Stage Granulomas Research Articles

Dynamics of Macrophage, T and B Cell Infiltration Within Pulmonary Granulomas Induced by Mycobacterium tuberculosis in Two Non-Human Primate Models of Aerosol Infection.

Non-human primate models of Tuberculosis (TB) are one of the most commonly used within the experimental TB field because they closely mimic the whole spectrum of disease progression of human TB. However, the early cellular interactions of the pulmonary granuloma are still not well understood. The use of this model allows investigation into the early interactions of cells within pulmonary granulomas which cannot be undertaken in human samples. Pulmonary granulomas from rhesus and cynomolgus macaques from two timepoints post infection were categorised into categories 1 – 6 (early to late stage granulomas) and immunohistochemistry was used to identify CD68+ macrophages, CD3+ T cells and CD20+ B cells. Multinucleated giant cells and acid-fast bacilli were also quantified. At week four post infection, cynomolgus macaques were found to have more CD68+ cells than rhesus in all but category 1 granulomas. Cynomolgus also had a significantly higher percentage of CD20+ B cells in category 1 granulomas. At week twelve post infection, CD68+ cells were most abundant in category 4 and 5 granulomas in both species; however, there were no significant differences between them. CD3+ T cells and CD20+ B cells were significantly higher in the majority of granuloma categories in cynomolgus compared to rhesus. Multinucleated giant cells and acid-fast bacilli were most abundant in categories 5 and 6 at week 12 post challenge in both species. This study has identified the basic cellular composition and spatial distribution of immune cells within pulmonary granulomas in both rhesus and cynomolgus macaques over time. The data from this study will add to the knowledge already gained in this field and may inform future research on vaccines and therapeutics for TB.

Evaluation of the Interstitial Histological Lesions in Pulmonary Langerhans Cell Histiocytosis.

Pulmonary Langerhans cell histiocytosis is a cystic lung disease characterized by the proliferation of parenchymal dendritic cells. The disease can become chronic or even cause pulmonary fibrosis. Our aim in this study was to investigate the typical histological findings and interstitial fibrosis in pulmonary Langerhans cell histiocytosis cases. In the study, cases that had undergone diagnostic resection were screened. Smoking, histological stage (subacute, subacute-chronic), and cystic and eosinophilic granulomas were confirmed in the cases. In addition to emphysema, chronic nonspecific bronchiolitis, interstitial fibrosis (subpleural-paraseptal fibrosis, peribronchial fibrosis, fibrotic nonspecific interstitial pneumonia), honeycomb-type fibrocysts, and unexpected lesions were investigated. Descriptive and comparative (Fisher exact test) statistical analyses were used in the study (p < 0.05). A total of 27 cases were detected; age distribution was 17-68 (36.4). Smoking was present in 15 (55.5%) cases. Six (22.2%) cases were subacute, and 21 (7.7%) cases were subacute-chronic histological stage. A cystic lesion was present in 22 (81.4%) cases. All cases had emphysema accompanying the underlying lesions. Chronic nonspecific bronchiolitis was detected in 14 (51.8%) cases. Interstitial fibrosis was detected in 8 (29.6%) patients. Compared to interstitial fibrosis and nonfibrosis, there was no significant difference between being younger than 39 years, gender, smoking, and histological stage (p=0.41; 1; 0.69; 0.63, respectively). There is a risk of developing interstitial fibrosis patterns and honeycomb-type fibrocysts in the progression of pulmonary Langerhans cell histiocytosis. Histopathological evaluation can play an important role in the detection of risk groups.

Histopathological and microbiological study of porcine lymphadenitis: contributions to diagnosis and control of the disease

Tuberculosis like lesions (TBL) in free-range pigs are characterised by presenting a marked heterogeneity in pathology and microbiology features, with a notorious role of Mycobacterium tuberculosis complex (MTC), Trueperella pyogenes and different Streptococcus species. However, the capacity of these microorganism to spread to different organic cavities leading to a generalised disease is unknown. Therefore, this study evaluated the organic distribution of these agents in free-range pig carcasses whole condemned due to generalised TBL.A total of 37 totally condemned animals were analysed, and samples of lymph nodes and organs were obtained (n = 262) and subjected to histopathological and microbiological examination. In addition, T. pyogenes and streptococci species were further characterised by PFGE analysis. Two different patterns were evidenced with lack or occasional lesions in superficial inguinal (SILN) and popliteal (PLN) lymph nodes and advanced lesions in submandibular (SLN) (35/36) and gastrohepatic (GHLN) (33/35) lymph nodes (stages III and IV). Early stage granulomas (stage I and II) prevailed in lungs (16/20), liver (14/31) and spleen (7/18). The microbiological analysis revealed that MTC, detected by qPCR, was present in 31 out of 37 animals and 90 (90/262) samples. In 26 out of the 31 pigs, MTC was detected from two or more organs. SLN (24/31) and GHLN (19/31) were the MTC+ organs most frequently detected, with 29 out of 31 MTC+ pigs detected as positive in one or both samples, which points out that both lymph nodes must be included in the sampling of surveillance programs. Other pathogens, such as T. pyogenes and Streptococcus spp., were also involved in generalised lymphadenitis, being frequently isolated from SLN and other organs, such as liver (T. pyogenes), tonsils or lung (Streptococcus spp.). A wide genetic diversity among streptococci was observed, showing the ubiquitous character of these pathogens, however, the isolation of a single clone of T. pyogenes from different organic locations from animals with generalised TBL was a common finding of this study, highlighting that the role of this pathogen in porcine lymphadenitis may be underestimated. These results should be considered in future studies on the pathogenesis and control of porcine lymphadenitis.

Differential Cytokine Gene Expression in Granulomas from Lungs and Lymph Nodes of Cattle Experimentally Infected with Aerosolized Mycobacterium bovis.

The hallmark lesion of tuberculosis in humans and animals is the granuloma. The granuloma represents a distinct host cellular immune response composed of epithelioid macrophages, lymphocytes, and multinucleated giant cells, often surrounding a caseous necrotic core. Within the granuloma, host-pathogen interactions determine disease outcome. Factors within the granulomas such as cytokines and chemokines drive cell recruitment, activity, function and ultimately the success or failure of the host’s ability to control infection. Hence, an understanding of the granuloma-level cytokine response is necessary to understand tuberculosis pathogenesis. In-situ cytokine expression patterns were measured using a novel in situ hybridization assay, known as RNAScope® in granulomas of the lungs, tracheobronchial lymph nodes and caudal mediastinal lymph nodes of cattle experimentally infected with Mycobacterium bovis via aerosol exposure. In spite of microscopic morphological similarities, significant differences were seen between late stage granulomas of the lung compared to those of the tracheobronchial lymph nodes for IL-17A, IFN-γ, TGF-β, IL10 and IL-22 but not for TNF-α. Additionally, significant differences were noted between granulomas from two different thoracic lymph nodes that both receive afferent lymphatics from the lungs (i.e., tracheobronchial and caudal mediastinal lymph nodes) for TNF-α, IL-17A, IFN-γ, TGF-β and IL-10 but not for IL-22. These findings show that granuloma morphology alone is not a reliable indicator of granuloma function as granulomas of similar morphologies can have disparate cytokine expression patterns. Moreover, anatomically distinct lymph nodes (tracheobronchial vs caudal mediastinal) differ in cytokine expression patterns even when both receive afferent lymphatics from a lung containing tuberculoid granulomas. These findings show that selection of tissue and anatomic location are critical factors in assessing host immune response to M. bovis and should be considered carefully.

Multinucleated giant cell cytokine expression in pulmonary granulomas of cattle experimentally infected with Mycobacterium bovis

Regardless of host, pathogenic mycobacteria of the Mycobacterium tuberculosis complex such as Mycobacterium bovis, induce a characteristic lesion known as a granuloma, tubercle or tuberculoid granuloma. Granulomas represent a distinct host response to chronic antigenic stimuli, such as foreign bodies, certain bacterial components, or persistent pathogens such as M. bovis. Granulomas are composed of specific cell types including epithelioid macrophages, lymphocytes and a morphologically distinctive cell type, the multinucleated giant cell. Multinucleated giant cells are formed by the fusion of multiple macrophages; however, their function remains unclear. In humans, giant cells in tuberculous granulomas have been shown to express various cytokines, chemokines and enzymes important to the formation and maintenance of the granuloma. The objective of this study was to quantitatively assess multinucleated giant cell cytokine expression in bovine tuberculoid granulomas; focusing on cytokines of suspected relevance to bovine tuberculosis. Using calves experimentally infected with M. bovis, in situ cytokine expression was quantitatively assessed using RNAScope® for the following cytokines TNF-α, IFN-γ, TGF-β, IL-17A and IL-10. Multinucleated giant cells in bovine tuberculoid granulomas expressed all examined cytokines to varying degrees, with differential expression of TGF-β, IL-17A and IL-10 in giant cells from early versus late stage granulomas. There was a modest, positive correlation between the level of cytokine expression and cell size or number of nuclei. These results suggest that multinucleated giant cells are active participants within bovine tuberculoid granulomas, contributing to the cytokine milieu necessary to form and maintain granulomas.

Oral vaccination of white-tailed deer (Odocoileus virginianus) with Mycobacterium bovis Bacillus Calmette-Guerin (BCG).

Wildlife reservoirs of Mycobacterium bovis represent serious obstacles to the eradication of tuberculosis from livestock, particularly cattle. In Michigan, USA tuberculous white-tailed deer transmit M. bovis to other deer and cattle. One approach in dealing with this wildlife reservoir is to vaccinate deer, thus interfering with the intraspecies and interspecies transmission cycles. Thirty-three white-tailed deer were assigned to one of two groups; oral vaccination with 1×108 colony-forming units of M. bovis BCG Danish (n = 17); and non-vaccinated (n = 16). One hundred eleven days after vaccination deer were infected intratonsilarly with 300 colony-forming units of virulent M. bovis. At examination, 150 days after challenge, BCG vaccinated deer had fewer gross and microscopic lesions, fewer tissues from which M. bovis could be isolated, and fewer late stage granulomas with extensive liquefactive necrosis. Fewer lesions, especially those of a highly necrotic nature should decrease the potential for dissemination of M. bovis within the host and transmission to other susceptible hosts.

Vaccination with Mycobacterium bovis BCG Strains Danish and Pasteur in White‐tailed Deer (Odocoileus virginianus) Experimentally Challenged with Mycobacterium bovis

Wildlife reservoirs of Mycobacterium bovis represent serious obstacles to the eradication of tuberculosis in domestic livestock and the cause for many faltering bovine tuberculosis eradication programmes. One approach in dealing with wildlife reservoirs of disease is to interrupt inter-species and intraspecies transmission through vaccination of deer or cattle. To evaluate the efficacy of BCG vaccination in white-tailed deer, 35 deer were assigned to one of three groups; one s.c. dose of 10(7) CFU of M. bovis BCG Pasteur (n = 12); 1 s.c. dose of 10(7) CFU of M. bovis BCG Danish (n = 11); or unvaccinated deer (n = 12). After vaccination, deer were inoculated intratonsilarly with virulent M. bovis. Lesion severity scores of the medial retropharyngeal lymph node, as well as all lymph nodes combined, were reduced in vaccinated deer compared to unvaccinated deer. BCG Danish vaccinated deer had no late stage granulomas characterized by coalescent caseonecrotic granulomas containing numerous acid-fast bacilli compared to BCG Pasteur vaccinated or unvaccinated deer where such lesions were present. Both BCG strains were isolated as late as 250 days after vaccination from deer that were vaccinated but not challenged. In white-tailed deer, BCG provides protection against challenge with virulent M. bovis. Issues related to vaccine persistence, safety and shedding remain to be further investigated.

Absence of the SP/SP Receptor Circuitry in the Substance P-Precursor Knockout Mice or SP Receptor, Neurokinin (NK)1 Knockout Mice Leads to an Inhibited Cytokine Response in Granulomas Associated with Murine Taenia crassiceps Infection

Neurocysticercosis, caused by the cestode Taenia solium, is the most common parasitic infection of the human central nervous system that leads to seizures. Taenia crassiceps cysticercosis in mice is an experimental model for Taenia solium cysticercosis. Similar to the human infection, live parasites cause little or no granulomatous inflammation. Dying parasites initiate a granulomatous reaction. The neuropeptide, substance P (SP), stimulates T-helper (TH) 1 cytokine production. In the current studies, we determined whether absence of SP/SP receptor circuitry in the SP-precursor, preprotachykinin, knockout or SP-receptor, neurokinin (NK) 1, knockout mice affected granuloma cytokine production. We hence compared the levels of Th1 cytokines interleukin (IL)-2 and interferon (IFN)-gamma, and levels of Th2/immunoregulatory cytokines IL-4 and IL-10, by enzyme-linked immunosorbent assay in T. crassiceps-induced granulomas derived from infected C57BL/6 wild type (WT) versus SP-precursor knockout and NK1 knockout mice. We found that mean levels of IL-2, IFN-gamma, IL-4, and IL-10 in infected WT-derived granulomas were significantly higher than those of granulomas derived from infected SP-precursor knockout or the NK1 receptor (NKIR)knockout mice. Levels of Th2/immunoregulatory cytokines, IL-4 and IL-10 were higher in early stage granulomas (histologically-staged on basis of evidence of parasite remnants) versus late stage granulomas (no parasite-remnants) of both knockouts, whereas the reverse was noted in WT-derived granulomas. These study established that the absence of an SP/SP receptor circuitry in the SP precursor knockout mice or NK1 receptor knockout mice led to an inhibited cytokine response.

Vaccination of white-tailed deer (Odocoileus virginianus) with Mycobacterium bovis bacillus Calmette Guerín

Wildlife reservoirs of Mycobacterium bovis represent serious obstacles to the eradication of tuberculosis in domestic livestock. In Michigan, USA tuberculous white-tailed deer transmit M. bovis to cattle. One approach in dealing with this wildlife reservoir is to vaccinate deer in order to interrupt the cycle of deer to deer and deer to cattle transmission. Thirty-one white-tailed deer were assigned to one of three groups; 2 SC doses of 10(7)CFU of M. bovis BCG (n=11); 1 SC dose of 10(7)CFU of M. bovis BCG (n=10); or unvaccinated deer (n=10). After vaccination, deer were inoculated intratonsilarly with 300 CFU of virulent M. bovis. Gross lesion severity scores of the medial retropharyngeal lymph node were significantly reduced in deer receiving 2 doses of BCG compared to unvaccinated deer. Vaccinated deer had fewer lymph node granulomas than unvaccinated deer, and most notably, fewer late stage granulomas characterized by coalescent caseonecrotic granulomas containing numerous acid-fast bacilli. BCG was isolated from 7/21 vaccinated deer as long as 249 days after vaccination. In one case BCG was transmitted from a vaccinated deer to an unvaccinated deer. In white-tailed deer BCG provides measurable protection against challenge with virulent M. bovis. However, persistence of vaccine within tissues as well as shedding of BCG from vaccinates remain areas for further investigation.

PROINFLAMMATORY CYTOKINES IN GRANULOMAS ASSOCIATED WITH MURINE CYSTICERCOSIS ARE NOT THE CAUSE OF SEIZURES

Neurocysticercosis is a parasitic infection of the human central nervous system caused by the cestode Taenia solium. The most common clinical manifestations of neurocysticercosis are seizures. Taenia crassiceps cysticercosis in mice has been used as an experimental model for T. solium cysticercosis. Granulomas surrounding murine cysticerci have striking immunopathological resemblance to human neurocysticercosis; early stage granulomas were able to induce seizures in a rodent model. To assess the role of proinflammatory cytokines in early stage granulomas, we isolated RNA from murine cysticercal granulomas and checked for cytokine expression by reverse transcriptase-polymerase chain reaction (RT-PCR) and/or ribonuclease (RNase) protection assays. Cytokine expression was compared with histological stages. Interleukin (IL)-1alpha, IL-1beta, IL-1 receptor antagonist, and tumor necrosis factor (TNF-alpha) were the major cytokines detected in all granulomas. Signals for IL-12, IL-18, and IL-6 RNA were not consistently detected and, when detected, were barely demonstrable. Expression of migration inhibitory factor (MIF), IL-6, IL-1alpha, TNF-alpha, and IL-18 was not significantly different between early and late-stage granulomas. Expression of IL-1beta, IL-1 receptor antagonist, and IL-12 p40 were higher in late, compared with early, stages. Thus, we demonstrated a broad range of cytokines in these granulomas. However, we did not document preferential expression of any proinflammatory cytokines in early stage granulomas. Thus, proinflammatory cytokines are not responsible for the seizures in the rodent model of neurocysticercosis.

Advanced Granulomatous Lesions in Mycobacterium bovis-infected Cattle are Associated with Increased Expression of Type I Procollagen, γδ (WC1 +) T Cells and CD 68 + Cells

The pathognomonic characteristic of tuberculosis (TB) is the formation of a tuberculous granuloma. The objective of this study was to classify lymph node granulomas from experimentally infected calves into different histopathological stages and characterize them further by studying cell types and markers of fibrosis associated with each of the stages. Four stages of granuloma were identified and mRNA and protein expression for cell markers, cytokines and pro-fibrotic markers were studied by immunohistochemistry (IHC) and in-situ hybridization (ISH). In advanced stage granulomas, there was an increase in the expression of TGF-beta, and of type I procollagen as demonstrated by IHC and ISH. As the granulomas advanced, there were fewer CD3+T cells and they tended to be more prominent towards the periphery of the lesions, with a steady increase in the number of CD68+ cells and gammadelta (WC1+) T cells. Granuloma classification and application of cell cytokine markers will assist in improving understanding of the pathogenesis of bovine TB and may help to identify the immunopathology of active disease versus contained or inactive disease. Such disease correlates may help to inform the development of improved diagnostic methods and support vaccine development programmes.

Epileptogenic activity of granulomas associated with murine cysticercosis

Neurocysticercosis, caused by Taenia solium, is a common cause of neurologic disease in developing countries and among immigrants to the United States. Seizures are the most common clinical manifestation of neurocysticercosis. Imaging studies of patients with seizures from neurocysticercosis typically reveal evidence of an inflammatory reaction associated with the parasite or calcified granulomas. This study investigated whether a substance produced by the host granulomatous reaction to the dying parasite, in a mouse model of the infection, is sufficient to induce epileptiform activity. Granulomas associated with Taenia crassiceps cysticerci were removed from the peritoneal cavity of infected mice. One piece of the granuloma was used for blinded histological staging of the dying parasite. The second piece was used to generate extracts, which were injected into the hippocampus of an anesthetized Sprague-Dawley rat. Positive controls included animals injected with kainic acid, picrotoxin, or bicuculline. Seizures were recorded after injection of extracts from 6 out of 6 early stage granulomas, but only 1 out of 9 late stage granulomas. Injections of buffered saline, extracts from non-stimulated mouse spleen cells, and homogenates of viable parasite material caused no epileptiform activity. The data suggest that a substance in the granulomas early in the inflammatory response to the dying parasite is capable of inducing seizure activity. Further experiments are needed to dissect out the exact seizure mediator in the granuloma extracts.

Hypertrophic pachymeningitis: case report

Hypertrophic pachymeningits is an unusual cause of neurological symptoms and is often secondary to infections, carcinomatosis or inflammatory diseases. It may also be idiopathic. We report a case of pachymeningitis which was manifested primarily by psychosis and visual loss with optic atrophy and destruction of nasal septum. The patient, a 45 year old woman was submitted to extensive investigation without evidence of any underlying disease. A meningeal biopsy was performed and showed a mostly unspecific inflammatory process with extensive fibrosis of the dura and few early stage granulomas. These findings suggest either neurosarcoidosis or idiopathic hypertrophic pachymeningitis.

The role of macrophage inflammatory protein 1 alpha in Schistosoma mansoni egg-induced granulomatous inflammation.

Macrophage inflammatory protein 1 alpha (MIP-1 alpha) is a 6-8-kD, lipopolysaccharide-inducible monocyte and neutrophil chemotactic protein that may be important in acute and chronic inflammation. The present study determined the sequential production, source, and in vivo contribution of murine MIP-1 alpha in synchronized Schistosoma mansoni egg pulmonary granuloma formation. Granulomas were examined under conditions of primary, secondary vigorous, and secondary immunomodulated immunity. Secreted MIP-1 alpha was measured in 24-h supernatants from intact granulomas (700/ml) cultured with or without soluble egg antigen (SEA). Primary granulomas isolated from naive mice over a 16-d period showed low spontaneous MIP-1 alpha production (< 1 ng/ml). However, when primary granulomas were challenged with SEA, significant MIP-1 alpha production was observed beginning at day 4 and peaking at day 16. Intact vigorous (isolated from 8-wk-infected mice) and modulated (isolated from 20-wk-infected mice) secondary pulmonary granulomas demonstrated comparable spontaneous MIP-1 alpha production. Addition of SEA to vigorous stage granulomas augmented expression of MIP-1 alpha at all time points, whereas stimulated modulated stage granulomas did not increase production. The latter observation is likely related to endogenous immunoregulatory mechanisms reported for modulated stage animals. Immunohistochemical localization of MIP-1 alpha in granuloma sections and cytocentrifuge preparations from vigorous lesions localized MIP-1 alpha production to macrophages within granulomas. Treatment of mice with rabbit anti-mouse MIP-1 alpha antibodies significantly decreased 8-d primary granuloma formation (> 40%) when compared with control mice. Anti-MIP-1 alpha sera also decreased vigorous (> 20%), but not modulated granuloma formation. These findings demonstrate that MIP-1 alpha contributes to cellular recruitment during schistosome egg granuloma formation.