbors immune evasion mechanisms that impair DC responses and prevent optimal CD4 T cell immunity. The vaccine strain Mycobacterium bovis Bacille Calmette-Guérin (BCG) shares many of the immune evasion proteins utilized by Mtb, but the role of these proteins in DC and T cell responses elicited by BCG is poorly understood. We previously reported that the Mtb serine protease, Hip1, promotes sub-optimal DC responses during infection. Here, we tested the hypothesis that BCG Hip1 modulates DC functions and prevents optimal antigen-specific CD4 T cell responses that limit the immunogenicity of BCG. We generated a strain of BCG lacking hip1 (BCGΔhip1) and show that it has superior capacity to induce DC maturation and cytokine production compared with the parental BCG. Furthermore, BCGΔhip1-infected DCs were more effective at driving the production of IFN-γ and IL-17 from antigen-specific CD4 T cells in vitro. Mucosal transfer of BCGΔhip1-infected DCs into mouse lungs induced robust CD4 T cell activation in vivo and generated antigen-specific polyfunctional CD4 T cell responses in the lungs. Importantly, BCGΔhip1-infected DCs enhanced control of pulmonary bacterial burden following Mtb aerosol challenge compared with the transfer of BCG-infected DCs. These results reveal that BCG employs Hip1 to impair DC activation, leading to attenuated lung CD4 T cell responses with limited capacity to control Mtb burden after challenge.

Type 2 Porcine Reproductive and Respiratory Syndrome Virus infection mediated apoptosis in B- and T-cell areas in lymphoid organs of experimentally infected pigs

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection is characterized by persisting in lungs and lymphoid tissue, resulting in systemic lymphoid depletion. The aim of this study was to correlate the histological changes, viral antigen expression and apoptosis phenomena in tonsil, medial retropharyngeal and mediastinal lymph nodes of 12 pigs inoculated with a type 2 PRRSV isolate (Chilean strain 2402). Apoptosis phenomena were observed mainly in lymphocytes and secondly in macrophages of lymph nodes and tonsils of inoculated animals, showing a peak of both apoptotic cells and viral antigen expression at the end of the study (21 dpi). However, the number of apoptotic cells was higher than the number of PRRSV-positive cells at the end of the study. This finding together with the location of apoptotic cells and PRRSV-positive cells in different structures of lymphoid organs supports the hypothesis that PRRSV-positive macrophages might modulate the apoptosis phenomena in other cells, mainly lymphocytes, by means of an indirect mechanism. Furthermore, apoptotic cells were detected both in B- and T-cell areas of lymphoid organs, suggesting that apoptosis phenomena may play a role in the impairment of the host immune response during PRRS.

Effect of single post-ovulatory administration of levonorgestrel on gene expression profile during the receptive period of the human endometrium

The hypothesis that levonorgestrel (LNG) used as an emergency contraceptive interferes with endometrial receptivity remains unproven. We compared the endometrial gene expression profile during the receptive period after administering a single dose of LNG 1.5 mg or placebo on day 1 of the luteal phase. An endometrial biopsy was done on day LH+7 or LH+8 and samples were taken from seven volunteers, each one contributing with one cycle treated with placebo and another with LNG. The expression of 20 383 genes was determined using cDNA microarrays. Real-time RT-PCR was used 1) to confirm the differences found in DNA microarray analysis and 2) to determine the effect of LNG on transcript levels of C3, C4BPα, COX2, MAOA, S100A4, and SERPINB9, known to be upregulated during receptivity, and on cPLA2α, JAK1, JNK1, CTSL1, and GSTP1, known to respond to mifepristone. Additional endometrial biopsies were done during the pre-receptive (LH+3) and receptive (LH+7) period and samples were taken from eight untreated volunteers in order to determine the changes associated with acquisition of receptivity of 14 genes. Mean levels of PAEP, TGM2, CLU, IGF2, and IL6ST mRNAs increased after administering LNG while those of HGD, SAT1, EVA1, LOC90133, ANXA1, SLC25A29, CYB5A, CRIP1, and SLC39A14 decreased. Except for the level of ANXA1 transcript, all changes remained within the range observed in untreated controls, and none of the transcripts responding to mifepristone changed in response to LNG. Post-ovulatory administration of LNG caused minimal changes in gene expression profiling during the receptive period. Neither the magnitude nor the nature or direction of the changes endorses the hypothesis that LNG interferes with endometrial receptivity.

Evaluation of the pathogenicity and transmissibility of a chilean isolate of porcine reproductive and respiratory syndrome virus

The objective of this study was to determine clinical features, shedding and transmission of a Chilean Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) strain upon experimental inoculation of 4-week-old pigs. Six groups of five animals each were used. The G1 (donor) group was inoculated with PRRSV, maintained in an isolation unit for 35 days, and sampled daily to determine shedding in mucosal secretions and faeces, viraemia and seroconversion. An uninfected control group (G6) was equally maintained and sampled under strict isolation. Four other groups (G2 to G5) were exposed to PRRSV via direct contact with G1 for 5-day periods in a staggered manner, throughout the 35-day period, and were later placed in an independent isolation unit to monitor infection status for 7 days. All the animals in G1 and G6 were killed at 35 days post-inoculation (dpi) and the contact groups at 12 days post-contact (dpc). Samples were obtained from diverse organs for histopathological, immunohistochemical (IHC) and virological analysis. No clinical symptoms were evident in any group, except for a transient fever observed in G1. Histopathologically, all the animals of G1 had interstitial pneumonia, although scarce PRRSV-positive cells were detected in the lung using IHC. PRRSV-positive cells (IHC) were detected in the lymphoid tissue of all animals in infected groups, but especially in G3 and G4. Viraemia was detected in G1 (3-35 dpi) and in the all contact groups (5-12 dpc). Likewise, ranging from 3 to 19 dpi, PRRSV was detected in at least one animal from the tonsils and lungs in all infected groups, in nasal and ocular secretions, saliva or faeces. These results indicate that the donor group excreted infectious PRRSV and was able to transmit the infection to susceptible pigs. The critical shedding period was 7-19 dpi, during which, most likely, transmission took place.

Deficient expression of monoamine oxidase A in the endometrium is associated with implantation failure in women participating as recipients in oocyte donation

Successful implantation depends both on the quality of the embryo and on the endometrial receptivity. The latter depends on progesterone-induced changes in gene expression, a process that has been characterized by microarray analysis. One of the genes whose transcription appears to be enhanced during the receptive period is monoamine oxidase A (MAO-A). Our first objective was to confirm the increased expression of MAO-A in the endometrium during the receptive phase of spontaneous normal cycles using real time PCR and immunofluorescence. The second objective was to examine the endometrial expression of MAO-A during the receptive phase induced by exogenous estradiol (E(2)) and progesterone in patients whose endometrium was shown to have been either receptive or non-receptive to embryo implantation in repeated cycles of oocyte donation. Results showed that MAO-A transcript levels increased between the pre-receptive (LH+3) and receptive phase (LH+7) in all spontaneous cycles examined, with a median increase of 25-fold. Immunofluorescent labelling demonstrated MAO-A localization to the glandular and luminal epithelium with an increasing positive score between LH+3 and LH+7. Conversely, prior failure of embryo implantation was associated with a 29-fold decrease in MAO-A mRNA levels and a substantial reduction in MAO-A protein immunofluorescent label score. These results show a strong association between endometrial receptivity and MAO-A expression in the endometrial epithelium, suggesting an important role for this enzyme in normal implantation.

African swine fever and classical swine fever: a review of the pathogenesis

This paper describes major pathogenetic mechanisms of African and Classical Swine Fever virus infections. The interactions between both viruses and the monocyte-macrophage-system result in the release of mediator molecules, which are important for the further progression of the diseases. The causes of the thrombocytopenia and the mechanisms of the haemorrhages, which are characteristic in both infections, are described. Apoptotic cell death is regarded as the predominant cause of lymphopenia in both virus infections.

Classical swine fever: morphological and morphometrical study of pulmonary intravascular macrophages

To gain further insight into the pathogenesis of classical swine fever (CSF), the changes induced by hog cholera (HC) virus in pulmonary intravascular macrophages (PIMs) were examined. Twelve pigs were inoculated by the intramuscular route with a virulent strain of HC virus (Quillota strain) and killed in groups of three at 4, 7, 10 and 14 days post-inoculation. Immunohistochemical and ultrastructural examination revealed HC virus infection in endothelial cells, PIMs, and interstitial and alveolar macrophages. In addition to viral replication, a predominant feature was the secretory activation of PIMs, characterized by expanded rough endoplasmic reticulum and hyperplastic Golgi complexes. The results obtained suggest that macrophage activation and the subsequent release of pro-inflammatory mediators play an important role in the pathogenesis of CSF.

Classical swine fever: pathogenesis of glomerular damage and immunocharacterization of immunocomplex deposits

Twenty-six pigs were inoculated with a virulent isolate (Quillota strain) of classical swine fever (hog cholera) virus to determine the chronological development of lesions in the renal glomeruli and the pathogenesis of glomerular damage and immunocomplex deposition. The study included the use of histopathological, ultrastructural and immunohistochemical (detection of viral antigen gp55, myeloid-histiocyte antigen, IgM, IgG and C1q) techniques. The main changes in glomerular structure were observed from 7 days post-inoculation (dpi) onwards, at which time the glomeruli showed macrophage infiltrations in the mesangium, and viral infection in circulating cells, glomerular endothelial cells and podocytes. Moreover, significant subcellular changes were detected in podocytes, which appeared swollen, with fusion of foot processes. Immunocomplex deposits immunoreactive for IgM, IgG and C1q were detected in mesangial, subepithelial and subendothelial areas from 10 dpi, but viral antigen was not detected as a component of these deposits; fusion of foot processes had increased in severity, especially near immunocomplex deposits. All these changes had increased still further in the final phase of the experiment (14 dpi), with neutrophil infiltrations in the mesangium.

Atypical cilia in the bronchiolar epithelium of pigs experimentally infected with hog cholera virus

To study the effect of hog cholera virus on the epithelial cells of the bronchiolar mucosa, 12 pigs were inoculated with a highly virulent strain. Immunohistochemical and ultrastructural examination of the ciliated epithelial cells demonstrated an increase in the number of atypical cilia. The latter showed alterations in the microtubular pattern, possibly resulting from viral interference with the normal metabolism of the epithelial cells.

Characterization of lesions caused by a South American virulent isolate ('Quillota') of the hog cholera virus

In this study, macroscopic and histopathological lesions produced by a virulent South American isolate ('Quillota') of hog cholera virus were studied. The virus was inoculated in doses of 10(5)TCID50 in each of 35 pigs of 20 kg live weight. The animals were slaughtered from 4 to 18 days post-inoculation. The presence of virus antigens in lymphatic tissue was confirmed by both direct immunofluorescence and Avidin-Biotin-Peroxidase techniques in formalin-embedded tissue samples. Histological sections were stained with haematoxylin-eosin and Mallory's phosphotungstic acid haematoxylin methods. The 'Quillota' isolate used in this study caused a disease characterized by vascular lesions (splenic infarcts, haemorrhages in the lymph nodes and the urinary system and disseminated microthrombosis), and necrosis of lymphocytes, particularly in the B-areas of the lymphoid organs, lesions that are characteristic of the acute form of the disease. Other lesions observed were a non-purulent meningoencephalitis, the necrosis of the epithelial cells of tonsils, the presence of fibrin nets in the red pulp and a marked thickening of the alveolar septa.

Pathogenesis of classical swine fever: renal haemorrhages and erythrodiapedesis

Thirty pigs were inoculated with a virulent isolate (Quillota strain) of classical swine fever (hog cholera) virus to establish the chronological occurrence of lesions in the kidney and to determine the mechanism responsible for renal haemorrhages. The study included the use of histopathological, ultrastructural, immunohistochemical (detection of viral antigen gp55, MAC387, lambda chains, CD3 and C1q) and morphometrical techniques (vascular area). Renal interstitial oedema and haemorrhages were detected from 7 days post-inoculation (dpi), associated with a slight interstitial mononuclear infiltrate and evidence of viral infection in macrophages and fibroblasts, and in a small proportion of lymphocytes. Viral infection was not detected in capillary endothelial cells. An intense mononuclear infiltrate, with B cells, T cells and small numbers of macrophages, was detected from 10 dpi. In the final phase of the experiment (14 dpi), slight proliferation and degranulation of mast cells were observed. Increased expression of the C1q component of complement was also detected. A significant increase in vascular area was observed from 7 dpi. These results suggest that haemorrhages observed in the kidneys of pigs inoculated with the Quillota strain resulted from erythrodiapedesis and increased vascular permeability, probably aggravated by mast cell degranulation in the final stage of the experiment. The results suggested that mast cell degranulation was linked to activation of the complement system.

Immunohistochemical and ultrastructural evidence of hog cholera virus infection of megakaryocytes in bone marrow and spleen

Twelve pigs were inoculated with a highly virulent strain of hog cholera virus (HCV) to study viral infection of megakaryocytes in the bone marrow and spleen. Immunohistochemical and ultrastructural examination revealed HCV infection in a small proportion (2.5-9.0%) of these cells from the 2nd to the 9th day after inoculation, at which time the experiment was terminated. Megakaryocyte infection accounts for the presence of viral antigens in platelets. The latter may represent a passive vehicle for spreading the virus in the animal.

Immunohistochemical detection of Brucella abortus antigens in tissues from aborted bovine fetuses using a commercially available polyclonal antibody

A commercially available polyclonal antibody and an avidin-biotin-peroxidase immunohistochemical technique were used to detect Brucella abortus antigens in formalin-fixed, paraffin-embedded tissues of lung and liver from 20 aborted bovine fetuses. Thirteen fetuses were obtained from farms with a previous history of brucellosis, and 7 were collected from farms without a history of brucellosis. Among the 13 aborted bovine fetuses obtained from farms with a history of brucellosis, immunoreactivity to B. abortus was detected in lung (9 fetuses) and in liver (1 fetus), whereas Brucella was cultured from abomasal contents in 9 fetuses (8 were immunohistochemically positive). In addition, 11 dams of these 13 aborted bovine fetuses had antibodies to Brucella. Brucella abortus was not detected by immunohistochemistry in the 7 aborted bovine fetuses collected from farms without a history of brucellosis. Bacteriologic culture and serologic tests were also negative for Brucella. The results of this study revealed that the immunohistochemical technique was sufficiently sensitive for detecting B. abortus antigens in formalin-fixed lung tissues from naturally aborted bovine fetuses. Although additional studies are necessary to rule out cross-reaction of the polyclonal antibody with other microorganisms that cause bovine abortion, this immunohistochemical technique could be a complementary tool to serology and bacteriology for the diagnosis of brucellosis.

Immunohistochemical detection of hog cholera viral glycoprotein 55 in paraffin-embedded tissues

Formalin-fixed, paraffin embedded tissues obtained from 40 pigs inoculated with a field isolate of hog cholera virus were examined for the presence of Gp55, a major structural protein of the virus envelope, using a monoclonal antibody-based immunohistochemical test with the avidin-biotin-peroxidase complex method. Immunoreactivity was detected in hog cholera virus-infected tissues but not in control pigs tissues, African swine fever virus-infected tissues, or bovine viral diarrhea virus-infected porcine or bovine tissues. The first positive reactions were seen in lymphatic tissues, digestive tract and skin on postinoculation day (pid) 4, respiratory and urinary tissues on pid 5, nervous tissues on pid 6, and endocrine tissues on pid 7. These staining reactions persisted until the last observation on pid 18. Hog cholera virus antigen was not detected in heart tissue at any time. The highest levels of antigen detection were found in tonsils, spleen, and pancreas, although the esophageal mucosa and skin epithelial cells were also intensely and widely stained. The cellular staining pattern of Gp55 had a ubiquitous distribution. It was found in epithelial cells, macrophages and circulating monocytes, endothelial cells, lymphoid cells, and glial cells. The results showed a high specificity and high sensitivity for detecting hog cholera Gp55 in formalin-fixed, paraffin embedded tissue samples. This method allows precise association of Gp55 with specific cells, tissues, and histologic lesions, making the technique suitable for use in routine diagnosis of hog cholera.

Cryptosporidiosis in chickens from southern Spain

Cryptosporidiosis in chickens from southern Spain is reported. Cryptosporidia were found in the trachea, esophagus, and epithelium of the bursa of Fabricius in chickens from different regions. In one flock, cryptosporidiosis was associated with respiratory problems and high mortality. In another flock, it was associated with low mortality and weight loss.