Mycobacterium avium subsp. paratuberculosis Antigens Elicit a Strong IgG4 Response in Patients with Multiple Sclerosis and Exacerbate Experimental Autoimmune Encephalomyelitis

Neuroinflammation can be triggered by microbial products disrupting immune regulation. In this study, we investigated the levels of IgG1, IgG2, IgG3, and IgG4 subclasses against the heat shock protein (HSP)70_533-545 peptide and lipopentapeptide (MAP_Lp5) derived from Mycobacterium avium subsp. paratuberculosis (MAP) in the blood samples of Japanese and Italian individuals with relapsing remitting multiple sclerosis (MS). Additionally, we examined the impact of this peptide on MOG-induced experimental autoimmune encephalomyelitis (EAE). A total of 130 Japanese and 130 Italian subjects were retrospectively analyzed using the indirect ELISA method. Furthermore, a group of C57BL/6J mice received immunization with the MAP_HSP70_533-545 peptide two weeks prior to the active induction of MOG_35-55 EAE. The results revealed a significantly robust antibody response against MAP_HSP70_533-545 in serum of both Japanese and Italian MS patients compared to their respective control groups. Moreover, heightened levels of serum IgG4 antibodies specific to MAP antigens were correlated with the severity of the disease. Additionally, EAE mice that were immunized with MAP_HSP70_533-545 peptide exhibited more severe disease symptoms and increased reactivity of MOG_35-55-specific T-cell compared to untreated mice. These findings provide evidence suggesting a potential link between MAP and the development or exacerbation of MS, particularly in a subgroup of MS patients with elevated serum IgG4 levels.

Adjuvant Activity of Mycobacterium paratuberculosis in Enhancing the Immunogenicity of Autoantigens During Experimental Autoimmune Encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) induced by myelin oligodendrocyte glycoprotein (MOG) requires immunization by a MOG peptide emulsified in complete Freund's adjuvant (CFA) containing inactivated Mycobacterium tuberculosis. The antigenic components of the mycobacterium activate dendritic cells to stimulate T-cells to produce cytokines that promote the Th1 response via toll-like receptors. Therefore, the amount and species of mycobacteria present during the antigenic challenge are directly related to the development of EAE. This methods paper presents an alternative protocol to induce EAE in C57BL/6 mice using a modified incomplete Freund's adjuvant containing the heat-killed Mycobacterium avium subspecies paratuberculosis strain K-10. M. paratuberculosis, a member of the Mycobacterium avium complex, is the causative agent of Johne's disease in ruminants and has been identified as a risk factor for several human T-cell-mediated disorders, including multiple sclerosis. Overall, mice immunized with Mycobacterium paratuberculosis showed earlier onset and greater disease severity than mice immunized with CFA containing the strain of M. tuberculosis H37Ra at the same doses of 4 mg/mL. The antigenic determinants of Mycobacterium avium subspecies paratuberculosis (MAP) strain K-10 were able to induce a strong Th1 cellular response during the effector phase, characterized by significantly higher numbers of T-lymphocytes (CD4⁺ CD27⁺), dendritic cells (CD11c⁺ I-A/I-E⁺), and monocytes (CD11b⁺ CD115⁺) in the spleen compared to mice immunized with CFA. Furthermore, the proliferative T-cell response to the MOG peptide appeared to be highest in M. paratuberculosis-immunized mice. The use of an encephalitogen (e.g., MOG35-55) emulsified in an adjuvant containing M. paratuberculosis in the formulation may be an alternative and validated method to activate dendritic cells for priming myelin epitope-specific CD4⁺ T-cells during the induction phase of EAE.

A mucosal immune response induced by oral administration of heat-killed Mycobacterium avium subsp. paratuberculosis exacerbates EAE

Findings in humans and animals have demonstrated a potential role for Mycobacterium avium subsp. paratuberculosis (MAP) antigenic components in encephalitogenic T cell activation. Here we reported that oral administration of MAP activates the mucosal immunity and exacerbates active experimental autoimmune encephalomyelitis (EAE) in C57BL/6J mice, modulating the immune cell traffic from secondary lymphoid organs to central nervous system. The detection of antigenic mycobacterial components by intestinal antigen-presenting cells may modulate the immune system and the subsequent inflammatory status through various signaling mechanisms, including the synthesis of pro-inflammatory cytokines involved in EAE pathogenesis.

Control of paratuberculosis: who, why and how. A review of 48 countries

Paratuberculosis, a chronic disease affecting ruminant livestock, is caused by Mycobacterium avium subsp. paratuberculosis (MAP). It has direct and indirect economic costs, impacts animal welfare and arouses public health concerns. In a survey of 48 countries we found paratuberculosis to be very common in livestock. In about half the countries more than 20% of herds and flocks were infected with MAP. Most countries had large ruminant populations (millions), several types of farmed ruminants, multiple husbandry systems and tens of thousands of individual farms, creating challenges for disease control. In addition, numerous species of free-living wildlife were infected. Paratuberculosis was notifiable in most countries, but formal control programs were present in only 22 countries. Generally, these were the more highly developed countries with advanced veterinary services. Of the countries without a formal control program for paratuberculosis, 76% were in South and Central America, Asia and Africa while 20% were in Europe. Control programs were justified most commonly on animal health grounds, but protecting market access and public health were other factors. Prevalence reduction was the major objective in most countries, but Norway and Sweden aimed to eradicate the disease, so surveillance and response were their major objectives. Government funding was involved in about two thirds of countries, but operations tended to be funded by farmers and their organizations and not by government alone. The majority of countries (60%) had voluntary control programs. Generally, programs were supported by incentives for joining, financial compensation and/or penalties for non-participation. Performance indicators, structure, leadership, practices and tools used in control programs are also presented. Securing funding for long-term control activities was a widespread problem. Control programs were reported to be successful in 16 (73%) of the 22 countries. Recommendations are made for future control programs, including a primary goal of establishing an international code for paratuberculosis, leading to universal acknowledgment of the principles and methods of control in relation to endemic and transboundary disease. An holistic approach across all ruminant livestock industries and long-term commitment is required for control of paratuberculosis.

Altered humoral immunity to mycobacterial antigens in Japanese patients affected by inflammatory demyelinating diseases of the central nervous system

Mycobacterium avium subsp. paratuberculosis (MAP) and Mycobacterium bovis (BCG) have been associated to several human autoimmune diseases such as multiple sclerosis (MS), but there are conflicting evidence on the issue. The objective of this study is to evaluate their role in Japanese patients affected by inflammatory demyelinating disorders of the central nervous system (IDDs). A total of 97 IDDs subjects including 51 MS and 46 neuromyelitis optica spectrum disorder (NMOSD) patients, and 34 healthy controls (HCs) were tested for the detection of IgG, IgM and IgA against mycobacterial antigens by indirect ELISA. The levels of anti-MAP IgG were higher in MS patients compared to NMOSD patients (AUC = 0.59, p = 0.02) and HCs (AUC = 0.67, p = 0.01), and the anti-MAP antibodies were more prevalent in MS patients treated with interferon-beta (OR = 11.9; p = 0.004). Anti-BCG IgG antibodies were detected in 8% of MS, 32% of NMOSD and 18% of HCs, the difference between MS and NMOSD groups was statistically significant (AUC = 0.66, p = 0.005). Competition experiments showed that nonspecific IgM were elicited by common mycobacterial antigens. Our study provided further evidence for a possible association between MAP and MS, while BCG vaccination seemed to be inversely related to the risk of developing MS.

Structure determination of lipopeptides from Mycobacterium avium subspecies paratuberculosis and identification of antigenic lipopeptide probes

Mycobacterium avium subspecies paratuberculosis (MAP) causes chronic illnesses mostly in ruminants. MAP infection of intestinal tissue triggers a fatal inflammatory disorder, Johne's disease (paratuberculosis). Development of fast and reliable diagnostic methods for Johne's disease in clinically suspected ruminants requires the discovery of MAP-specific antigens that induce immune responses. Despite a longtime interest in finding such antigens that can detect serum antibody responses with high sensitivity, the antigens currently used for a diagnosis of the MAP infections are the crude extracts from the whole cell. We performed the serum antibody response assay-guided purification of the ethanol extract from MAP isolated from an infected cow. With the results of extensive fractionations and in vitro assays, we identified that arachidyl-d-Phe-N-Me-l-Val-l-Ile-l-Phe-l-Ala-OH (named lipopeptide IIß, 3) exhibited the highest antibody binding activity in serum of a MAP-infected cattle compared with the other lipopeptides isolated from MAP. The absolute chemistry of 3 was determined unequivocally via our high-performance liquid chromatography (HPLC)-amino acid databases. α-Amino lipopeptide IIß and its fluorescent probes were synthesized and evaluated in serum antibody binding activity assays. Lipopeptide IIß-(2S)-NH2 (9) and its dansyl and fluorescein isothiocyanate (FITC) probes (10 and 11) exhibited antibody-mediated binding activity; thus, such MAP-specific lipopeptide probes can be potential biomarkers for the development of rapid and accurate diagnosis of Johne's disease.

Elimination Half-Lives of Acute Phase Proteins in Rats and Beagle Dogs During Acute Inflammation

The half-lives of typical acute phase proteins in rats and beagle dogs during acute inflammation were investigated. Acute inflammation was induced by injection of turpentine oil in rats and administration of indomethacin in beagle dogs. Serum concentrations of α2-macroglobulin (α2M) and C-reactive protein (CRP) were measured by enzyme-linked immunosorbent assay and α1-acid glycoprotein (AAG) was measured by single radial immunodiffusion. Half-life was calculated as 0.693/elimination rate constant (K). The mean half-lives in the terminal elimination phase of α2M and AAG were 68.1 and 164.8 h, respectively. The half-life of AAG was significantly longer than that of α2M. Mean half-lives in the terminal elimination phase of CRP and AAG were 161.9 and 304.4 h, respectively. The half-life of AAG was significantly longer than that of CRP in beagle dogs. No significant differences in the half-life of AAG were observed between rats and beagle dogs. Furthermore, serum concentrations in the terminal elimination phase could be simulated with the K data acquired in this study.

Seroprevalence of IgG1 and IgG4 class antibodies against Mycobacterium avium subsp. paratuberculosis in Japanese population

Mycobacterium avium subsp. paratuberculosis (MAP) is the established causative agent of Johne's disease in cattle and other ruminants, and it has also been speculated to be a putative etiological agent of several human autoimmune diseases. It is acknowledged that dairy products deriving from infected animals play a role (could be vehicles) in exposing humans to MAP. MAP could stimulate the human immune system by means of their complex antigen (in the case of lipids, multivalent antigens) and may modulate it, acting as adjuvant molecules such as Freund's complete adjuvant. The immune system might be abnormally stimulated by the constant presence of MAP antigens (for example, in the dairy products), and this might be particularly relevant in genetically predisposed individuals. However, there is limited understanding about the current human exposure to MAP. The present study analyzed the antibody recognition profile of MAP lipophilic antigens in a cohort of 126 healthy Japanese. We measured the serum levels of total immunoglobulin G (IgG) and subclasses targeting MAP surface antigens through ethanol vortex indirect enzyme-linked immunosorbent assay (EVELISA) by using serum absorbed with Mycobacterium phlei. Elevated IgG (especially IgG1 and IgG4) responses were observed in 14% of the sera. To assess the specificity of EVELISA, the same samples were analyzed by means of a commercially available Johnelisa II kit. It was noteworthy that a high degree of correlation was observed when comparing the two methodologies (rs=0.7, p<0.0001). Moreover, in order to investigate the specificity of the binding, inhibition assay experiments were carried out also searching for antibodies against Bacillus Calmette-Guérin antigens, but no cross-reaction was observed. The result obtained represents the first evidence implying that the Japanese population is exposed to MAP, and additionally the existence of a foodborne chain of exposure that transmits MAP antigens to humans.

An immuno-epidemiological model for Johne's disease in cattle

To better understand the mechanisms involved in the dynamics of Johne’s disease in dairy cattle, this paper illustrates a novel way to link a within-host model for Mycobacterium avium ssp. paratuberculosis with an epidemiological model. The underlying variable in the within-host model is the time since infection. Two compartments, infected macrophages and T cells, of the within-host model feed into the epidemiological model through the direct transmission rate, disease-induced mortality rate, the vertical transmission rate, and the shedding of MAP into the environment. The epidemiological reproduction number depends on the within-host bacteria load in a complex way, exhibiting multiple peaks. A possible mechanism to account for the switch in shedding patterns of the bacteria in this disease is included in the within-host model, and its effect can be seen in the epidemiological reproduction model.

Mycobacterium avium subsp. paratuberculosis lipophilic antigen causes Crohn's disease-type necrotizing colitis in Mice

Background: A 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced murine colitis model was developed to investigate the pathogenesis and to evaluate a method of treating human Crohn’s disease. This experimental model rapidly induces colitis similar to human Crohn’s disease lesion in a reproducible manner. However, natural exposure of the human digestive tract to TNBS is unrealistic. A novel animal model based on realistic data is eagerly anticipated in future research on pathogenesis of CD. Method: We evaluated the potency of Map antigen molecules in an effort to develop a novel colitis model using a more realistic source than TNBS. We prepared the Map antigen by ethanol extraction and developed a mouse model in a manner similar to that of the well-known TNBS-induced colitis in mice. In the experiment, seven days after subcutaneous (SC) injection of the antigen into normal C57BL/6 mice, the same antigen in 50% ethanol was injected into the colon by the transanal route with a fine cannula. Results: On the fifth day after the transanal injection, histopathological examination revealed full-thickness necrotizing colitis with erosion and ulcers; severe infiltration with neutrophils, lymphocytes, macrophages, and perforation. However, no change was detected with each single Map-antigen injection. Conclusion: The present results provide a novel animal model for research on CD and may be the key to clarifying the relationship between CD and Map. This is the first evidence that mycobacterium antigen induces necrotizing colitis.

Impairment of α(2)-macroglobulin synthesis in experimental hepatopathic rats treated with turpentine oil

The aim of this study was to investigate the synthesis of α(2)-macroglobulin (α2M) in hepatopathic rats injected with turpentine oil to induce acute inflammation. Hepatopathy was induced by oral administration of acetaminophen at a dose of 1 g/kg daily for 2 weeks or a 25% solution of carbon tetrachloride (CCl(4)) at 2 ml/kg body weight three times per week for 7 weeks. Acute inflammation was induced by intramuscular injection of turpentine oil at a dose of 1.0 ml/kg body weight. Serum concentrations of α2M were measured by enzyme-linked immunosorbent assay. Aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and total protein differed significantly between acetaminophen or CCl(4)-induced hepatopathic rats and acetaminophen control (AA-control) or CCl(4) control (CC-control) rats. Furthermore, pathological examination confirmed hepatopathy in rat livers. Peak serum concentrations and area under the time-concentration curve for α2M showed significant differences between hepatopathic rats and AA-control or CC-control rats. Thus, serum concentrations of α2M did not increase when compared with nontreated rats.

Epidemiological situation and control strategies for paratuberculosis in Japan

Paratuberculosis (Ptb), caused by Mycobacterium avium subsp. paratuberculosis (Map), is a chronic and progressive granulomatous enteritis that affects many livestock and wild animals worldwide. The clinical disease is called Johne's disease (JD). In Japan, all dairy cattle (harf million head) are examined for Ptb every five years. About 1000 the officially examined cattle are diagnosed annually as positive for Ptb, but most of these exhibit only minor or no clinical signs and typical lesions in recent years. In contrast to the situation in Japan, the disease prevalence in western countries is very high. We have used ELISA and a culture examination of Map, and recently real-time PCR to diagnose this disease. In this review, the author outlines the history of the epidemic and national practical strategies to control paratuberculosis in Japan.

Decreased expression of matrix metalloproteinase-9 and increased expression of tissue inhibitors of matrix metalloproteinase-1 in paratuberculosis-infected cattle in the ELISA-negative subclinical stage

We investigated the gene expression of matrix metalloproteinases-9 (MMP-9) and tissue inhibitors of matrix metalloproteinases-1 (TIMP-1) in peripheral blood cells from infected cattle with Mycobacterium avium subsp. paratuberculosis (Map) in the ELISA-negative subclinical stage compared with uninfected control cattle. Significant decreased MMP-9 expression and increased TIMP-1 expression were found in peripheral blood cells from Map-infected cattle after stimulation with Map lysate and Map purified protein derivative (PPD) than in control cattle by real-time RT-PCR analysis. In contrast to the uninfected controls, the activity of MMP-9 was also decreased in peripheral blood cell culture supernatants from Map-infected cattle at 24 hr after Map lysate and MapPPD stimulation by gelatin zymography analysis. As a result, the MMP-9 may play an important role in the development of Mycobacterium avium subsp. paratuberculosis disease.

Localization of insulinoma associated protein 2, IA-2 in mouse neuroendocrine tissues using two novel monoclonal antibodies

AIMS

Insulinoma-associated protein 2 (IA-2) is a member of the protein tyrosine phosphatase family that is localized on the insulin granule membrane. IA-2 is also well known as one of the major autoantigens in Type 1 diabetes mellitus. IA-2 gene deficient mice were recently established and showed abnormalities in insulin secretion. Thus, detailed localization of IA-2 was studied using wild-type and IA-2 gene deficient mice.

MAIN METHODS

To localize IA-2 expression in mouse neuroendocrine tissues, monoclonal antibodies were generated against IA-2 and western blot and immunohistochemical analyses were carried out in IA-2(+/+) mice. IA-2(-/-) mice served as a negative control.

KEY FINDINGS

Western blot analysis revealed that the 65 kDa form of IA-2 was observed in the cerebrum, cerebellum, medulla oblongata, pancreas, adrenal gland, pituitary gland, muscular layers of the stomach, small intestine, and colon. By immunohistochemical analysis, IA-2 was produced in endocrine cells in pancreatic islets, adrenal medullary cells, thyroid C-cells, Kulchitsky cells, and anterior, intermediate, and posterior pituitary cells. In addition, IA-2 was found in somatostatin-producing D-cells and other small populations of cells were scattered in the gastric corpus. IA-2 expression in neurites was confirmed by the immunostaining of IA-2 using primary cultured neurons from the small intestine and nerve growth factor (NGF)-differentiated PC12 cells.

SIGNIFICANCE

The IA-2 distribution in peripheral neurons appeared more intensely in neurites rather than in the cell bodies.

Corticotropin-releasing hormone and urocortin expression in peripheral blood cells from experimentally infected cattle with Mycobacterium avium subsp. paratuberculosis

Urocortin (UCN) is a new neuropeptide of the corticotrophin-releasing hormone (CRH) family which plays an important role in immune responses. Mycobacterium avium subspecies paratuberculosis (Map) is the etiological agent of paratuberculosis (Johne's disease). The role of UCN or CRH in the pathogenesis of Map-infection is unknown. In the present study, we first cloned the bovine UCN gene and demonstrated the profile of UCN or CRH expression in peripheral blood cells from Map-infected cattle and uninfected controls by real-time reverse transcription-polymerase chain reaction (RT-PCR) and ELISA analysis. These data are the first observations of the characteristic kinetics of these neuropeptides in Map-infection. UCN or CRH expression in non-stimulated blood samples from infected cattle was higher than that in similarly treated samples from uninfected controls; however, exposure to Map lysate and live Map resulted in down-regulated expression of UCN in infected cattle compared to their counterparts from uninfected controls. These results have provided a direction in understanding the pathogenesis of paratuberculosis and improving diagnostic methods for Map-infection.

IL-1beta inhibits intestinal smooth muscle proliferation in an organ culture system: involvement of COX-2 and iNOS induction in muscularis resident macrophages

Intestinal inflammation causes hyperplasia of smooth muscle that leads to thickening of the smooth muscle layer, resulting in dysmotility. IL-1beta is a proinflammatory cytokine that plays a central role in intestinal inflammation. In this study, to evaluate the effect of IL-1beta on proliferation of ileal smooth muscle cells in vivo, we utilized an organ culture system. When rat ileal smooth muscle tissue was cultured under serum-free conditions for 3 days, most smooth muscle cells maintained their arrangement and kept their contractile phenotype. When 10% FBS was added, an increased number of smooth muscle cells per unit area was observed. Moreover, immunohistochemical staining for PCNA demonstrated that FBS induced proliferation of smooth muscle cells. IL-1beta inhibited the proliferative effect of FBS. Furthermore, IL-1beta upregulated inducible nitric oxide (NO) synthase and cyclooxygenase-2 mRNA and protein and thus stimulated NO and PGE(2) productions. Moreover, exogenously applied NO and PGE(2) inhibited the increase of bromodeoxyuridine-positive cells stimulated with FBS. Immunostaining revealed that the majority of cyclooxygenase-2 and inducible NO synthase was located in the dense network of macrophages resident in the muscularis, which were immunoreactive to ED2. Based on these findings, IL-1beta acts as an anti-proliferative mediator, which acts indirectly through the production of PGE(2) and NO from resident macrophage within ileal smooth muscle tissue.

Intestinal inflammation downregulates smooth muscle CPI-17 through induction of TNF-alpha and causes motility disorders

Motility disorders are frequently observed in intestinal inflammation. We previously reported that in vitro treatment of intestinal smooth muscle tissue with IL-1beta decreases the expression of CPI-17, an endogenous inhibitory protein of smooth muscle serine/threonine protein phosphatase, thereby inhibiting contraction. The present study was performed to examine the pathophysiological importance of CPI-17 expression in the motility disorders by using an in vivo model of intestinal inflammation and to define the regulatory mechanism of CPI-17 expression by proinflammatory cytokines. After the induction of acute ileitis with 2,4,6,-trinitrobenzensulfonic acid, CPI-17 expression declined in a time-dependent manner. This decrease in CPI-17 expression was parallel with the reduction of cholinergic agonist-induced contraction of smooth muscle strips and sensitivity of permeabilized smooth muscle fibers to Ca(2+). Among the various proinflammatory cytokines tested, TNF-alpha and IL-1beta were observed to directly inhibit CPI-17 expression and contraction in cultured rat intestinal tissue. Moreover, both TNF-alpha and IL-1beta inhibited CPI-17 expression and contraction of smooth muscle tissue isolated from wild-type and IL-1alpha/beta double-knockout mice. However, IL-1beta treatment failed to inhibit CPI-17 expression and contraction in TNF-alpha knockout mice. In beta-escin-permeabilized ileal tissues, pretreatment with anti-phosphorylated CPI-17 antibody inhibited the carbachol-induced Ca(2+) sensitization in the presence of GTP. These findings suggest that CPI-17 was downregulated during intestinal inflammation and that TNF-alpha plays a central role in this process. Downregulation of CPI-17 may play a role in motility impairments in inflammation.

Anti-bovine CD34 monoclonal antibody reveals polymorphisms within coding region of the CD34 gene

OBJECTIVE

Monoclonal antibodies (mAbs) against CD34 are widely used for purification of CD34+ hematopoietic as well as nonhematopoietic stem/progenitor cells. We produced mAbs against bovine CD34 (boCD34) to facilitate the study of hematopoiesis in cattle.

METHODS

MAbs were produced by immunizing BALB/c mice with BALB/3T3 cells transfected with boCD34 cDNA. Staining of bone marrow mononuclear cells (BMMNCs) from 10 newborn Holstein calves with the mAbs was examined by flow cytometry. The nucleotide sequence of the coding region for boCD34 in each calf was determined after amplification of the cDNA by reverse-transcription polymerase chain reaction (RT-PCR). BoCD34 fusion proteins, each representing one of the boCD34 alleles found to exist in the calves, were expressed in HeLa cells by DNA transfection, and the staining of these proteins with the mAbs was assessed.

RESULTS

One mAb, N21, stained relatively high percentages of BMMNCs from 4 calves but failed to stain those from the other calves. RT-PCR analysis revealed single-nucleotide polymorphisms within the coding region, 3 of which led to amino-acid substitutions. A CD34 mutation experiment indicated that mAb N21 bound to a boCD34 allele with tryptophan at amino acid 167 but not to that with arginine.

CONCLUSION

By using mAb N21 as an allelic cell marker, it would be feasible to detect and isolate boCD34+ cell species derived from N21+ donors in N21- recipients following allogeneic in utero transplantation; this would make cattle potentially useful as large animal models with a unique experimental advantage.

Role of TNF-alpha in muscularis inflammation and motility disorder in a TNBS-induced colitis model: clues from TNF-alpha-deficient mice

Macroscopic and histological analysis revealed that the colonic inflammation induced by 2,4,6-trinitrobenzenesulphonic acid (TNBS) was of lower grade in tumour necrosis factor-alpha (TNF-alpha)(-/-) mice than in wild-type mice. Myeloperoxidase activity, an indicator of neutrophilic infiltration, was also low in both the mucosal and smooth muscle layer of the TNF-alpha(-/-) mouse colon. After the induction of inflammation with TNBS, the levels of proinflammatory cytokines, such as TNF-alpha, interleukin-1beta and interleukin-6, were elevated both in the inflamed mucosa and muscle layers in the wild-type mice; however, the productions of these cytokines were greatly reduced in the TNF-alpha(-/-) mouse colon. The contractions of isolated colonic smooth muscle strips induced by several stimulatory agents were significantly decreased after treatment with TNBS in wild-type mice; however, these contractions were scarcely affected in TNF-alpha(-/-) mice. Finally, using the organ culture method, we found that TNF-alpha directly (independent of mucosal inflammation) disturbs the smooth muscle function. These results suggest that TNF-alpha plays an essential role not only in mucosal inflammation but also in muscularis inflammation in the colon of mice with TNBS-induced colitis, and that TNF-alpha directly induces motor dysfunctions by acting on the smooth muscle.

Protective effects of synthetic antibacterial oligopeptides based on the insect defensins on Methicillin-resistant Staphylococcus aureus in mice

Synthetic 9-mer peptides, ALYLAIRRR-NH2 and ALYLAIRKR-NH2, designed from the amino acid sequences of active sites of insect defensins, were examined for their protective effect on Methicillin-resistant Staphylococcus aureus (MRSA) in infected mice. These peptides protected mice from lethal MRSA challenges, despite having their antibacterial activity diminished in physiological high salt conditions. These peptides suppressed the induction of tumor necrosis factor alpha gene expression by lipopolysaccharide or lipoteichoic acid in murine macrophages, contributing to protection of mice from lethal MRSA infections in vivo. The results suggest that these peptides are potential candidates for future therapeutic agents against antibiotic-resistant bacterial infection.

Susceptibility of TNF-alpha-deficient mice to Trypanosoma congolense is not due to a defective antibody response

C57BL/6 mice deficient in one or two copies of the gene for tumor necrosis factor alpha (TNF-alpha) were more susceptible to Trypanosoma congolense infection than their resistant, wild-type counterparts. The number of TNF-alpha genes was correlated with the capacity to control parasitaemia and with survival time. Absence of TNF-alpha resulted in a diminished capacity to form germinal centres in lymph nodes and spleen. Since germinal centres are involved in antibody production and affinity maturation, the susceptibility of the TNF-alpha-deficient mice could have been due to this secondary defect. Despite the lack of the germinal centres, the antibody responses to internal and exposed trypanosome antigens and to non-trypanosome antigens were not significantly different. Also the relative avidities measured in infected sera did not significantly differ between the two mouse strains. These data suggest that the role of TNF-alpha in control of T. congolense was not due to its role in the development of an antibody response.

Muscularis inflammation and the loss of interstitial cells of Cajal in the endothelin ETB receptor null rat

Endothelin receptor null rats [ETB(-/-)] are a model for long-segment Hirschsprung's disease. These animals have significant intestinal distension (megaileum) proximal to a constricted region of the gastrointestinal tract lacking enteric ganglia. Experiments were performed to determine the pathophysiological changes that occur in these animals and to examine the tunica muscularis as a unique, immunologically active compartment. We observed abnormal intestinal flora in ETB(-/-) rats, which included a marked increase in gram-negative aerobes (Enterobacteriaceae) and anaerobes (Bacteroidaceae) in the distended region of the small intestine. Histochemical observations showed that neutrophilic infiltration was rarely or not observed, but the number of ED2 positive macrophages was increased in the tunica muscularis. Expression of IL-1beta and IL-6 mRNA was also significantly increased, and the level of CD14 (LPS receptors) were increased significantly in the tunica muscularis. Spontaneous phasic contractions were irregular in the distended intestinal regions of ETB(-/-) rats, and this was associated with an increased number of macrophages and damage to interstitial cells of Cajal (ICC) as revealed by using Kit-like immunoreactivity and electron microscopy. These results suggest that ED2-positive resident macrophages may play an important role in the inflammation of tunica muscularis in ETB(-/-) rats. Increased numbers and activation of macrophages may result in damage to ICC networks leading to disordered intestinal rhythmicity in regions of the gut in which myenteric ganglia are intact.

Neutralization of interleukin-10 significantly enhances gamma interferon expression in peripheral blood by stimulation with Johnin purified protein derivative and by infection with Mycobacterium avium subsp. paratuberculosis in experimentally infected cattle with paratuberculosis

Monoclonal antibody neutralization of interleukin-10 (IL-10) increased Johnin purified protein derivative-induced whole-blood gamma interferon (IFN-gamma) secretion 23-fold and also increased IFN-gamma secretion ninefold following in vitro Mycobacterium avium subsp. paratuberculosis infection of peripheral blood mononuclear cells. These results demonstrate the suppressive effect of IL-10 on immune responses to M. avium subsp. paratuberculosis infection in cattle.

Mycobacterium avium subsp. paratuberculosis infection causes suppression of RANTES, monocyte chemoattractant protein 1, and tumor necrosis factor alpha expression in peripheral blood of experimentally infected cattle

Blood from cattle with subclinical Mycobacterium avium subsp. paratuberculosis infection was stimulated with M. avium subsp. paratuberculosis antigens, and expression of interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), RANTES, monocyte chemoattractant protein 1 (MCP-1), and IL-8 was measured. Expression of TNF-alpha, RANTES, and MCP-1 was lower in infected than in uninfected cattle. The reduced response may weaken protective immunity and perpetuate infection.

In vitro and in vivo activity of antimicrobial peptides synthesized based on the insect defensin

Synthetic antimicrobial 9-mer peptides were designed from the amino acid sequence of an active site of insect defensin to increase the number of positively charged amino acid residues. These peptides, RLRLRIGRR-NH2, RLLLRIGRR-NH2 and RLYLRIGRR-NH2, showed strong antimicrobial activity against bacteria and fungus. These peptides showed no growth inhibition activity against murine fibroblasts or macrophages and no hemolytic activity against rabbit erythrocytes in vitro. Furthermore, the administration of these peptides protected mice from a lethal methicillin-resistant Staphylococcus aureus (MRSA) challenge. In addition, these peptides suppressed tumor necrosis factor alpha (TNF-alpha) gene expression and production induced by lipopolysaccharide (LPS) or lipoteichoic acid (LTA) in murine macrophages.

Production of a monoclonal antibody that recognizes bovine stem cell factor (SCF) and its use in the detection and quantitation of native soluble bovine SCF in fetal bovine serum

Stem cell factor (SCF) is a pluritropic hematopoietic cytokine that acts predominantly on the proliferation and differentiation of hematopoietic progenitor cells. SCF has long been thought to be present in fetal bovine serum (FBS) as an endogenous factor that stimulates the growth of hematopoietic progenitor cells in FBS-supplemented cultures. To detect and quantitate bovine SCF in FBS, we produced a monoclonal antibody (mAb) by immunizing mice with recombinant soluble bovine SCF protein, which was expressed in insect cells by using a baculovirus system. Using the mAb, we purified native soluble bovine SCF from FBS by immunoaffinity chromatography. Western blot analysis revealed that the purified SCF protein had a molecular weight of 33 kDa. In addition, an enzyme-linked immunosorbent assay (ELISA) incorporating the mAb revealed that the levels of native soluble SCF in commercially available FBS were likely to be <100 pg/ml. These results suggest that the concentration of native soluble bovine SCF present in FBS may be insufficient to promote additive biologic effects on the growth of hematopoietic progenitor cells in FBS-supplemented cultures.

Myxoid leiomyosarcoma of the gizzard in a broiler chicken

A leiomyosarcoma was found in the gizzard of a 57-day-old female broiler chicken weighing 1.8 kg. Grossly, the tumor mass, 13.0 x 8.5 x 10.0 cm, enveloped the gizzard and had a gelatinous appearance due to the rich production of mucin. Miliary metastatic tumors were noted in the liver. Histopathologically, there was marked production of mucus throughout the tumor tissue, and densely or loosely arranged long spindle-shaped leiomyosarcoma cells proliferated. The tumor cells had a low rate of mitosis, showed slight cellular atypia, and, immunohistochemically, were positive for actin, alpha-smooth muscle actin, and desmin. Electron microscopically, various amounts of microfibrils with focal densities, dense patches, and basal plates were observed.

Salivary gland extract of Rhipicephalus appendiculatus ticks inhibits in vitro transcription and secretion of cytokines and production of nitric oxide by LPS-stimulated JA-4 cells

There is increasing evidence that compounds in tick saliva and salivary gland extract (SGE) have a suppressive effect on host immunity and that tick-borne pathogens exploit this situation to their benefit thus causing diseases. We have demonstrated that SGE derived from Rhipicephalus appendiculatus ticks has a suppressive effect on a macrophage like cell line, JA-4, in terms of secretion as well as mRNA transcription of three cytokines. Percent suppression of cytokine secretion by JA-4 cells cultured in the presence of lipopolysaccharide (LPS) and SGE in comparison to JA-4 cells cultured in the presence of LPS alone was 67.8, 89.1 and 82.0% for IL-1alpha, TNF-alpha and IL-10, respectively (P<0.05). A similar pattern of results was demonstrated in terms of mRNA transcription where SGE-induced suppression was 36.9% for IL-1alpha, 25.0% for TNF-alpha and 31.5% for IL-10 (P<0.05). In addition, we have demonstrated that SGE partially inhibited nitric oxide production by JA-4 activated with LPS. The results of the present study suggest that tick salivary gland compounds may exert their effect in vivo by blocking the functions of macrophages in the transcription of cytokines and production of nitric oxide. This SGE-induced immunomodulation may comprise a major gateway in the facilitation of tick feeding and transmission of pathogens in hosts.

Expression of Kit, the receptor for stem cell factor, in bovine peripheral blood

The expression of Kit, the receptor for stem cell factor (SCF), on bovine peripheral blood cells (PBCs) was examined by using monoclonal antibodies against the bovine Kit protein. Flow cytometric analysis showed that approximately 1.5% of PBCs expressed Kit. In cytospin preparations, the morphology of most Kit+ PBCs was similar to that of large lymphocytes. Subsets of Kit+ PBCs coexpressed CD3, IgM, and/or CD11b but not CD14 or G1. SCF did not induce the proliferation of Kit+ PBCs in vitro. These results indicate that Kit is expressed on subsets of lymphocytes in bovine peripheral blood, but the ligand of Kit, SCF, does not directly induce the proliferation of this cell population.

Exacerbated spongiform lesions in the cerebral cortex in Japanese sheep, in an outbreak of scrapie during 1984-1987

The present study dealt with the pathology of natural scrapie in Japanese Suffolk sheep in a certain selected area. Vacuolations in the cytoplasm of neurons were conspicuous. They were particularly evident in many areas of the medulla and pons, extending into and through pedunculus cerebri and thalamus to the septal area and olfactory tubercle. Proliferation of astrocytes was also easily observed with glial fibrillary acidic protein staining. Neural vacuolations in the cerebral cortex were observed in 73% of the cases. Abnormal prion protein deposits were seen in all cases observed by hydrolytic autoclaving, and subsequent peroxidase and anti-peroxidase immunostaining. Abnormal prion protein staining was the most conspicuous in the polymorphic layers of the hippocampus.

Dissecting aortic aneurysm in a horse

A case of dissecting aortic aneurysm in a 4-year-old male thoroughbred horse is reported. The horse had a history of inflammation in the right thigh and a fever 2 weeks before sudden death. At necropsy, aortic aneurysms were observed from the aortic valve to the aortic arch, spreading over a distance of 40 cm. An irregular rupture of the intima of the ascending aorta was located in the cardiac side of a ramification to the tunica branchiocephalicus communis. An intramural haematoma, apparent on the cut surface and in the pericardium, had caused cardiac tamponade and sudden death.

Synthesis and characterization of bactericidal oligopeptides designed on the basis of an insect anti-bacterial peptide

Defensin from a beetle, Allomyrina dichotoma, is known to have anti-bacterial activity against Gram-positive bacteria. This peptide, which comprises 43 amino acid residues, was effective against methicillin-resistant Staphylococcus aureus. We identified the active site of beetle defensin by measuring anti-bacterial activity against S. aureus of 64 overlapping 12-mer peptides with either a free carboxylate or a free amide group at their C-termini. An LCAAHCLAIGRR-NH2 (19L-30R-NH2) fragment showed the greatest activity of the synthetic oligopeptides. The 19L-30R-NH2 fragment was effective against both Gram-positive and Gram-negative bacteria. CD spectra showed that the 19L-30R-NH2 fragment formed an alpha-helical structure in the lipidic environment. The anti-bacterial effect of the 19L-30R-NH2 fragment was due to its interaction with bacterial membranes, judging from the leakage of liposome-entrapped glucose. Its anti-bacterial activity was increased when certain amino acid residues were replaced. Truncated peptides having had some amino acids removed from the N-terminus of the 19L-30R-NH2 fragment (8-10-mer peptides) still had strong anti-bacterial activity. Deleting some amino acids from the C-terminal region of the fragment dramatically reduced activity, indicating that the C-terminal region of the 19L-30R-NH2 fragment, i.e. RR-NH2, is important for exerting anti-bacterial activity. The AHCLAIGRR-NH2 (22A-30R-NH2) fragment and its analogues exhibited about 3-fold and 9-12-fold higher activity against S. aureus than did the 19L-30R-NH2 fragment, and these analogues were effective against methicillin-resistant S. aureus and Pseudomonas aeruginosa isolated from patients. These oligopeptides showed no haemolytic activity and did not inhibit the growth of murine fibroblast cells.

Cloning and sequencing of cDNA encoding bovine macrophage colony-stimulating factor (bM-CSF) and expression of recombinant bM-CSF using baculovirus

The cDNAs encoding bovine macrophage colony-stimulating factors alpha and beta (M-CSF alpha and M-CSF beta) were cloned and recombinant bovine M-CSF alpha (rbM-CSF beta) in its dimeric form was expressed by using a recombinant baculovirus/insect cell system. The predicted amino acid sequence of rbM-CSF alpha and rbM-CSF beta shared 83.3 and 75.9% (alpha), 75.3 and 65.9% (beta) similarity with the sequence for human and murine M-CSFs, respectively. The biological activity of rbM-CSF beta was confirmed by the colony-forming assay using mouse bone marrow cells. SDS-PAGE under a reducing condition showed that the molecular weight of rbM-CSF beta was approximately 34 kDa. On the other hand, Western blot analysis under a non-reducing condition revealed that this rbM-CSF beta was secreted in dimeric form into the cell supernatant.

Expression of biologically active recombinant porcine GM-CSF by baculovirus gene expression system

The full length porcine granulocyte/macrophage colony stimulating factor (GM-CSF) cDNA, including secretion signal peptide coding region was recloned into baculovirus transfer vector pAcYM1. The vector was then transfected with Autographica californica nuclear polyhedrosis virus (AcNPV) DNA into SF21AE cells and the recombinant virus AcPGM was recovered. Recombinant porcine GM-CSF (rpGM-CSF) was obtained from the serum-free culture medium of Tn5 cells infected with the AcPGM virus, and was shown to be a glycosylated 21 kDa protein as confirmed by tunicamycin treatment and [3H]-glucosamine uptake. The biological activities of rpGM-CSF in AcPGM-infected cell culture supernatants were demonstrated by porcine bone marrow cell proliferation and haematopoietic cell colony formation assays. The use of rpGM-CSF enabled us to culture porcine monocytes/macrophage and dendritic-like cells, derived from either porcine bone marrow or peripheral blood, for up to 4 months.

The effect of oligosaccharides on the production of tumor necrosis factor-alpha by macrophage-like cell line J774/JA-4

Stimulation and modulation of tumor necrosis factor-alpha (TNF-alpha) production during treatment of the murine macrophage-like cell line J774/JA-4 with 25 oligosaccharides were studied. Direct stimulation of TNF-alpha production by oligosaccharides was measured with a cytotoxic assay using the L929 cell line. Twelve samples showed a significantly higher production (P < or = 0.01) of TNF-alpha than the controls. Modulation of TNF-alpha production by treatment with oligosaccharides, followed by stimulation with lipopolysaccharide (LPS) from E. coli, was examined using the L929 bioassay system. In three samples TNF-alpha production increased significantly, but in four samples, production was reduced significantly (P < or = 0.01). No samples showed modulation of growth or viability of L929 cells within the first 26 hr. The present results are useful in the application of these oligosaccharides which is potentially applicable in medical and food technology.

Failure of germinal center formation and impairment of response to endotoxin in tumor necrosis factor alpha-deficient mice

To study the pathophysiologic roles of TNF alpha, we produced TNF alpha gene-disrupted mice by gene targeting. TNF alpha-deficient mice develop normally without any alteration in the lymphocyte populations. However, in these mice, the germinal center formation in the peripheral lymphoid organs failed in response to the T cell-dependent antigens. TNF alpha-deficient mice are resistant to lethal doses of endotoxin and D-galactosamine without hepatocyte apoptosis, yet demonstrate thymus apoptosis. Our results indicated an important role for TNF alpha in germinal center formation and in the sepsis-induced hepatocyte apoptosis that precedes liver failure.

Immunoreactivity of specific epitopes of PrPSc is enhanced by pretreatment in a hydrated autoclave

An abnormal protein (PrPSc) accumulates in animals affected with scrapie. Immunoblotting procedures have been used widely to detect PrPSc. Blotted membranes were subjected to pretreatment in a hydrated autoclave, and the subsequent immunoreactivity of PrPSc was examined. The immunoreactivity of PrPSc to antisera against the synthetic peptides of the mouse PrP amino acid sequences 199 to 208 and 213 to 226 was enhanced by the pretreatment. However, the reactivity to antisera of peptide sequences 100 to 115 and 165 to 174 was not affected. The antibody-binding ability of the specific epitopes which are located close to the C-terminal end of PrP27-30 the proteinase-resistant portion of PrPSc, was enhanced by pretreatment in a hydrated autoclave. This pretreatment increased the sensitivity of PrPSc, and it would be useful for diagnosis of scrapie.

Granulomatous lesions caused by Pseudomonas aeruginosa in the ostrich (Struthio camelus)

Granulomatous lesions were observed in imported ostriches aged 3 months. Clinically, the birds showed lassitude, incoordination, and inappetence. At necropsy, yellowish white nodules often accompanied by a pseudodiphtheritic membrane were found in the oral, pharyngeal, tracheal and air sac mucosae, the lungs, oesophageal serosa, and abdominal peritoneum. Histopathological examination revealed purulent granulomatous lesions containing central bacterial colonies with an outer shell and club formation. The bacteria were small Gram-negative bacilli, which showed positive immunohistochemical staining for Pseudomonas aeruginosa. The bacterial colonies were positive for chicken IgM. Clubs around the colonies were negative for P. aeruginosa and chicken IgM. Such findings have not previously been reported in the ostrich.

Endogenous tumor necrosis factor (TNF) production and modification of pathological lesions in experimental Escherichia coli endotoxemia of piglets

We examined the kinetics of tumor necrosis factor (TNF) production induced by Escherichia coli lipopolysaccharide (LPS) in relation to LPS tolerance and endotoxemic lesions of piglets. The plasma of piglets demonstrated cytotoxicity to TNF-sensitive L929 cells between 0.5 and 4 h after inoculation with 200 micrograms kg-1 of LPS. This cytotoxicity was neutralized by anti-bovine TNF serum. These piglets had disseminated intravascular coagulation (DIC) and meningoencephalitis. However, if piglets were first treated with three doses of 40 micrograms kg-1 of LPS, both TNF production and the occurrence of DIC were inhibited when 200 micrograms kg-1 of LPS was inoculated into these piglets. Repetitive inoculation with increasing doses of LPS induced fibrinoid vasculitis, meningoencephalitis and pneumonitis, while hemorrhage was minimal. A very low amount of TNF activity was detected from most of the samples of a piglet after repeated LPS inoculation. These results suggested that severity of the hemorrhagic and thrombotic lesions might relate to the amount of endogenous TNF activity, and that LPS tolerance might relate to inhibition of TNF production.

Preparation of anti-canine serum amyloid A (SAA) serum and purification of SAA from canine high-density lipoprotein

Antiserum to canine serum amyloid A (SAA) was prepared in rabbits by immunization with crude SAA which was prepared from high-density lipoprotein 3 (HDL3) obtained from canine acute-phase serum. The antiserum was absorbed for contaminating antibodies by affinity chromatography using Sepharose 4B coupled with normal canine serum proteins. The rabbit anti-canine SAA serum reacted with a protein and formed a single precipitin line at the position of the alpha 1-region of the immunoelectrophoresis of canine acute-phase serum but did not react with the normal canine serum on immunoelectrophoresis. The antibody to canine SAA was also confirmed by Western blotting analysis. Canine SAA was purified as a low molecular weight protein component from crude SAA by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) after gel filtration chromatography. Purified canine SAA had a molecular weight of 15,000 as estimated by SDS-PAGE. This SAA level was found by enzyme-linked immunosorbent assay (ELISA) to increase 1 day after inoculation with Bordetella bronchiseptica to 9.0-20.1 times the preinoculation value.

Isolation of a cDNA clone for a cytokinin-repressed gene in excised cucumber cotyledons

Rapid changes in gene expression were studied during incubation of cucumber (Cucumis sativus L.) cotyledons with cytokinins in darkness. Complementary-DNA clones for mRNAs whose levels decreased within 4 h of treatment with N6-benzyladenine (BA) were isolated by differential hybridization. One of them (CR9) was sequenced. It is 588 bp long, and would encode a protein consisting of 137 amino-acid residues and having a molecular mass of 15 kDa. The sequence shows a high homology with a light-induced gene from rice. Northern blot analysis of the CR9 transcript showed the level of the mRNA (0.7 kb) to decrease tenfold within 4 h of BA treatment, i.e. well before BA-induced cotyledon expansion was observed. The repression became greater with increasing concentration of BA (10(-8)-10(-5) M). The expression of the CR9 gene was repressed specifically by cytokinins (BA, isopentenyladenine and t-zeatin), but not by adenine or 2,4-dichlorophenoxyacetic acid (auxin). The results are discussed in relation to the primary action of cytokinin.

Immunohistochemical distribution of S-100 alpha-positive cells in bovine mycobacterial and non-mycobacterial granulomas

By means of immunohistochemistry, the distribution of the alpha-subunit (S-100 alpha) and the beta-subunit (S-100 beta) of S-100 protein was studied in bovine granulomas caused by Actinomyces bovis, Actinobacillus lignieresi, Actinomyces (Corynebacterium) pyogenes, Pseudomonas aeruginosa, Staphylococcus aureus, Mycobacterium bovis and Mycobacterium paratuberculosis. S-100 alpha-positive epithelioid cells or dendritic cells were scattered among the predominantly S-100 alpha-negative cells of the mononuclear phagocyte system (MPS). S-100 beta was not found in the MPS cells of granulomas but was observed in the endothelial cells of blood vessels. A positive reaction to S-100 was also seen in normal cells in the lymphoid and mammary tissues. Mycobacterial granulomas contained more S-100 alpha-positive cells than did non-mycobacterial ones.

Induction of acute phase protein by recombinant human interleukin-6 (IL-6) in calves

Interleukin-6 (IL-6) is a major inducer of acute phase proteins in human and murine species. However, the effects of IL-6 have not yet been investigated in cattle. Following continuous infusion of recombinant human IL-6, serum concentrations of bovine haptoglobin and fibrinogen increased in a manner similar to those in cattle with acute phase reaction. In contrast, C-reactive protein and alpha 1-acid glycoprotein, as well as the other hematologic parameters, did not change significantly. Intravenous administration of recombinant human IL-6 resulted in only a mild and transient increase of bovine haptoglobin. These results suggest that the regulation of acute phase protein production in cattle is similar, but not identical, to that observed in human and murine species.

Phenotyping of lymphocyte subsets in the vascular and epithelial lesions of a cow with malignant catarrhal fever

Surface marker analysis of lymphoid cells infiltrating the vascular and epithelial lesions of a cow with malignant catarrhal fever (MCF) was conducted by immunohistochemistry using ten monoclonal antibodies. The majority of lymphoid cells in these lesions had BoCD8, BoCD6 or BoCD2, but they rarely possessed N-cell (BoCD5+/BoCD4-/BoCD8-, non-T non-B) markers. Similar reactivity was seen in lymphoid cells of perivascular infiltrates in the liver, heart and brain, and in T-dependent areas of lymph nodes. These results suggest involvement of cytotoxic T-lymphocytes in the pathogenesis of MCF.

Immunohistochemical identification of ferritin, lactoferrin and transferrin in leprosy lesions of human skin biopsies

Granulomatous lesions of human leprosy contained ferritin and lactoferrin but little or no transferrin, as demonstrated by the avidin-biotin complex immunoperoxidase method. Lactoferrin was found in the neutrophils. These results suggested that the cells of the host mononuclear phagocyte system in leprosy granulomas provide an adequate nutritional environment for iron acquisition by M. leprae. A possible role of iron binding proteins in the granulomas is discussed in relation to previous data on bovine paratuberculous granulomas.

Pre-clinical and clinical diagnosis of scrapie by detection of PrP protein in tissues of sheep

The usefulness of detecting the scrapie-associated fibrillar protein (PrP) in the lymphoreticular organs of sheep as a diagnostic tool was investigated. The PrP was detected by means of a rabbit-anti-sheep PrP polyclonal antibody by Western blot analysis. PrP was detected in samples from the central nervous system (CNS) of five of six sheep showing clinical signs of natural scrapie infection, in spleen samples from four of the six sheep and in lymph node samples taken from three of the sheep. PrP was detected in the spleen and lymph node samples, but not in the CNS samples from one of the six sheep that was clinically and histopathologically abnormal. This animal appeared to be in the early clinical stage of the disease. A total of 47 clinically normal sheep were examined for the presence of PrP. It was detected in spleen samples from three of the 47 sheep and in lymph node samples from three of the 39 sheep tested. Similarly, PrP was detected in a sample of lymph node obtained surgically from one of three experimentally infected sheep 14 months after inoculation. The PrP-positive sheep and one of the remaining PrP-negative sheep showed clinical signs of scrapie six and five months later respectively. One sheep euthanased 18 months after experimental infection was positive for PrP in the CNS, spleen and lymph node, but five other sheep which were killed or died two, eight, 16, 18 and 21 months after infection were negative or doubtful for the detection of PrP.

A comparison of central nervous lesions directly induced by Escherichia coli lipopolysaccharide in piglets, calves, rabbits and mice

To evaluate the role of endotoxin during Gram-negative bacterial meningitis, the nervous lesions of piglets, calves, rabbits and mice were compared by direct inoculation of Escherichia coli lipopolysaccharide into the central nervous system. Suppurative leptomeningitis was induced in piglets by small doses of lipopolysaccharide. Mice also had a mild suppurative inflammation in the leptomeninges. In contrast, calves showed suppurative pachymeningitis, but no lesions in the leptomeninges. Leptomeningeal inflammation was not induced in rabbits. Induction of the leptomeningitis by endotoxin was compared with sensitivity to intravenous or intraperitoneal endotoxin in these species.

Immunohistochemical study of bovine lymph nodes with antibodies against S100 protein subunits: comparison between lymph nodes of healthy and Mycobacterium paratuberculosis-infected cattle

Using immunohistochemistry, the differential distribution of the alpha subunit (S100 alpha) and beta subunit (S100 beta) of S100 protein was studied in mesenteric lymph nodes from normal or Mycobacterium paratuberculosis-infected cattle. In epithelioid cell granulomas, S100 alpha-positive epithelioid cells and some giant cells were scattered among S100 alpha-negative cells, which were predominant. The S100 beta-positive and -negative cells contained acid-fast bacilli. The presence of S100 beta-positive cells was not demonstrated in the granulomas. In normal component cells in the lymph nodes, follicular dendritic cells in the germinal centres and endothelium of lymphatic sinus and lymph vessels were positive for S100 alpha. S100 beta was positive only in the endothelial cells of blood vessels. Results shown in the present paper are discussed in light of results obtained in other work on human tissues using the same sources of antibodies.